Talk to me about cross-compatibility of road hydro disc brakes

[FastforaSlowGuy]

I have a 3-year old's understanding of disc brakes. If I've got a set of Ultegra hydro levers with matching Shimano calipers, are the calipers compatible with Sram/Campy levers? Is there a proprietary amount of fluid that gets pushed around when braking?

[batman1425]

Even if the fluid volume/stroke were compatibile, Sram used Dot fluid, shimano mineral oil. The two system are not compatible as the rubber seals are specific to each fluid type. Mixing and matching will lead to the seals breaking down from fluid incompatibility and failure.

[d_douglas]

But do Shimano calipers work with Campy hydros because they both use mineral oil ??

Mostly out of interest, as I wouldn't want to mess around with brake safety.

[benb]

If you have to ask the question, don't mix and match as it is/can be a safety issue.

I find even mixing and matching rim brake calipers/levers is a poor solution.

I've yet to ever ride a bike that had say Shimano Brifters + Tektro calipers and have it brake satisfactorily.

I guess I rode a Specialized that had Shimano 105 Brifters + Axis (house brand) calipers and it was "OK" but it was still noticeably inferior to the matched 105 Brifter + Caliper pair.

Look at all the threads about using STI Shifters with Cantis or Mini-Vs and poor performance too.

[dddd]

Originally Posted by FastforaSlowGuy

I have a 3-year old's understanding of disc brakes. If I've got a set of Ultegra hydro levers with matching Shimano calipers, are the calipers compatible with Sram/Campy levers? Is there a proprietary amount of fluid that gets pushed around when braking?

The fluid volume will correlate with the area of the caliper pistons.
Campa I believe had Magura get them started with their disc brake efforts, and Magura uses mineral oil like Shimano does.

I would have liked to try using SRAM hydro rim brake calipers with Shimano levers, but that would involve mixing incompatible fluids.
Don't ask me why I would want to do this!

[cachagua]

I find even mixing and matching rim brake calipers/levers is a poor solution... "OK" but still noticeably inferior to matched...

Can you say more about that? I've hooked up 7400, 7700, old-fashioned Suntour, and Campy dual-pivots, as well as assorted cantilevers, to Tektro/Cane Creek levers, and been nothing but happy...

And I ask particularly because I've been contemplating using the same levers with Hy/Rd disc calipers, and if it's gonna be disastrous I'd rather know beforehand.

I mean, probably do it anyway. But -- rather know about it beforehand.

[oldpotatoe]

Originally Posted by d_douglas

But do Shimano calipers work with Campy hydros because they both use mineral oil ??

Mostly out of interest, as I wouldn't want to mess around with brake safety.

Well, since the Campag hydro stuff really isn't 'in the wild' yet, who knows but I would guess no. A lot of shimano disc stuff isn't intercompatible between their own product lines..

[FastforaSlowGuy]

Originally Posted by benb

If you have to ask the question, don't mix and match as it is/can be a safety issue.

I find even mixing and matching rim brake calipers/levers is a poor solution.

I've yet to ever ride a bike that had say Shimano Brifters + Tektro calipers and have it brake satisfactorily.

I guess I rode a Specialized that had Shimano 105 Brifters + Axis (house brand) calipers and it was "OK" but it was still noticeably inferior to the matched 105 Brifter + Caliper pair.

Look at all the threads about using STI Shifters with Cantis or Mini-Vs and poor performance too.

I hear what folks are saying about hydro (I'll keep kit together), but I'm not sure the analogy you draw with mechanical is a good one. You're talking about matching really good brake levers with calipers that are, well, meh. I've paired Shimano calipers with all three big brands' levers, and they work beautifully across the board. Same with Campy calipers. Cantis are a different breed. If you buy ones made for mountain bikes, I've found road levers (of any brand) don't pull enough cable.

[benb]

I mentioned those combinations because a bunch of the big bike manufacturers frequently put good levers on a bike and then put "meh" calipers on it to hit a price point.

It's gotta be the worst place they can cheap out on a bike since it's one of the biggest items that can contribute to safety. Downgrade the cranks or the rear derailleur instead since those have little effect on performance or safety. (Except they're probably trying to hit a mass target at a price point and the cranks are a big delta in mass whereas the cheaper brakes probably don't change the mass of the bike much)

It's a pet peeve of mine.

The thing with Cantis, etc.. is that we're all just stuck with it. Shimano/SRAM/etc.. somehow decided the solution is to get us to buy new bikes with well matched Hydro disc setups instead of just making some road brifters that work really well with Cantis/V-brakes. I'm one of the people who crap on Cantis/V-Brakes around here but it's not the calipers fault, those exact same brakes work great if you switch to a flat bar setup and use MTB levers that are designed to work with them. The newer shimano levers do work a little better but they're still nowhere near as good as the MTB levers. It's gotta be a cost thing AFAICT because the issue is a STI lever that worked flawlessly with Cantis/Vs would probably no longer work with normal road calipers. So instead we get slightly changed STI levers that still work great with road calipers and work "OK" with Cantis and Mini-Vs.

