Widest rim fit R8000 ultegra regular brake?

Discuss light weight issues concerning road bikes & parts.
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ogcsmith
Posts: 5
Joined: Mon May 27, 2019 1:17 pm

by ogcsmith

So I have a 2018 Cervelo R2 and looking to put some deep, wide rims on it. I have r8000 Ultegra non-direct mount brakes. According to Shimano they can handle 28 mm rims with thinnner brake pads.

Wanted to check in with folk and see what the braking was like in this setup and if I really do need thinner pads?

I was thinking of getting LB 46mm wheels which are 28 mm wide but if that is too wide might go for the farsport 50mm which are 25 mm.

by Weenie


dcorn
Posts: 312
Joined: Thu Oct 05, 2017 4:21 pm
Location: NoVA

by dcorn

A friend of mine has 28mm wide wheels (Roval CL50) with 28c tires on 6700 Ultegra rim brakes, so I'd think the newer ones would fit at least that. I don't think he got thin pads.

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Beaver
Posts: 708
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

https://www.bike-components.de/en/Shima ... es-p57999/

28mm is the offical clearance, you should be fine with normal pads.

Nejmann
Posts: 465
Joined: Mon May 06, 2013 6:25 pm

by Nejmann

Plenty of space on my winterbike with hed Belgium plus with 28mm gp5000

JScycle
Posts: 243
Joined: Wed Mar 08, 2017 11:41 pm

by JScycle

Nejmann wrote:
Tue May 28, 2019 6:43 pm
Plenty of space on my winterbike with hed Belgium plus with 28mm gp5000
However those are only 25mm rims. The OP isn't asking about tyre clearance he is talking about whether the brakes can handle a wide rim

ogcsmith
Posts: 5
Joined: Mon May 27, 2019 1:17 pm

by ogcsmith

Thanks folks. Good to hear. I got something from the house which was 30 mm (actually a book!), took the wheel out, let the cable out and I was easily able to fit it with standard pads and still have some slack. Of course the quick release lever on the caliper doesn't do much though!

I think the gap with the caliper slack is nearly 35mm. I could go with 30mm rims if I pushed it but I think 28mm will be fine.

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pdlpsher1
Posts: 2419
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Besides width you also need to check for height. Height clearance is dependent on the frame.....how low or high the brakes are mounted. Each bike is different. A bike with a lowly mounted brake will rub between the tire and the brake. When I see a brake on a bike I know immediately the height clearance by looking at the vertical position of the brake pad in the brake arm. If the pad is mounted at the bottom of the arm then there’s a lot of vertical clearance. If the pad is near the middle or top of the arm then the brake is mounted very low. On a fork the brake mounting point is determined by the CTA (crown to axle) distance.

After looking at many bikes I see Trek as the one having the most width and height clearances. Whereas Colnagos as having the worst.

Bottom line is that the brake is only part of the tire clearance equation.


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integration
Posts: 18
Joined: Wed Feb 19, 2014 11:08 pm

by integration

ogcsmith wrote:
Tue May 28, 2019 3:29 pm
So I have a 2018 Cervelo R2 and looking to put some deep, wide rims on it. I have r8000 Ultegra non-direct mount brakes. According to Shimano they can handle 28 mm rims with thinnner brake pads.

Wanted to check in with folk and see what the braking was like in this setup and if I really do need thinner pads?

I was thinking of getting LB 46mm wheels which are 28 mm wide but if that is too wide might go for the farsport 50mm which are 25 mm.
I have 30mm external width rims on regular (non-direct mount) R8000 Ultegra rim brakes. They will fit with a normal sized pad. This definitely maxed out the brake calipers yet have no issues with braking.

ogcsmith
Posts: 5
Joined: Mon May 27, 2019 1:17 pm

by ogcsmith

It looks like my brake pads are mounted fairly centrally so I think I have a bit of space.

It seems some of the rims are listed at 30mm width but the actual brake track is slightly futher in. Ideally I would like to run the 56mm Light bicycle rims but they are 30 mm at the widest point. I'm wondering if they are really 28 mm at the brake track. Anyone measured these?

kevinw
Posts: 80
Joined: Fri Jan 25, 2019 3:49 pm

by kevinw

Officially the r8000 are compatiable with up to 28mm external width rims - with anything over 24mm shimano recommend using the smaller pads.

I think that this is conservative.

https://si.shimano.com/pdfs/dm/DM-RACBR01-01-ENG.pdf

Also, I believe i'm correct saying that the majority of carbon specific pads will be the smaller type as standard?

by Weenie


ericoschmitt
Posts: 186
Joined: Fri Apr 21, 2017 7:47 pm

by ericoschmitt

ogcsmith wrote:
Wed May 29, 2019 1:28 am
It looks like my brake pads are mounted fairly centrally so I think I have a bit of space.

It seems some of the rims are listed at 30mm width but the actual brake track is slightly futher in. Ideally I would like to run the 56mm Light bicycle rims but they are 30 mm at the widest point. I'm wondering if they are really 28 mm at the brake track. Anyone measured these?
Theres a long thread about LB wheels. On page 3 I have posted a review on 56x30mm wheels. The brake tracks are actually 30.5mm. I run Campagnolo Skeleton non-series, the cheapest ones you can find, they work absolutely amazing and brake at least as well as any alloy wheel I have ridden, and better than my old Zipps with alloy brake track.

Go for those wheels and nothing less. They are *f##k* great. Have no fear, you won't regret.

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