Track TT vs Keirin frame
My 16 yrs old son has been competing regularly in road and road TT cycling events. He wish to do some track cycling. I know that the road vs TT road frame has a different seat tube angle. Does this apply to velodrome cycling too.
Or is it???
The geometry from a track frame to a road frame is drastically different. Even within track some geometries can be different.
The TT frames generally have much steeper angles than anything else, track bikes included. The exception to that are TT bikes for the track, otherwise known as pursuit bikes. These can often be essentially identical to their road-going brethren, just without the derailleurs and brakes, etc.
For general track use, the bikes are actually quite similar to standard road bikes. Often they will be a degree or so steeper than the typical road bike, with less fork rake, but for the longer races (points, madison, etc.) the appropriate track frame can again be just about identical to a standard road frame.
If you are wondering if one of your son's existing bikes will work for the track, the answer is that it depends. Road bikes are safe to use on relatively shallow tracks -- those with less than 30 degree banking. They are not safe to use on any track if other people are riding brakeless track bikes on it at the same time, because the ability to coast and brake endangers those without those abilities. And they are not safe to use on tracks with steeper banking, as the relatively low bottom bracket and long cranks on the road bike substantially increase the risk of striking a pedal on the banking which can cause a crash. But by himself on a shallow track, your boy can give it a try, if the manager allows it.
If you are considering buying him a track bike, don't worry too much, and don't spend too much. A simple steel or aluminum frame with no gimmicks will do just fine, and if junior takes to the game, it can easily be traded off down the road.
A keirin frame, btw, is a specialized track frame, except when it isn't.
A true keirin frame is essentially a sprint frame, with fairly steep angles (+/- 75 degrees or so), minimal fork rake, and very stiff tubing. It is also approved by the Japanese keirin society, which is a very conservative group, so the bike will be lugged steel with spokes wheels and traditional equipment.
On the Japanese keirin circuit, that is the only type of bike you will see. On the international circuit, people ride all sorts of bikes, including standard points/madison/omnium bikes and the latest swoopy carbon aerodynamic wonder bike.
Japanese Keirin is all about the gambling, so they want to make sure the rider is the only variable. Not allowing for "improvements" in technology prevents it from becoming an equipment arms race.
Originally Posted by Six jours
Run What 'Ya Brung
How is this statement relevant?
Originally Posted by andr0id
Originally Posted by doofo
I believe he was trying to illustrate the idea that NJS approved bike specs aren't developed out of conservatism but for want of an equal playing field for gambling.
Tomato, tomaato. I call it conservative because the organization could easily approve disk wheels for everyone, aerobars for everyone, or 30cc motors for everyone, if they wanted to. It would still be a level playing field. Not that it's germane to the question...
I figured to give the OP the simplest answer possible without getting into details about the various governing bodies, etc. Anybody who feels like amplifying is fine with me.
aerobars would be silly for a keirin.
Hey, it's the irrelevant nitpick thread! Lol.
I think that the question was more about the difference between a general use track frame and a TT track frame.
Huh. I'm pretty sure I didn't just throw keirin frames into the discussion for the fun of it. Either the OP edited his post, or I'm losing my mind.
<Edit> Oh. It's actually in thread title. So I did have a point in mentioning keirin frames, but I am also losing my mind. Nice.
Last edited by Six jours; 04-27-09 at 05:48 PM.
the thread has gotten a little confused, so, here I go... as I see it the differences between road frames and road TT frames is usually a slightly steeper ST angle but more importantly, a shallower HT angle. The shallower HT angle, combined with an appropriately raked fork, will make the handling stable even with somebody's weight in the aerobars (i recently rode aerobars for the first time for a kilo, and the sensation was strange, especially with my track bike's HT angle of 75 degrees).
Originally Posted by webber45
Track TT bikes - usually called pursuit bikes - rarely have such a dramatic difference to them. Many companies make all-arounder frames that are sort of a middle ground between the traditional, tight track frames (good for sprinting in particular - 74-75 degree angles, low rake, tight clearances) and road frames. A lot of stuff with 73.5 degree angles, which is toward the steep side for a road bike and toward the shallow side for a track bikes.
If your question is, can your son ride a TT road frame on the track, the answer is, Probably, since a lot of them have rear-facing track ends. The HTA might be a bit shallow so the appropriateness depends on the velodrome, but i've seen a bundle of people ride cervelo TT/pursuit bikes, which seem to have shallow HTA, on my local velodrome (Kissena - banking only 17degrees, somewhat bumpy, 400m track).
If you're asking whether or not your son needs two track bikes, the answer is no. Lots of bikes make for solid all-arounders. Talk to folks at your local track, take a look at what they ride and how they make changes between events. I'm pretty sure (not positive though) that even in International competition a lot of people ride the same bike... all-arounders will have a lower top tube so that aerobars can be mounted low for TTs, and then for sprints, they use a stem with some rise to put the bars at the right spot. Although for dedicated pursuitists that might not be true...
sorry to ramble.