[Gummee]

Since we're talking about it:

Shimano itself says that as long as you match the hose to the lever, their 'same level' brake calipers can be swapped between road and mtn.

IOW if you have a new set of hydro shifters and a post-mount bike, you can swap in some XT/XTR calipers with your Ult/D/A and it'll work. OR if you have an older set of post-mount brakes and a new flat-mount bike, you can swap the other way.

Note: I haven't personally tried this 'cause I'm on cantis, but the next bike's likely to be disc. May be post mount if I go closeout. May be flat mount if I go 'this year's'

If you run a TRP hybrid system and some compressionless housing, you can sidestep the whole thing. ...but that's another topic

M

[FastforaSlowGuy]

Originally Posted by benb

I mentioned those combinations because a bunch of the big bike manufacturers frequently put good levers on a bike and then put "meh" calipers on it to hit a price point.

It's gotta be the worst place they can cheap out on a bike since it's one of the biggest items that can contribute to safety. Downgrade the cranks or the rear derailleur instead since those have little effect on performance or safety. (Except they're probably trying to hit a mass target at a price point and the cranks are a big delta in mass whereas the cheaper brakes probably don't change the mass of the bike much)

It's a pet peeve of mine.

The thing with Cantis, etc.. is that we're all just stuck with it. Shimano/SRAM/etc.. somehow decided the solution is to get us to buy new bikes with well matched Hydro disc setups instead of just making some road brifters that work really well with Cantis/V-brakes. I'm one of the people who crap on Cantis/V-Brakes around here but it's not the calipers fault, those exact same brakes work great if you switch to a flat bar setup and use MTB levers that are designed to work with them. The newer shimano levers do work a little better but they're still nowhere near as good as the MTB levers. It's gotta be a cost thing AFAICT because the issue is a STI lever that worked flawlessly with Cantis/Vs would probably no longer work with normal road calipers. So instead we get slightly changed STI levers that still work great with road calipers and work "OK" with Cantis and Mini-Vs.

Agree with all of this. Even if cheapo brakes are safe (and I think 99.9% of the time they're perfectly adequate), it's deeply irritating to have an otherwise beautifully riding bike with squishy brakes. Every single time I hit the levers, it makes me feel like I got hosed.

[FastforaSlowGuy]

Originally Posted by Gummee

Since we're talking about it:

Shimano itself says that as long as you match the hose to the lever, their 'same level' brake calipers can be swapped between road and mtn.

IOW if you have a new set of hydro shifters and a post-mount bike, you can swap in some XT/XTR calipers with your Ult/D/A and it'll work. OR if you have an older set of post-mount brakes and a new flat-mount bike, you can swap the other way.

Note: I haven't personally tried this 'cause I'm on cantis, but the next bike's likely to be disc. May be post mount if I go closeout. May be flat mount if I go 'this year's'

If you run a TRP hybrid system and some compressionless housing, you can sidestep the whole thing. ...but that's another topic

M

I have this on my CX bike. Shimano 785 shifters and Shimano MTB hydro calipers. It was an unintentional mix and match, but it works just fine.

[benb]

Originally Posted by FastforaSlowGuy

I have this on my CX bike. Shimano 785 shifters and Shimano MTB hydro calipers. It was an unintentional mix and match, but it works just fine.

What are you using the brake levers up on the bar tops?

[benb]

Originally Posted by FastforaSlowGuy

Agree with all of this. Even if cheapo brakes are safe (and I think 99.9% of the time they're perfectly adequate), it's deeply irritating to have an otherwise beautifully riding bike with squishy brakes. Every single time I hit the levers, it makes me feel like I got hosed.

Yah it drives me nuts.. they're make a bike they claim is "105" and then put the Tektro calipers on it.

Throw the Tiagra rear derailleur on it or something like that instead since Rear derailleurs seem to always work better than a lot of the other components at a given price point. There must be some marketing thing where some consumers don't care what brakes they have but feel like their bike in inadequate without a higher spec rear derailleur. You'll see them do 105 + an Ultegra rear derailleur and Tektro brakes, really weird combination. I know that's a bad example since right now Tiagra is 10s and 105 is 11s but something like that.

[RudAwkning]

Chances are the hoses, barbs, banjos, etc. won't be compatible between the systems. So even if the fluid volume to move the pistons were identical (most likely not), you'd still have connectivity issues.

As for Shimano/Shimano compatibility, I'm running 7000 series SLX levers on Zee quad pot calipers and it works perfectly. I wanted the toolless lever-reach adjust and ditched the stock Zee levers. The only thing I haven't tried is road hydro levers with quad pots. But that would be silly unless I rode a tandem or something.