Bearings. All you could ever wish to know about...

Lately I have been trying to understand bearings...

There are lots of references buried in ES threads about bearings (problems eg spacers) but I am a bit surprised to see that the list of threads w/bearings in the title barely fills one screen...

EVen though my interest is EV-related, my readings (off-ES) so far have been about applications w/RPMs to 30K and EVen 40K...

Also, bearings "immersed" in hostile environments, exposed to salt water and grit whatever while most of the ES tappity-tap seems about bearings "protected" inside motors and wheels that are isolated inside hub motors or elevated above road slop on axles that are a foot or more off the ground...

I am suspicious of all things "Made in China" (all aboard the Good Ship ES can relate, right?) and although I read about stuff here like Clyte using bearings with balls and good to go for a "lifetime", are they really (stock, made in China) really the most energy efficient?

No ES threads about ABEC numbers. ABEC versus "swiss". Permanent seals versus removeable. Ceramics. Oil versus grease options...

"Lithium" is a perennial subject on ES these daze... but in batts and not in grease? Versus for example graphite?

EVen ambient temps below 0°... Probably not a factor after the first few tens of thousands of revolutions?

Any ES ppl whose life revolves around bearings? (Sorry, couldn't resist but actually in my view you all do!)

Pls. post your thoughts, comments and links? Myself, I am only interested in the best performing* bearings money can buy today.

tks
lOcK

*Performance. Yah, subjective, I know...

Years ago a friend of mine came to me all exited about the new(Japanese made)bearing in his skateboard wheels.
I didn't get what the big deal was. So he demonstrated by turning the board over and spinning one of he wheels. It just kept going and going. We stared at it for what seemed like a long time waiting for it to stop, a full couple of minutes. It made an impression on me. Occasionally I will spin something I encounter, usually in the course of woodworking , to see how long it will go. But, nothing has ever even come close. I glad that I know that such quality of bearing exist. I hope I will see them again at some point.

Years ago I worked for a company that manufactured high performance DC electric motors. Computer applications. Zero to 3000 rpm and back to zero 60 times a second. Fiddled with bearings a fair amount. Static friction torque was a big concern, so the fit of the seal on the inner race and the type and amount of grease fill was critical. But the amount of drag was in the ounce-inch range and probably not applicable to e-bikes.

Grease is nothing but oil mixed with a filler to keep the oil from running out. The type of grease depends on the application. Other than near the motor, nothing on a bike would require high temp grease. Water-resistant would be a better choice, something similar to the grease used to pack wheel bearings on boat trailers. Then again, unless you frequently ride in a downpour, plain old lithium grease inside a sealed bearing will probably do the job.

"Lubricated for life" doesn't mean your life. It only means until the lubrication breaks down and the bearing fails, thus ending its life. Dried out lube was the biggest cause of bearing failure. If you notice it in time and if extreme care is used, it's possible to gently pry out a seal without bending the molded-in metal insert. It's also very easy to bend it. Assuming the bearing isn't contaminated with dirt, simply work in a small amount of fresh grease and press the seal back on.

Nearly all applications used seals, not shields. I see no reason to even consider shielded bearings on bikes. Seals are the way to go. On motors we would install a slinger washer if the application was especially dirty. This would be installed on the shaft immediately next to the bearing. The idea was that anything potentially headed towards the bearing would encounter the washer first and be slung away by rotation before reaching the bearing.

Normal applications used ABEC 1 bearings. If noise was a concern we'd specify ABEC 7 for tighter control of internal bearing clearances. I don't see why higher grade bearings would benefit ebikes, although the cost differential between ABEC 1 and 7 was typically only a few dollars.

Cleanliness is critical, both internal and external to the bearing. External dirt or burrs can affect the fit of the bearing in a housing or on a shaft. Forcing it will reduce the internal clearance in the bearing and cause premature failure. A bearing needs to have some internal clearance to function properly. Internal dirt causes accelerated wear. You can't be too clean when working with bearings.

Proper installation technique and fits are critical. Press on the wrong race during assembly/disassembly and the balls will create tiny dings on the opposite race. Pressing is greatly preferred over tapping with a hammer. If you have no choice but to tap, try to use a soft mallet. Often times a wrench socket can be used to press a bearing.

When cleaning a bearing and after the old grease if flushed out, resist the urge to entertain yourself by blasting it with an air hose to spin it up and listen to it scream like a siren. Part of the noise you hear is the balls bouncing around against the races and leaving microscopic dings and premature wear. It's called 'Brinelling.'

Bearings, if you can buy them from a bearing distributor, aren't terribly expensive. They are precision-made little things, but the world uses so many of them. And sizes tend to be common. Even if you don't know the bearing number usually the guy behind the counter will love the challenge of cross-matching it.

My rule of thumb working with bearings is, if things are disassembled and I think there's a even a chance that a bearing has been damaged, I'll try to replace it within the practical limits of cost and availability. Easier to do it then than have to tear things down later.

