Bianchi48

Hello.
I recently bought a cannondale Superx bike from 2015. The bike comes with sram 11 speed. The last owner actually put on at narrow wide chainring. He did this because he could not shift the front gears.
I have to change the brake/gear levers. But I am wondering if you would change the whole groupset or just the levers. I am looking at upgrading to grx 12 speed, with 1x. Could I do this, and still keep the hydraulic brakes that's on the frame?
Sorry for this messy writing, but I would like to hear how you would change this bike.

I will post a picture in the gallery section. Its a blue cannondale

Russ Roth

Shimano and sram are not cross compatible in almost any way. neither's shifters will work with the other's derailleurs. Sram uses dot4 brake fluid while shimano uses mineral oil. Change levers and the brakes and derailleurs have to change. The 1x crank will be fine but there's a small chance the chainring isn't 12sp compatible.

base2 

Russ Roth

Why use the real thing and have quality shifting when we can use an adapter that'll produce ok shifting and won't be in any danger of being completely clogged on a muddy cross bike? Which also won't solve the whole 11sp sram to 12sp GRX since the adapter doesn't deal with the needed extra click. I really fail to see what your post does to change what I've originally posted. They're largely not cross compatible.

base2 

You said that the derailleurs and shifters are not compatible. Watch the video again. I am using a Shimano Ultegra 11 speed road shifter, converting it to generic 11 speed mountain pull, operating a SRAM 11 speed derailleur on a Shimano 11 speed cassette. Other than shifting one handed because I am holding the camera in the other, the shifting is flawless. This is because mountain 11 speed is mountain 11 speed is mountain 11 speed. Brand is irrelavent so says the good people at Jtek. Look under Shift Mate Y. The TanPan is only there to convert Shimano road pull to mountain and demonstrate the extremes of brand agnosticism possible. Which for a gravel/cx bike could be useful information. Though in the video I am using a Wolftooth version, for Shimano shifters the Shiftmate 8 converts to mtn (which I have had 7800 miles of good luck with.) For SRAM shifters the equivalent is the Shiftmate 9. The point still remains 11 speed mountain is the same pull across all brands however you get there.

The popular thing to do is run road and GRX derailleurs out of spec with 40 tooth cassettes. Running an XT/XTR or SRAM mountain derailleur in spec nets you even one lower cog option (a 42t) and averts premature wear and stress on the springs, pivots or undue stress on the hanger.

Furthermore, looking at the chart, for either 11 or 12 speed... as long the derailleur matches the shifter, cassette choice of another brand does not matter. So long as the cassette is the same number of speeds. Great news for XDR wheel owners with Shimano shifters and derailleurs.

As long as the systems match the brand is essentially irrelavent in actual practice. I thought you and the OP might find the demonstration of that fact useful.

More useful to the OP, gearing system aside, you are correct: His bikes current SRAM DOT fluid brake system will not work with a Shimano mineral oil system. So switching levers only is out as an option.

But if the OP were to change his brakes, keep his number of speeds (11), his XDR wheel and his current many, many hundred dollar SRAM cassette can remain. Or if switching to Shimano 12 like he says he wants too, he need only matching shifters/derailleurs & XDR 12 cassette that fits his wheel, not a Shimano freehub or compatible wheel too.

The OP does not say how big his cassette is. If memory serves, XT/XTR tops out at 46 teeth in 1x. If his current SRAM cassette is 50 or some such then AFAIK this whole exercise is moot. I am happy to learn though. Keeping up on specs is a tiresome endeavor.

Fentuz

Strictly speaking, you cannot mix and match different brands and in most cases, modern road and mtb range don t mix either. This is because each design has its own pull ratio. That said, there are "travellers" that you can add to the cable line; they will convert the pull ratios. These travellers are specific to the shifter and derailleur you are trying to match (and also exist for V brake conversion). While they work, they can be a little messy as not as crisp a proper setup would be.
Then , the brake is an issue, As said, one is DOT5.1 (flow better than 4.0 but more hydrophilic) and the other is mineral oil. Here again, you could swap the seals to be compliant with the fluid chemistry by you then have to deal with the volume ratios and the old (PV = nRT). If the caliper pistons and caliper fluid chamber is not the same volume as the shimano calipers, the Shifter brake will be either spongy or to hard with poor modulation. So not a good idea; doable but would require development and modifications.

So to the OP, why do you want to change the current groupset? what don't you like about it? why are you interested in 12 speeds? Ready many reviews, the difference in gear gaps between 11 and 12 speeds is not very noticeable and mechanical 12 speed seems a little bit fiddly to setup as there is very little tolerance in the mechanism (if you want e shifting, that's another story). There is also a cassette cost to consider.

if the issue is range, there are some excellent cost effective options in 11speed that may not require a groupset upgrade.

Russ Roth

I said mostly not and only mentioned the ders/shifters because 11 and 12 mostly don't care about cassettes and cranks though cassettes can care about wheels. I did watch the video the first time and expressly mentioned that I would find any form of adapter on a cyclocross bike (now extra emphasized) that will spend 40 minutes running through muddy courses that fill up ders enough to destroy them, both stupid and useless as its one more item that will get ruined or screw up shifting. I'm glad it works for you, maybe it will work for the OP, I've never seen a cross bike running an extreme gear. At the end of the day it looks like a solution looking for a problem.
If the OP wants 12sp GRX shifting he should simply buy the requisite ders, cassette that fits the wheels he has and deal with swapping over the very not cross compatible brakes or just leave things as is.

msu2001la

I don't have much to add on the SRAM/Shimano conversation, but I own a SuperX with GRX 1x11sp and it's pretty great. I run 11-34 rear with a 40T for CX racing, and swap to a 44T for gravel/road. It's got limited range, but I live in a flat area and don't really need climbing gears.

If I were starting over on a drivetrain I'd definitely prioritize getting a 10t on the rear, or maybe consider going with 2x. I think SRAM's XPLR with 10-36 with a 40T front would work perfectly and give me the same top end as my 44x11 (which is plenty) and even more low range.

tFUnK

I guess my question is why do you (OP) "need to change out the levers"? If it's functional minus the front shifting, I would probably just run it as-is (SRAM 1x11). If there is a need or strong preference to change to Shimano 12s, then I would change out the whole drivetrain. Even if there is cross compatibility, a mismatched drivetrain would trigger the OCD in me.

msu2001la

One thing to consider for CX racing - you don't need big gear range. On most courses you aren't going much above 20mph so something like a 40x11 is plenty - even for that finish line sprint. On the flip side - the climbs are short and steep, and if you're spinning super low gears to get up a steep climb, it's likely faster to just dismount and run it. I have never felt the need to have anything more than 40x32 on the low end, even for the super muddy stuff.

That said - I use my CX bike for gravel trails and road riding too - and for those uses I find 40T with 11-32 a bit more limiting.