Mr_Orange

Got it. you, when reading through threads, it seemed like most people say the higher BB is easier for trials stuff, but there were also a few people defending the lower bb too. Is there such a thing as short chainstay + very low bb? How that would feel like? I ran across this: http://www.pinkbike.com/news/Bike-Check-Stout-Sigma-136-2012.html. It's a 26" bike with 13.6 chainstays. They did this by cutting a groove into the BB (you can see in the pics). Say you took that same style frame construction (with the BB cutout thing) and did a 24" wheel version. This means you can have a 24" bike with 12.6" chainstays (there are bmx frames this short and commonly used too). However, unlike a bmx frame which has BB rise, you give this a 20mm BB drop. So 24" tires, with 12.6" chainstays, and a 20mm BB drop. I wonder if the BB drop will give you the same extra leverage bunnyhop feel of a longer chainstay bike, while short chainstay gives you the benefit of a much shorter wheel base for spins.

I only have vague glimpses into the trials world from just browsing videos online so please excuse my naivete. I definitely get the whole 'trials is more about being on the back wheel' thing though. And yes i get that BB rise refers to height above the imaginary line across the two wheel axles. Isn't there stuff though where guys are riding across really thin hand rails or thin train tracks. Doing 180s and landing back on the same thin rail. That's why i thought 2 wheel balance might've been equally important. Also, there's guys doing pretty much street bmx tricks on those 26" octane frames. It's not just a dirt jumping thing. So what's the deal with those Inspired frames. I guess it would be nice to have something where i can do street bmx type tricks along with trials stuff too. Is that what I'm looking for? Are there other companies like Inspired?

I ride bmx bikes and the bb height range is from 11.5 inches to 11.8 inches off the ground, and people even have particular preferences between such a small spectrum. When looking at even just mod frames, it goes from +50 all the way to +90mm. And when you factor in the extra height of 24" and 26" wheels, it seemed like trial riders are on a huge range of bb heights. I was originally looking at 26" dirt jump bike frames like this http://octane-one.com/void/, which has a bb rise of just 3mm. I assumed the reason the bb rise was so low was to take into account the extra wheel height, lowering you to a more tolerable elevation closer to where the bb's on bmx bikes or 24" bikes are. Then when i looked into 26" trial frames with bb's ranging from +10 to +70mm, it seemed like that all went out the window.

So you're saying as long as your bars/stem is in an ideal position, that'll make all the difference in balance, despite being physically higher up? What if you really exaggerate this idea and made a bike with 60 inch wheels. Your saying as long as your bar/stem position is ideal, the lateral stability is really not going to be affected by you bb being that high up? Are you really not loosing any lateral stability by being higher up in terms of actual physics, or are you just saying that this 3 inch difference isn't so hard to get use to as long as your bars are in your comfortable ideal position; even though there actually is a slight loss in lateral stability.

Do stock bikes feel like they have a very high bb? I'm mainly concerned with lateral (side to side) stability/balance. Tracking standing. Riding through narrow sections. A mod bike with a bb of +70mm is really placing you 70mm + 10 inches (from ground to axle center of a 20" wheel) off the ground right? But a stock bike frame with +70mm bb would be 70mm + 13 inches (from ground to axle center of a 26" wheel). Like this frame: http://www.tartybikes.co.uk/26_inch_frames/b1k3_eklipse/c14p12701.html That's an additional 3 inches right? So isn't that supposed feel like riding a mod with +146mm bb? Are stock's just way harder to balance side to side than mod bikes?