I am sure this have been discussed before, but what should be expected when switching from a 9 tooth driver to an 8 tooth? I know better take off and higher rpm, but how much higher or will the clutches counter act and actually run in a higher ratio? What would the comparable gear change be? Is it like dropping a tooth on the top gear? or even two teeth? The track is a 136" 1.25 Hacksaw/ Thanks Al
staggs65
Moderator
pm me your email. Ive got a gear calculator I can send you and you can plug in the different numbers to see the differences
alswagg said:
it will do all those things you listed, anytime you gear a sled down its easier for it to pull clutch weight because your taking load off the engine. It will shift out faster,and a little bit further but you wont exceed what the clutch can go, your not going to get way up into the top of the sheave on a yamaha, always a good 3/8-7/16" line left of unused sheave face.
If for example we use 20/40 gears, with 9 tooth drivers you are at 2.00 ratio, with 8 tooth drivers you are at 2.25 ratio. So it does gear the sled down a bit when going to them.
The downside going to 8 tooth drivers is is eats up a little bit of power by making it harder to turn the track from the decrease of diameter, the smaller the radius the harder it is to bend something around it. I would only advise using 8 tooth if your going to stud the track as you can easily fit a 1.25 track with the stock 9 tooth drivers. I have even gone as far as using a 1.75" lug track on 9 tooth drivers.
You will also need to change the speedo drive to that of a mtn max or your speedo will read way fast from the ratio change.
Thanks for the info. We are studding the 1.25. Not really worried about top end speed anyway. We like two tracks and deep snow. I ordered a driver/shaft assy from a Mountain Viper, I hope the shaft will include the appropriat tone wheel. Al
mattysmith440
New member
dont mean to hack, but mrviper, how far off does the speedo go? ive got 8 tooth drivers with 1.75 track, 24/40 gears and my speedo shows 117-119 mph. i know its not accurate but just curious if theres a ratio of calculation that can be made
My SX Viper was off by 20%. I have a 144" track with 8T drivers. Gears were 22/38 at the time.
In regards to the speedo, on a Viper, if you grind off opposing teeth on the speedo gear, it will put you just about on par w/ stock. I've done it and after riding w/ a buddies Polaris, we were almost the same on speed. Tom Hartmann told me about this, and it does work.
ottawaair
New member
I have messed with this for some time. The easiest way to figure the new ratio is to multiply your current ratio by 1.125. So, as don said, a 20/40 gear would be a 2.00 ratio with 9 tooth drivers. Multiply 2.00 by 1.125, you get 2.25 with the 8 tooth. I have a 136, 1.25 ", ripsaw studded with 8 tooth drivers. I run 23/37 gears, which works out to 1.8 gear ratio. I have a mtn. Max speed drive unit and can run about 110 on the speed. Give or take with the conditions.
ottawaair said:
Sorry, I am confused by this. I have an '02 Viper that had original gears of 22/38. This would be a ratio of 1.73. So if I drop to an 8T No-Slip driver you are saying my new ratio I should try to achieve is (1.73 * 1.125 = 1.94)? Seems backwards to me, but I really don't understand the whole gearing calculation.
if you dont change anything but the drivers, with your original gear set using the calculation, your final drive would be at the 1.94. you would want to use the calculation to re-gear back to the 1.73, if you were happy with that ratio.
your not trying to achieve the 1.94, thats what you will have by dropping to 8t drivers. what you would want to achieve by changing gear combinations is to return to the ratio you had with the 9t drivers.
your not trying to achieve the 1.94, thats what you will have by dropping to 8t drivers. what you would want to achieve by changing gear combinations is to return to the ratio you had with the 9t drivers.
ottawaair
New member
right, u will end up with a 1.94 if u use the existing gears u ran with the 9 toothers.
snowdad4 said:
So would I take the new gears, say I try 24/37 which has a ratio of 1.54 then multiply that by 1.125 which results in 1.734? That gets me back to where I was but now running 8T drivers?
