Gearing....Would like some options

1344 Views 22 Replies 13 Participants Last post by doo rider, Oct 6, 2006

PATRIOT 67

Discussion Starter · Oct 2, 2006

I was considering changing the gearing in my sled, just for sh&%s and giggles my stock gears and chain are 43B 23T and 74 link chain......My ? is how many teeth can I add to the top gear without changing chains...........The sled is an 800ho with under a thousand miles on it

Would like to try a 26t on top if possible

Thanks in advance for your advice.......Doug

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1 - 20 of 23 Posts

madman

· #2 · Oct 3, 2006

GEARING UP ON TOP WILL GIVE YOU MORE TOP END. YOU CAN ONLY GO 1 TOOTH UP (24) WITH STOCK CHAIN HAVE TO GET 76 LINK AFTER THAT. WAS CONSIDERING DOING THIS TO A 06 800 GADE (STOCK) ( 1-TOOTH UP, ADDING SOME PIN WEIGHT, AND SEEING HOW IT WAS

REVin soon

· #3 · Oct 3, 2006

Why do you want to gear up? These sleds are already geared to a higher top speed then they can attain. Gearing up will probably not provide you any higher top end but will definately provide you with a dog on the bottom end. You can drop 2 teeth on top and drastically improve your low end response while having little if any affect on top speed.

djm

· #4 · Oct 3, 2006 (Edited by Moderator)

With the 10 lug drivers you have... you will hate a 26 tooth top gear with the 43 bottom gear.... if you did go spend the money for the longer chain. You will not only lose acceleration but you will probably also lose top end... no way can you pull that gear ratio..

You will probably have better acceleration and higher top speed with a 22 or 21 tooth top gear. Doo's are notoriously over geared from the factory..

But trial and error is the best way to learn... I probably have one of the longer chains and the 26 tooth gear if you want to make yourself unhappy..

REVin soon is right on.....

Dynamo^Joe

· #5 · Oct 3, 2006

http://www.dootalk.com/forums/index.php?sh...indpost&p=77538

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GadeX

· #6 · Oct 3, 2006

These guys are right.
Drop 2 teeth to 21
You will find a big difference low end and little if any on top.
It allows the engine to wind up quicker on acceleration
and make better power
It's worth the price of a gear to find out.
Good bang for your buck.

Zert2Rev

· #7 · Oct 4, 2006

Wouldn't be better if you went with a 46 t bottom gear?

djm

· #8 · Oct 4, 2006

Zert2Rev said:
Wouldn't be better if you went with a 46 t bottom gear?

That's the right approach, go with both bigger bottom and top gears and a longer chain.. rolling the chain over bigger radius a little less friction loss probably hard to measure .. but it's one of those things in the right direction.. keep stacking things up in the right direct and pretty soon you are faster..and quicker..But most people go with the cheaper approach (gears are roughly two dollars a tooth.. and thus top gears are cheaper then bottom gears..so most opt to go with a couple of less teeth on the top gear..

PATRIOT 67

Discussion Starter · #9 · Oct 4, 2006

Thanks for the info guys......Dy.Joe very helpful I know just what to do now ..

Thanks ...Doug

loots-42

· #10 · Oct 4, 2006

ok, needs some opinions on this.

I've got an 03 800 that has some nice mods to it. Porting, head, etc. Maybe a new pipe yet too. Anyway, 26/43 gears were stock w/ 9 tooth drivers. At a 1:1 ratio, thats 102 mph. Maybe get a little into overdrive.

I believe that efficiency goes to he11 after 1:1 ratio. I saw a graph somewhere (I think it was Aaen's manual). So wouldn't it be better to gear up and attain a higher speed at 1:1? I would hope that my sled should put 110 with decent conditions, and gearing down would require it to go way into overdrive to attain 110.

Also, if you gear down you probably are spinning the track like mad at launch. Is this the best way to accelleration, or would it be better to be right at the verge of spinning but not spinning, like in a car?

thoughts? Thanks!

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dono

· #11 · Oct 4, 2006 (Edited by Moderator)

Maybe you should buy the 1000, Im sure that will be fast enough.
I was told by a few different shops that you should only change one tooth up or down, then you should change the bottom.
Call Bill Cudney,, he will set you straight or at least in the right direction.

loots-42

· #12 · Oct 4, 2006

loots-42 said:
ok, needs some opinions on this.

