Wheel build tolerance

Unicycles and Equipment
1

Hi guys,

I ordered recently a K1 Light hub to lace on an Alexrim DX32 to have a trial/flat wheelset.

I received the hub yesterday and I installed it in a frame to give it to a friend of mine for building the wheel. However, when he was playing with the hub, we noticed that the flanges of the hub weren’t perfectly straight (with the usual waving effect when turning the hub in the frame) but it seems light and the flanges seems still parallel.

The big question is: what is the tolerance for a wheel build ? Must the flanges be perfectly parallel and straight (and I have to have the hub replaced) ? Or is a slight waving perfectly fine because it will get back in line once laced, tensioned and trued ?

Thanks in advance for your feedback =)

2

Hey there,

Since you have no responses yet I thought I would throw in my 2 cents. I’m not an experienced wheel builder by any means, having only built one 24 incher in my “career” :D. However, I’ve seen quite a few posts about warped flanges. It seems that if the wheel is going to be used for anything besides basic riding such as muni, trials, doing big drops, etc. then eventually the warped flange may bend and break.

You seem to have mentioned that this is a brand new hub you just received. Depending on the degree of the warping of the flange, it may be best to try to get it replaced under warranty.

Can you provide pictures of the hub?

Hope this helps!

3

Hi,

we tried to measure the deviation during the rotation with a fixed point. On one side it is about 1 mm and, on the other side, between 1mm and 2mm.

I tried to make pictures to show the effect (difficult to get right as it is a small variation and it is hard to picture motion):


Full resolution for left


Full resolution for right

4

I wouldn’t bother for such a small difference. I rode for a long time a KH hub with bent flanges, I did unbuilt my wheel and rebuilt it several times (for new paint jobs!). My rim was true and round, no problems with it until it broke, after 3 years of intense riding I think.

Here’s a picture of my old hub!

5

What matters is the run out of your rim, If you hadn’t noticed the hub flanges you would have trued the wheel to make the rim straight and not even realised. I could not tell you how straight my flanges are.

It is pretty poor quality but if it bothers you just use an adjustable spanner to bend them straight.

6

Thanks jaco_flans, Thanks Feisty for your feedback.

If both of you abused not-that-straight-hubs for a while without major issue, I am far from making mine begging :smiley:

7

Jaco is the bench mark, I merely dabble at riding next to him :stuck_out_tongue: I have built lots of wheels now though and definitely think you don’t need to worry, you will blow the spokes and rim before the flange gives up.

The hub Jaco nuked was the old blue KH CroMo one which had large KH initial shaped cutouts that made the flange weak and liable to bending with just moderate riding, even then most people just increase spoke tension a little and left them bent. Your hub has super stiff solid flanges that are just slightly warped so they are not going to bend or do anything really.

Anyway breaking things is an excuse for an upgrade :stuck_out_tongue: I actually aspire to do big enough things to break something, although the reality is I am going to break something by running out of talent rather then exceeding my Unis limits :stuck_out_tongue:

:slight_smile:

8

Tall flanges tend to bend inwards from the forces going through the wheel and spokes when riding. Sometimes they don’t bend symmetrically. Jacob’s hub is a good example.

I have tall flange hubs in almost all my unicycles and while they weren’t bent on initial build they are all at least slightly warped now. I have no qualms about riding them or re-using them in other builds.

I would not worry about a mm or two.