I don't have firsthand experience with the quality of Chinese bearings, but lately I've made some parts using stainless steel from Chinese sources. Even though the type of steel is theoretically the same, 303, that I've used before, I can categorically state that it is not the same stuff. It machines differently and its magnetic properties aren't as good. I've never seen an analysis, but I, too, would question Chinese qualiity control, especially for bearings in low-end applications.

MT

Thanks guys.
Below is my reply to Parker before I saw yours Midnight... I'm just collecting components to hand off to some guys. Their front office are all process control engineers, and their machinists out back are all state-of-the-art. Food biz so they are used to high-grade only for everything. I'm pretty sure they know all about bearings...

Just perhaps not in my particular application as I am interested in running these in 3" of frozen slush (dirty oily frozen salt water)!

I'm beginning to think that I want fully sealed bearings, and suspect there's really no such thing? In the long-term everything fails, so it's just a question of what might survive the longest. Apart from the (maybe) higher efficiency of ceramics, one attraction is that the fully ceramic ones (there are hybrid ceramic-steel ones too) don't rust. Nice!

Can seals really provide a full seal? Thinking that the heating and cooling of the bearings can suck in water if/as there is any air inside contracting as it cools...


Original msg to Parker:
Ya man... that's what I'm curious about!

ES'ers tap about various efficiencies, and the when Clyte has their act together the bearings they supply will "last the life of the motor"... I still wonder how efficient they are. Whether bearings are an easy upgrade...

Quantum Precision Group LLC would like us all to buy their Silicon Nitride ceramic bearings:
"Ceramic balls are >60% lighter, >50% stiffer, >70% smoother, and much, much harder than steel balls.
"Ceramic balls have >100X better rolling contact fatigue life in comparison to Vacuum Melt 52100 Steel."
From here:
http://www.quantumprecisiongroup.com/ceramic_steel.php


Here:
http://www.inlineplanet.com/08/05/begg-bearings.html
"World renowned speed coach Bill Begg shares his vast knowledge... " (from the world of inline skates)
On the question "Which Are Better: Ceramic or Steel Skate Bearings?"
"...don't know which bearings spin faster. But I can tell you one that spins for a very long time: the Mini Jesa Bont ceramic. A few years ago, I watched as Luca Presti spun one of his Bont Crager wheels with a used Jesa ceramic inside of it. It went on spinning for 6 minutes and 34 seconds. I have never seen anything like it!"

and
"Ceramic bearings appear to spin longer when they are not bearing a load. But it's not clear whether they maintain that advantage under the weight of a skater."

and
"Skaters used to believe that ceramic bearings were faster but that perception seems to be fading. My daughter is one skater who has done well with steel bearings. She won gold at the last two World Championships on Jesa Bont Swiss steel bearings."

From Bont, here:
http://www.bont.com/products/bearings/swiss.htm
"Bont is proud to announce a new partnership with Jesa bearings. Jesa is the largest specialty bearing manufacturer in Switzerland and was established in 1969. "

and
"For Bont's inline racing application Jesa has produced a bearing with the lowest friction on the market."


Here's Jesa:
http://www.jesa.com/english/homepage/homepage.html

That Bont page has their current prices and they price packages of 16 and 20pcs. For 16pcs:

608 Ceramic $267
688 Ceramic 259
608 Steel 57
688 Steel 51

I doubt these particular sizes are right for ebike apps, but perhaps illustrate the price diff. ceramic versus steel. But their "top"? bearings work out to only approx. 20 bux a pop (yay!). Speed skaters also are not out in January snow either!

Bont also touts that they use oil lube from "Kleber". These ppl I expect:
http://www.klueber.com/start.cfm

I come from a world where grown men sit around talking about how smooth their bottoms are (hulls) so I hope EVers won't mind discussing their balls (bearings) some hehe

tks again
Lock

Teams using Xootr wheels sweep top three places at American Soap Box Derby championships in July 2008. Pretty sure these racers concern themselves with their wheels quite a bit!

Mr.Brown reports here about his Xootr experience:
http://www.mrbrown.com/blog/2008/08/riding-the-xoot.html
"...the wheels are really smooth. They are larger than most kick scooters and feel more stable. The bearings inside, I don't know what they use but they is incredibly smooth, almost frictionless. One push and off you go, gliding for a really long time."

Curious if any ES ppl know what bearings are used by Xootr for their scooters?

On the Xootr site they sell their 7.1 in (180 mm) "Ultra wheel" with bearing for only $29.95 each...

