Anybody out there know what the stock gearing is on the Attak and Apex sleds? They both have 9 tooth drivers - right?
Also, how does the gearing compare to the Warriors and RX1s?
yrunderattak
Newbie
stock gearing on attak is 23/38 I change mine to 22/38
yrunderattak said:
yrunderattak.........I'm thinking of doing the same. I don't really care about top end (100 mph is plenty fast) I'm more concerned with low end torque. Do you think dropping the top gear by only one tooth will make that much difference? How small can you go on the top gear (20 tooth?) and keep the stock chain? Before I do any changes, I'll ride the sled with the stock gearing for the break in period.
I read stories all the time about how the RX1 gets beat out of the hole, but eventually catches up and blows by the other sled around 60 mph. Why does Yamaha gear these sleds so high? Gas milage? :roll:
Some say lowering there gearing took dropped fuel economy as well.
yrunderattak
Newbie
last year I ran 2004 rev 800 drop top gear 1 tooth sled perfrom very well and did not effect my mpg or top end enough to matter great mod
Slush Monster
Expert
I went 22 /39 on my attak.I Do alot of deep snow riding and lake riding.
You will notice no change in MPG with a small gearing change.
You will notice no change in MPG with a small gearing change.
Slush Monster.......According to MPI's gearing chart, a 22/39/9 tooth driver set up gives you a final drive ratio of 1.77. A 22/38/9 combination results in a final drive ratio of 1.73. The stock ratio of 23/38/9 has a final drive ratio of 1.65. Here's a link to MPI's gearing chart: http://www.mountainperformance.com/yama ... _chain.htm
Changing the top gear is fairly cheap. Changing the bottom gear, however, is expensive. (About $35.00 for the top gear, but $127.00 for the bottom gear.) Also, you have to keep on eye on the chain length.
yrunderattak........According to MPI's chain chart, switching from a 23/38 (stock) gear ratio to a 22/38 gear ratio requires a shorter chain (68L vs. 70L.) Did you switch to a shorter chain?
Changing the top gear is fairly cheap. Changing the bottom gear, however, is expensive. (About $35.00 for the top gear, but $127.00 for the bottom gear.) Also, you have to keep on eye on the chain length.
yrunderattak........According to MPI's chain chart, switching from a 23/38 (stock) gear ratio to a 22/38 gear ratio requires a shorter chain (68L vs. 70L.) Did you switch to a shorter chain?
Polaris Hyvo gear works on the bottom for a RX-1. Cost is like $30. My 03 RX-1 was slower & thirstier on fuel when I geared from 24/38 to 24/40.
yrunderattak
Newbie
wfo no I still have the 70 link chain in mine but I am thinking of changing to 68 link 70 seems a little long. new chain from yamaha is 110.00
yrunderattak said:
yrunderattak...........Rather than buying a shorter chain, you could buy a 39 tooth lower gear for about the same price and keep the stock 70L chain.
Slush Monster...........I like your idea of dropping the top gear by one tooth and increasing the bottom gear by one tooth. As I mentioned above, you would be going from a stock final drive ratio of 1.65 to a ratio of 1.77 (about a 7.25% drop in ratio.) I'm not sure if this is correct, but it would be like going from a 3:15 to a 3:42 differential in a car.
170plus
TY 4 Stroke Junkie
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- Snowmobile
- 2021 polaris assault 850,18 sidewinder ltx,14 nitro xtx,06 apex rtx,
i found that 23/40 was the best on my 03shorty,the stock was 24/38 so it was quite a change but worked with 70 chain,was wondering about the gearing on the rtx as far as being light weight bottom gear,i had a light weight 40 which was considerably lighter than the stock 38,i tried everything from21/40 up to stock gearing,21/40 wasnt at all quicker and it lost lots of top end speed,it didnt stay in sled long,23/40 is the way to go,06 rtx undergoing some changes as we speak,cant wait for snow
