BB Height Importance?? (gravel bike content)

I’m hoping to come into an injury claim windfall in the next few months so I’m starting to think about a new gravel frame. Need to dip into the stw hivemind for some advice

I’ve had a Whyte Glencoe in the past which with the 650b wheels that came with it had a BB height of 265mm which felt low and solid although sometimes annoying for pedal strikes. I am currently on a Day One set up fixed with a BB height of 267 which feels about right.

I am looking at a Pipedream A.L.I.C.E frame which is longer and slacker but has a BB height of around 315mm with XC tyres on, does this seem too high for STW or am I being a fanny worrying about this?

I worried about it when considering a CX frame as a gravel bike.

I was looking at BB drop though, e.g. how much lower it is compared to wheel axles.

I wanted a gravel/road BB drop of 70-75mm but frame came with 60-65mm (I forget which, may even have been 63mm or something).

Either way, I accepted it as a compromise but have never thought about it since, bike handles like a dream in every scenario, and higher BB probably advantageouswhen my optimistic route planning takes me a bit further off-road than intended.

Read up on pedal stack heights also, you might be surprised at differences, my Time ATACs are about 7mm lower than the Look Keos on my road bike, which eats into the difference in BB drops from a centre-of-gravity point of view.

…it had a BB height of 265mm which felt low and solid although sometimes annoying for pedal strikes…blah…with a BB height of 267 which feels about right.

Slightly confused by this bit, you found 265mm low and annoying for pedal strikes, but 267mm felt about right?

That’s 2mm, within a measuring error and not really something you would be able to discern. Was there another factor at play such as crank length? ie: were the cranks on the fixed shorter? (they often are) or were the tyre sizes significantly different enough that the extra sag/squish in the tyres was lowering it further?

FWIW you need to take ALL factors into consideration. Pedal stack height, Pedal platform width, crank length, tyre size (and pressure), crank Q-factor can also play a part as wider Q can result in more pedal strikes when leant over.

As an extreme example, if you take two bikes with a static BB height of Xmm, and one is on 2.4in MTB rubber @20psi, and the other is on 32mm gravel tyres @50psi the ‘working’ BB height will be different between them before you even throw any other factors in like propensity to clout wide Q 175mm cranks with big wide flats Vs 165mm low Q and SPDs.

Overall though you can (and will) get used to fairly big differences, the problems come when you swap between different bikes and then ride the same trails before your brain has re-adjusted 😉

Fwiw, my Arkrose BB means I clip a wooden step that I can ride over on my old Soul, and it preys on my mind every single ride on that route….

Slightly confused by this bit, you found 265mm low and annoying for pedal strikes, but 267mm felt about right?

I was also confused. 2mm difference is not noticeable, whereas new frame of 315 is 5cm higher, 5cm is massive.
Sitting 5cm higher off the ground is very noticeable and should have a bearing on that choice of frame.
I ride track frames which are typically 10-15mm higher BB than road frames and that is noticeable and it feels a bit more like sitting on the bike rather than in the bike. Given the choice I would have the lower BB but when riding fixed on single track pedal strikes are unavoidable so going lower is not sensible.

@amedias

Haha yeah just realised reading that. You’re right it will be the crank length that will be causing the pedal strikes I had issues with before. Probably the 650 wheels on the Glencoe made it feel much lower and stuck to the ground.

Thanks for the input here, I feel like it shouldn’t make a big difference once I’m used to it.