Wheel Building!!

[MitchJi]

Hi Bob,

I've had a chance to reconsider my pricing and £75 does seem to be stretching it a bit.

For high quality work with a good warranty I don't think £75 is totally unreasonable (although you might do better with a lower price). Gravy charges about $100 with a lifetime warranty on the build:
http://www.gravyprowheels.com/95.html

Of course he has a long-standing reputation with a lot of repeat customers:
http://www.gravyprowheels.com/116.html

STEVE "Gravy" GRAVENITES

A native of Marin County, California, Gravy was there (circa 1976), riding with the early pioneers of
mountain biking Joe Breeze, Gary Fisher, Steve Potts and Charlie Cunningham.

Since then, Gravy has built wheels and bikes for National and World Champions TINKER JUAREZ, STEVE LARSEN, JURGEN BENEKE, DAVE CULLINAN, MISSY GIOVE, MYLES ROCKWELL and ALISON SYDOR. Along with notable riders
Elke Brutsaert, Colin Bailey, Sara Ballentine, Jimmy Deaton, Curly & Sara Ellis, Rishi Grewai, Tammy Jaques, Mike King,
April Lawyer, Tattoo Lou, Cail Noble, Ned Overend, Jacquie Phelan, Daryl Price, Kurt Stockton and Kurt Vories.

Gravy has witnessed and participated in the entire history of the sport of mountain biking. He was wrenching for MISSY and MILES when they both medaled at the Mountain Bike World Championships. Gravy wrenched for the Volvo/Cannondale Mountain Bike Race Team through a zero-mechanical-failure season in 1994.

Throughout the years, Gravy has learned his trade from the best mechanics and bike builders in the world. His mentors include Buck Berardi, Bill Woodal & Jim Ingram from Campagnolo, John Parker & Frank The Welder from Yeti Cycles and Tracey Wilde.

The box in my bike was made by myself at work. I made the battery pack of 10ah headway cells at 48v to fit the shape of the box. Also inside are all the connections between controller, motor, on/off switch, charger input plug, LVC plus controller too.

It's a bit cramped, and as it is the MK1 box. There are still some mods needed to make it 100%. I need to make the next one a few millimeters wider and get an extra couple of mil out of the hight too!! It's made from sheet aluminum and MIG welded for joining! I will be starting to offer this service for other e-bikers as and when they want it! If you know the dimensions of the area to be filled it can take a day or two to get it from nothing to finished. Mine's not powder coated yet, but can be done locally to me for around £50+, style/colour dependent.

Is £50 the total price or just the powder coating? Roughly what would you charge for a box (no electronics) including powder coating?

 

[nomad85]

Is £50 the total price or just the powder coating? Roughly what would you charge for a box (no electronics) including powder coating?

Just to double check, the £50 was just for the powder coating of the finished box!! I used about £30 of Ali, plus about 8Hrs of actual build time(the more I do the quicker it will get!!). I don't know how much it would cost to ship one out to you, but all in, a box could be made for around the £200 arena (plus postage), again style dependant!! But then that would bring it back in line with what you would pay over there i suppose.

 

[MadScientist]

The most common killer for braking spokes however is lack of spoke tension ... for that reason that the standard 12/13g spoked wheels suffer more so than the 14g.

Thinner spokes (higher gauge numbers) stretch more, which good because they lose less tension at the bottom of the wheel than thicker spokes. Maintaining tension prevents the nipple from loosening (and unscrewing) and reduces flexing at the elbow where the spoke goes through the hub. I'm not convinced that the thread pitch (lower TPI for thicker spokes) is a significant factor in the durability of well build wheels.

 

[B0B]

Hey recumbent. Sounds like you're on to a winner with that wheel of yours!! Nice one!


The only reason I rekon the thread pitch makes a bit of a difference is because it is coupled with the fact that vibrations through the wheel can cause spokes to rattle loose. On pretty much all standard Bicycle wheels they tend to use 14g spokes which have a higher TPI than the 12g. After seeing a lot of wheels in my time, is has become fairly clear that, if you have a loosely tentioned wheel the compression of the rim caused by rider wieght when riding allows the nipples to rattle loose (over time!). This is particularly noticable in radially laced wheels on road bikes. There was a particular road bike my old shop used to sell, that after the first 100miles or so you would need to have a good 5 or 6 spokes tentioned and have the whole wheel re worked to stop the nipples unwinding again.

