Steering damper

[Lowell]

Might be an idea for fixing head shake on faster ebikes, and seems to get excellent reviews all around.

http://www.mtbr.com/spotlight/hopey/
http://www.mtbr.com/reviews/Extras/product_68285.shtml

 

[CGameProgrammer]

That seems awesome, but the reviews suggest it might not work with integrated headsets, which I believe is what all the cheap bikes use, like any bike that's $500 or less. If it worked with my Trek 820 then I'd love to have it.

 

[safe]

$219

Better to just lengthen your wheelbase and build a stronger frame. A steering dampener is an attempt to correct a deeper problem. (a properly setup bike doesn't wobble at speed and would not need one)

Spend the money building a new frame instead...

(custom frames cost a lot in terms of man hours, but not in money... the steel costs only $50)

 

[Lowell]

Aren't all bikes using threadless headsets these days? As a pure bolt on, if it fixes the wobble it sounds like a much easier modification than a stiffer, longer wheelbase frame.

Good components cost money... look at any of the top line forks. Marzocchi 888RC2X, Rock Shox Boxxer world cup, Fox 40RC2, all around $1500.

$219 is not bad when compared to steering dampers for motorcycles.
http://www.muzzys.com/ZX14/ZX14_Steering_Damper/zx14_steering_damper.html
http://www.exoticsportbike.com/suzuki74.htm

Speed sensitive damping:
http://www.sportrider.com/bikes/2004/146_04_honda_cbr1000rr_steering/

 

[CGameProgrammer]

They use threadless steerers, but the headsets (containing the ball bearings) are integrated into the head tube. Er my terminology may be slightly mixed up.

 

[Lowell]

They use threadless steerers, but the headsets (containing the ball bearings) are integrated into the head tube. Er my terminology may be slightly mixed up.

Got it. That sounds like an aweful design.

 

[safe]

Lowell, can't you tell just by looking at your bike that it's way too short?

Compare your bike to a motorcycle shape. Use some mental image mapping from one thing to the next and it becomes obvious that a typical bicycle is way too short for the demands of high speeds.

The history of bicycles is all about trying to save weight and reduce bottom bracket flex while pedaling. A long time ago they realized that the shortest frame possible was the best way to reduce those two problems. But while solving those problems they've produced a frame that is not well suited for speeds above about 30 mph.

You have to take my word for it that you enter a whole new world of handling when you get a long wheelbase and rigid frame. (imagine being able to slide the bike at speeds above 30 mph and feeling confident while doing it)

Think of skiing:

1. Slalom - Shorter skis, quick handling.

2. Downhill - Longer skis, slow and predictable handling.

We're effectively racing the downhill. I just think you are wasting money on stuff that doesn't address your central issue which is the need for a custom frame.

52" wheelbase... it's where you need to be...

 

[Ypedal]

Hm.. interesting..

My frame uses Ahead headset.. so it would work.

Not entirely for high-speed, but handy on the BMX track...

Going up a 45 degree wooden ramp at slow speeds makes the front end twitchy on my bike with the big front wheel and small rear.. this would help keep me straight !

 

[Malcolm]

I just think you are wasting money on stuff that doesn't address your central issue which is the need for a custom frame

Surely adding a steering damper is addressing the issue; it slows down steering response so that it mimics that of a bike with a longer wheelbase.

It's a bit much criticising Lowell's approach, when you yourself are building a custom machine for similar speeds but have decided that there's no need for suspension. Doesn't that have significant drawbacks from the handling viewpoint? :lol:

 

[Lowell]

A long wheelbase doesn't make a bike immune to shake, although it should help.

http://www.guzzitech.com/SteeringDamp-Ed_M.html

http://youtube.com/watch?v=RnuNfzK9Ab0

 

[CGameProgrammer]

Not everyone can build their own custom frame, safe. You've been doing motorcycle repair/modifications for, what, several decades? I think Lowell does something similar for cars but I don't and I need to use pre-built frames. But ordering a custom frame from a builder would cost several thousand dollars. Hell, even mass-produced tandem bikes (long wheelbase) cost at least $2000.

