SRAM Red Brake Clearance

[Schnavel]

As part of the Black Friday specials, I purchased a set of 28c Hardshell Gatorskins from Wiggle. They arrived on my doorstep yesterday (great service from Wiggle & Dawn Wing), so I was like a kid in a toy store and all I wanted to do was fit the tyres and then take my bike out for a ride.

 

My frame (Swift Ultravox TI) specifies acceptable use of tyres up to 28C, so I was very excited to use these tyres on my training wheels (American Classic Victory 30) as they will make the ride extra comfortable, and the additional weight will be good for training.

 

So I fit the front tyre and check the clearance with the fork and brake caliper and there is ample clearance. Enough clearance that I could get an even larger tyre if necessary.

 

I then proceed to change the back tyre and fit the wheel back into the frame. I check the clearance with the frame and again, ample space. However, as I spin the wheel, the sound of disappointment rises as I hear rubbing. first I check the brake pads to ensure that they aren't touching - lots of clearance. To my dismay, the tyre is actually touching the inside of the brake caliper.

 

On the SRAM red brake calipers, there is a spring system which is incorporated into the single pivot design:

 

 

That part of the spring under the pivot bolt (marked in red) is rubbing against the tyre. I have contacted Swift to ask them if they are aware of a flaw in the design where the brake caliper is mounted too low on the rear relative to the wheel as the front is perfect. 

 

For a frame in the high end range which specifies that 28C tyres will fit, I'm rather disappointed that a high end caliper such as the SRAM red is causing an issue. Anyone else had a similar issue? Do the latest calipers have a slightly different design to prevent this?

[shaper]

Seems to be a problem and is a combination of frame, wheel and choice of tyre http://forums.roadbikereview.com/sram/sram-red-black-brakes-28mm-tires-315728.html

[Schnavel]

Seems to be a problem and is a combination of frame, wheel and choice of tyre http://forums.roadbikereview.com/sram/sram-red-black-brakes-28mm-tires-315728.html

 

That discussion is around the old brake type, the version before the aerolink.

 

If I look at the setup, I don't think it is the fault of the caliper. As mentioned previously, the front caliper has plenty clearance with the 28C tyres, the rear caliper has no clearance, but the frame has plenty.

 

It looks to me to be a fault in the design of the position of the brake caliper on the frame. I'm wondering if this is the case only on my specific frame where the hole was drilled in the wrong place, or if all of the Ultravox frames have this issue?

[Mongoose!]

You need wide rims.

On normal rims, wider tyres are not really as wide as it should be, but "balloon" upwards causing a higher profile.  

What is the inside measurement of the rims?

[Capricorn]

slowbrain day struggling with balloons.

[Pulse]

You need wide rims.

On normal rims, wider tyres are not really as wide as it should be, but "balloon" upwards causing a higher profile.

What is the inside measurement of the rims?

.

 

Correct

[David Marshall]

Wider rims will help but there are other factors.  I have had difficulties with 25mm tires on some frames.  (Pinarello, Giant, Dedacci and Swift). Gatorskins have fitted where GP4000 have made contact.  

 

You might try a small spacer between the calliper and frame.  This will move the calliper backwards and give a bit more space.  I used a race number holder that fitted on the caliper bolt on one frame.  

 

On my Swift Attack the tire fitted ok but when I rode on wet sand the sand sticking to the tire scratched the arch of the frame.  Went back to 23mm.

[Captain Fastbastard Mayhem]

Wider rims will help but there are other factors.  I have had difficulties with 25mm tires on some frames.  (Pinarello, Giant, Dedacci and Swift). Gatorskins have fitted where GP4000 have made contact.  

 

You might try a small spacer between the calliper and frame.  This will move the calliper backwards and give a bit more space.  I used a race number holder that fitted on the caliper bolt on one frame.  

