Technical > Wheels, Tyres and Brakes

40h rims , still available?

<< < (2/3) > >>

mickeg:
If I recall Sputniks have a different drilling pattern.  French vs European, I do not recall which is which.  I could be wrong on that.

Blodwyn Pig:
40 holes is 40 holes, shirley?

Danneaux:
Yes, rims may have the same number of spoke holes,, but they can be offset (staggered) oppositely in relation to the valve stem hole.

This affects the lacing pattern of the spokes (and key spoke) in relation to the valve stem. It can also make a difference in how the hub flanges are stressed on a rebuild using an existing hub.

There are also rims drilled with no offset/stagger; I have two pairs hanging in my garage rafters.To complicate matters further, some rims may have their drilling offset all to the same side. This can result in wheel with less dish to accommodate a freewheel/cassette or disc brake. A more symmetrical (less dished) wheel has greater lateral strength because the spoke bracing angles are more similar side to side.

Beyond that, spoke holes may be single-walled and plainly drilled in an unreinforced rim or the holes may be plain but in a thicker section where the holes are located (as in the Rigida/Ryde Andra 30, which has a reinforced center in the rim extrusion). Spoke holes may also be reinforced with single (in single or double-wall rims) or double have ferrules (in a box-section rim) to better distribute stress, especially in a rim extrusion with thin walls.

Rims intended to work with large diameter hubs (i.e Rohloff) may have their holes drilled directionally to provide more direct spoke angles at the nipple seat to reduce stress on the spoke threads at the edge of the nipple.

Rims with angular drilling may also differ in their offset. For example, I have two spare Andra 30 rims. One has French drilling while the other has European.

Rim cross-section an therefore spoke seat diameter can vary also.

Having typed all the above, I found Sheldon Brown's site has already addressed the particulars here...
https://www.sheldonbrown.com/wheelbuild.html
wrt French or European drilling, he calls them "left-" and "right-handed"...

--- Quote ---Rims are drilled either "right handed" or "left handed". This has to do with the relationship between the valve hole and the spoke holes. The spoke holes do not run down the middle of the rim, but are offset alternately from side to side. The holes on the left side of the rim are for spokes that run to the left flange of the hub. With some rims, the spoke hole just forward of the valve hole is offset to the left, with others it is offset to the right (as illustrated). Which type is "right handed" and which "left handed"? I have never met anyone who was willing to even make a guess!
--- End quote ---

Best, Dan.

Blodwyn Pig:
Yebbut they’ll still work won’t they? They will be built of by renowned UK wheel builder, if needed.

mickeg:

--- Quote from: Blodwyn Pig on August 09, 2023, 12:58:59 PM ---Yebbut they’ll still work won’t they? They will be built of by renowned UK wheel builder, if needed.

--- End quote ---

Should work.  But as Dan mentioned, the offset could mean that one side of the rims, the spokes would go in a different direction than they used to.  Flanges often show where a spoke has been from the high tension on the spoke will leave a slight depression in the flange.

In the case of a Rohloff that has soft flanges, that could mean an increased chance for a flange crack is my understanding.  Rohloff has started using flange reinforcing rings, so that if a flange cracks, that does not make you stranded, you can still ride the bike.

Non-Rohloff, for example front wheel, less of an issue.

I think there was a conversation a few years ago on this forum about drilling a new valve hole in the rim to solve that, but that might not work on a Ryde rim drilled for Rohloff.

Do you need new rims, or is this just contingency planning for the future?
 

Navigation

[0] Message Index

[#] Next page

[*] Previous page