Rear caliper clearance issues

Discuss light weight issues concerning road bikes & parts.
ylwgto
Posts: 19
Joined: Mon Jul 30, 2018 3:29 pm
Location: NYC

by ylwgto

shimmeD wrote:
Thu Aug 16, 2018 10:24 pm
I have given measurements on the TriRig, but the OP has not responded if it will work, $80 vs $70 for the bracket. The bracket might not work as it might move the brake too high so that the pads do not contact the rim. Potenza brakes (set of front & rear) are cheaper yet; I'll measure it up for the OP. What about letting us know the measurement from the centre of the brake bolt to the top of the Conti tyre (like adding a ruler to the pic)?
Yes, TriRig would likely work. But, I'd rather try to find a single or dual pivot rear as opposed to a cam style brake.

Have not measured brake bolt center to top of current 25c Conti, but it is ~10-13m. Bottom of brake bridge to tire is ~8mm. Top of tire to underside of caliper is ZERO!

I have my hopes up that the 25c Corsa G+ will sneak in there. They arrive today and I'll update.

Also looking into a Zero G for the rear caliper only for 2 reasons. 1. looks like more tire height clearance available than current SR single picot caliper and 2. it look like the caliper is pushed out a bit farther than a the SR caliper due to the length of bolt spacers (by design). This may give me the room I need, but I have no measures to confirm these ideas.
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by Weenie


gramsqueen
Posts: 62
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

What is the clearance to the brake bridge. If it is fine then you need to get some real brakes

ylwgto
Posts: 19
Joined: Mon Jul 30, 2018 3:29 pm
Location: NYC

by ylwgto

gramsqueen wrote:
Fri Aug 17, 2018 7:22 pm
What is the clearance to the brake bridge. If it is fine then you need to get some real brakes
~8mm

which "real brakes" would you suggest to maximize tire clearance (height, not width)?

gramsqueen
Posts: 62
Joined: Wed Jun 27, 2018 5:15 am

by gramsqueen

I mean son e regular sram or Shimano

8mm flat or inflated? But 8mm doesn’t seem like a lot. I’ll have to check mine later. Do the drop outs look ok to you? Also yes contis run bigger. My 25 sprinters blow up to 26ish

ylwgto
Posts: 19
Joined: Mon Jul 30, 2018 3:29 pm
Location: NYC

by ylwgto

inflated.

drops look ok and there is tons of clearance at seat tube and chainstays.

8mm isn't a ton, but enought not worry. will be more with conti's swapped out. even so, will be too close for comfort on current SR single pivot caliper so I'll need a rear caliper swap (also b/c I can't get brake blocks high enough in caliper to seat on rim sidewall well)

ylwgto
Posts: 19
Joined: Mon Jul 30, 2018 3:29 pm
Location: NYC

by ylwgto

Shop sent wrong tires (Standard Vittoria Corsa in 25c), but I mounted rear up anyhow. Slightly better than Conti, but still contacting caliper. So, the hunt is on for a caliper with better clearance. I tried and older non-skeleton Daytona dual pivot our and it was also too tight. Ugh.

shimmeD
Posts: 434
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

Measured new Potenza rear, 7mm from centre of bolt directly downwards. From what I can tell it will work, ie you should be able to see 1mm of brake bridge with brake installed.
Really liking my newly installed front Potenza, with an ee at rear.
Less is more.

shimmeD
Posts: 434
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

Trying to help you out but I find it frustrating, as on reading the measurements you have given I'm not sure now which is which. Going back to my pic of the TriRig, it's 9mm from the centre of the fixing bolt down (on the ruler, between 40 and 31 = 9). This measurement is 7mm on the Potenza. Since you said the TriRig will fit, I'd say that the Potenza will fit, but you do confuse the hell out of me so I'm not even sure. Under $60 for the Potenza set, just tell us all you're buying a set and be done with it!
Less is more.

ylwgto
Posts: 19
Joined: Mon Jul 30, 2018 3:29 pm
Location: NYC

by ylwgto

appreciate the help. i think i've been pretty clear on measures, however.

i'll be heading to my LBS to try several calipers in stock. i may have to just accept that the frame won't accommodate lager than 23c tires.

still, the inability to get the brake pads where they need to be on the rim with the SR caliper is beyond weird.

shimmeD
Posts: 434
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

No need to argue: I just couldn't know for sure, maybe I'm just dumb in that respect or maybe I wasn't clear what I wanted to know. I wanted the measurements straight down: from the centre of the bolt to the bottom of the brake bridge, centre of the bolt to the top of your tyre, centre of bolt to the top of your rim. You could've just added a ruler to your pic, then I'd have been able to figure out if what I have would have enough clearance for the tyre as well as and have the pads contacting the rim.
But you go to your LBS, and good luck.
Less is more.

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