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I currently have a Compact Ultegra 6800 chainset on my Canyon, but im wanting to increase the chainring up front to the mid size 52/36 combo. Are the bigger chainrings compatible with the compact cranks?
I think the BCDs are all the same but you can't mix and match the ring sizes so you need to have 34/50, 36/52 or 39/53. You couldn't have 34/52 or 36/50.
Or at least that was my understanding when I considered this.
So I think you should be OK to swap 34/50 for 36/52 on the same arms.
I'm sure someone will be along to set me straight on that one though.
Yes you can get a 52/36 to fit compact cranks. In fact the 36 won't fit on a standard chainset. A standard crankset is typically 130 BCD and a compact is 110 BCD so they're certainly not all the same.
FWIW I think 52/36 is a nice ratio up front.
Yes you can get a 52/36 to fit compact cranks. In fact the 36 won't fit on a standard chainset. A standard crankset is typically 130 BCD and a compact is 110 BCD so they're certainly not all the same.
5800/6800/9000 are all the same - they've got the assymetric 4-bolt pattern for this reason exactly. They're not a standard 110/130.
As Alan says according to Shimano you have to match the pairs of rings, but I suspect a 36/50 would be fine, perhaps a very slight degradation in shifting performance.
You can certainly fit the 36/52 though.
Ultegra 6800 only has a single 4 bolt fitment that fits all sizes of rings, so 53/39 and compact 50/34 fits the same bcd
I've ran a 34 inner with a 52 and 53 outer and it changed perfectly, couldn't tell any difference in shift quality
This was with DI2, so mechanical may be different!
I've ran a 34 inner with a 52 and 53 outer and it changed perfectly
That is good to know. I'm getting used to 52/36 having moved from a compact and its great so far. Nice to know I have the option of bolting on a 34 inner ring if I ever contemplate something like the Fred. Wasn't sure if my front mech could cope with an 18 tooth jump (or indeed whether I could live with it). Also running Di2 so presume front mech is the same?
The etape d'dales was the reason I tried changing inner rings, I had a 52/36 and 53/39 so just got a 34 inner to try
I don't think I even had to adjust the front mech, just keep an eye on chain length as it'll be a bit slacker with a small ring
Good advice ta.