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When setting up an EBB what are your experiences of having the BB axle on the high side or the low side?
Recommendations?
I always think that about 1:30ish at the driveside minimises slippage. But I haven't got the maths to prove it at hand.
Low definitely. With a high BB, gravitational effects as you stamp on the pedals will tend to force it downwards anyway. Made worse by increased g-forces when shredding berms as a result of the high BB making you think you're on a long travel bike.
High forward position as brant says, chain tension will act against slippage. Never had mine slip from there on the SS mtb or the tandem
Chain tension pulls the BB back about 3x harder than you can push it down. So the best place is about (looking from the drive side) 2 o'clock or 8 o'clock so that chain tension is pulling it back and working against your weight pushing it down.
In reality that's nigh on impossible to achieve that exactly so anywhere high/forward or low/back is better than high/back or low/forward. The difference between going high/low is probably about 5mm on average, and it's only 10mm if the chain tension puts your right in the middle, so it's rarely going to be enough to alter the handling.
Textbook reply TINAS.
Thanks!
for chain tension I think that's what I aim for. If you're fine with the tension being retained anyway, then it depends on purpose to some extent - CX / VC stuff you'd want a neutral or a bit higher BB to clear rock strikes (if you're as clumsy as me, anyway) but for touting then maybe a bit lower for slightly lower COG and stability.
Then you're into saddle / seat post height and crank length variables, too.
Does anyone tweak their saddle height after moving the EBB? Can't say I do, but I do notice it sometimes.
Mine's been at about 10:30 from the driveside for a while, to combat pedal strikes and steepen the seat angle. Currently running it geared, so it's not been moved for ages. Never had it slip.
Mine's set at high as it'll go (ie 12 o'clock), running gears because when I had a front mech (double specific), it would clash with the chainstay unless I had the BB mounted as high as it would go. It's never moved.