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Hi, I’m wondering if anyone has fitted a road (105/ultegra) chainset onto a gravel frame that was originally fitted with grx.
Lbs (and the cube rep) reckon it’s no problem, but i am concerned about the chainline being 2.5mm further in, especially considering the rings will be larger too, 34/50 on the road cranks, compared to 31/48 on the grx.
Reason for the change is my cube nuroad is currently fitted with 1x11 grx, 1x doesn’t really suit me for this bike, so I’m gonna go 2x, upgrading to di2 at the same time.
TIA, if anyone can help.
the extra mm on GRX is because the front mech sticks out further to accomodate the wider tyre/stays. If your bike has massive tyre clearance (say 40mm + you might struggle getting a 50/34 set of chainrings in as the sit closer. 105 is a road groupset after all and you'll only see up to 34mm tyres on those generally
FWIW I'm running 50/34 105 and there's 12mm between the chain and my Nano 40s. My other gravel wheels have 650x47 Rutlands and there's loads of clearance with them too.
Rocketdog, my bike has clearance for 45mm tyres, what you’re describing is exactly what i feared, so perhaps I’m best going for grx then
Scotroutes, I’m not too worried about tyre clearance tbh, but it’s a carbon frame, I’m worried about actually being able to turn the cranks at all
Yeah, I was just clarifying what RD said.
Thanks guys, I think I’m just gonna go with grx, safer bet all round.
I fitted an ultegra front mech on a grx chainset on my grail, and couldn't get it matched up properly, it just wouldn't move far enough out so I could frequently hear the chain rubbing on the mech, as soon as I was able to get a proper grx mech I swapped it out again.
Not sure if it would cause the same problem the other way around but I wouldn't mix and match if I could avoid it.
I’m gonna buy a full groupset, but I’m worried about the rings/cranks actually rubbing on the frame if i go 105/ultegra. So I reckon I’ll just go with grx for safety
Ok. Update.
My bike is a cube nuroad c62.
It comes fitted with 1x grx.
I’ve fitted a 105 chainset off my road bike and . . . It’s fine. There’s about 4mm clearance between the 50 tooth outer ring and the chainset, slightly more with the inner ring (34t).
So I’m gonna fit ultegra.
Reasons for going road groupset are wireless shifters, and no junction box at the front, so it’ll be easier to use with a handlebar bag.
What's wrong with GRX Di2?
Nothing wrong with it, I’d just rather go ultegra.
I have grx 1x currently, I can’t fault it mechanically, in any way.
But I want di2, and i prefer ultegra to grx.
They’re basically the same price, give or take a few quid.
I have Ultegra on my Defy and GRX on my Gradient, both Di2. I find that the GRX hood shape suits the gravel bike, and I like having the 2 extra buttons in the hoods too - I use them to control my Garmin - although it would be nice if they were a bit easier to press. But if you've tried both and you prefer Ultegra, fair enough.
I had ultegra cranks on an sensa gravel bike. Before GRX came out. It Came with 36/46 rings. I converted to 1x with a 48t and have about 2mm gap to the frame after spacing the cranks out via a 1mm BB shim. Runs no issues but you wont get a standard ultegra set up on. It’ll rest on the chainstays.