Rim brake clearance for larger tires

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SilverSteve
Posts: 43
Joined: Wed Nov 04, 2020 4:54 pm

by SilverSteve

I have a 2016 Giant TCR with Dura ace 9000 rim brakes.
I recently installed 28mm Michelin Poxer Cup Competition TLR tires and they measure close to 31mm on LB AR 46 rims (21mm internal 28mm external).

The 9000 calipers have about 2mm of clearance on either side of the tire and only 1mm or so clearnce in height.

Does anyone know if the Dura ace 9100 rim brakes or Cane creek ee G4 brakes would provide more clearance between the top of the tire and the caliper?

Thanks

by Weenie


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StanleyM
Posts: 66
Joined: Wed Aug 03, 2022 5:25 pm

by StanleyM

9100 Rim Brake on one of my bikes has nearly a pinkie finger's worth of top clearance to a 28.

Singular
Posts: 537
Joined: Mon Jul 27, 2020 8:59 am

by Singular

StanleyM wrote:
Sat Sep 24, 2022 6:11 pm
9100 Rim Brake on one of my bikes has nearly a pinkie finger's worth of top clearance to a 28.
(But keep in mind that rim brake clearance is less a matter of brake caliper model and more a product of frame design.)

StanleyM
Posts: 66
Joined: Wed Aug 03, 2022 5:25 pm

by StanleyM

Singular wrote:
Sat Sep 24, 2022 7:28 pm
StanleyM wrote:
Sat Sep 24, 2022 6:11 pm
9100 Rim Brake on one of my bikes has nearly a pinkie finger's worth of top clearance to a 28.
(But keep in mind that rim brake clearance is less a matter of brake caliper model and more a product of frame design.)
Yup. My 9100 install has basically an arc of clearance distance to the tire. I forget the rating on that caliper but it looks like 32s easy on any rim width the caliper could accept. However, to pull a wheel you'd have to drop the tire pressure to clear the pads if new-ish.

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wheelsONfire
Posts: 6283
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

SilverSteve wrote:
Sat Sep 24, 2022 3:54 pm
I have a 2016 Giant TCR with Dura ace 9000 rim brakes.
I recently installed 28mm Michelin Poxer Cup Competition TLR tires and they measure close to 31mm on LB AR 46 rims (21mm internal 28mm external).

The 9000 calipers have about 2mm of clearance on either side of the tire and only 1mm or so clearnce in height.

Does anyone know if the Dura ace 9100 rim brakes or Cane creek ee G4 brakes would provide more clearance between the top of the tire and the caliper?

Thanks
Yes, EE / Cane Creek have more clearance. I can run a set of (old) Schwalbe S-One 30mm without problems.
19mm internal rims. You can also easily run wide rims (wide at brake track).
You could use AR 56 or AR55 with EE, but i guess that's same width you now use with AR46.
Anyway, EE would solve your issues.
Bikes:

Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)


Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

SilverSteve
Posts: 43
Joined: Wed Nov 04, 2020 4:54 pm

by SilverSteve

Thanks everyone for the help.
I'm starting to think the frame mounting point has more to do with the clearance than the caliper itself. The 9000 caliper on the front has plenty of clearance. The rear cliper is where the problem lies.
My plan is to swap the tires out for 25s. It's the least expensive solution. The 25 Michelin Power Cup TLR are now in stock at Bike Inn.
Fingers crossed!

StanleyM
Posts: 66
Joined: Wed Aug 03, 2022 5:25 pm

by StanleyM

SilverSteve wrote:
Sun Sep 25, 2022 4:26 pm
Thanks everyone for the help.
I'm starting to think the frame mounting point has more to do with the clearance than the caliper itself. The 9000 caliper on the front has plenty of clearance. The rear cliper is where the problem lies.
My plan is to swap the tires out for 25s. It's the least expensive solution. The 25 Michelin Power Cup TLR are now in stock at Bike Inn.
Fingers crossed!
Or just work on the rear mount / caliper. Sometimes you can shim to gain angle for instance, or do drop-out tweaks cost is your time.

In my instrumented testing, the braking forces from the rears solo are quite low before skidding due to no weight on the tire. Often 0.25 Gs, sometimes less, sometimes a bit more but always way weaker than front potential. Weight-Weenie wise I found that it is better to do brakes more like is done on cars and trucks. IMO it is an error to have the same sizes F/R. Bigger up front, smaller out back due to weight transfer and stability. Some of the "too weak" caliper sets are just fine for rear use as a side note.

SixThirteen
Posts: 222
Joined: Sat May 24, 2014 11:49 am

by SixThirteen

StanleyM wrote:
Sat Sep 24, 2022 7:55 pm
Singular wrote:
Sat Sep 24, 2022 7:28 pm
StanleyM wrote:
Sat Sep 24, 2022 6:11 pm
9100 Rim Brake on one of my bikes has nearly a pinkie finger's worth of top clearance to a 28.
(But keep in mind that rim brake clearance is less a matter of brake caliper model and more a product of frame design.)
Yup. My 9100 install has basically an arc of clearance distance to the tire. I forget the rating on that caliper but it looks like 32s easy on any rim width the caliper could accept. However, to pull a wheel you'd have to drop the tire pressure to clear the pads if new-ish.


On my 9100 a 32 rubs the caliper, specifically Maxxis Refuse, which measured fairly true. You can use the little lever to open the pads if you need to remove a wheel with pumped up tyre.
Scott Foil RC10 Ultegra 12 speed / Creston 50 - 7.9Kg

SilverSteve
Posts: 43
Joined: Wed Nov 04, 2020 4:54 pm

by SilverSteve

StanleyM wrote:
Sun Sep 25, 2022 5:54 pm

Or just work on the rear mount / caliper. Sometimes you can shim to gain angle for instance, or do drop-out tweaks cost is your time.

In my instrumented testing, the braking forces from the rears solo are quite low before skidding due to no weight on the tire. Often 0.25 Gs, sometimes less, sometimes a bit more but always way weaker than front potential. Weight-Weenie wise I found that it is better to do brakes more like is done on cars and trucks. IMO it is an error to have the same sizes F/R. Bigger up front, smaller out back due to weight transfer and stability. Some of the "too weak" caliper sets are just fine for rear use as a side note.
I never thought to shim the caliper mount. Interesting idea.
I did a quick drawing to see what sort of gains would be possible. It appears I would have to shim the caliper quite a bit to get significant clearance.
Image

StanleyM
Posts: 66
Joined: Wed Aug 03, 2022 5:25 pm

by StanleyM

SilverSteve wrote:
Mon Sep 26, 2022 3:47 pm
StanleyM wrote:
Sun Sep 25, 2022 5:54 pm

Or just work on the rear mount / caliper. Sometimes you can shim to gain angle for instance, or do drop-out tweaks cost is your time.

In my instrumented testing, the braking forces from the rears solo are quite low before skidding due to no weight on the tire. Often 0.25 Gs, sometimes less, sometimes a bit more but always way weaker than front potential. Weight-Weenie wise I found that it is better to do brakes more like is done on cars and trucks. IMO it is an error to have the same sizes F/R. Bigger up front, smaller out back due to weight transfer and stability. Some of the "too weak" caliper sets are just fine for rear use as a side note.
I never thought to shim the caliper mount. Interesting idea.
I did a quick drawing to see what sort of gains would be possible. It appears I would have to shim the caliper quite a bit to get significant clearance.
Image
That's a whole lotta shim? Not sure u'd want to do just that, but the idea is to see what can be done.

by Weenie


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Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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