Looking at next bike for the boy, I reckon at his height he's better on 27.5" wheels for a bit but there's much less options out there versus 29" for what I'd like.
By my maths, 27.5" wheels on a 29" frame would drop BB by about 19mm (the radius difference between 27.5 & 29), so given he'd be on 155cm cranks the pedal clearance would be same as a 29" frame with 175 cranks..... so basically fine. Am I missing anything?
The BB drop is way less as the BB is going to be less than half way from the rear axle to front axle. A drop of <9.5mm will be expected, the amount dependent on the front centre.
EDIT I should probably read it better you're going both wheels 27.5, in which case yes, as long as clearances at those points work, then 19mm is the drop and while short cranks will correct some of it, you get 19mm lower chainring clearance, which could be an issue. Fitting a bash guard would be advised!
I cant fit 27.5" wheels on my Sonder Signal (29) due to the shape of the chain stay yoke wrapping around the tyre at its 29" size, a 27.5" wheel physically wouldn't fit unless i fitted a super skinny tyre, might be something to look out for
benpinnick
The BB drop is way less as the BB is going to be less than half way from the rear axle to front axle. A drop of <9.5mm will be expected, the amount dependent on the front centre.
Is that for a mullet setup, or am I misunderstanding? Think the OP is looking at 27.5 both wheels
at his height he’s better on 27.5″ wheels for a bit but there’s much less options out there versus 29″ for what I’d like.
The 27.5 bikes should be the cheaper used options though?
If it's a full-sus then the amount of sag you run changes things a lot. With a 160mm bike you could run anywhere from 20-35% sag, which is a difference of 24mm. That gives you some flexibility to adjust the BB height upwards if it's too low by taking out tokens and/or reducing compression damping but increasing air pressure.
The 27.5 bikes should be the cheaper used options though?
Yeah, keeping an eye out but for what I want but the older 27.5 stuff is either nice and light but steep geo, or nice geometry but an overly heavy frame for a younger rider.
Of course his solution is a XC race bike and an Enduro bike, but I reckon a more progressive new school XC frame should be able to do both until he's a teenager! Ideal is the next size up in the HUP hardtail he currently has which does exactly what we want, but is now discontinued and no sign of any 2nd hand.
My lads just grown out of his 27.5 Giant Trance in size Small if thats any use? I thinks it a 2013 model.
I bought it with about 5 rides on the clock, the missus rode it for bit then my boy. Overall decent condition, I've kept the forks serviced as the are Overdrive and the shock. Its 1 x with an external dropper post as I had one in stock.
I was thinking £500 but open to offers and I'm in Brighouse.
@tenacious_doug what about the new hup hardtail. Gets 29 wheels in the small but not smallest size.
29" only and a bit steeper than the old one, but it's a possible if smaller wheels work (hence the original post). The plan all along was just to move him to next size up from his current HUP which is perfect, had I known they were discontinuing it I'd have bought one of the old frames last year and stored it. If you know of anyone with a 2nd hand 17" going in the next few months, let me know!