I’ve got an old 24" generic unicycle. I’ve put a miyata seat on it. It has a walmart b*ke tire and cottered 110s (I think).
What it the prefered setup for the races? Would this work? Is reeeeal skinny tire better?
Describe a 24 inch racer? About two feet across and fast.
I think I’m right in saying that the rules for racing specify a maximum inflated diameter of 24 inches for the tyre, and a maximum of 125 mm for the cranks. If you follow the links from unicycling.org, I think you’ll find the rules somewhere. I know I saw them once, ages ago.
If it’s cottered I suspect the cranks are 127/5" or 150/6".
You do not want 6" for racing, those with 5" will have too much advantage.
A skinny tire on a 24" rim will reduce your effective diameter. A skinny tire on a 26" rim may still be within the 24" requirement for IUF/USA racing.
Hey T-Max (Memphis Mud),
Take a look at the TCUC calendar (May, I think) there is a great picture of the starting line from the Nationals. Take a peek and see what everybody is racing with.
Are you planning on going to SLC this summer? It looks like my plans are chaning the include SLC and not Tokyo.
Tommy
The maximum allowed diameter of the inflated tyre is 24.333" .
For me as metric person, the rollout of the wheel is then 194.17cm.
The minimum allowed crank length (for the 24" unis) is 125mm
(just a bit under 5")
Here in Switzerland most people race using 24" x 1 3/8" tyres
(that’s in ETRTO 37-540). There are some good Dutch tyres
around for that size. These tyres are quite forgiving and
most people can ride them reasonably fast.
From the limits point of view it’s also possible to use a 26" rim
and a skinny racing tyre (ETRTO 25-559). You have to carefully
combine a wide 559 rim (say 21) with a 25-559 racing tyre. Normally you can not pump it up to its allowed pressure limit without going beyond the allowed 194.17cm. So, these are more tricky to find and also more tricky to ride, especially on wet ground.
So skinnier is not necessarily better.
HTH
–
Franz http://www.einradsport.ch
Tommy
What is SLC? When is it?
Bill
Hi Bill,
“SLC” is Salt Lake City - the NAUCC Nationals. It is mid-july.
Tommy
See http://www.unicycling.org/usa/naucc/2004/ for the announcement of the 2004 North American Unicycling Championships and Convention in Salt Lake City July 13 (new information - different from the announcement) - July 18. The announcement is also on page 3 of the new issue of On One World (in the mail as of 01/24/2004).
Tom Daniels
President, Unicycling Society of America, Incorporated
bbraf: Thanks for the tech measurements. That’s just what I needed.
Tommy, thats too bad about Tokyo. I’m really aching to go to Salt Lake City…dang.
So there is a most common setup for MUni (with minor variations). Theres a most common setup for Freestyle (with minor variations). Theres a most common setup for Commuting (with minor variations). Theres a most common setup for Trials (with minor variations).
And I could use my old 24" to race if I can get the math to work out on circumference and minimum crank length? The minor variations I can consider are:
Thin tire…fast of the start
Fat tire…better, smoother flywheel effect
T-Max,
Unicycle.Com had special on a racing wheel right before NAUCC last year. Perhaps they still have a deal that they could offer you.
If you are thinking of rebuilding a wheel it seems not to make much sense to spend money and energy lacing a new, thin rim on to a cottered crank hub. I’ll happily build a wheel for if you want.
If nothing else, ask around using the list of winners from the NAUCC.
Tommy