"I find the advantages of the 650b conversion to be huge (cushy tires and fender clearance), and the risk of pedal scrapes to be a minimal disadvantage. ATMO."
Also, just in case you want or need corroboration from somebody not-named-Grant, check Bicycle Quarterly when they do the review of the Lyon L'Avecaise. They loved it, and it had a BB height lower than even Grant's "safe minimum" of 260mm, and that is a purpose-built 650B race bike. I don't have it in front of me, so I forget if it was 256 or 254mm, but it's in the 250s and they LOVED it. Disclosure: Even though Jan loved that bike and even though that bike had a low BB, Jan pretty emphatically states elsewhere that BB height has almost nothing to do with ride quality. Conventional wisdom is a lower BB height gives more stability. Jan pretty convincingly debunks that. Lower BB height doesn't do much of anything. It's neutral. You don't *need* a low BB, and you don't necessarily need to be scared of a low BB. Maybe 250mm should be the new safe minimum for conversions? On Thursday, December 5, 2013 11:47:09 AM UTC-8, Tim Gavin wrote: > > Gen 1 Riv Roads have 80mm of drop, for a BB height of 260mm (according to > the early catalog) > http://www.campyonly.com/images/mystuff/2006/rivendell_road/rivendell_catalog_3.pdf > > That BB height is measured on 700x25c tires. Converting to 650x38 equals > a frame drop of 6mm (19mm smaller wheel radius, 13mm larger tire), for a BB > height of 254mm. Not a huge difference. > > But in the same article, Grant already warns about pedal clearance in > corners. Lower the bike by 6mm and you should be very conscious of pedal > scrapes. Gaining back 5mm of that clearance with shorter cranks isn't a > bad idea. > > I find the advantages of the 650b conversion to be huge (cushy tires and > fender clearance), and the risk of pedal scrapes to be a minimal > disadvantage. ATMO. > > Tim > > > On Thu, Dec 5, 2013 at 1:19 PM, Greg J <[email protected] <javascript:>>wrote: > >> I'm pretty sure the early production Riv Roads had 75mm drop. I also >> vaguely recall Grant mentioning how he increased the drop on the >> Rambouillet, maybe to 78mm? >> >> Greg >> >> -- >> 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 [email protected] <javascript:>. >> To post to this group, send email to >> [email protected]<javascript:> >> . >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/groups/opt_out.
