Hi,
I started a weird (and a bit naive) gravel-building project based on a 80's MTB frame. I discovered important stuff on the way, like pull-ratio, Q-factor and chainline ;).
Now I have a beautiful 26'' half-functionning 2×10 "gravel/MTB" that needs a proper front derailer.
The only one that might be working for my setup is the GRX (or, maybe, the Deore). But I have 2.1'' tyres, and Shimano says "max 42mm tyres" for GRX.
Has anyone tried GRX with big tyres ? 🙂
Also, do mini V-brakes actually work with brifters instead of cantilevers ?
Thanks a lot 😀
by Malykopec
10 Comments
I have a GRX FD-RX810 in a gravel bike with 50 mm tires and have enough clearance. I haven’t tried more (my frame is only rated for 50 mm but the front derailleur may be an issue with 55+ tires).
PD: electronic front derailleurs are bulkier, so they’ll have a smaller tire clearance.
The statement that 42 mm is max for GRX is wrong. A lot bikes comes with bigger tire size from stock. How is the max tire size connected with GRX groupset?
I had 50c on a GRX 2x system and it was fine.
Can’t tell for 700c, but I run 48x650B and 57×26″ wheels on my bike with GRX810.
It depends. On my MOG, 2x allows me to run 48mm tires max (Tufo Thunderos on 32 IW wheels to be precise). More than that and it would rub on the derailleur. My understanding is that bikes with longer chainstays might allow for bigger tires with 2x. I’ve seen pictures of the new Giant Revolt with big MTB tires and a SRAM front derailleur.
55mm and no issues
Are you sure that even GRX will reach the MTB chainline that you’re going to get from an MTB bottom bracket setup? I believe than mini-V is designed for the same pull as cantilever but I’ve forgotten the names of the pull specs. I remember it was googleable and I could replace the canti with mini-v but not standard v
1. GRX with 50mm tires is fine even with a braze-on adapter.
2. I ran mini-V’s with brifters for years. The answer is, your mileage may vary. There are different arm lengths for mini-V brakes that give a different feel based on what shifter you’re using. Lots of posts from old CX forums debating what’s the best combo. I ran TRP ones with Shimano 10 speed shifters which I found solid-ish. Way better than cantis and I’d say 90% of the way there compared with Shimano dual pivot brakes except with more clearance.
I run 2.25 schwalbe rick in the summer and 50mm G one Rx with full fenders in the winter. No issues at all with my 2×12 speed Giant Revolt.
I’ve had 2.2 (measured 53.5mm) on mechanical GRX 2×11 without any issues at all. Could’ve done 55m if the frame cleared it, but it didn’t. That was on an Otso Waheela — 27.5×2.2 in 420mm chainstay mode and 700×2.2 in 440mm chainstay mode.