Xootr says:
"Xootr wheels are the key to its high performance. Our wheels are custom made for the Xootr and are not available on any other product. These wheels are made by molding polyurethane onto aluminum centers. Our wheels offer the lowest rolling resistance of any small-wheeled vehicle."

and
"Why should you care about rolling resistance? In a human-powered vehicle travelling at speeds of about 10 mph (16 kph) on level ground, nearly all of your effort goes into overcoming rolling resistance. Rolling resistance is pure dissipation of your energy...the less resistance, the less effort you have to apply to get where you're going. See the chart below for a quantitative assessment of what this means to you. Frankly, after riding the Xootr, skateboards, in-line skates, and competitive scooters feel like they are rolling through mud...the Xootr is that fast."

and
"Xootr has plenty of type-A, hyper-analytical engineers on the team. To further support our claims of wheel superiority, they ran some tests with the Xootr and the obvious competitive devices. They simply measured the speed of these products rolling down a 1% grade (a just noticeable incline). The Xootr rolls almost twice as fast as a nice skateboard (with Kryptonics 65mm wheels) and 50 percent faster than the cheap scooters that use 100mm in-line wheels like the Razor brand scooter. Pneumatic-tired scooters with wheels smaller than 200mm (about 9inches) barely roll on this incline...we wouldn't even recommend one of these for a child."


tks
Lock

Seen here:
http://www.skates.com/Bones-Ceramic-bearings-for-fast-skates-p/brlwbc816.htm

Bones Ceramic bearings in 16 pack. Regular 608 bearings.

The new ceramic bearing is similar to the original Bones Ceramic bearing, but with a redesigned inner race and two new labyrinth shields to keep dirt out even better than before. Bones Labyrinth shields are non-contact, so they do not increase friction, only the distance dirt particles must travel to get past the shields. The only difference you will notice is that the labyrinth shield Bones will last several times as long as the original Bones between cleanings. This significant increase in service life comes at a very small increase in retail cost, so the value is greatly increased.

Bones Swiss Ceramics are the fastest skate bearings you can buy. A winning combination of precision ground and polished Swiss bearing races, glass fiber reinforced Nylon high speed ball retainer, Cerbec silicon nitride ceramic balls, Speed Cream low viscosity synthetic bearing lubricant, and a non-contact gray rubber shield.

Ceramic balls are non-corrosive, reduce weight, last longer, accelerate faster and roll smoother, with less friction than polished steel ball bearings, giving you the absolute fastest, longest lasting skate bearings available at a break through price (for ceramics).

If you need the very best, this is it Bones Swiss Ceramics are in a class by themselves. If you want the best skateboard bearing there is, this is it. The Cerbecâ„¢ Ceramic balls are much lighter, harder, stronger, waterproof, and longer lasting than the finest steel balls.

Each package comes with set of bearings, pre-lubed with Speed Cream, instructions and a sticker. Bearing spacers sold seperately

Features
Accelerate faster
Roll farther and faster
Labyrinth Shields Resist dirt and moisture better
Outlast the races, allowing them to be reused in most cases
Pre-lubricated with Speed Creamâ„¢ racing lubricant
Single non-contact removable rubber shield for easy cleaning & less friction
High speed Nylonâ„¢ ball retainer for greater strength and speed
Non-contact removable rubber shield
Skate Ratedâ„¢ clearances, tolerances, materials and lubricant provide the best performance and durability possible

Includes
Set of 16 bearings
Pre-lubed with Speed Cream
Instructions
Sticker

Our Price: $189.99


So, only $12 a pop for (maybe) state-of-the-art ceramics...

tks
Lock

I'm beginning to think that I want fully sealed bearings, and suspect there's really no such thing? In the long-term everything fails, so it's just a question of what might survive the longest. Apart from the (maybe) higher efficiency of ceramics, one attraction is that the fully ceramic ones (there are hybrid ceramic-steel ones too) don't rust. Nice!

Can seals really provide a full seal? Thinking that the heating and cooling of the bearings can suck in water if/as there is any air inside contracting as it cools...

Click to expand...

I never found a full seal. But in my work I was always fighting static friction torque, so anything more than a feather light contact between the lip of the seal and the shoulder on the inner race couldn't be used. The brg mfg used to trim seals especially for us to control the seal ID and the fit to the shoulder. We'd even pull seals from high torque bearings and install replacements that were molded or trimmed differently in an attempt to salvage the bearing.

At one point I experimented with a seal that was nothing more than a thin piece of epoxy impregnated fiber glass cloth with the ID trimmed to contact the inner race where the seal normally touched. Friction torque was great, but it leaked oil like crazy compared to a rubber seal.

You are dead on about a bearing "breathing" as it undergoes temp change. The motors were rated to 155C, so containing oil from the grease at that temp while maintaining low friction torque was tough. There would always be at least a thin bead of oil around the lip of the seal. Then when the motor cooled it tended to draw the oil back inside. If contamination (salt crystals?) had gotten into the oil the potential to get inside was there. Fortunately, since the application was usually computer equipment in a controlled atmosphere dirt wasn't a major problem. And if friction torque hadn't been such a concern we could have opted for more wiping. But like you said, everything eventually fails and a wiping seal is no exception.

For us, cost was always a consideration, too. A dime's difference in price was enough to switch mfg's.

