Building a Coker wheel

The spoke calculator at suggests 369 mm spokes for a wheel built with an airfoil rim around the Wide Coker CrMO Hub (125 mm bearing to bearing).

How does that compare to the spokes I have now on my standard Coker wheel with steel rim and narrow (63 mm flange to flange?) hub?

Will I be able to reuse the standard spokes in the new setup?

See this thread Help on Tom Miller Spokes for the numbers if you’re getting custom spokes. Don’t trust the spoke calculator for Coker spokes.

You can use the standard length stock Coker spokes with the Airfoil rim and the wide hub. Just go with a 4 cross instead of a 3 cross and it magically works.

Thanks John. Even though you say magic is involved I don’t quite understand. If you choose 4 cross instead of 3 cross wouldn’t that call for longer spokes instead of shorter?

According to the thread on Tom Miller’s spokes a 4 cross on airfoil with wide hub would take 375 mm spokes and a 3 cross 372 mm. That is almost no difference! Is it because the wheel is so huge or what?

Magic or not. I think I will first measure one of my standard spokes before rebuilding the wheel. Or has anyone already done that?

The Airfoil rim is a deep section rim so its ERD (Effective Rim Diameter) is smaller than the ERD of the stock Coker rim. The stock Coker spokes would be too long for the Airfoil rim if laced 3-cross. It just happens that the stock Coker spokes will work if laced 4-cross. That’s the magic, or a at least a convenient coincidence.

Ah, yes of course!

I just got my new 36" wheel built and I used the udc wide hub and airfoil rim and Tommi Miller ss spokes and I ordered them using the spoke length calculator for three cross, 369mm, 14.5". And guess what they were the perfect length, the spokes came just to the top of the nipples, if you use 14-5/8" spokes they are going to stick out past the nipple and may bottom out on the threads. It won’t be a problem that they stick out a little bit with the airfoil rim because the rim has such a deep channel that the nipples are deeply recesed, and there may be enough threads to not bottom out but trust me for three cross 14-1/2" is the correct length.

I just built a wheel with the UDC hub and Airfoil rim with 4 cross spoking. 14-3/4 worked out just right with a lot of spoke tension. I also used spoke washer on the heads because there was quite a bit of play in the hub spoke holes.

To get the right fit for the airfoil rim you need to get the nipples from semcycle, they have nipples that are the same size OD as the stock coker 12 gauge nipples but are threaded for 14 gauge spokes and they fit the rim holes perfect.

Oops I guess I should read more carefully before replying. You said hub spoke holes not rim. I thought the spokes worked OK at the hub even though it is drilled for 12 guage spokes.

There is quite a bit of play around the spoke at the hub. This will allow movement of the spokes in the hub causing broken spokes at the spoke head. The washers tighten everything up nicely.

Information taken from “The Art of Wheelbuilding” by Gerd Schraner

are the washers like standard washers or are they a sleeve to make the spokes a larger gauge?

They are tiny brass washers that just fit over the spoke. Once the wheel is laced, you will have to tap the spoke heads into the washer and hub using a special pin punch with a concave surface that fits over the spoke head.

I made mine from a Craftsman punch using a dremel tool and grinding stone attachment to recreate the shape of the spoke head into the end of the punch. You can also purchase a spoke head punch for @ $14.00

You can get the washers from Bike Tools Etc. They are online. A bag of 100 is $2.50 plus $6.00 shipping.

Ah yes I saw your pictures in your DIY coker thread. It looks nice but I think I will stick with what I have, the spoke heads are cone shaped and set into the holes without them and if they are kept tight I think it will be allright. But definitly better with. I am building my own frame and useing the same type bearing holders as GB uses they are called split shaft collars, I bought ones that fit 35mm bearings and am having them machined to fit 40mm bearings leaving a lip.