So my thinking, is that if you have a lower TPI threaded spoke set on a wheel that is less able to be tentioned properly in the first place and spokes that soak up less of the vibrations etc. then the thread is easier to rattle loose. As an example of what the thread difference feels like, the only thing I can think of to hand is comparing hub axel threads. On a standard bike hub, you will have a max thread size of M10. If you look at a hub motor thread, it is bigger diameter for one, and has thicker courser threads.

Now, which wheel feels harder to tighten? Even though you might put the same effort on both, the standard hub will be more secure because you're moving inwards less per revolution than the thicker thread (somebody was posting about X5 hubs moving in frames because they couldn't get them tight enough). Same rule applies for spokes, but the accumulative affect is greater as you have 36 spokes to consider. For this reason why on BMX hubs they have a thicker axel than MTB because they have pegs and grind the feck out of them hence more strength required, but they use a thread pitch that is thinner than an M10. It allows them to tighten there wheels up without the risk of them rattling loose or turning as a result of grinding on their pegs.

BTW if I am talking crap here I do appologise, but that's how it it makes sense to me!!!

Hello to MitchJi. I like the look of what your man does there! Yeah, for the moment I have settled on £55 for a wheel build. AS you say warranty is important for what we do here and I would be prepared to offer a liftime warranty with all the wheels I produce. The £55 will cover the labour of the build plus spokes and a rim tape. Cost of rim is extra.

As I said in an earlier post, I would also like to get to the stage of being able to offer spoke soldering and rapping. This basically means that you wrap the last spoke crossing with a very thin wire and then solder it after. What it does is gives you a bigger effective flange diameter resulting in a stiffer and more responsive wheel(they used to do it back in the days before alloy rims on road bikes!). I have had one of these wheels build in the past to see if it works. It does! Never had to true the thing and it was given some serious abuse!! (I ride mtb trails http://www.endless-sphere.com/forums/download/file.php?id=17470)

Here's a few wheels I've produced recently specifically for e-bikes and all for paying customers!

 

[MadScientist]

I have only built wheels with 14 or 15 gauge (preferably butted) spokes with 56 tpi threads, so I can't speak from experience here, but with fewer threads per inch, a thicker spoke should have a similar thread ramp angle, allowing you to reach the same tension. You can check spoke tension with a tensiometer if there is any question and adjust you method as necessary (though you might have trouble finding a tensiometer for very short spokes). A little oil (gear oil is probably best, but just about any sort of oil will help) allows the nipple to turn smoothly as the wheel is tensioned. I used to tension my wheels as tight as I could get them (assuming strong rims), but with new sources of torque (disc brakes and powerful electric motors) I believe you can exceed the elastic limit of thin gauge spokes and so I tension these wheels less aggressively.

If you believe your wheels are going slack, you can use Wheelsmith's spoke prep or DT Swiss' locking nipples to prevent them from unscrewing (or even the old time standby, linseed oil), but while the wheels may stay true, the spokes are likely to break due to fatigue at the hub or nipple. Ordinarily, bicycle wheels should never go slack. However, the short spokes used with big hub motors have less stretch than on normal bikes. Combine that with a high torque motor or (worse) disc brakes on a highly dished rear wheel and you have quite a balancing act! Half radial lacing, like you used on the wheel with the Hookworm tire can help, but you put the radial spokes on the wrong side! The radial spokes need to go on the low tension (left) side of the wheel they prevent lower tension "leading" spokes from unspooling (going slack) when torque is applied to the wheel.

Don't bother with tied and soldered spokes, unless your intent is to keep them in place after they fail or your client demands them. Jobst Brandt authoritatively disproved [http://yarchive.net/bike/tying-and-soldering.html] the notion that T&S changes wheel performance in his book, The Bicycle Wheel. T&S wheels do not behave as if they had bigger flanges. Nevertheless, the myth that tying and soldering alters wheel "feel" and longevity persists.

