Wide Hub for Nimbus 36er Frame?

Okay, so I know that the Nimbus 36" Frame is made for UDC’s extra wide hub, and that a wheelbuild with an extra wide hub is stronger, but I also know that the Nimbus frame is CrMo, and that Dustin Schaap said in this post that wider hubs generally lead to more wobble and lower speeds.

That being said…speed is paramount for my 36er :smiley: . Dustin also mentions in the same post that with the airfoil, the extra wide hub is overkill, strength-wise.

I’m definitely willing to “take it easy” on the wheel if I put on the regular wide hub, if it makes me go faster, but is it possible to (easily) bend the legs in to fit a regular UDC wide hub? Has anyone done this? What tools are required?

Thanks for helping me in my quest for my (ever-evolving) idea of a “perfect” 36er… :stuck_out_tongue:

I favour the narrower hubs because of the lower q-factor. I have not noticed any flex in the wheel when using a Std Coker frame; but I am fairly light (58kg), tend to ride in a fairly straight line, and don’t have brakes on my Coker. Having said that, I’m pretty sure I won’t notice any flex even if I had brakes mounted on the Coker. The frame has a lot to do with the flex- I notice a lot of flex when using the Aluminium 1st Generation Schlumpf frame on my Coker- it’s almost unrideable; yet I don’t notice any flex at all with the Std Coker frame. I’m pretty sure the Nimbus frame will be fairly stiff, so unless you are heavy, you may find it’s Ok with a narrow hub.

You can also narrow the Q-factor with straight cranks (ie the ones that don’t flare outwards) like the Bicycle Euros.

Ken

p/s I’m using a Std UDC hub, stainless spokes and Airfoil rim.

so would it be feasible to bend the frame in to fit the standard wide hub?

Yes. There would be 2 bends on each frame side, one at the frame somewhere above the bearing holder (even as far up as the top curve area), going inward, and one at the bearing holder, going outward. That will leave your bearing holders perfectly vertical while narrowing the spacing.

You can do it visually, but you’d need a good jig and a good eyeball.
You don’t even need to heat the frame (he says, having made these corrections before).

But don’t use anything that will bite into the material in order to grip it, otherwise you risk obvious finishing issues.

Note how the wheel is centered in the frame before you begin, and make darn sure the wheel looks the same after your bending exercise.

I have the super wide hub, stainless spokes, airfoil rim, standard frame, no brakes, and 127mm “Q” factor prowheel cranks. I experience no “wobble” at all, and it’s crazy fast when I want it to be. Smooth as silk and very responsive. I [personally] see no advantage to a narrow hub, unless you have “wobbling” tendencies.

really? cause you’ve said before that you only have the regular wide hub…and the radial frame is only meant to fit the narrow hub, so even the regular wide hub is a stretch.

and thanks for the replies, guys. would a fork aligning/bending tool be of any use?

The Radial is a tyre not a frame. The Nimbus is the frame.

…no the Radial is a frame. I believe its a little stretch to fit the extra-wide hub…but that’s what it comes with.

Hmm, I said that I have the regular wide hub? I don’t remember saying that but if I did i meant to say *super-wide". But no, if you buy a new radial, it comes standard with the superwide hub. Now if you have an old standard coker frame, then yeah, that’s made to fit the narrower hub. This new radial also has the 25.4mm seatpost, the same as the nimbus frame.

http://www.unicycle.com/shopping/shopexd.asp?id=822

dug up this thread because I am in the same situation

I punched some numbers regarding the flange spacing and flange heights. I came up with needing spokes 4mm shorter if I use the UDC wide (as opposed to super-wide) hub. It seemed to me that 4mm is enough that I would definitely need to have the threads cut further down the spoke.

then I figured if I was going to have to modify the spokes anyways I might as well get them cut for a 3X pattern instead of the 4X pattern which I am not really a fan of. I punched more numbers and came up with 364mm spokes.

All my calculations assumed that 376mm (the size they sell at UDC) is the ideal length to lace an airfoil with a 4X pattern on the super-wide hub.

Ken, or anyone else with an Airfoil on a UDC wide hub: do you know if your spokes were shortened or modified at all when your wheel was built up?