I can see the importance of low friction bearings in competitive applications, and especially where many bearings may be involved. What's the difference between winning and losing worth? Also, zero maintenance was the assumption in motors. I'd guess bearings used in competition may receive a little more TLC.

MT

Seen here:
http://www.tokenproducts.com/htm/tech.php


- Tiramic Bearings: A patented product of Token Products Inc. that is composed of a set of Titanium coated bearing race & cone, combined with solid ceramic balls & Klüber lubricant.
- Patent No.: M304599

Tiramic Bearing Technology (TBT)
- Non-Corrosive
- Weight Reduction: Ceramic Balls are 60% Lighter than Steel Balls
- Durability: Lifetime 5~10X Longer than Steel Balls
- Accelerate Faster: Speed Increase Approaching 4%
- Smooth Rolling: Ceramic Balls are Rounder and Smoother than Steel Balls
- Low Friction: To keep momentum
- Less Vibration: Resulting in a smooth ride
- Resistant to Contamination

TBT Distinctive Mark
- All Token Products equipped with Tiramic Bearings carry a distinctive “TBT” Sticker or Laser Etched Logo
- Token Products equipped with Tiramic Bearings include: Hubs, Integrated BB, ISIS Drive BB, Square BB, Rear Derailleur Pulley, Headset


Tiramic Bearing comments from Athletes
“I began using Token’s Tiramic Bearing Pulleys in the spring of 09’. Since then I have had no issue with them. The Tiramic Bearings do make a noticeable difference in reducing chain drag when compared to other pulleys I have used. They spin incredibly freely, shed dirt and grime better than others. Thanks to their design they always catch stares from other riders. A truly outstanding product and well worth the nominal investment.” Jeff Irwin – Pro mountain bike racer, Gunnison, Colorado USA


The Comparison Chart of Starting Torque & Turning Torque between Normal Bearings & Tiramic Bearings.

Starting Torque:
- Normal Bearing is 0.27
- Tiramic Bearing is 0.20
- The rate = 0.20/0.27*100% = 74%
This means that the Starting Torque of Tiramic Bearing is only 74% of Normal Bearing. That’s why you can get “Lighter Pedaling”.

Turing Torque:
- The Normal Bearing is 0.15
- Tiramic Bearing is 0.10
- The rate = 0.10/0.15*100% = 67%
This means that the Turing Torque of Tiramic Bearing is only 67% of Normal Bearing. That’s why you can get “More Smooth Running”.



Titanium Coating (Races)

- Hardness : HV2800~3000 kg/mm2
- Low Friction Coefficient
- Extremely strong adhesion method: molecular bond to substrate metal
- Titanium coating thickness: 3 µm (0.000118”)
- Able to withstand temperatures up to 600°C (1,100°F) in air.
- Resistant to corrosion and chemical impurities
- Non-toxic
- Metallic gold appearance
- Fatigue resistant


Dual lip labyrinthian low-friction seal

This special designed seals keep the grease inside the bearing and prevent dust and/or water from getting in. The light-contact type seal has a high-quality water proof function with extremely low friction. Resulting in smooth clean rolling, longer lasting lower maintenance bearings.



Reinforced, stabilized nylon cage

The ball cage is made of heat stabilized nylon with 33% fill short fiberglass reinforcement for added strength. The nylon material provides a natural lubricity for longer life. Fiberglass reinforcement allows higher operating temperatures than plain nylon, yet is more resistant to fatigue than metallic cages. Short fiberglass allows greater flexibility than steel or normal fiberglass, especially under misalignment. That means longer life in mounted bearings where some degree of misalignment is unavoidably encountered.

Ceramic Balls

Ceramic Ball Characteristics

- Composition: Si3N4
- Density: 3.2g/cm3
- Vickers: 1700~2700kg/mm2
- Bending Strength: 3500Mpa
- Thermal Expansion coefficient: 3.2x10-6/℃
- Resistance: ＞1014Ω．cm
- Deviation from Spherical Form 0.13 µm
- Surface Roughness(µm Ra) 0.020 and better
- Grade 5 Balls

Sizes of Ceramic Balls available:

- 1/16”, 3/32”, 1/8”, 5/32”, 3/16”, 7/32”, 1/4”

Token Tiramic Bearing Grease: TK400

TK400 is a combination of ester oil, synthetic hydrocarbon oil, mineral oil and Barium complex soap. This combination makes it an excellent lubricant for rolling bearings and can be easily applied by brush, spatula, grease gun or cartridge. It has a service temperature range of -40°C → 130 °C with a Klüber viscosity grade of M. All these characteristics make TK400 the perfect complement to Token’s Tiramic Bearings.

- Increased Corrosion Protection
- Superior Resistance to Environmental Elements
- Increased Resistance to Mechanical and Chemical Induced Corrosion
- Excellent Load-Carrying Capacity
- Improved Sealing Effect

just fyi
tks
lock

Totally non technical response...

