I’m just a recreational rider doing gravelish type stuff and am a little clueless when it comes to frame geometry. All my previous frames have had fixed BBs but I treated myself to a Singular Swift and now have an eccentric bottom bracket to play around with. The trouble is I don’t really know how BB placement will affect things (or indeed whether I’d even notice with my low grade pootling).

Fore and aft presumably alters the chainstay length and up and down the BB height (I can’t drop it too low as I’m still running a triple and need the front mech. to clear the chainstay). Are there any advantages to tweaking it, is it just a case of trying and seeing or should I forget about it and just ride the thing?

should I forget about it and just ride the thing?

It’s about a 12mm circle, so only really +/- 6mm from the center.

I could feel the difference, but it’s not really completely ride changing. It’s there to adjust the chain tension when running singlespeed.

It will make **** all difference, even to those who claim to be able to feel it.

(Same answer as when you asked the same thing recently?).

It’s there to adjust the chain length for running SS or hub gears, see above. It’s used to prevent a slack chain from falling off too easily.

Thanks for the replies and fair enough, I’ll leave it where it is for now.

Don’t listen to those cynics, have a play.  What’s the worst that could happen?

the Jones plus I had breifly came with the EBB at 12 O’clock – I rotated it to 6 O’clock (ie lowest point) and it made a big difference to me to how the bike rode. Have had many EBB bikes down the years and currently have 2 and its not made a huge difference, apart from the Jones, but yeah, experiment and find what works for you.

When I had traditional gears I always ran mine in the lowest possible position. But I fairly swiftly moved to a internal hub gear and used it for tension. Cant say I noticed any real difference in handling……

It can be handy to twek if you have a problem.

Toe overlap (not an issue on the Swift, I’m sure) – shift it back

pedal strikes – shift it up

feeling gangly on the bike and want more planted handling – shift it down,

knee problems – could be anything, it helped mine to shift back

want to be over the pedals more for a steeper effective angle for climbing –  shift it back

Any combination of the above.

As other’s have said, it’s not a huge adjustment, but it might help optimise some things is you want to optimise some things.   If you’ve got not problems to fix, run it at the bottom.