And what did you guys use to bend the lower portions of the legs near the bearing holder? Im thinking a vice with leather grips would work.

Thanks in advance for any advice

I DON’T use the extra wide hub. If you mean the Std hub then yes that’s what I use.

I used Tommy Miller spokes. No cutting involved. You should check with Roger Davies from UDC UK about spoke compatibility

I’ve seen him build a wheel for Dustin Schaap with UDC stainless steel spokes and a std (ie not wide) hub.

Ken

Eric, your suppositions about spoke length are correct. It is unfortunate that the only retail size of the 14g spoke is 376mm, which is good for 4-cross on a superwide hub (100mm flange width). Using a narrower hub (flange width of about 70-75mm) but the same flange diameter will ideally require shorter spokes by about 2mm. You might still be able to use the 376s, but run the risk of bottoming out the nipple.

Going to a 3-cross pattern requires even shorter spokes.

I have a high-flange hub of “regular” width, and with 3-cross it takes 357mm spokes. I have to buy the 376s, cut them down, and have them re-threaded locally. It’s too expensive for the maker to offer several lengths at 36" wheel spoke sizes.

thanks!

Thanks for the input guys.

I think I will go with a 3X pattern then since I will have to modify the spokes anyway, I know that my LBS can cut and re-thread spokes.

Ken, I meant the standard/skinny hub, UDC has their standard hub listed as the “wide” where there super-wide is listed as, well the Super-Wide hub.

Nope, there’s still a difference, Saskatchewanian. UDC’s “standard wide” hub is still wider than a standard coker hub.

I know that the standard coker hub is quite a bit more narrow at the flanges but to me this ^^^ means the UDC “wide” CroMo hub as UDC doesn’t have its name on anything narrower on their site, maybe they used to have something narrower, I don’t know, I am still relatively new at this. The “wide” (standard) hub still has standard bearing spacing so I think of it as a standard size.

I have one of these hubs in a wheel I never plan on riding again and it is what I will be using in my 36er wheel.

Wonderful, isn’t it? We’ve become as bad as B#^&ers when it comes to multiple reference standards.
The “standard” uni hub flange width is about 65mm, which was simply taken from a common bike hub flange width. Its frame bearing centers are 100mm apart.
The UDC “wide” hub has about a 72mm flange width. The Schwinn “wide” hub has a 79mm flange width, about the max within the 100mm bearing center width.
The UDC “superwide” hub has a 100mm flange width, and about a 130mm bearing center. There are also other hubs out there with 130mm bearing centers.

I was thinking exactly the same thing the other day when riding to work on my narrow/standard width/old Sem hub. It’d be much better to describe hubs by flange and bearing widths

I have just been and put the UDC CrMo hub up against a Schwinn hub and they are both identical at the flange… so I am not sure where the 79 dimension comes from, I guess the base of the flange. Basically this dimesion is the largest that will fit in a frame with the bearings at 100mm.

The Nimbus frame will bend in as you need it, I do this all the time. Although I would not recommend doing this too often. I use a standard UDC hub for road and wide for offroad.

The width of the hub depends on you… Ken, Dustin, Sam and me all have small hips… there for the narrower hub is definately best for us. :slight_smile:

Spokes… the difference in the flange distances makes only a little difference in a wheel this size. So you can use the standard spokes. I personally perfer 4 cross although I have not done a direct comparison but from what I have read and surmise it makes a better wheel on these really big wheels.

Roger

36er q-factor is considerably larger than typical bicycle q-factor. Wheel strength aside, I would think that a narrower hub is better for most everyone. Or is bike q-factor abnormally small?

The goal with the hub width issue is spoke angle. All else being equal, a wider hub creates a greater spoke angle in toward the rim, thus a stronger wheel (i.e. able to better resist lateral and vertical deflections).

But this is not to say that our “standard” narrower hubs cannot be made into a strong-enough wheel. While hub width is a factor in the wheel build, lots of other factors, like spoke material and strength, contribute to an overall strong wheel. (When you put them all together you have U-Turn’s “World’s Strongest Coker Wheel”!)

Obviously a wider hub, offset cranks, wider pedals, etc. will all locate the pedals wider. This final “pedal width” is the “q” factor.