Chainring bolts - ahhh

diy

seems I didn't correctly tighten these when I replaced my granny and middle chain ring, lost the whole lot today. A search of the specific part suggest that M760 chainring bolts are now obsolete, so just bought a new M770 (my large ring was fairly worn, but the granny and middle are new). I will keep looking, as it wont hurt to have a backup, but I can't believe that variation is shimano component sizes. Hardly anything is compatible within the same range.

Chunkers1980

Granny and middle are different sets of bolt. How did you loose the lot.

tom_howard

Forgive my ignorance, but arent chainring bolts just chainring bolts? ie you can use any brand/model/colour as long as the length is OK?

The Rookie

Apart from length, nearly all chainring bolts are the same, just the odd one where you have things like screw into middle rings that are different.

Simon

diy

Sorry "lost the lot" meant I lost the whole set of chain ring bolts (4 bolts holding the large and middle), the granny was still attached, so I was able to get home albeit with cadence above 100 rpm and a dodgy looking chain line

The Double Gear Fixing Bolt on the m760 is M8 x 9.2
On the m770 and 780 is M8 x 9.1

given the load on these parts I'm assuming .1mm will make a difference? I might see if I can get som 9.1s as a backup.

The SLX and deore are M8 x 8.5

ricardo_smooth

Jesus, you must have only had them in finger tight... bet you don't have a peg tool either for the back do you :?:

tom_howard

.1 of a mm?! When I said the length needed to be OK I meant as long as they were long enough to go though the rings and still tighten. I'm pretty sure all the lengths you mentioned will be fine!

diy

oh yeah duh - its the length isn't it, I was thinking it was the diameter of the nut. I could probably get away with the 8.5mm then.