Gearing for asphalt, help me figure this out

[NOS-PRO]

Ok math genious'......

Asphalt track is 2.52 pitch so that is gospel right now.....

I ordered a brand new axle with 2.52 drivers from a 2012 Arctic Cat and I think they are 10 tooth.

RTX and LTX are 24/50 (2.083 ratio) gears. XTX is 21/41 (1.952 ratio). XTX is higher actual gear but because of the pitch and number of sprocket teeth its lower geared overall

RTX/LTX is 9 tooth 2.86 pitch drivers which gives you about 101 mph top speed @ 1:1 clutch ratio.

XTX is 8 tooth 3.0 pitch drivers which gives you about 95 mph top speed @ 1:1 clutch ratio.

I will find out what diameter the 2.52 drivers are as soon as I get the driveaxle. I want to have close to or even just a little taller gear ratio as I won't be having all the snow drag and want this thing to have the best mph. **My question is.....What gearing am I going to need?** Are the 8 tooth sprockets the same diameter as the 10's?

 

[NOS-PRO]

I guess I would like to be around the 115mph area for speed as I think it will do it in the quarter.

 

[shagman]

Try this bud.
http://www.turboaddictionparts.com/cata ... lator.html

 

[shagman]

this formula takes diameter into consideration due to the pitch and number of teeth. change your top sprocket to 22 and you will be at 113.96. 23 would be 119.14.

 

[TD Max]

Wouldn't it make sense to have Allen do the machining on the clutches first? You'll probably get enough OD to be spot on. Eliminate your limitations first then see if you need gear?

 

[NOS-PRO]

TD - I was hoping to try the clutching without machining first so I can see the difference in MPH. I want to try the stock gearing but this 2.52 driver setup has me worried. The calculator shows 109 with stock gearing so I will try it first.

Shaggy - That s cool information! I never knew about the calculator....

 

[TD Max]

If you are targeting 115 then wouldn't you overshoot that with machining if the machine rolls free and you gain say 10% with machining?

I would think that if you wanted to see just how much mph you gain with machining you would gear short (say 100mph) so that you run out of gear a solid 10%+ below target. Machine for the added 10% and you should be up in the range that you want to be and on the limiter again. Then you can creep the gear up to get it just off the limiter.

I'm anxious to see how this works. In talking with Allen I'm thinking I'll gear back my Viper a bit (provided it remains N/A) and machine the clutches for full shift. This should give more explosive bottom and still top out plenty fast.

 

[NOS-PRO]

good point TD

I believe the sled should pull 109 easy on the tar. I think I will still use the stock gear set and see where it is. I can run it out longer also past the finish line to see where it tops out.

 

[TD Max]

Are the brakes that good? I get nervous about running deep thru the traps.

I suppose the rolling resistance helps. I know I'm in the deep lane every time, but I'm 8000# and trapping 118-124 depending on tuning. Never been to Kaukauna.

 

[NOS-PRO]

Kaukauna has the hill which I take everytime with my SRX and I'm running mid 9's. The turn off is before the hill and I know some heavy fast cars that can still make the turn, but it's nice not hitting the brakes so hard and letting it coast more. High 10's-low 11's on the Viper should be no problem.

 

[TD Max]

OK hill makes sense. Rock Falls not so much as far as hill.

 

[NOS-PRO]

I will be recording a run or two in the near future showing how much shut down we actually have. Even rails don't have to pull their chutes when using the hill. It's not the smoothest shut down but it works.

 

[Srxspec]

I have 22 tooth gears on hand if you need a few more MPH out of your stock clutches.