|Why are track bikes built with higher BB's?||timfire|
Nov 22, 2002 11:30 AM
|I have heard that Track bikes have higher BB's for better pedal-clearance, and it seems logical at first. But watching the world-championships last night, it seems that on the turns in the velodome, since the track is slanted the riders aren't neccessarily that far off from perpendiculer to the track.
I must say that I've never ridden in a velodome, and that might be my problem. But watching video of track races it doesn't seem like pedal clearance would be that much of an issue.
Do I just not know what I'm talking about? Is the video misleading? Is it a "better-safe-than-sorry" measure? Is there another reason for the high BB?
|re: Why are track bikes built with higher BB's?||JBergland|
Nov 22, 2002 11:49 AM
You are correct in some respects. When a someone is carrying a good amount of speed, pedal clearance is not that much of an issue. However, you are not ALWAYS going 20+ MPH and every bit of clearance helps. Our track has close to a 45 degree banking... even at 25+ MPH riders are not perpendicular!!
|re: Why are track bikes built with higher BB's?||eddie m|
Nov 22, 2002 2:53 PM
|When sprinters do a track stand on high banked turns, the outside pedal sometimes can touch the ground. It's not a problem if they are moving fast enough to lean into the turn, but sometimes they go very slowly looking for an advantageous position for the sprint finish. If you opponent puts a pedal down and falls, that's the most advantageous position of all!|
|They're not always going race pace ...||Humma Hah|
Nov 23, 2002 7:41 AM
|... I've ridden slow laps on a relatively shallow-banked velodrome (San Diego's) riding behind a group of track racers who were practicing racing. They'd typically crawl around the track at an amazingly slow speed until, usually sometime leading into the bell lap, one of 'em would decide to start the sprint and they'd shoot off into the distance.
On those slow laps, my relatively low-BB cruiser's pedals would clip the track surface on the corners unless we were doing at least 12 mph. Sometimes they were as slow as 8. That's on about a 30 degree bank. On a 45 degree bank, it would have been hopeless to try to pace with them.
Nov 23, 2002 12:50 PM
I'm glad to see some of you have ridden on San Diego's Velodrome. I recently finished a track class at the velodrome and I love it. My question is this: I'm 6'1" and use a 175mm crankset on my road bike and I've been told that I should use a 165mm crankset for the track. Isn't that a bit extreme? Depending on the track, could I get by with a 170 or 172.5mm crankset instead?
Nov 23, 2002 6:06 PM
|The 165's would be useful for a pure sprinter and most omnium or mass start racers. So much of track racing is about accelerating quickly and spinning fast. Longer cranks are good for higher gearing and power, like a kilo TT racer might need. Most of us start out riding mass start races like miss-n-outs, points races, snowball, unknown distance, and several others. The associated varying pace and accelerations are best handled by a gear and crank that we can accelerate quickly, as well as a general purpose track bike. Unless you ride a super steep banked track (who knows what other tracks you might race at?) or matched sprints, you might be able to use a 170 with no problem. Talk to the more experienced racers and coaches you meet at your track for their input before you buy.|
|I'm guessing you used a loaner Madison ...||Humma Hah|
Nov 25, 2002 6:26 AM
|... for that class, or one of the other rat-bikes from the trailer? Check to see what length cranks it used ... probably 165's.
I tried 160's on the cruiser for a while, in an effort to improve its ground clearance when riding off-road. I was amazed how well they worked and how comfortable they were, and still have my off-road chainwheel rigged with them.
Depending on the frame, 175's are likely to clip the surface on at least some tracks when your competitors decide to pace slowly. I visited the Trexlertown Velodrome recently and was amazed at how steep it is. If your competition discovers you can't crawl thru the corners, they may force you to do it just to bug you.