Brake calipers 5800/6800/9000 vs r7000/r8000/r9100 tire clearance

[alcatraz]

Hey fellow riders

We're doing a big tire fit and the 9000 caliper is contacting ever so gently around the inner arch.

Does anyone know if the next gen (7000/8000/9100) calipers provide a bit more clearance? We just want like 1mm extra.

Thank you!!!

[gkski]

It’s most likely the photo, but that wheel doesn’t look centered in the stays.

[MasterBean]

Yes they do.

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[alcatraz]

We removed the caliper and the centerline on the tire is exactly under the caliper bolt hole. As well as the clearance in the caliper. The windows in the room are to the left so that's where most of the light is.

But never mind that. Do you know if the new gen calipers have more clearance?

[alcatraz]

Yes they do.

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Thank you. Is the clearance in all directions you think? We kind of need it both sideways and up against the center.

Does anyone know if all three calipers (7000/8000/9100) have the same clearance? I'm tempted to buy a 7000 caliper and try.

[patchsurfer]

This suggests that the ultegra calipers at least are bigger than DA

https://www.cyclingweekly.com/news/prod ... a%20weight.

[alcatraz]

I compares r7000 and r8000 at a bike store and the spring on r7000 did seem to take up more space as well as the thickness of the cast aluminum parts seemed a bit more generous, and thus likely less clearance.

We ended up getting an r8000 rear caliper. To be honest it didn't provide much more clearance than the 9000 series, but the material is thicker so if we grind down the critical points by a millimeter we are less likely to break the caliper.

[alcatraz]

For anyone interested. Here are the pics taken at a bike store. We're comparing r8000, r7000 and 9000 calipers. (The calipers aren't mounted but resting on the tire.)

It's not obvious to me that the 9000 series provides less clearance. We do have an arm length problem though. The R8000 solves that and thus enables us to lift the caliper away from the tire by a millimeter or two. By slightly ovalising the caliper bolt hole in the frame. Right now it's ~6.5x6.5. We're going to make it 6.5x8.0 or thereabout.

(the 9000 pic is in the first post)

[CyclingGiraffe]

Maybe its the angle but even with the new brakes, I think that is too tight. What size tires/rims are you using?

[Mr.Gib]

Yeah what size tires?
FWIW the greatest clearance I have ever encountered in a normal caliper (as opposed to long reach), is with Ultegra 6700. Way more space than 6800. I run 30mm tires with lots of clearance. Dura Ace 9100 should also be good.

[alcatraz]

We have a solid 2mm clearance all around. It's not pictured here.

We ovalised the brake bolt hole a bit, and ground down the edges inside the caliper (brand new r8000 caliper )

It's a Pirelli Cinturato 35C on a 30mm Lightbicycle AR56 rim.

2mm is on the limit, but not as crazy considering the wheels are very stiff laterally. They're not your average 21/24 spoke wheels with cx-ray/sprint.

[Mr.Gib]

35? Well no wonder things are tight.

I wouldn't do it. A couple of things might ruin your day. It doesn't take much in the way of debris to cause the wheel to jam. And secondly, although rare, if the front goes flat the caliper or fork proximity may cause the tire to wrap around the rim and snag on the brake pad. More likely with very supple tires. Happened to me 7 months ago and has left me with a permanent disability. Only 50% use of my left arm. I was using 30mm Corsa's with decent clearance. Nice to have big tires but there is some risk. Yes I am Buzz Killington.

[alcatraz]

The front has loads of clearance to the caliper and fork. Also it's running a 32c but could easily do a 35c.

The tires were a PITA to get on the rims. These are unlikely to blow off. Besides we are running inner tubes.

We have two 32c and two 35c tires. 32c is plan B but a 32/35 combo with a spare set ready, sounds the most tempting right now.

As mentioned, the result isn't pictured. The guy already did 100-200km of testing and he loves it.

Thank you for the insight. Sorry to hear about the injury. I've had a shoulder injur myself and it's annoying when realising it's never going to be 100% again. We will do more testing before he sets off on his big journey.

[patchsurfer]

Top research, whichever way you go! Following on from what Mr Gib said, I had an issue last year - our roads here are volcanic chip and seal, and it's pretty usual after roadworks in summer to have sodding great lumps of rock stuck to the tyre. Found with the ultegra 6800 caliper there's a couple of handy places for them to get stuck, which was a bane of my life for a while - swapped that out for a DA 7800 I had in the garage, and I've not had a single once since.

Not sure if the current generation of shimano calipers are all variations on a theme, or if one design or another has a smoother underside...

[alcatraz]

I remember reading your post when it happened patchsurfer. That's interesting, thank you.

I'm sure he'll put at least 500km and some on poor road quality before he sets off.

My concern really was that if he hit a huge pothole and somehow damaged the wheel that the bike would be unrideable but he seems confident he can handle that. He's got spare spokes and nipples with him.

The front has tons of clearance. That's a relief safetywise.