I’m building up a frame and have a few options regarding headset, forks and adjustable shock position…

Current trends say everything needs to be slack and low, but how low is too low?

Too low is too low.

How low too low is will depend on your weight, ridng, terrain, prefered shock setup etc etc etc.

My pitch (pretty low) is good for me because I run it about 28% sag with the propedal on so it rarely bottoms out and tends to sit at quite a consistent level.

I got used a 13″ BB on my my Marin. Everyone says ‘but that high makes the cornering rubbish” I say it’s barely noticable and I hate the lower bikes on anything techy, too many pedal strikes and I’ve got a big ring, not a bash…

As above, low bottom brackets may be great for stability and cornering but compromise ground clearance.

Yeah I know it subjective, Depending on setup I can go anywhere between 12.5″ and 13.6″ with 5″ of travel at the back.

What is the lowest BB you’ve seen on a 5″ bike?

I’ve no idea how low it is on mine now. Pretty damn low. It works for me though it does scrape out a bit earlier than other bikes I’ve had.

But ideal? no such thing, it’s all a compromise and ideal for you depends on where you ride, how you ride it… Amount of travel the bike has and its wheelbase have to play a part too. And all the rest of the geometry which adds up eventually to how it handles.

My first post is badly worded but what I’m really trying to work out is at what height do things get unrideable due to unavoidable pedal strikes. What would you consider to be stupidly low? I was thinking just under 13″ would be about as low as you would want to go but wanted to gather other opinions….

Remember, it’s not all just about the quoted angles and measurements either. Tyre sizes can have a marked effect on things such as BB height given there seems to be no standards on how to actually measure a tyre properly from one manufacturer to the next.

It depends on the bike, is it a hardtail or full suss?

As others have said, tyre size and the amount of sag you’re running has a large effect on the dynamic BB height.

(assuming FS as you mention a shock) also the height of it the bike in a static position is not going to be the same with you on it and the sag taken up.

It’s just a number. A good bike with a high BB is still a good bike, a crap bike with a low BB is still a crap bike.

i had a bike which you could touch the ground with your heel. had to buy shorter cranks. thats too low. 08 meta 5.5 btw.

I think 12″ (sagged) seems about average/low as the pitch is 14″, so 6″*33% is 2″, 14″-2″ is 12″, which is pretty much where most bikes seem to be.