Flush / recessed chainring bolts

[pickerd]

I am using an outer chainring from a triple chainset on a double chainset. I have gone from a double ring length chainring bolt to single ring bolt. It fits and works fine with the exception that the chain catches on the chainring bolt nut. This only happens when on the inner chainring and using the smaller sprockets on the rear cassette.
On inspection I can see that the nuts protrude beyond the chainring inner surface by a few millimetres.
Can I buy chainring bolts (and nuts) that are flush with the chainring? Any suggestions?

[meic]

Working out from what you have written, this is not an ordinary double chainset is it?

If it was then the outer ring would be the same double or triple and the bolts would be well away from the chain holding both rings together.

[landsurfer]

I'm always mixing and matching my chainsets and rings but i think a pic would tell a thousand words in this case.

[Brucey]

I agree a picture (or a thousand words!) might better tell what is going on here.

I'm guessing that you have 'converted' a triple to a double by losing the middle ring, then fitting the outer ring where the middle used to be, with shorter bolts.

If so, this won't work; I would say you likely need to buy a plain chainring (that, unlike a typical triple outer, can be turned either way) or a ring that is the correct size but intended as the middle ring of a triple. In the latter case it is a good idea to fit a chainguard in place of the outer ring, since a middle ring can easily let the chain unship in either direction. In any event you may not have a peg to catch an overshifted chain, but that is something you may learn to live with.

If you are feeling adventurous, you could try countersinking the chainring you have, and machining the square flange on the bolts to match; this might give a flush bolt, but on the other hand the chainring may distort when the bolts are fully tightened or something; they are not made that way to start with for a reason, I'd have said.

cheers

[9494arnold]

Also "flying blind" , how about turning the bolts round.
(Guessing you have a Triple where inner is smaller Bolt Circle Diameter than outer 2 , you have dithced the outer one and running one where the inner (middle) ring would normally sit. If you are using the original bolts they will stick out more (ie the width of the "missing" chainring.
(If you have access to machining Facilities you could always turn the teeth off the Outer and use it as a Spacer/Chain guard.)

[9494arnold]

and

Although you are using "single" bolts, a True Single(Piste) Crank arm would be recessed for the bolts whereas the "Double" Relies on the Recess in the Inner ring .

[pickerd]

Thank for your replies.
I'll try a description but will add a picture when I am back home.
The chainset I have built is as follows, hopefully you can picture it? :
- SRAM Rival 22 crank arms (from compact 34/50 chainset - had 5 arm 110bcd spider)
- SRAM 2x10 64/104bcd spider (modified to accept crank arms and rings)
- shimano XT triple outer 42T chainring
- shimano XT inner 28T chainring
It works fine, in fact I'm really pleased with it, all but the chainring nuts on the inside of the outer ring. The outer ring, being triple, is not as thick as the outer ring from a double and does not have recesses for the nuts.

[pickerd]

A chainring bolt / nut like this would be great. I can't find out what brand this is?

bolt.PNG (164.05 KiB) Viewed 853 times

[Brucey]

A chainring bolt / nut like this would be great.....

that is a middle chainring (or at least one that is meant to be fitted to the left side of a spider) so it has recesses in it on the left side. Almost any chainring bolt will work with that chainring, and that chainring bolt will probably still stand proud of your chainring (either that or it doesn't have a lip on the head which would make it useless).

I would suppose that you just need the correct SRAM chainring for your 104/64 spider, or an alternative as I previously suggested; what you have done is slightly different to what I assumed but the bottom line is about the same.

cheers

[pickerd]

Sorry if I have mislead you, but that is not my chainset. It is merely an example of the sort bolts / nuts that would work for my application. I will post a picture.
I thought buying bolts / nuts would be cheaper than a new chainring!!!???

[Brucey]

I don't think it will necessarily matter what bolts you use; if there is no recess in the chainring on the left side then the bolts will stick out.

cheers

[pickerd]

I've now realised that the only way is s recessed chainring. It's so obvious I feel stupid.

I'm a trendy consumer. Just look at my D5803 using hovercraft full of eels.

[531colin]

40T 104 BCD middle ring here...http://www.spacycles.co.uk/m2b0s149p486/STRONGLIGHT-104-BCD-Zicral-Middle-Inner

[pickerd]

Thanks for all the replies. One thing I have done which improves things is fit the inner ring the correct way. They are not symmetrical!

I'm a trendy consumer. Just look at my D5803 using hovercraft full of eels.