Quote:
Originally Posted by leftsidedrive
Not a dumb question. The BB standard (hollowtech 2) is the same for the GRX and the 6800 crank. You do not need to change BB's.
The grx specific FD is to address the change of the chainline standard the group is built around. The GRX group has a slightly wider chainline to work with modern "gravel" bikes that need wider tire clearance. Yes, a standard 11 spd fd will work, but you will find that it struggles to get outboard far enough. I've set up a few of them now that don't even hit the high limit screw. The new crank flat out works better with the GRX specific FD.
Also, I've found the GRX crank prefers a clamp style fd mount opposed to the braze on style. The braze on style can sometimes limit the amount you can drop the FD to accommodate the 46 or 48 big ring.....
Blah blah blah....
I really recommend people check out a gear inch chart to help them decide if a GRX front end is a good choice for them. You can see far lower gearing drops by running a 11/34 cassette if you haven't done that already. Gear inch per dollar is where its at right now in modern road drivetrains. If you are spending 300 dollars to drop 1.5 gear inches, you might be wasting your money...
It's funny about our industry. We are constantly reinventing the wheel for no other reason than marketing purposes. A "boost" chainline has existed for years with a 73 or 83 mm BB. Some ding dong at a major company just renamed it so they could be on the cutting edge of cycling technology.
I install these things all day at work. Everyone's idea of "it works just fine" is different. Feel free to PM me if you all have any questions. I'll be glad to chime in my 2 cents or help anyone with questions about compatibility.
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Great info. Thanks a lot... I've been thinking about smaller gearing for a while on my bike. I already have a 11-32 cassette at back (and a 12-25 for indoor riding during winter). I'm more into mountain biking than road or gravel but when I do ride my Hatchet I'm mostly alone on week days. I don't mind having a lower top-end so to me, a 46/30 or 48/31 makes sense . Smaller gap/range cassette for road ride without too much climbing, and 11-32 for longer rides, light-bikepacking or gravel. I intend to do Paris to Ancaster "race" in Ontario this spring and could use lower than 34-32 for the final climb... I could walk that last part like many do, but I guess I'm just looking for a raison to make the move to sub-compact...
My bike has a braze-on type FD but I still got probably 8mm of downward movement possible which should be ok for at least a 48... I don't need the +2.5mm chainline though. Maybe I should go with FSA Energy cranks (can get them pretty cheap from germain web site) and a new BB. But I would need to bring my bike to LBS for that...
Maybe I would be ok with a 11-34 cassette with my actual 50-34 crankset...