Caliper brake recommendations for 35mm tires

[Bob Warner]

I currently have Shimano BR650 calipers on my Riv Roadeo, and have to deflate the 35mm tires to remove the wheel.  I'm looking for recommendations for calipers that would open wide enough for the RH Bon Jon Pass tires I'm using (35mm wide).

I believe the Velo Orange Grand Cru calipers would accommodate these tires.... any thoughts on these?

Also, not sure about Paul Racer M's??  I appreciate the wisdom and insight of the forum!!

thanks!

Bob

[iamkeith]

I hope I have these model numbers correct and not transposed, but the Tektro R539 was originally designed by and for Rivendell, as the first "Silver" branded brake.  It was designed specifically for this purpose - as an upgrade for Rambouillets and Romuli and Redwoods, etc, which were designed to fit 33-37 tires, at at time when medium-reach brakes were few and far between.   Tektro eventually started selling them to anybody.  I'm not sure why Rivendell doesn't still carry them, but does still carry the even-longer-reach R559.  At any rate, they're still available but it might take some looking to find some in a proper silver finish.  I don't think I'd ever rave about any caliper brake, but have them on my Ram and they are fine and do what you are looking for.

[Ryan]

I have 32mm Stampede Pass tires on my Rivendell Road. I realize they're not 35mm. I also have Grand Cru brakes and TRP road levers with the additional QR button, for additional slack on the inside of the brake hoods. Maybe that combo could work? Don't have a wheelset with 35 mm tires ready to hand to tell you for sure, however, unfortunately, but maybe someone else on the list has this brake/lever combo AND >= 35 mm tires and could tell you for sure. One reviewer on Orange Velo site  mentions that the Grand Cru  brakes on their own don't release enough to mount a wheel with a 35mm tire...but in combo with the TRP levers, they just might clear your 35mm tire. Functionally and aesthetically they are a nice combo.

[Benz Ouyang, Sunnyvale, CA]

Ryan's recommendation of doubling up on QR with QR on the calipers and QR on the levers is probably your best chance of getting adequate clearance. I have a similar setup with Grand Cru brakes and Campagnolo Ergopowers (with the built-in QR).

One thing you didn't mention is what rims you're using. The narrower the rim, the less the QR is able to clear wider tires when opened. As an extreme example, if you're running 30mm rims with 35mm tires, the QR only needs to nominally clear the 5mm difference. However, if you're running super narrow 19mm rims with the same 35mm tires, you're looking to clear 16mm of "tire bulge", which is more of a challenge.

[Bob Warner]

Thanks for the many suggestions!  My Roadeo is currently setup with Shimano 105 brifters, so unfortunately the road lever QR functionality is not an option.  Perhaps I'll look into the Tektro 539 option.  I've heard great things about the VO Grand Cru's, and think they look really nice too; so would love to go that route if I could confirm the caliper width when open up with QR.

[Bill Lindsay]

"if I could confirm the caliper width"

This depends mostly on you and your setup.  The four things that depend exclusively on you are:

1. How wide is your tire, really?  There's some objective measurement, lets call that X1

2. What width of brake pads do you require to "clear" that tire?  Let's call that X2.  Is X2 1mm larger than X1?  Or are you OK with forcing it out a little, so that X2 is a little bit smaller than X1?  

3. How wide is your rim?  That's X3

4. How wide do you choose to run the brake pads relative to that rim width?  Some generations of 105 brifters are high mechanical advantage levers.  They pull very little cable.  Combine that with things like small hands and the desire for hair trigger barking and you might run your brakes super close to the rim.  Let's call this X4, which has some relationship to X3.  So it depends on you in two ways.  

The only thing a person with Grand Cru calipers can tell you is how much the calipers open when you throw the QR from the closed position to the open position.  I've got a bike with Grand Cru calipers.  I threw it on the stand for you and pulled the front wheel.  It barely gets out with some force.  A solid whack with my fist and out it comes.  Not enough of a problem to worry about knocking out the brake adjustment, but it's pushing it.  

My tire measures 33mm actual width.  X1 = 33mm

My rim measures 23mm wide.  X3 = 23mm

My brake pads with the QR closed measure 26mm wide, 3mm wider than the rim width.  X4 = 26mm

When I throw the QR to the open position, the brakes open up just a tiny bit to 29.5mm.  X2 = 29.5mm

So the DIFFERENCE between Closed and Open on Grand Cru calipers is 3,5mm as-measured on my front brake.  X2 (29.5mm) is quite a bit smaller than X1 (33mm) so that's why it is hard to remove the tire.  I knew this would be the case when I pulled the build together and I feel that road bikes with caliper brakes and wide tires should have a brake-lever QR in addition.  My build uses Campagnolo brifters, which I gutted so they are just brake levers.  I have a QR button, and that button allows X2 to grow from 29.5mm out to 32mm.  That allows pretty easy front wheel removal: the tire just squeaks past the brake pads with a little friction but I don't have to whack it, like I would if I didn't have a brake lever QR button.  

If I hypothetically had Shimano brifters and if I wanted to earn myself another couple of millimeters without ditching my brifters, a few options would include:

-run wider rims, increasing X3 and correspondingly increasing X4, which will grow X2 as well

-consider running the brakes looser from the rim

-consider using the barrel adjuster as an auxiliary QR

-consider running an inline QR mechanism, like the Shimano SM-CB90

That's what I've got for you.  

Bill Lindsay

El Cerrito, CA

[Bob Warner]

Wow Bill!!  Thanks for this!  Very helpful.... really appreciate the analysis!