Originally Posted by
mountaindave
Sorry for the confusion. '79 Trek 710 has 38mm Loup Loup Pass (accurate claim) Compass tires. '91 RB-1 has 38mm Soma B-Line tires (38mm claimed, 36-ish actual). How it fits all depends on the shape of the chainstays. I could get 700c 28mm tires on it, but the chainstay geometry doesn't spread out very fast behind the BB.
For the pump, I found a frame clamp peg, cut it down to the diameter of the seat stay and installed it. The peg part is located at the bolt so it was not too hard to cut it down, drill a new hole and mount it. Getting the length correct is the hard part. A little short isn't terrible, just open it up. But too long and you can't just redrill, you just end up making the bolt hole bigger so you have to use a shim instead.
FWIW, I haven't ever experienced pedal strike, but I don't often power through tight, fast corners.
If you're running a 650b x 38 mm tire or larger, pedal strike should be a non issue since that wheel and tire will have roughly the same diameter as a 700 x 20c (or perhaps a bit larger). The online sites are not in agreement on this when it comes to measuring wheel diameter but this is close enough.
This is very useful. I have a 1979 Trek 510 hanging on a hook in my workshop that I was thinking of using for a 650b conversion. I measured it out and thought it would work fine based on the measurements but it's good to know that you managed 38mm tires on your 1979 Trek 710. The 1979 710, 510, and 910 all have the same geometry; the difference is in the tubing. Do you think you could fit a 42 mm tire on your 1979 Trek 710?
And I'm really surprised (pleasantly) that you managed 38 mm tires on your 1991 RB-1 but your bike may have more clearance than my 1993 RB-1. I'd switch over in a heartbeat to 650bs if I could fit a 650b x 38mm tire on my RB-1 . . .