I'm also not convinced that solves the steering problem. This isn't the body flexing, it's the front wheel not being planted on the ground. I discovered that simply placing more weight on the front of the bike (specifically by putting batteries within the front triangle) improves steering stability, but that's effectively two-way dampening vs the one-way with this device (which doesn't dampen return-to-center).

Besides, normal bikes have a wheelbase between 41-45 inches. Is 52" really such a dramatic difference?

 

[Lowell]

I'm not really sure about the one way damping of the Hopey unit, but it turns out there's a local dealer on the North Shore so I'm going to give it a look next time I'm out that way.

 

[safe]

...when you yourself are building a custom machine for similar speeds but have decided that there's no need for suspension. Doesn't that have significant drawbacks from the handling viewpoint?

No, not really.

Suspension helps the most when your bike is very heavy. Since this upcoming bike project will be 60 lbs lighter the need for suspension goes down. (you use your body as suspension)

The true question is:

What is more important at speed, suspension or having a long wheelbase that is flex free?

My experience is that suspension helps to soften the ride, but it doesn't actually help the bike handle better. Suspension introduces a lot of issues that aren't all that good including things like the nose diving during braking (changing the geometry when it does) and the fact that the ride height changes as you squat in a turn. Flex is the number one enemy at speed and many speed wobbles are the direct result of frame flex. My current bike at 50 mph feels solid as a rock... and I have done controlled slides in sweeper turns at speeds above 32 mph (on my practice track) on a pretty regular basis. Today I figured out a hot new line through that turn and managed an exit speed of 24 mph which is smoking fast for that turn. (you would have to see it... one day I'll take pictures)

Seriously... would ANYONE out there with a flimsy short wheelbase frame and sloppy suspension risk taking a turn fully leaned over at 32+ mph?

If they do they are a little nutty... with my bike, it's no big deal...

One day I'll focus on the $$$ suspension side of things, but for now the first priorities are a long wheelbase and no flex.

 

[safe]

Besides, normal bikes have a wheelbase between 41-45 inches. Is 52" really such a dramatic difference?

Yes.

It smooths the bike out dramatically. At speeds below 10 mph it's a little clumsy, but at speeds above about 30 mph it all of sudden feels smooth as silk.

I own a mountain bike with good quality suspension (I paid $1400 for it several years ago) and know how they handle. In fact I might "borrow" the Rock Shox dampened air suspension for a while for the new project to give the seat a cushy ride. Eventually it has to go back to the mountain bike however because it's still an excellent bike. (great for California hills, but boring in Missouri)

 

[safe]

My hope is to one day sell the frame / fiberglass (injection molded plastic?) as a kit so that other people can build their own "Road Racer" bikes. Eventually some chinese company would probably build the actual components (free trade being what it is) but I'm just pushing the design side.

So one day someone might be able to "buy" what I'm dreaming up today. (and if all goes as is normal I don't earn a penny and others make the profit... :lol: but that's fine)

 

[knightmb]

Seriously... would ANYONE out there with a flimsy short wheelbase frame and sloppy suspension risk taking a turn fully leaned over at 32+ mph?

If they do they are a little nutty... with my bike, it's no big deal...

One day I'll focus on the $$$ suspension side of things, but for now the first priorities are a long wheelbase and no flex.

*raise hand* but, I have no suspension on my bike. The fastest I've taken a 90 degree turn is 35 MPH, lots of lean. It was scary the first time, but now I've done it so many times, it comes natural. It is funny to see motorist try to keep up as I've heard a many of wheels squeal behind me when they like to follow on my tail until they hit the curve and slide out of control. Lucky for them, it's a wide enough turn with "shoulder" on a two way, ditch separated street that if they slide out they won't crash into on coming traffic. I might have it in one of my ride videos, from the camera perspective (straight on), it looks like I was scraping the bike along the ground on the curve. But I actually wasn't leaning over quite that far as the camera makes it look.