I've got an 03 800 that has some nice mods to it. Porting, head, etc. Maybe a new pipe yet too. Anyway, 26/43 gears were stock w/ 9 tooth drivers. At a 1:1 ratio, thats 102 mph. Maybe get a little into overdrive.

I believe that efficiency goes to he11 after 1:1 ratio. I saw a graph somewhere (I think it was Aaen's manual). So wouldn't it be better to gear up and attain a higher speed at 1:1? I would hope that my sled should put 110 with decent conditions, and gearing down would require it to go way into overdrive to attain 110.

Also, if you gear down you probably are spinning the track like mad at launch. Is this the best way to accelleration, or would it be better to be right at the verge of spinning but not spinning, like in a car?

thoughts? Thanks!

Any clutching gurus care to comment?

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Dynamo^Joe

· #13 · Oct 4, 2006

L]...I believe that efficiency goes to he11 after 1:1 ratio.
J]...How so?

L]...I saw a graph somewhere (I think it was Aaen's manual).
J]...What secondary details was he using?

L]...102, 1:1 way overdive to get 110.
J]...full o.d. = 122 in your case.

L]...Also, if you gear down you probably are spinning the track like mad at launch.
J]...make suspension transfer better.

L]... Is this the best way to accelleration, or would it be better to be right at the verge of spinning but not spinning, like in a car?
J]...make suspension transfer better.

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marc_brown98

· #14 · Oct 4, 2006

Never fear the Gear! I look at it as this. Where do I spend the bulk of my riding time? I spend a majority of time at lower speeds under 85 mph. So, I gear it to where it helps me most for the bulk of the riding that I do. 21/45 for me.

blackmxz

· #15 · Oct 4, 2006

Ok guys I have a question. I have an 05 Rev. Adrenaline with a 600 SDI and Joe's kit in it.
1 What is my stock gearing?
2 If I am reading this right I should reduce my top gear
3 Where do you buy the gears from
Thanks all.

loots-42

· #16 · Oct 4, 2006

Dynamo^Joe said:
L]...I believe that efficiency goes to he11 after 1:1 ratio.
J]...How so?

L]...I saw a graph somewhere (I think it was Aaen's manual).
J]...What secondary details was he using?

L]...102, 1:1 way overdive to get 110.
J]...full o.d. = 122 in your case.

L]...Also, if you gear down you probably are spinning the track like mad at launch.
J]...make suspension transfer better.

L]... Is this the best way to accelleration, or would it be better to be right at the verge of spinning but not spinning, like in a car?
J]...make suspension transfer better.

Hey Joe,

The manual talks about efficiency looses due to belt stretching, belt side pressure, turning radius, belt speed, etc. When in overdrive, the secondary clutch is spinning faster than the primary, and this high belt speed yields efficiency loss due to belt tension and centrifigul force. I'd also imagine that having less contact area with the secondary while in overdrive lends to more slippage. It states that best efficiency is between 2:1 and 1:1. With stock gearing on the 03, thats between 51 and 101 mph.

So if the starting ratio is 3:1 (this probably varies some), I think that means that the clutches don't start shifting until 34 mph. So there is low efficiency between 34 and 51, best between 51 and 101, and then falls off in overdrive.

So, if you're doing alot of corner to corner riding, you'd want lower gears so that when you exit the corner, and you you nail the throttle, the clutches haven't fully closed, and your rpms will go right to peak hp without having to be down on the power curve and then have to pull back up toe peak before beginning to shift out the clutches.

I know it's alot more complicated than that, but am I even making sense?

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blackmxz

· #17 · Oct 5, 2006

blackmxz said:
Ok guys I have a question. I have an 05 Rev. Adrenaline with a 600 SDI and Joe's kit in it.
1 What is my stock gearing?
2 If I am reading this right I should reduce my top gear
3 Where do you buy the gears from
Thanks all.

Anyone can help?

djm

· #18 · Oct 5, 2006

blackmxz said:
Ok guys I have a question. I have an 05 Rev. Adrenaline with a 600 SDI and Joe's kit in it.
1 What is my stock gearing?
2 If I am reading this right I should reduce my top gear
3 Where do you buy the gears from
Thanks all.