I am building a electric motorcycle from a down hill full suspension bicycle (Rocky Mountain RM7), pics and build notes coming soon, and using the BB as a jackshaft. The original BB assembly has 17x30x7 (I think) sealed bearings, AND in the aluminum cups that hold the BB together, these little cute SEALS. You guys probably already know all about this stuff but for me it was a revelation to see the outside seals to protect the sealed bearings. My guess is that these outer seals provide a better sealing function and keep the rocks and water and...away from the bearings, so the bearing seals function to keep in lubrication and not have to deal with external contaminants. Someone earlier mentioned slingers and it seems to me that these little external seals function in a similar way.

I wonder why people use shielded, rather than sealed, bearings for our application. I guess there is a bit less friction... My take on this is that unless one is building for a very competitive situation - reliability is most important. It's my sense that one of the issues we are all dealing with here on ES is getting reliable but powerful and innovative machines. Once I have achieved reasonable reliability, then, at least in my mind, I seek some kind of competitive advantage and smaller, lighter, more powerful, aerodynamics, less friction, are are all worth a second look.

My 2 cents...


I do have a question though...what kind of lubricant comes with standard sealed bearings and what could I use instead to increase longevity and perhaps reduce friction? Again as previously mentioned, I remember carefully removing seals, cleaning, inspecting and finally re lubing bearings...but these were larger automotive bearings. Something as small as the 1/2" x 1-1/8" or 17x30x7 bearings I am using may be more difficult to get the seals out without damaging them.

I remember using some kind of sharp, self made tool, and gently prying this between the seal lip and inner race to get behind the seal. Seems like it was kind of U or J shaped with a sharp flat ground end to slip under the seal and then the tip once under the lip would rotate to push on the back side where the metal was to get it free of the bearing. But, as I said, this was for larger bearings and the coat hanger or welding rod I used to make the tool might be too large to work on small bearings...I am sure there is another way to get the seals out.

It's nice to see this link posted in late 2008 still good:
http://www.skates.com/Bones-Ceramic-bearings-for-fast-skates-p/brlwbc816.htm

...either the seller is out of date with his web offerings or this bearing is well on its way to being a "classic"...

Recently I went ahead and bought two of the Xootr replacement Ultra Wheels (one spare) `cause of their claims (see above):
http://www.xootr.com/kick-scooter-wheel.html

...and my ME guy described the wheel as having "good" ("industrial") bearings... must press him for details

Also noted... while the "Bones Ceramic skate bearings 608" were (supposedly) near state-of-the-art in 2008 at $12 each today sites like skates.com still offer them in batches of 16 at $12.50ea and inlinewharehouse.com at 16 for $11.25 ea...

Token is still offering their EX-TYPE BB with Tiramic® Sealed Bearings but only for bottom brackets as far as I can find:
http://www.hyperbolts.com/catalog/product_info.php?products_id=534&osCsid=0jgfg3hc33fgoo5nca36plijs7

While the Xootr bearings seems to be the same 8mm ID as inline skate wheels (and 28mm OD according to my bad eyes) I think I'll pick up a pack of the Bones 608 Ceramics and have the Xootr wheels milled if necessary to accomodate...

Tks
Lock

Lock said:

... while the "Bones Ceramic skate bearings 608" were (supposedly) near state-of-the-art in 2008 at $12 each today sites like skates.com still offer them in batches of 16 at $12.50ea and inlinewharehouse.com at 16 for $11.25 ea...

Token is still offering their EX-TYPE BB with Tiramic® Sealed Bearings but only for bottom brackets as far as I can find:
http://www.hyperbolts.com/catalog/product_info.php?products_id=534&osCsid=0jgfg3hc33fgoo5nca36plijs7

While the Xootr bearings seems to be the same 8mm ID as inline skate wheels (and 28mm OD according to my bad eyes) I think I'll pick up a pack of the Bones 608 Ceramics and have the Xootr wheels milled if necessary to accomodate...

Click to expand...

Obsessing about bearings is folly. Good bearings can be a lot more efficient than crude ones, but that efficiency can only reduce the amount of loss in the bearing-- which is almost nothing, even for a crappy bearing. Seal drag of a rubber sealed bearing can be ten or a hundred times more than the rolling resistance of the bearing elements, but it's still so small that you would not notice or measure any difference in speed or elapsed time if you pulled the seals off. You'd only notice that your bearings got trashed quickly.

The primary source of resistance to forward motion at e-bike speeds is aerodynamic. Lowering your handlebars usually makes a noticeable difference in cruising speed and top speed. Making that change usually costs nothing except comfort-- just drop the stem down or flip it over.

The next most important factor is tires. If your tires have any tread blocks on them, or are thick for puncture resistance, or have stiff casings or tread belts, you are wasting an order of magnitude more energy to them than to all your bike's bearings put together. Underinflating your tires drags down your speed through rolling resistance, and overinflating them can slow you down too: On a less than smooth surface, it causes you you to lose kinetic energy to jolting your bike and body.

