so i have a 2010 xprezo furax with a fox 40. 26" wheels. a former teammate had mentioned that he was able to fit 275 wheels in his so that got me curious about trying it. should also add, aside from the wheelsize and overall length/reach (wheelbase is 46.75"), the geometry of the bike has aged pretty well by modern standards.
a local buddy let me borrow his 275 dh wheels to do a test fitment. and sure enough, there was plenty of clearance in both the fork and the frame. i did measure the BB height with it, and woof. it was a bit over 14.5". with the 26" wheels it's about 13.5" as it stands. so it increased the bb height by just over an inch, which is more than just the wheel size change itself. his tires were a fair bit bigger than mine. bontrager g5 2.5. i've got michelin dh34 in 2.4 on my 26" wheels, but those are a small 2.4 and not a very big casing. so i'm kind of assuming that the roughly extra quarter inch of height was just due to tire size (based on 275 rims having 0.75" larger radius / BSD).
the other thing i remembered is i was messing around with head angle at the end of the season, and had the stanchions of my 40 pushed as low as possible, and the head angle was something silly - about 61°. so i pushed the stanchions back up until the head angle was a more reasonable ~63° and that dropped the bb to about 13 3/8".
so with that correction, and assuming i'd be using the same tire if i built up 275 wheels, the bb height would still be a hair over 14" (i'd guess about 14.125"). would that still be worth it? at what point is it just too high? i'm not racing anymore and aren't going as fast as possible, but i don't want it to ride like crap because of the extra bb height.
a local buddy let me borrow his 275 dh wheels to do a test fitment. and sure enough, there was plenty of clearance in both the fork and the frame. i did measure the BB height with it, and woof. it was a bit over 14.5". with the 26" wheels it's about 13.5" as it stands. so it increased the bb height by just over an inch, which is more than just the wheel size change itself. his tires were a fair bit bigger than mine. bontrager g5 2.5. i've got michelin dh34 in 2.4 on my 26" wheels, but those are a small 2.4 and not a very big casing. so i'm kind of assuming that the roughly extra quarter inch of height was just due to tire size (based on 275 rims having 0.75" larger radius / BSD).
the other thing i remembered is i was messing around with head angle at the end of the season, and had the stanchions of my 40 pushed as low as possible, and the head angle was something silly - about 61°. so i pushed the stanchions back up until the head angle was a more reasonable ~63° and that dropped the bb to about 13 3/8".
so with that correction, and assuming i'd be using the same tire if i built up 275 wheels, the bb height would still be a hair over 14" (i'd guess about 14.125"). would that still be worth it? at what point is it just too high? i'm not racing anymore and aren't going as fast as possible, but i don't want it to ride like crap because of the extra bb height.