Brakes for 700x45's

[p nut]

I'm having a custom MTB frame built currently. Maybe I've got the bug, but now I'm contemplating building up a road frame as well. I currently have a fixed gear road bike and a SS cross bike. I don't do any cross races, but I do like dirt road/singletrack rides. I currently have BG RnR's (700x43) and they're great, although I'd like the ability to run something like Panaracer Firecross (700x45). So I was thinking for the new frame, I'd essentially combine the two bikes into one. I'll keep one set of wheels for road rides/races and the other for more offroad-ish rides. One thing I'm not sure of is the brakes. I'm not opposed to canti's or discs, but wondering if there are other options. Will something like Paul's Racer brakes clear 45's? I think those look the best. If they won't work, I'd probably just stick to canti brakes or possibly discs. (Not big on V or mini moot brakes).

Also, one other question. Would there be any advantage of 130 vs 120 rear spacing?

Thanks for any suggestions.

[JAGI410]

Disc brakes don't care about tire sizes. I'm assuming you mean 130 or 135mm spacing, in which case, use 135 for discs. Or do 132.5 with rim brakes and you can use any 130 or 135mm hub you like.

Not sure if the Paul Racer's would work with 45's, but they work with 650Bx42s with fenders, so it's probably safe to assume.

[Stan Lee]

Will something like Paul's Racer brakes clear 45's? .

Yes

[p nut]

Yeah, if I go disc, I'll go 135. But if not, I'd go 120 or 130. Track frames are 120 spacing (which my road bike has now). But now typing this out, I didn't think about tire clearance with the narrower spacing. So you're right, 130 or 135.

[rperks]

Yeah, if I go disc, I'll go 135. But if not, I'd go 120 or 130. Track frames are 120 spacing (which my road bike has now). But now typing this out, I didn't think about tire clearance with the narrower spacing. So you're right, 130 or 135.

130 is fine to clear 700x45mm. If your builder keeps the stays about 45cm long there wile be no black magic needed, and many pre-bent off the shelf chain stay options will work. The Paul racers are hard to beat in terms of feel, performance and ease of setup. The only reason I would choose disk is if you are in a place where wet and mud days far outnumber the dry.

[Michael_S]

The Fire Cross is a big tire. I've read they measure 48-49 mm wide at the knobs on a 23 mm wide rim. I just had a 'mountain cross' bike frame built that will fit a 50mm real width tire so I can run the Fire Cross or Nano raptor.
https://www.flickr.com/photos/37142352@N05/5617216161/in/faves-37347002@N05/
I decided to go with Paul neo retro canti's. I was worried the Racer's wouldn't open wide enough to get the bigger tires in w/o deflating in the front with a Pacenti PBP crown. I live in So Cal so I don't have to worry too much about mud.

[p nut]

130 is fine to clear 700x45mm. If your builder keeps the stays about 45cm long there wile be no black magic needed, and many pre-bent off the shelf chain stay options will work. The Paul racers are hard to beat in terms of feel, performance and ease of setup. The only reason I would choose disk is if you are in a place where wet and mud days far outnumber the dry.

45cm is a bit too long for me. The MTB is going to have 42cm stays with clearance for 2.3's, so he should be able to get that done with shorter stays. Mud isn't an issue here, as it is considered a desert, so don't need lots of clearance. I still may go for discs, though.

The Fire Cross is a big tire. I've read they measure 48-49 mm wide at the knobs on a 23 mm wide rim. I just had a 'mountain cross' bike frame built that will fit a 50mm real width tire so I can run the Fire Cross or Nano raptor.
https://www.flickr.com/photos/37142352@N05/5617216161/in/faves-37347002@N05/
I decided to go with Paul neo retro canti's. I was worried the Racer's wouldn't open wide enough to get the bigger tires in w/o deflating in the front with a Pacenti PBP crown. I live in So Cal so I don't have to worry too much about mud.

Thanks for the input. I will have to contact Paul to see what the max clearance is like.