 

[safe]

The fastest I've taken a 90 degree turn is 35 MPH, lots of lean. It was scary the first time, but now I've done it so many times, it comes natural.

Here's where it gets interesting though...

Traction has some limit. At some point you will begin to pass the limits of your tires and they will begin to slip across the top of the road. Now the question is whether you have experienced this behavior or if you have been taking turns with a "ride the rails" mentality. Frame flex only surfaces as an issue once the tire has broken loose. A less rigid frame will tend to absorb the lateral loads that the tire creates when it slids and then catches. It then becomes a spring that will turn around and bite you when it releases. This is what is known as a "high side" when the tire breaks loose, drifts out, then catches and then throws you.

For most people the first time they learn what the limits of their tires are they crash. For me, I can slide the tires here and there and the results are predictable because the frame is stiff enough to prevent problem behavior.

Do you know that feeling of "drifting" the tires in a turn?

At race speeds people drift their tires into turns and out of turns on motorcycles. Most bicycle racers avoid any tire sliding realizing that most races are won on the hill climbs and not the downhills. But the electric bike... one's that are built for speed... need to fit the "motorcycle category" more than the bicycle one.

We're in a "weird" design area where the two sets of rules are unclear...

 

[CGameProgrammer]

Well how many people drift? Certainly I don't. And I'd much rather have suspension to dampen bumps. My first electric bike was fully rigid (except the seat) and only went 34 mph, but even at 30 mph bumps and potholes hurt a bit, particularly my hands on the handlebars. Now I've a front-suspension bike and the worst bumps no longer bother my arms, though of course I wince when the 54-lb lead-acid pack in back absorbs the bumps.

 

[safe]

Well how many people drift? Certainly I don't. And I'd much rather have suspension to dampen bumps. My first electric bike was fully rigid (except the seat) and only went 34 mph, but even at 30 mph bumps and potholes hurt a bit, particularly my hands on the handlebars. Now I've a front-suspension bike and the worst bumps no longer bother my arms, though of course I wince when the 54-lb lead-acid pack in back absorbs the bumps.

If I could find some forks that could fit my VERY custom situation that were lightweight, were extremely rigid in twisting, had about one inch of high quality travel, cost next to nothing and were full length so that I can use clip on handlebars then I would do it.

Realisitically, all the regular forks that are strong enough are like on Lowells bike having something like 5" of travel. (they are designed for a mountainbike) Aerodynamically that's 5" extra inches of air that I would have to push.

And yes, if you are building a "Road Racer" bike you are going to need to be able to drift at speed, otherwise you are not being faithful to the "Road Race" concept.

Race bikes always sacrifice some degree of comfort compared to cruiser type bikes and the plush suspension that would be "nice" is not mandatory for the kind of "Road Race" concept I'm after.

Maybe I'll try some rubber mounts on the clip on handlebars somehow to give a little less direct shock. :?

IMPORTANT: Don't forget I'm running 3" tall tires... the extra inch gives a lot more inherent suspension than the regular tire. I'm running:

24" x 3" Racing Slick design...

 

[agent86]

I wonder how these would work for you, Safe?
http://www.pantourhub.com/products.html

 

[safe]

I wonder how these would work for you, Safe?
http://www.pantourhub.com/products.html

Thank you very much. That's a great idea. At $199 for the disc brake version that's about what I'd expect to pay for a suspension fork, so the price is not fantastic, but the idea is really good. They give just an inch of travel which is just enough to provide the comfort factor that a rigid fork does not give. Hmmmm...