 

On my Swift Attack the tire fitted ok but when I rode on wet sand the sand sticking to the tire scratched the arch of the frame.  Went back to 23mm.

Very good, and cheap solution!

 

May need to have 2 small washers, but it should give the necessary space. 

[Mongoose!]

Very good, and cheap solution!

 

May need to have 2 small washers, but it should give the necessary space. 

 

cannot see that it will work  (as it did not worked for me : Giant TCR / 25c Michelin tyres  ) but lets wait till the OP tried it as -  each frame is different.

[Captain Fastbastard Mayhem]

cannot see that it will work  (as it did not worked for me : Giant TCR / 25c Michelin tyres  ) but lets wait till the OP tried it as -  each frame is different.

Thinking about it now - it depends on the seatstay. If the seatstays are straight, and there's no trickery going on, the brake will be pushed further outboard, which will help as the wheel / tyre falls away from the mount. Think of a ruler balanced on a ball - the further out from the centre of the ruler you go, the larger the distance between teh ruler and the ball.  

[JA-Q001]

Atleast thorns wil be scraped out before penetrating too deep

[Schnavel]

You need wide rims.

On normal rims, wider tyres are not really as wide as it should be, but "balloon" upwards causing a higher profile.  

What is the inside measurement of the rims?

 

I'm running the American Classic Victory 30 wheels (https://amclassic.com/index.php/wheels/victory-30-tubeless-pair.html) which have an internal width of 18,1mm and an external of 23mm, so not very narrow...

[Schnavel]

Wider rims will help but there are other factors.  I have had difficulties with 25mm tires on some frames.  (Pinarello, Giant, Dedacci and Swift). Gatorskins have fitted where GP4000 have made contact.  

 

You might try a small spacer between the calliper and frame.  This will move the calliper backwards and give a bit more space.  I used a race number holder that fitted on the caliper bolt on one frame.  

 

On my Swift Attack the tire fitted ok but when I rode on wet sand the sand sticking to the tire scratched the arch of the frame.  Went back to 23mm.

 

I will try the spacers, but I don't know if that will solve the problem. Will attempt this tonight and then post feedback and pictures tomorrow. 

 

There is plenty of clearance with the frame, both on the chain stays, as well as the frame wheel arch, but as the brake is sitting rather low, it catches the tread on the tyre.

[Captain Fastbastard Mayhem]

I will try the spacers, but I don't know if that will solve the problem. Will attempt this tonight and then post feedback and pictures tomorrow. 

 

There is plenty of clearance with the frame, both on the chain stays, as well as the frame wheel arch, but as the brake is sitting rather low, it catches the tread on the tyre.

Hence the spacing of the caliper itself, to elevate it slightly. 

[Cat2forLife]

Are the brake shoes/ pads sitting quite high on the rear caliper? Then you'll know that the caliper is sitting too low. If, however, they are sitting in a relatively normal place, it's not the frame.

 

I think it might be a tire/ wheel combo as well. I'm sure all the pro riding those Red calipers and 28mm tubbies didn't have issues. Then again, their crafty mechanics might have taken care of all the issues.

 

I also have a set of these brakes on my bike. Granted I only run 25mm tires, I still have plenty of space available.

 

I do have a set of 28mm tires somewhere. I'll give them a try and let you know what happens.

[Rocket-Boy]

Are the brake shoes/ pads sitting quite high on the rear caliper? Then you'll know that the caliper is sitting too low. If, however, they are sitting in a relatively normal place, it's not the frame.

 

I think it might be a tire/ wheel combo as well. I'm sure all the pro riding those Red calipers and 28mm tubbies didn't have issues. Then again, their crafty mechanics might have taken care of all the issues.

 

I also have a set of these brakes on my bike. Granted I only run 25mm tires, I still have plenty of space available.

 

I do have a set of 28mm tires somewhere. I'll give them a try and let you know what happens.

Its not the caliper that is the problem, its where the mount hole is in the frame, its too low.