If you give a keirin framebuilder his own head and he builds to the optimal performance on the keirin track (which is very long and shallow, not at all like most decent velodromes), you tend to get a 75 to 75.5 degree seat angle up to 57 or 58 cm frame size, and then dropping down to 74. On the head tube, you tend to get 73 pretty much for all sizes, give or take a little. Before designing around rider needs, a generic keirin frame tends to be pretty much square (same length seat tube and top tubes), with small frames perhaps a centimeter longer on the top tube out of necessity. Top tubes are always level, by the way. Bottom bracket height is high, even by European track standards -- 5 to 5.5 cm drop is common, which is something to bear in mind if you want to ride a keirin frame on the road -- it affects comfort, stability, and of course standover height for those who care.

As for toe clip overlap, it definitely isn't nice, but on smaller frames it's very hard to avoid unless you ride an extremely long top tube. And if you put a longer-than-165 crank length on your keirin frame, you increase the problem since they're pretty much all designed for 165's or 167.5's. A designer has a few basic ways to get rid of toe clip overlap, but always at a price -- the most common are to steepen the seat angle (which pushes your front end farther forward as well, all else being equal) or to lower the head angle and increase the fork rake (done together, it keeps trail about the same and buys you more clearance, but does change the liveliness and wheelbase of the bike). Most track match sprinters have quite a bit of toe clip overlap (both Look KG496 and BT frames have noticeable overlap in all but the largest sizes) and riders deal with it just fine. So it may be more something to get to know rather than to try to engineer around.

Question: Does toe overlap mater much on the track ? How much does overlap affect the ability to play tactical games before the sprint to the line ?
This will shed light on if track frame builders would ever care enough to eliminate overlap over other design requirements.

i am shooting blindly in the dark here, having never ridden on every track on the face of the planet,,, but i would imagine it would differ between them somewhat--- however: isn't it true that one never really "turns" ones front wheel much on the track? i mean, a certain amount of steering is neccessary, but isn't it so minimal (on the velo) that one would never touch one's toes to one's wheel?

same goes for geometry in general, the bike is steep and uncomfy on the street, but this doesn't matter at the track as the bike wasn't designed with commuting in mind. look at those down/forward sloping top tubes, or the bikes with handlebars affixed to the front fork!

International Keirin is done that way not Japanese or Korean keirin they have a rider pace them with 2- 2 1/2 laps to go or bell lap.

S/F,
CEYA!

My keirin frame is perfect for the street. Feels great on longer rides, but isn't as taint-punishing as shants' bike. I think mine is 75 degree seat and head tube, with pretty square lengths. Feels nice.

truth be told, keirin frames aren't much different than the track bikes the Jamaicans started riding in NYC back in the day. and like all great trends, it got watered-down. thus, track looking frames with road geometry. maybe, just maybe, the current popularity of keirin frames doesn't have anything to do with being a hipster, it has to do with people who want quality lugged track frames, that handle like track frames, to ride around an urban environment.

potus, couldn't have said any other way. Even back then frames with laid back geometry was good to go.

We messengered on Atala, Lotus,Panasonic, Olmo,Cinelli. We knew what they were and had fun riding them.

Most rather have a true steep track frame due to it handles better in traffic. That is why I ride 54 cm in traffic. You flow like water.


S/F,
CEYA!

What's interesting about keirin frames from Japan is that the Japanese were practically infatuated with Italian designs from the 70's or so, and those are the specs that tended to get locked down. Just look at the bikes -- lugged, steep angles, rather tight clearances (even by track standards), higher bottom brackets, low trail, standard tubing diameters, you name it. At the time you couldn't tell a keirin frame from a good Italian one, but of course Italy has moved on and Japan hasn't as much. It'll be interesting to see keirins raced on disc wheels this year, and approval for carbon frames in keirin in the works.

I just wanted to toss in my proverbial two cents. I love my kierin frame because I found it to be more comfortable, being shorter length wise for a female rider such as myself. I DO lean a bit more into turns rather than turning the handlebars.

I disagree Japanese have moved on. just the keirin has a set standard. go to any place even to a keirin shop you see they are way up or beyond the times.

I'm happy keirin has this standard it shows steel is real ( a lovely craft).

Look at the road bikes most (really all) are today's style frames.

S/F,
CEYA