Chainring Bolt Length/Size

[migrantwing]

Shimano 5700 compact 50/34. What size/length chainring bolts do I need? Some sellers don't list the length/size in mm, which is what I need to make 100% sure they will be direct replacements for the ones I have now.

When did things get so complicated?

TIA

 

[Nibor]

Go to your LBS with one of the old ones I am sure they will be able to advise and supply suitable replacements.

 

[migrantwing]

Go to your LBS with one of the old ones I am sure they will be able to advise and supply suitable replacements.

Looks like that's my only option. I can't believe there are so many different sizes/lengths, for what is predominantly a 1, 2 or 3 chainring affair.

 

[Nibor]

Your only difference is one or more as the outer bolts have to go through one or two rings. The inner rings on a triple are generally bolted on using separate bolts into tapped holes in the chainset. However some single rings are thicker than average and require the bolt length for two rings as I found out to my cost wheent the single ring bolts I tried did not fit. What do you actually require them for?

 

[migrantwing]

I never knew that about triple chainrings, that the inner ring had separate bolts.

I require them for a compact double 50t/34t Shimano 5700 crank.

 

[gbb]

Just whip one out and measure it....

 

[migrantwing]

Just whip one out and measure it....

I've whipped it out and measured it before, and it got me into a lot of trouble

 

[migrantwing]

Just a smidge over 10mm.

The male bolt is around 10mm in length, the female sleeve/nut is around 8mm, but when tightened down together, the overall length is 10.3mm. Outer diameter of male bolt across threads is 7.7mm, outer diameter of female sleeve/nut is 9.6mm. Diameter of both across the pan head is 11.6mm.

These are the measurements for a Shimano 5700 compact crank 50/34 stock chainrings, for future reference. Make it a sticky!

**Update**

Just found that the measurement for a chainring bolt is determined by locking the two parts together and then measuring the distance between the underside of the two lips. So, my 10mm chainring bolt (overall length) is actually a 6.5mm chainring bolt (distance between the underside of the lips/heads.)

 

[Ajax Bay]

Did one of yours break then?

 

[migrantwing]

Did one of yours break then?

One came loose as I'm missing one.

 

[Ajax Bay]

Threadlock when you put it/them in.

 

[migrantwing]

Threadlock when you put it/them in.

Always do, this time I had forgotten

 

[Nibor]

I think the main thing is whether the bolt retains twon rings or just one. The ones for single chainrings are hard to come by and I suspect these will do the job
http://www.chainreactioncycles.com/race-face-replacement-chainring-bolts/rp-prod40501