A worn or filthy chain and sprockets exact a significant power penalty-- 10% of your effort can be wasted meshing a dirty, worn chain with the smaller sprockets of your freewheel.

Poorly adjusted brakes can drag on the rim. Out of true wheels or wheels with loose hub bearings can rub the brake pads hard. Sometimes such drag is intermittent, only occurring when the bike is being ridden and not when it's in the service stand. Disc brakes often drag all the time, even when properly adjusted.

The above are the kinds of things where attention to detail can reward you with measurably, not necessarily noticeably, better performance. But fancy bearings will never make a measurable or noticeable difference. They're just a waste of money if that's why you use them. Use good bearings because they can last longer and feel better, but don't expect any difference whatsoever in performance.

For an ordinary pedal bike, it's typical for the sum of all the bearing losses at speed to be a single digit number of watts. Thus all the energy you can save with the smoothest possible bearings is an even smaller single digit number of watts.

Chalo

Outstanding advice Chalo my friend.

Chalo said:

Lowering your handlebars usually makes a noticeable difference in cruising speed and top speed.

Click to expand...

Explain how this helps on a foot bike (stand-up kick scooter)?

The next most important factor is tires. If your tires have any tread blocks on them, or are thick for puncture resistance, or have stiff casings or tread belts, you are wasting an order of magnitude more energy to them than to all your bike's bearings put together. Underinflating your tires drags down your speed through rolling resistance, and overinflating them can slow you down too: On a less than smooth surface, it causes you you to lose kinetic energy to jolting your bike and body.

Click to expand...

How does any of this relate to a solid and smooth tire made of polyurethane?

A worn or filthy chain and sprockets exact a significant power penalty-- 10% of your effort can be wasted meshing a dirty, worn chain with the smaller sprockets of your freewheel.

Click to expand...

Watt if the vehicle has no chain or sprockets?

Poorly adjusted brakes can drag on the rim. Out of true wheels or wheels with loose hub bearings can rub the brake pads hard. Sometimes such drag is intermittent, only occurring when the bike is being ridden and not when it's in the service stand. Disc brakes often drag all the time, even when properly adjusted.

Click to expand...

These concerns seem fix-able... The bearings, not so much.

The above are the kinds of things where attention to detail can reward you with measurably, not necessarily noticeably, better performance. But fancy bearings will never make a measurable or noticeable difference. They're just a waste of money if that's why you use them. Use good bearings because they can last longer and feel better, but don't expect any difference whatsoever in performance.

Click to expand...

I'll guess you don't appreciate the difference between a cheap radio and a hi fidelity sound system either :wink:

Folks that enjoy skateboards and roller blades appreciate the difference better quality bearings can make. In truth I suspect the real concern with bearings, whether better quality or not, is keeping contamination out. Unlike the pedal bike style vehicles most on ES enjoy, I am used to wheels where the bearings are only a few inches off the ground/puddles/slush/snow...

For an ordinary pedal bike, it's typical for the sum of all the bearing losses at speed to be a single digit number of watts. Thus all the energy you can save with the smoothest possible bearings is an even smaller single digit number of watts.
Chalo

Click to expand...

Fine! If I am kicking and so burning 100W plus/minus of food energy a few free watts will be a significant improvement. For a few extra bux spent on a better quality bearing seems a fair trade off. I thought this image was pretty straight forward:


Hadn't really expected to have to shoehorn this tread into your limited perspective! :lol:
Tks
Lock

Lock said:

Chalo said:

Lowering your handlebars usually makes a noticeable difference in cruising speed and top speed.

Click to expand...

Explain how this helps on a foot bike (stand-up kick scooter)?

The next most important factor is tires. If your tires have any tread blocks on them, or are thick for puncture resistance, or have stiff casings or tread belts, you are wasting an order of magnitude more energy to them than to all your bike's bearings put together. Underinflating your tires drags down your speed through rolling resistance, and overinflating them can slow you down too: On a less than smooth surface, it causes you you to lose kinetic energy to jolting your bike and body.

Click to expand...

How does any of this relate to a solid and smooth tire made of polyurethane?

Click to expand...

Ah; I thought you were taking about a bike. In that case, what I wrote may be of more value to others here. You only have bearings in the wheels, and they aren't preloaded angular contact bearings like a bike's. So if you were using "bad" bearings, both wheels might dissipate less than a watt at full speed. (I have heard figures between 0.5W and 4W for the bottom bracket of a bike, the biggest and most preloaded spinning bearing on a bike, and I have a hard time accepting the latter figure because the bearing does not noticeably warm up in use.)

Standing up straight in the wind gives you maximum frontal area and maximum coefficient of drag. Urethane wheels and small diameter wheels both exact penalties in rolling resistance. So right up front you have accepted the highest at-speed drags available in a two-wheeler other than clamping the brake on. And you already have less than the minimum bearing drag a normal bike would ever have. So the percentage of your energy being expended on bearings is lower than a bike rider's, and the difference you can make is thus even smaller.

