I am currently in the proccess of building a stadium lite. I am going to be building a transmission for it and wanted to find out if it was a straight 1:1 ratio or is it a reduced ratio? Does it have a differential or is it a solid spool? Also what are the displacement limitations for stadium lites.


Thanks

 

The ratio is not 1:1. The required ratio is dependant on a lot of factors. One is the ratio of your clutches.

Assuming that is 1:1 and you use a gear box ratio of 6.4:1

(6000 RPM / 6.4) * (22" tire/12 inches per foot) * 3.14 = 5400 feet per minute

5400 * 60 minutes per hour / 5280 feet per mile = 61 MPH

Drop your numbers in place for RPM, tire diameter and clutch ratio. Figure out what top speed you want and figure a gear box ratio for that.

Realize that if you figure for 150 MPH top speed, it won't work. Your clutches will just not shift out all the way and you will have bad acceleration. Also, you cannot hit top speed at most tracks. 60 MPH is more than you will hit at most of them. You can hit higher at Crandon. Since the turns are sweeping there and you want more ground clearance (softball size rocks sometimes get dug up by the trucks), you can run a taller tire. My Drakart is geared to hit 100 MPH from the factory. I probably have never been above 80 because I run out of room.

Every lite I know of has a live axle (solid spool).

The size limits can vary by race, but it is pretty well accepted that 625cc (600 motor plus overbores) is the new standard over the old 500cc limit for the pro modified class. In order to run in the limited class, you would need to get it approved by the other drivers. That class is mildly modified Odysseys and Pilots. Aftermarket shocks are allowed, but suspension geometry must otherwise remain the same. A lite with 8" of travel and a 400cc would probably be OK. A Triple E Desert Star is an example.

There will be a race in Chillicoth, IL again this year. It will be July 27th and 28th. This promoter does at least 100% payback. He will add in extra money with a good turnout.

There are also desert races out west that you could look into.

 

Thanks Livewire for the info that really helps out. I hope I have the thing done in time to compete this summer.

 

You can buy a gear box. Drakart was selling theirs for $1350. I'm not sure if they still are. The owner told me that no one has blown one since he started making it in 1988. He puts the same one in the two seater version with an 800 triple.

I think the RPM tranny is $1300. It is also known as a Roberto trans. That is also a very tough unit. A lot of lites run this gear box.

Both are available with different gear ratios. The RPM is even available with a quick change option that lets you change the final drive ratio without taking the whole box apart.

Drakart was offering the Formula Cross as a frame kit for a while, but no longer is. People would put it together wrong and then want to make warranty claims because of problems they caused.