Bicycle Mechanics - Brake Caliper sizing

Here's a question of opinion:

The brake reach that my bike requires is 47mm. I've found that almost all the calipers I've looked at come in two "reach" dimensions: 39-49 and 47-57.

Since I can run either, would you recommend leaning towards big or small? To provide one more piece of info, I intend to at times run tires as wide as 28mm (the widest the fork will accomodate). I don't know that leaning "big" will make a difference there, since for the most part only the reach changes. But I may be wrong.

One of the few exceptions I've found to this sizing convention is the Nashbar Long Reach Brake (http://www.nashbar.com/profile.cfm?category=600069&subcategory=60001014&brand=&sku=11499&storetype=&estoreid=&pagename=Shop%20by%20Subcat%3A%20Road%20Brakes) which is stated to have a reach of 41mm to 56mm. I'm right in the heart of that range, but it's such an "oddball" size compared to everything else I kind of wonder about it. I know that most Nashbar brakes are re-branded Tektros...but I don't think Tektro makes a caliper in that "tweener" reach dimension.

Your thoughts are appreciated!

Cheers!

Nothing?

Oh well...

I would go with the larger of the two, the 47-57. That gives you more options later for bigger tires or fenders, and there are no real downsides.

You might want to doublecheck that 47mm measurement. Old bike designed for 27" wheels or ?

If it was my bike the decision would be driven by the rest of the equipment on the bike.

I'd probably go with the Nashbar brake for a budget build and a standard reach 105 (or nicer) if that would match the rest of the components on the bike.

A longer reach brake isn't going to give you any more fender or tire clearance because the brake pad location will be dictated by the rim diameter. Likewise, a shorter reach brake won't give you more brake leverage or power for the same reason.

Operator,

It is an old bike designed for 27" wheels. I've measured a few times now...just to be sure. Measure twice, cut once!

Retro Grouch,

That's kinda what I was thinking (rim diameter) but I wanted some confirmation. That being the case, it may be best to just go with "standard" 39-49mm reach. I'll fit that window. I'll probably go with Nashbar or Tektro anyway, though I would love to go with 105 to match the crank and headset...but I'm running out of budget room and the wife is starting to get upset with how much money I'm putting into this free frame.

Operator,

It is an old bike designed for 27" wheels. I've measured a few times now...just to be sure. Measure twice, cut once!

Retro Grouch,

That's kinda what I was thinking (rim diameter) but I wanted some confirmation. That being the case, it may be best to just go with "standard" 39-49mm reach. I'll fit that window. I'll probably go with Nashbar or Tektro anyway, though I would love to go with 105 to match the crank and headset...but I'm running out of budget room and the wife is starting to get upset with how much money I'm putting into this free frame.

Ok, I now agree with RG, there won't really be any clearance advantages to the longer reach brakes.

However, I advise you to be very sure the 39-49 will reach (it sounds like you are very sure). I bought some 39-49 brakes for my early 80s Univega Sportour (came with 27" wheels and recessed mount in front) and the brakes didn't reach. I had to grind out the slots by about 2mm so the pads would reach.

I tried using the same brakes on my '81 Trek 710 that I converted to 700c, and they didn't reach even with the grinded out slots. I guess that's really why I recommend the larger brakes; you don't really lose anything and you will have more functional adustment.

Free frames get expensive fast, that's for sure!

[QUOTE=Banzai;6205137I'm running out of budget room and the wife is starting to get upset with how much money I'm putting into this free frame.[/QUOTE]

I hate when that happens.

Thanks for the input and feedback, guys. The biggest question mark I had was about the longer reach brakes giving extra tire room. (I've only ever used/worked with "short reach" calipers.)

I went ahead and got the Nashbar Silver brakes in the short reach, since I'm in that range and they look nicer than the Long Reach brakes.

Free frames do get expensive fast.

By the way, I looked on Tektro's website and they have a new brake QR that swings the arms extra wide for large tires...but only on their 47mm+ calipers.

Again, thanks for the replies!

Last time i used short reach tektros on a 27" -> 700c and they were barely just barely wide enough.

The long reach brakes may allow you to fit a smaller diam 700c with wider tyres and fender clearance.