But I'll give you this: There isn't much you can do to hot rod a solid-tired kick scooter, and the Xootr seems to have done the hard part for you. So bearings are about all you have left to mess with. Who could blame you for doing what you can? If the total silence and oiled-glass feeling you get from really choice bearings makes you enjoy your scooter more, then that's more than enough to justify them.

Folks that enjoy skateboards and roller blades appreciate the difference better quality bearings can make. In truth I suspect the real concern with bearings, whether better quality or not, is keeping contamination out. Unlike the pedal bike style vehicles most on ES enjoy, I am used to wheels where the bearings are only a few inches off the ground/puddles/slush/snow...

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Well, be advised that good seals make a bearing drag a lot more than lousy seals or no seals. That's the dirty secret of the folks selling ceramic bearings to bicycle racers for big money (typically $100 per wheel)-- the reason they spin so much better when you rotate them with your fingers is because of inferior seals, not superior bearing surfaces. D'oh!

I would try to find bearings with multiple contact wiper seals, and accept whatever bearing materials came along with the best possible seals.

I thought this image was pretty straight forward:

Hadn't really expected to have to shoehorn this tread into your limited perspective! :lol:

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The gradient in rolling resistance reflected in that chart is a function of wheel diameter and associated energy transfer to the rider, similar to what I was saying about overinflated tires above. (Also note that if you throw a little chip seal or other surface roughness into the equation, that pneumatic tire will quickly prove to be the fastest of the lot.) The Xootr seems to have pushed the wheel diameter just about as far as feasible for the folding-umbrella category of kick scooter, so there's not much more to be done there.

A kick scooter with large diameter bike wheels and pneumatic tires would ride better and faster yet-- but if that were going work for you, you might want to consider just riding a bike, right?

Enjoy your ride,

Chalo

Chalo said:

A kick scooter with large diameter bike wheels and pneumatic tires would ride better and faster yet-- but if that were going work for you, you might want to consider just riding a bike, right?
Chalo

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Wrong, actually. The fold up scoots go lots of places pedal bikes cannot. Up and down the aisles of the grocery store. Fly as luggage at no extra cost. Park in offices and on restaurant patios. Through public transit turnstyles. Stand up scoot riders have fewer accidents than pedal bike riders and their injuries are less severe. No seat to get stolen or wet in the rain. Only handlebar height to adjust for a perfect fit.

Tks
Lock

Lock said:

Chalo said:

A kick scooter with large diameter bike wheels and pneumatic tires would ride better and faster yet-- but if that were going work for you, you might want to consider just riding a bike, right?

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Wrong, actually. The fold up scoots go lots of places pedal bikes cannot. Up and down the aisles of the grocery store. Fly as luggage at no extra cost. Park in offices and on restaurant patios. Through public transit turnstyles. Stand up scoot riders have fewer accidents than pedal bike riders and their injuries are less severe. No seat to get stolen or wet in the rain. Only handlebar height to adjust for a perfect fit.

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That's more or less what I meant. The advantages of large bicycle-sized wheels come with most of the disadvantages of a real bicycle, which is why you don't use them on a folding stand-up scooter, even though they are unsurpassed for operating in the bicycling environment. My impression is that the Xootr has wheels of approximately the largest diameter that would work in the manner you describe.

I personally could not ride a scooter in many interior settings, because I would brain myself on doorways. As it is, only my cultivated slouch lets me pass through most doors upright.

At my last workplace, there were Segways parked in my machine shop at all times and generally available. I rarely used them to go anywhere, but they were good fun for fooling around during a short break, or "pacing" around the shop while thinking something over.

Chalo

Lock said:

Chalo said:

A kick scooter with large diameter bike wheels and pneumatic tires would ride better and faster yet-- but if that were going work for you, you might want to consider just riding a bike, right?
Chalo

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Wrong, actually. The fold up scoots go lots of places pedal bikes cannot. Up and down the aisles of the grocery store. Fly as luggage at no extra cost. Park in offices and on restaurant patios. Through public transit turnstyles. Stand up scoot riders have fewer accidents than pedal bike riders and their injuries are less severe. No seat to get stolen or wet in the rain. Only handlebar height to adjust for a perfect fit.

Tks
Lock

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Nobody is trying to diss your stand-up scooter bro. It has it's applications, and it works great for them.

I think Chalo is just trying to put a reality check in on the total potential for loss or gain to be made. For example, I might upgrade to a bearing with 1/2 the drag of another bearing, which can sound great, but in practice, it could make 20x more differnce in drag on the vehicle by simply tucking in my shirt before riding.

I love exotic bearings, and often buy ceramics for my motors and things, so don't think I'm a quality bearing hater or something. Chalo is just trying to put things in perspective for the casual reader, so they don't run out thinking if the change bearings it's going to get them an extra 5 miles of range or something.

