40h rims , still available?

[Blodwyn Pig]

This bike I'm looking at has 40 hole rims, are these not 'hen's teeth' and as such if te rims are worn,then it's new wheel time?  What to replace with? Can you lace a 36h rim to a 40h hub, by leaving 4 out?   Anyone know of any 40 hole rim suppliers? am I worrying too much?

[mickeg]

I just responded to your other post on this topic, at:
http://thorncyclesforum.co.uk/index.php?topic=14929

[davefife]

What wheel diameter? To mount what width tyres on? Brake Rim or disc?
40 hole (and 48) rims are still available but in very limited sizes, I could source.
PM me, safe cycling
D

[Blodwyn Pig]

What wheel diameter? To mount what width tyres on? Brake Rim or disc?
40 hole (and 48) rims are still available but in very limited sizes, I could source.
PM me, safe cycling
D

Its a Thorn Tandem, so will be 26" , 40 hole, 559 x 1.5 tyres.  I think velocity do them , but in UK? cheers

[Blodwyn Pig]

Ah, i've managed to locate a secrit stash of 40 h 26" Sputniks. 

[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"...

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!

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]

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

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?
 

[PH]

If I recall Sputniks have a different drilling pattern.

According to Spa Cycles ex-wheel builder, they vary from batch to batch.  Worst case scenario it to build as is and have the valve in the wrong place, I've had a wheel built like that, on a 26" it's no big deal, just make sure you have a pump head that fits before you need it!

[Blodwyn Pig]

Ok thanks all. Deal’s off. I asked the seller to check the wheels for wear with a straight edge, to see if the rims were concave, and I got a torrent of abuse, saying that I had far to many questions about the bike to warrant traveling 5 hrs to see it. When I replied that I would still be interested if they were worn a bit, I was told not to come and view it as they would NOT be selling to me!      W*NKERS. 
SO I will not be buying a Thorn after all, and and now looking at other tandems. My Mrs always had a funny feeling about this one. By all!

[in4]

Sounds like you dodged a bullet there. In my experience the Thorn owners I’ve bought from have been pretty genuine, straight sort of people. Trust your instincts and move on. Check back in: links to Thorns for sale sometimes appear here and we’re a mostly agreeable lot!