nazzurro19 Posted September 17, 2008 Report Share Posted September 17, 2008 im a little confused by what is meant by the BB rise is it better to have more mm or less mm? also things like the geometry i dont quite understand how you know that type of bike to get judged by the geometry, as you can tell im a complete noob and need a few things answered cheers guys Quote Link to comment Share on other sites More sharing options...
JT! Posted September 18, 2008 Report Share Posted September 18, 2008 BB raise is how much higher the bottom bracket is from the imaginary line from axle to axle. It can vary from -10mm to about +60ish i think. Trials bikes often have a higher bb than from other bikes. I'm not 100% sure how this effects riding though. I'll let someone else explain it to your rather than me trying to stumble though it.Head angle is the angle of your headset (what the forks and bars are connected to), it usually sits around the 72 degree mark. Again, i'm not sure how this effects riding.Chain stay 'stay' length is the length from your BB to your rear axle, long stays allow for much better leverage for most trials moves, gapping, upping, side hopping. However, shorter stays make the bike much easier to get onto the back wheel, and will live you much more control when you're up there. Shorter stays make a bike much better at bunnyhopping, and general movement of the bike is easier.WB - wheelbase is measured from axle to axle and sits between 950mm and 1100mm. Like having short stays, having a shorter WB makes the bike much more maneuverable, better at bunny hopping and good for spins etc. Long wb's will be better for tapping and hooking, gapping and side hopping and all those general power moves.There's also the Centre of BB shell to top centre of head tube, i think it's referred to as cab length? Again, not sure how that effects riding, i think it may be more of a comfort thing.Your best bet in buying a frame is porting up how you like to ride, or what you ride (street / comp / natural etc) and people will suggest a frame as just looking at the numbers alone isn't going ti be much use unless you've had half a dozen frames. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted September 18, 2008 Report Share Posted September 18, 2008 BB raise is how much higher the bottom bracket is from the imaginary line from axle to axle. It can vary from -20 to about +90ish i think. Trials bikes often have a higher bb than from other bikes. I'm not 100% sure how this effects riding though. I'll let someone else explain it to your rather than me trying to stumble though it.Higher bottom bracket means your weight is centred farther over the rear wheel when on the backwheel, hence more control. higher bb means your centre of gravity is higher= less stability on two wheels, and harder to pull thge bike up to manual, bunnyhop etc......Head angle is the angle of your headset (what the forks and bars are connected to), it usually sits around the 72 degree mark. Again, i'm not sure how this effects riding.Chain stay 'stay' length is the length from your BB to your rear axle, long stays allow for much better leverage for most trials moves, gapping, upping, side hopping. However, shorter stays make the bike much easier to get onto the back wheel, and will live you much more control when you're up there. Shorter stays make a bike much better at bunnyhopping, and general movement of the bike is easier.Pretty much.....longer stays are better for manualing as wellWB - wheelbase is measured from axle to axle and sits between 950mm and 1100mm. Like having short stays, having a shorter WB makes the bike much more maneuverable, better at bunny hopping and good for spins etc. Long wb's will be better for tapping and hooking, gapping and side hopping and all those general power moves.Yep, longer bikes are also considered more stable on the backwheel; in general shorter bikes are easier to throw aroundThere's also the Centre of BB shell to top centre of head tube, i think it's referred to as cab length? Again, not sure how that effects riding, i think it may be more of a comfort thing.More commonly known as reach....effectively how far you have to stretch, hence making the bike feel longer or shorterYour best bet in buying a frame is porting up how you like to ride, or what you ride (street / comp / natural etc) and people will suggest a frame as just looking at the numbers alone isn't going ti be much use unless you've had half a dozen frames.exactly, just try some frames and you'll start to find out your ideal geometry Quote Link to comment Share on other sites More sharing options...
eskimo Posted September 18, 2008 Report Share Posted September 18, 2008 Also if you were to have extremes of these the bike wouldn't ride to great. But people like different things and each geo can suit different styles of riding better. You've also got standover height/ clearance. But this can't really be measured as we don't have seat tube's. And head angles can effect the wheelbase and reach allot. Also words like 'easier' aren't really to helpfull when it effects other tricks/ moves/ balance, whatever...Basically you've just got to test them yourself, and play with different components to get the feel right for yourself. Quote Link to comment Share on other sites More sharing options...
forteh Posted September 18, 2008 Report Share Posted September 18, 2008 A note on chainstay lengths, shorter chainstays are easier to lift into a manual but less stable when on the balance point Quote Link to comment Share on other sites More sharing options...
nazzurro19 Posted September 19, 2008 Author Report Share Posted September 19, 2008 wow cheers guys thats a big help im more intrested in doing spins manuals and the odd big drop so ill shop around and see what bikes are going for what prices and hopefully start riding again soon Quote Link to comment Share on other sites More sharing options...
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