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2) Thought about lowering the BB to 270mm high. I don't like pedal strikes, and have the habits of fixed gear pedaling almost constantly, but as this one will be geared and I read that low BB is preferable for bike stability, I thought it could be good to lower it. But I don't want to have it too low either ; so what are the advised BB height for this use? is 270mm coherent? is it really necessary to lower the BB?
) Thought about lowering the BB to 270mm high. I don't like pedal strikes, and have the habits of fixed gear pedaling almost constantly, but as this one will be geared and I read that low BB is preferable for bike stability, I thought it could be good to lower it. But I don't want to have it too low either ; so what are the advised BB height for this use? is 270mm coherent? is it really necessary to lower the BB?
I've done a bit of reading on the subject. A low BB certainly gives a more planted feel and interestingly it seems that a lot of custom bikes have a bigger BB drop than OTP. Some (most?) of it might be more psychological than pure physics, but for example a modern US geo CX bike feels more stable than an old school euro one.
270mm is a bit high for a rando bike IMHO, with no benefits, but if that's what you prefer go for it. Or, as always, let the builder do its job.
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Lolo
Hulsroy
Not sure this is the best place to ask about frame geometry, feel free to redirect me to the correct thread.
I have a current bike that I quite like how it rides, it is a 650B fixed gear custom frameset that I based on another bike with slight tweaks.
Current main specifics are:
I am beginning to think about a kind of rando bike inspired by french 650B bikes, to start making longer rides in tarmac and light dry gravel ; and I would like to base it on the current custom frame I have with adjustments:
1) Thought about changing the headtube angle to 73.5°, but with changes in fork rake to have the same 42mmtrail, this would help me limit toe overlap (already using 165mm cranks) without changing how the bike steers as I quite like how it is now. Is this coherent or the reasoning is wrong?
2) Thought about lowering the BB to 270mm high. I don't like pedal strikes, and have the habits of fixed gear pedaling almost constantly, but as this one will be geared and I read that low BB is preferable for bike stability, I thought it could be good to lower it. But I don't want to have it too low either ; so what are the advised BB height for this use? is 270mm coherent? is it really necessary to lower the BB? I guess it can also help to increase stack and thus comfort. Is it coherent thinking?
3) Current seat tube angle is 75°, what would be a benefit of changing it? Currently my fixed 650B has porteur bars as I always feel too stretched on drops, but I believe this is also due to the drop between saddle and handlebars. Basically I need a frame that is taller than long similar to @edscoble 's bike in this thread I believe which is another reason to go custom. Would 75° be problematic for a randonneur frame, as it is my current set-up, or it won't have any impact at all?
Thank you in advance for the advises