 

[B0B]

Something to consider about oil when tensioning a wheel. true enought that yes you can get better tention with less effort, buyt at the same time it works the other way too. So it becomes easier to unwind them!

Again, with disc brakes and motors, if the wheel is built in the correct manner with attention to detail there should be no problems. If anything the looser the spokes, the quicker it will fail for reasons mentioned earlier on this thread!
The radial spokes are on the correct side! You can now buy pre made £1000+ wheel sets for road bikes that use the same setup (and beleive me the roadies give them some real stick!). They even go as far as using Aluminum spokes too!! The reason behind radial on the drive side was for dishing the wheel corrctly as you can put more direct tention on them than crossed spokes, (the puma hub shell doesn't allow for an easy dish) and considering it's done over 1000 miles on an A123 pack at 72V I think I can stand by the fact that it has never needed re-truing and is still at the same tention as the day I built it!

Pro lock nipples are a great way of stopping nipples unwinding, but I don't like using the thread lock as future maintainance can be problematic.

 

[MadScientist]

Something to consider about oil when tensioning a wheel. true enought that yes you can get better tention with less effort, buyt at the same time it works the other way too. So it becomes easier to unwind them!

Oil on the threads only allows the nipples to unscrew if the spokes lose tension! Otherwise, friction (particularly nipple against rim) prevents them from unscrewing. Again, slack spokes are bad wheel juju, but if you are worried about it use some spoke prep (or linseed oil) which lock the threads.

Again, with disc brakes and motors, if the wheel is built in the correct manner with attention to detail there should be no problems. If anything the looser the spokes, the quicker it will fail for reasons mentioned earlier on this thread!

I think you missed my point. I believe it may be possible to exceed the elastic limit of thin gauge spokes on disc brake wheels when they are highly torqued. That's assuming the spokes were overtensioned to begin with. If that happens, then the spokes will stretch (by definition of elastic limit), which is counterproductive. I've done a back of the envelope calculation that tells me spoke tension may be near the elastic limit of stainless steel.

The radial spokes are on the correct side! You can now buy pre made £1000+ wheel sets for road bikes that use the same setup (and beleive me the roadies give them some real stick!).

This is not the place to critique all of the nonsense marketed to gullible road bicycle riders (and even some extremely good riders can be gullible)! Here's the late Sheldon Brown's explanation of half radial lacing [http://www.sheldonbrown.com/wheelbuild.html#half-radial]. Your lacing pattern is called "wrong-way half radial".

They even go as far as using Aluminum spokes too!!

Aluminum spokes are a scam! As far as I can tell, anyway. I've done the calculations and found that aluminum and steel have practically identical amounts of stretch per linear weight. If you build wheels of the same rigidity, one with alumimum spokes, and the other with steel, they will have the same weight. The aluminum will cost more. It can't be used in a normal flanged hub because aluminum has no fatigue limit. And the aluminum will have three times the cross sectional area, giving the aluminum spokes more air drag (unless they are aero shaped and the steel are not). So far, nobody has been able to tell me a legitimate technical reason for using aluminum spokes. Marketing reasons are much easier to find.

The reason behind radial on the drive side was for dishing the wheel corrctly as you can put more direct tention on them than crossed spokes, (the puma hub shell doesn't allow for an easy dish) and considering it's done over 1000 miles on an A123 pack at 72V I think I can stand by the fact that it has never needed re-truing and is still at the same tention as the day I built it!

Hmm... You are solving a problem I have never had to cope with. Likely because I use oil on my threads, I don't have any problem tensioning spokes. If it is not for lack of oil, could it be a problem with the brand of spokes you are using?

Pro lock nipples are a great way of stopping nipples unwinding, but I don't like using the thread lock as future maintainance can be problematic.

DT Swiss says the pro plock nipples can be adjusted a few times before losing their thread locking capability. None of the thread locks I have suggested are strong enough to interfere with wheel maintenance.