Anyone can help?
[/quote]

Go to www.hlsm.com and pick the year of your sled and then you can look it up... what parts - number or teeth are used.

http://216.37.204.206/wps/Skido

EM/Skidoo.asp

In this case it says you have a 22 top gear and a 43 bottom gear. If you are trail rider.. I would definitely go with a 46 tooth bottom gear .. instead of going to the small 20 tooth top gear. Of course it will cost twice as much.. as gears sell for roughly a little more then a dollar a tooth..

You can buy a doo gear from one of the mail order places on hlsm... or you can go some place like HPE (high performance engineering), Dennis Kirk or Micro Belmont. You can find their websites by using google or yahoo search feature..

Dynamo^Joe

· #19 · Oct 5, 2006 (Edited by Moderator)

Hey Joe,
The manual talks about efficiency looses due to belt stretching, belt side pressure, turning radius, belt speed, etc. When in overdrive, the secondary clutch is spinning faster than the primary, and this high belt speed yields efficiency loss due to belt tension and centrifigul force. I'd also imagine that having less contact area with the secondary while in overdrive lends to more slippage. It states that best efficiency is between 2:1 and 1:1. With stock gearing on the 03, thats between 51 and 101 mph.

So if the starting ratio is 3:1 (this probably varies some), I think that means that the clutches don't start shifting until 34 mph. So there is low efficiency between 34 and 51, best between 51 and 101, and then falls off in overdrive.

So, if you're doing alot of corner to corner riding, you'd want lower gears so that when you exit the corner, and you you nail the throttle, the clutches haven't fully closed, and your rpms will go right to peak hp without having to be down on the power curve and then have to pull back up toe peak before beginning to shift out the clutches.

I know it's alot more complicated than that, but am I even making sense?

Lootski howzit goinski...

L]...efficiency looses due to belt stretching,
J]...Heh, I really don't like talking as if im reading a resume', however its hard to describe otherwise without knowing my experiences to offer information with a little bit of weight. I do "reliablity specialist" studying vibration analysis and focus on static/dynamic belt driven equipment.
At one time, being part of a design group, I have discussed this comment with engineers from Reliant/Dodge, goodyear...

These gents quote: Regarding "Stretch".

The belt has that aramid fiber band woven, spun as the tension section; The rubber blend cover is made as a solution around this aramid fiber.
Under load the belt is like a steel band.
...Belt rubber deforming...yes; The rubber must deform to follow the sheave path when the belt is pulled.
...Belt stretch?...No!

L]...belt side pressure
J]...How do you calculate this? How would you use the values?

L]...turning radius
J]...Ok.

L]...belt speed, etc.
J]...What would the values tell you? Something good? Something bad?

L]...When in overdrive, the secondary clutch is spinning faster than the primary, and this high belt speed yields efficiency loss due to belt tension and centrifigul force.
J]...Ok then, what will you do with this information? Will it help you calculate something?

L]...I'd also imagine that having less contact area with the secondary while in overdrive lends to more slippage.
J]...GREAT! Now we're getting somewhere. Now you are talking with a principle.
Q]...What do you do to reduce belt slip?
A]...Grab it harder.

Question]...How do you grab the belt harder?
Answer]...Increase the side FORCE.....not "pressure" Do you weigh 195 lbs pressure? No, you weigh 195 lbs...gettit?!!

Question]...How do you increase the side force?
Answer]...Increase spring force and/or use lower helix angle vs. previous values.

Question]...How do we know to make a change in the right direction?
Answer]...How do you know there is slippage?

Comments]...Hot temperatures
Question]...Why is there hot temperatures?
Answer]...Belt slip
Question]...How do you reduce belt slip?
Answer]...Grab the belt harder.
.
.
.
.
...Gettit?!!
Efficiency losses due to, blah blah blah... Well we know inefficiency reveals high temperatures, then who cares about all that stuff - Yes it's good to know, however don't let that stop you from experimenting.

*Inefficient = belt slip = high temperatures. Efficient = less belt slip = lower temperatures.
Now would this "*" be more important to know than "efficiency loss, because" ?
Now only need to care how to reduce temperature.
Clamp the belt harder to reduce temperature and tell me anything else that matters.

How do you know how to grab the belt?.....Know "Clutching IQ" he he he

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loots-42

· #20 · Oct 5, 2006

Hey DJ,

I'm way over my head on this stuff, just restating what I've read. But yet I continue on...

So the question is, based on less belt contact area and a tighter radius as we approach overdrive, if I were to be setting up for a speed run event, wouldn't it likely be better to use gears that will allow me to top out at near 1:1, vs going way into overdrive?

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