The difference between 622 and 630 is 8mm in diameter and 4mm in radius. The 622 pad will be 4 mm (1/6 inch) closer to the canti post than the 630. If it is within the range of the standard slot for pad mounting, it is not a problem - every pad slot on a brake arm that I have seen was considerably longer than 4mm. I would not worry about 4mm upsetting the brake balance or feel. A 650b conversion from 700c using longer side or center pulls is a much more radical change to caliper ratio, and they seem to work pretty well.
Also remember that you can play around with the cantilever straddle cable length to change the brake pull ratio - a slightly longer straddle cable will cancel the 4mm pad closer to the pivot. Don't ask me to do the math - Google Sheldon Brown. The only problem that I have ever had with a 27 to 700c is on my P-15 Paramount, normal reach Campagnolo Nuovo Record sidepull on the rear with a Campagnolo dropbolt reaches a 27 x 1 but not a 700c (nor a 27 x 1-1/4) - When you are on the limits of the brake arm slot, the rim width can come into play. Back in the mid 70s all we had was 700c sewups and 27" clinchers, no 700c clinchers. Many bicycles had greater tire clearances in the rear than the front (thus the mixed Weinmann and later Dia-Compe 750R, 610F centerpull brake sets). I actually have Dia-Compe 750R, 610F centerpull brakes on a couple of Rivendells. 750s are 14mm longer than 610s - again I wouldn't worry about 4mm if it bolts on with no modification. Laing Cocoa FL On Wednesday, August 22, 2018 at 10:50:33 AM UTC-7, John G. wrote: > Any thoughts on the vertical adjustability of the pads? Wondering if >>>> they’d suit a 27inch to 700c conversion. I guess Canti post spacing is >>>> also >>>> an issue that is have to consider. >>> >>> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