I enjoyed all the info from both yourself and Chalo.

Best Wishes,
-Luke

Tks guys... Myself I would rather spend the extra $10 on a better bearing and not have to tuck in my shirt
And Chalo I don't ride indoors either. Your concern about braining yourself in doorways may be valid, except you have a cat :lol:
I've spent all my EV life as a "hypermiler"... kicking off from stops, coasting to stops etc rather than using the brakes etc. Not much ya can do on a stand-up about the lousy aero, `cept pick the side of the street or another route with less winds. I had to chickle about the link I posted here earlier to hyperbolts.com... the logo on their site "Candy for Weight Weenies"... So maybe we can write off high quality bearings as candy, and accept that some of us have a sweet tooth
loC

Hey Lock and or fellow brethren ,,, how do i fiind out the size or number of the bearings in a 9c clone motor,,, i would like to upgrade to ceramic and high ABEC rating,,, it will make a large difference ,,, but i need to know what size bearing to oreder and i cant find nuthin on the matter?

CORBINFIBER said:

Hey Lock and or fellow brethren ,,, how do i fiind out the size or number of the bearings in a 9c clone motor,,, i would like to upgrade to ceramic and high ABEC rating,,, it will make a large difference ,,, but i need to know what size bearing to oreder and i cant find nuthin on the matter?

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It won't make any difference whatsoever. All the drag that matters in a 9C type motor is magnetic, not mechanical. Good bearings will last longer, but they won't perform any differently.

ha ha ha, 'brinelling' reminded me of thesewhich we use at work 8) It's all in the name... :lol:

Chalo said:

CORBINFIBER said:

Hey Lock and or fellow brethren ,,, how do i fiind out the size or number of the bearings in a 9c clone motor,,, i would like to upgrade to ceramic and high ABEC rating,,, it will make a large difference ,,, but i need to know what size bearing to oreder and i cant find nuthin on the matter?

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It won't make any difference whatsoever. All the drag that matters in a 9C type motor is magnetic, not mechanical. Good bearings will last longer, but they won't perform any differently.

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i understand the magnetic drag of the un powered magnets and there little not no drag once powered,,, i also understand there greater resistances of aero and chain drag,,, but as i have worked so hard towards perfecting those now its time i cover the bearings,,, now bearing for bearing there IS a huge diff,,, and you will have to have owned or used high end bearings to understand this (if you have what dont you understand?),,, as an inline speed skater my body felt the diffrence tremendously,,, as a honda cbr rider i noticed the difference (and that was upgrading from honda bearings to ceramic insted of of upgrading from chinese to ceramic,,,
Chalo i can see you dont think its worth it even having your own experience with bearings but your showing a lack of detail and misunderstanding ,,, its all about the fine detail that take us further,,, like flush rivets on the skin of a plain (the details) and im thinking larger,,, maybe over a few feet ill be a nano second faster but 10thousand miles maybe a few miles faster =) but i appreciate your opinionated disapproval and discouragement sir =)
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CORBINFIBER said:

now bearing for bearing there IS a huge diff,,,

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I'm telling you there is absolutely not a huge difference by any standards you choose. If a coarse, draggy set of hub bearings squanders a whole 5W of power, then by switching to magical 100% efficient lossless bearings straight from Heaven, you save 5W. Big whoop. On a system of 1kW or more, will you notice a savings of say 3W? No you will not.

Like LFP points out, tucking in your shirt overwhelms any improvement you could make to the bearings. Magnetic drag in the 9C motor overwhelms any improvement you could make to the bearings. Tire rolling resistance overwhelms any improvement you could make to the bearings. Your drive chain is full of plain sleeve bearings, for chrissakes. If you think you're going to get a "huge diff" from ceramic bearings, tweeze your chin hairs first. That will make even more difference.

Failure to scale magnitudes of forces and losses means you lose the engineering game before you start.

bearing upgrades will not make a huge diff just a difference,,, just like many of the other things you listed. but my approach is quantum holistic,,, the details and big picture or micro/macro,,, lets just say ive perfected (perfection cant be obtained only striven and evolved towards) everything but the bearings
my question is,,,(not if bearing matter but) does anyone know any resources to find out about the bearings in the motor? i can take measurements but im sure theres a number sizing right? i haven't gone into my motors yet but id like to gather up all the upgrades first and then overhaul them.

CORBINFIBER said:

bearing upgrades will not make a huge diff just a difference,,, just like many of the other things you listed. but my approach is quantum holistic,,, the details and big picture or micro/macro,,, lets just say ive perfected (perfection cant be obtained only striven and evolved towards) everything but the bearings
my question is,,,(not if bearing matter but) does anyone know any resources to find out about the bearings in the motor? i can take measurements but im sure theres a number sizing right? i haven't gone into my motors yet but id like to gather up all the upgrades first and then overhaul them.

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ive been searchin around here for this data but cant find anything and china has been no help =(
need to know what size bearings to order