 

[safe]

This is an idea I'm working on right now. Maybe I might build my clipon handlebars (clipons "clip onto" the forks" directly) and normally you would have a few bolts to clamp the clipons to the fork tubes anyway, but you could add an extra plate which would isolate the clipon handle bar end with a thick piece of rubber. The bolts would first be tightened so as to make the contact to the forks rigid, then the secondary use of the bolts would be to secure the clipon handle. Or maybe two sets of bolts would be easier... I'll have to play around with the idea a little. Since I have to create the clipons anyway (well, you can buy them, but I build everything anyway and have built them before) I might as well experiment with rubber suspension.

Ironically this would tend to act like a steering dampener as well as an up and down suspension device. 8)

 

[Miles]

I have a Pantour hub on my Brompton bike, works well. Not sure I'd trust it at 60 mph, though....

 

[Toorbough ULL-Zeveigh]

This is an idea I'm working on right now. Maybe I might build my clipon handlebars (clipons "clip onto" the forks" directly) and normally you would have a few bolts to clamp the clipons to the fork tubes anyway, but you could add an extra plate which would isolate the clipon handle bar end with a thick piece of rubber. The bolts would first be tightened so as to make the contact to the forks rigid, then the secondary use of the bolts would be to secure the clipon handle. Or maybe two sets of bolts would be easier... I'll have to play around with the idea a little. Since I have to create the clipons anyway (well, you can buy them, but I build everything anyway and have built them before) I might as well experiment with rubber suspension.

Ironically this would tend to act like a steering dampener as well as an up and down suspension device. 8)

That looks very similar to this piece of <A HREF="http://cgi.ebay.com/GIRVIN-FLEXSTEM-retro-suspension-stem-1-inch-135mm-25-4_W0QQitemZ300122979626QQihZ020QQcategoryZ22694QQssPageNameZWDVWQQrdZ1QQcmdZViewItem">old school</A>.

Would it be safe or even adviseable to combine a damper with a suspension stem?
And then howz boot combined with a reglar suspension fork for the ultimate in cush?

BTW, mucho thanx Lowell for the heads up about the Hopey. I think it will work great for winter driving. Should cut back on the nose deflecting every time the front wheel hits a patch of powder & the assosciated nitro boost to the adrenaline while trying to recover balance on the pack ice.
Please let me know if your North Van LBS has stock & the cost, defiantly want one. Is it On The Top?

 

[safe]

That looks very similar to this piece of... old school.

The idea of rubber mounted handlebars is very old. I'm think my old 1979 RM125 (purchased new... oh what a joy that was!) had rubber mounted handlebars and I think many motorcyles still do it today.

Most handling problems are because of poor geometry (wheelbase too short, rake or trail that is incorrect, poorly shaped tires (too pointing, not pointy enough), or frame flex. Suspension increases the complexity and makes getting the handling right more difficult. When you are at the beginning of a new concept (the "Road Racer" electric bike... that actually goes fast) it seems to me that you are best served "keeping it simple". (K.I.S.S) Later on when all the basics are established you can fine tune with things like suspension. Money is another issue... suspension adds a lot of cost to the overall machine while not advancing the concept very much. Most of what I'm testing is about frame geometry, aerodynamics, gearing and powerbands. So something like rubber mounting the handlebars is a good temporary fix until I might later consider throwing bigger dollars into the project. In many ways "bad suspension" is actually worse that no suspension. At least without suspension you are dealing with a reliable foundation.

I was watching this tv show called "American Inventor" (or something like that) and this one guy had spent $300,000 on an idea for a drag racing toy. (using Hot Wheels) Now I'm sure the guy was sure that his idea was golden and that it was all worth it, but it's also a quick way to the "poor house". If I was part of a large corporation that had a big budget and was in the R&D department I'd go straight for the carbon fiber or aluminum and build in suspension and everything else. Of course then when it comes time to sell such a thing it's going to cost the public $3000 because it's "too sophisticated". (costly to build)

My thought is that you want to start off building things cheaply. Once the cheap version gets out there and people start using it then it builds it's own momentum and then you come out with new versions every year until then finally you have something that sells for $3000 for the "top of the line" buyer and yet you can still go to WalMart and get the cheap version for $500.