Probably don't need a GRX shifter, can get away with regular 105 - might not be perfect but it'll shift well enough. The issue will be getting a new chainset for the subcompact setup.
48/32 10 speed question
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Probably don't need a GRX shifter, can get away with regular 105 - might not be perfect but it'll shift well enough. The issue will be getting a new chainset for the subcompact setup.
As long as you can move the front derailleur further down the seat post, there will be no problems.
Id look at 46/30 or 44/28 if available. The top speed will not be compromised on the flat and you will have a lovely set of low gears for climbing hills- the latter will allow you to dial back your efforts and have a higher cadence.
Have a look at bikecalc.com. You can punch in all sorts of ratios, it will give you gear inches, ratios, speed at certain cadences in all the ratios of your desired setup, everything really
I use it to work out my touring bikes gearing. I ended up with a triple crank 48/36/26 and a 11-40 or 11-32 cassette for differing events
T4tomo
Legendary Member
GRX shifters is a red herring as the FD pull ratio is identical to rest of shimano range.
What may effect shifting is the front mech, as the GRX chainline is marginally wider than the road series chainsets (to allow for clearance of wider tyres) so your FD may not have enough swing to get the big ring. With a Sq taper BB yu could just use a short axle BB, but with Hollowtech II you cant change that. but then a GRX front mech isn't too expensive anyway.
Spa cycles do a range of "sub compact" chainsets, but they are for square taper BB's so then you'd need a new BB (and if your BB is press fit your farked - but if its thread its OK, you trade better longevity for more weight vs HT II)
