6800 vs. 8000 - Chainring Spacing

[vinuneuro]

Is the chainring spacing the same between 6800 and 8000 cranksets?

[savechief]

No

http://forums.roadbikereview.com/compon ... 60975.html

[tmr5555]

I am using an 6700 50/34 crankset with R8000 front deraullieur and dura ace 11sp chain, No issues! Absolutely fine.

[BdaGhisallo]

The 9100/8000 chainrings are 0.4mm further apart than they were on 9000/6800 cranks. The inner ring has been moved the 0.4mm inward to help cope with the wider hub spacing of disc hubs and shorter chainstays.

It's 0.4mm - it shouldn't make much of a difference in the real world at all, I shouldn't think. There have been plenty of WorldTour teams running 9100 front and rear derr's with SRM's 9000 based powermeter and I cannot imagine they would have done that if there was even the slightest hint of problems.

[TurboKoo]

I think the issue is other way round by using new cranks and old FD as they may not be able to get the chain to small ring.

[wingguy]

It's 0.4mm - it shouldn't make much of a difference in the real world at all, I shouldn't think. There have been plenty of WorldTour teams running 9100 front and rear derr's with SRM's 9000 based powermeter and I cannot imagine they would have done that if there was even the slightest hint of problems.

Yeah, Shimano always stated that the 9100 front mech is backwards compatible with the 9000 chainset so it should run perfectly well.

According to Shimano the reverse is not the case, the 9000 FD shouldn't be used with the 9100 rings. Tbh I'd be surprised if it didn't work almost as well in the majority of situations though.

[vinuneuro]

Thank you. Sounds like it will be ok to use a non-Shimano crankset with the new front mech then.

[morganb]

I'm using 9100 rings with a 9070 setup and it works fine. I have dropped a chain to the inside once but its perfect otherwise.

[zank]

Same. I'm using 6870 FD (with clamp adapter) with R9100 rings. No problem. The problem seems to come up with FD tabs that are further away from the centerline of the frame than Shimano's spec.

[cunn1n9]

Using 9070 FD with 9100 cranks and never made any adjustments from when I had 9000 cranks. Never had a problem.


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