So I just picked up a very clean 1st gen Coker big one, it is all steel for $175:D. I am fine with the steel frame, but am wondering what the weight difference is between the older wheel set and the new one?
I have done an extensive search and found nothing on the weight of the Coker steel wheel set.
The Coker sight says the new wheel set is 1170 grams without the tire and tube. So how much heavier is the steel one? They have the whole wheel set listed at $118.00 so it wouldn’t be a big investment to upgrade the wheel set…but I’d rather to waste the $ if they are about the same weight. I have contacted the Coker people and asked if I can buy just the rim and swap it out since that will make the biggest difference while riding. I found a rim alone on Unicycle.com but it was $115 and I might as well get the whole wheel set for that price right?
The old rim and the new rim have a different number of spokes; they are not interchangeable. You want an airfoil rim if you are going with the old coker, and upgrade to 14g ss spokes. That’s a good upgrade for what you have.
i have a steel oldschool coker wheel. they’re hella heavy i didn’t realize that coker sold the replacement wheelset! that’s suddenly become pretty high on my list
I swapped my old steel qu-ax wheel (an exact rip-off of the original Coker) for a Nimbus Stealth rim with 14 gauge spokes and ally cranks. It saved over 1330g (close to 3lbs) - very noticeable when riding.
Yes, all the weights are in the thread I linked to. Some of that 1330g was saved by swapping to alloy cranks, but most was the wheel (rim and spokes). Here’s the post.
Bear in mind mine’s a Nimbus Stealth Pro rim - I don’t know how that compares to the new Coker ones weight-wise, but I’d expect it to be similar. My old wheel (Qu-Ax steel with 12-gauge spokes) was pretty much identical to an old Coker wheel.
Rob
Edit: Are the new Coker wheels really that cheap? Seems like quite a bargain.
My understanding is moving weight is multiplied by a certain factor and spinning weight at the rim is double static weight…at least that is how I understand it at the simplest level.
Please note that the original Cokers used standard-width hubs. the newer ones use wide hubs, which could be an issue in fitting the frame. Not sure how much width difference there is, and it if will cause problems to widen the old Coker frame to fit.
If that’s true for bike wheels, it’s probably even more true for 36" wheels (bigger multiplier). But that’s a “virtual” weight savings rather than an actual one. Saving rotating weight is always a good thing!
I expect it’ll fit fine. My frame is an original qu-ax one (Coker copy), and was bent apart to fit a super-wide hub when the previous owner swapped the hubs. It was like that for a couple of years, then I bent it back to normal width for the new wheel. No problems
A standard hub has an outside bearing spacing of 110mm. The Coker hub is 140mm outside/outside bearing spacing. Because the old frame is steel, it should be possible to spread the frame to accomodate the new wheel. I have straightened, and opened many bike frames/forks and it is fairly straight forward if you have the right tools. The trick with opening the frame is doing it without denting the tubes.
Unfortunately, the tools used for squaring/alligning the dropouts on a bike won’t work in a uni frame, and so you will have to make a tool for this purpose.
I don’t think it would be too dificult to make a set of tools that gets clamped in the bearing hangers, and allows for applying leverage to the fork blade. I have an idea in mind, if you are interested I can draw it up for you.
I am glad to hear you can bend the fork to allow the 29mm (1.14") of difference to get the super-wide hub in. I guess I will have to try it and see what happens.
Put the wheel in it and see if the tyre is in the middle of the crown. If not, take it out and tread/pull on the frame again. Repeat until straight. That’s assuming you know your wheel is true, of course. It’s really easy - only took me two or three attempts - probably about 10 minutes.
Of course, you could make a jig or spreading tool to do it, but I don’t think it’s necessary for a cheap steel unicycle frame. The amount of spread between a super-wide hub and a normal one (125mm bearing spacing vs 100mm) isn’t even enough to worry about bearing holder parallel alignment - they don’t fit that well anyway!
Thanks for your common sence advice Rob, it doesn’t seem all that hard.
One question, does the frame need to stay put at the super-wide distance or can I spread the forks, then slide the wheel in and allow inward pressure on the bearings? To be clear if I then pulled the wheel out of the frame, the fork would spring back inward…is this OK or do I want to stretch it to the right distance.
The bearings aren’t made for sustained lateral force, and over time they will wear faster than if the pressure is more vertical perpendicular to the rotation.
You don’t want too much sideways pressure on the bearings, like the previous poster said. Try to get the legs as close as possible to the width of the hub, but if anything a tiny bit of inward pressure is better than outwards, otherwise the bearings can tend to drift outwards on the axle (obviously that doesn’t apply to hubs with spacers between the bearings and cranks).
