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Discussion Starter · #1 ·
Talked to the parts guy at my dealer today, I asked him about gearing down my 600 etec to 24/45 or 23/45, he said dont do it, it could possibly make my sled over rev and create other problems, mess with your RTA clickers first. Any one have to say anything about this?
 

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Fuzzy but not Blue........
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Completly different issues or your dealer is complete idiot, was it a sales/part guy or the mechanic ???

Your TRA "clickers" control the peak rpm's for the most part, while gearing effects different aspects of performance on how its applied. You could possibly gear it too low and fully shift out and over-rev but just dropping a tooth or two doubt it unless you're running full out on some very hard pack or ice.

Here play around with this:

https://www.ibackshift.com/article/top-speed-calculation-133.asp

-grover
 
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Why do you want to gear down? Unless your installing a different track I'd leave the 25 top gear in there for better top end.
 

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Gear it down if you want to, add pin weight or change primary spring to get your rpm' in the sweet spot. I'm constantly going anywhere from a 25/45 setup to a 27/45 on my 800
 

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Fuzzy but not Blue........
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Not always. Just because you're geared for 110mph dosen't mean you'll reach it.......... :wink_old:

Geared down alot of my sleds and never lost my top speed and in most cases gained

-grover
 

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I agree with Grover.

To get an idea of what your gears are doing for you- mark the clutches.

Tight twisty trails are a blast when you have geared down. The corner to corner acceleration is great.

If you are running long straights on frozen or hard pack, a bigger or stock gear is better.

Drag race short distance-smaller top gear.

By marking the clutches you can see how far the belt is traveling. If the clutches aren't close to shifting out then a gear drop would be fine.
 

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Discussion Starter · #8 ·
Completly different issues or your dealer is complete idiot, was it a sales/part guy or the mechanic ???

Your TRA "clickers" control the peak rpm's for the most part, while gearing effects different aspects of performance on how its applied. You could possibly gear it too low and fully shift out and over-rev but just dropping a tooth or two doubt it unless you're running full out on some very hard pack or ice.

Here play around with this:

https://www.ibackshift.com/article/top-speed-calculation-133.asp

-grover
It was a part guy
 

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With the 8 tooth drivers on that sled, 25/45 gives you an overall ratio of about 1.98/1. For trails and some off trail I would think that would be pretty good. 24/45 gives about 2.05/1. For the cost of a top gear, try it out. I think what the guy meant was your rpm's might go up slightly on hard pack, as it would pull the stock helix easier and might not be loaded enough. Iirc, there is a change to a different helix on that sled that helps. Do a search, I think it was djm who said that, and quoted a number.
 

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Discussion Starter · #12 ·
Why do you want to gear down? Unless your installing a different track I'd leave the 25 top gear in there for better top end.
I want to gear down because im increasing my track half an inch and going to be both powder riding and trail riding.
 

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Metalhead
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Talked to the parts guy at my dealer today, I asked him about gearing down my 600 etec to 24/45 or 23/45, he said dont do it, it could possibly make my sled over rev and create other problems, mess with your RTA clickers first. Any one have to say anything about this?
Start of rant

***************

The mechanic made a confession to you by using the words "could" and "possibly". He is confessing that he does not know any facts, nor personal firsthand knowledge of what "changing gearing" can do. He's only expressing to you either 1] his own assumption, or 2] He's parakeeting an assumption that someone else told him; its one or the other - thee end!

"and create other problems" is his protection by framing his conclusion being left open ended so that if anything does happen, he can say "I told you so" because the word "other" is wide open for any fact that pops up to react to. If dogs and cat's start to live together then he'll say "I told you that was because you geared 1 tooth lower".

His confession is framed as a statement so that whatever happens to you with a gear reduction, then in the future he would not seem to you to be an unlearned tuner and that he knows more than you - and link that supposed fact to the 1 lower gear.

End of rant.

**************

Latest 150+hp 800's for every 1/4 inch increase in track lug height you can drop one gear lower than current gear.

Latest 120~125hp 600etec's for every 1/4 inch increase in track lug height you can drop two gears lower than current gear. IF have 25:45 with a 1.25 track and go to 1.5" track then can go 23 top gear and you'll be fine.

  • The 600 ain't 150+hp.
  • For every 1 lbs of rotating weight, add "as-if" 7 lbs on the chassis.

If anything the engine speed will start to drift lower than 8100 as soon as the clutches shift into the overdrive portion - this is where tailoring drifting engine speed comes in with a change of primary spring end force. (raising it 20~30 lbs for every 200 rpm loss)

As far as theoretical top speed, what's wrong with a 23 top gear for pulling off about 1/2 of overdrive shift ratio (orange box)

If you are going from a 1.25 track to a 1.75 track, you would still have t|ts for top speed with a 21 top gear. :ride:

600gearing24.jpg
 

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Discussion Starter · #14 ·
Start of rant

***************

The mechanic made a confession to you by using the words "could" and "possibly". He is confessing that he does not know any facts, nor personal firsthand knowledge of what "changing gearing" can do. He's only expressing to you either 1] his own assumption, or 2] He's parakeeting an assumption that someone else told him; its one or the other - thee end!

"and create other problems" is his protection by framing his conclusion being left open ended so that if anything does happen, he can say "I told you so" because the word "other" is wide open for any fact that pops up to react to. If dogs and cat's start to live together then he'll say "I told you that was because you geared 1 tooth lower".

His confession is framed as a statement so that whatever happens to you with a gear reduction, then in the future he would not seem to you to be an unlearned tuner and that he knows more than you - and link that supposed fact to the 1 lower gear.

End of rant.

**************

Latest 150+hp 800's for every 1/4 inch increase in track lug height you can drop one gear lower than current gear.

Latest 120~125hp 600etec's for every 1/4 inch increase in track lug height you can drop two gears lower than current gear. IF have 25:45 with a 1.25 track and go to 1.5" track then can go 23 top gear and you'll be fine.

  • The 600 ain't 150+hp.
  • For every 1 lbs of rotating weight, add "as-if" 7 lbs on the chassis.

If anything the engine speed will start to drift lower than 8100 as soon as the clutches shift into the overdrive portion - this is where tailoring drifting engine speed comes in with a change of primary spring end force. (raising it 20~30 lbs for every 200 rpm loss)

As far as theoretical top speed, what's wrong with a 23 top gear for pulling off about 1/2 of overdrive shift ratio (orange box)

If you are going from a 1.25 track to a 1.75 track, you would still have t|ts for top speed with a 21 top gear. :ride:

attachicon.gif
600gearing24.jpg
Thanks for your expertise joe!
 

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Discussion Starter · #15 ·
djm So i made the change last season. I went from the 1in stock track on my 600 etec to a 1.5in. I dropped the top sprocket down from a 25 to a 24 24/45. Stock helix, stock springs. What i did notice was a sweet spot in my throttle. There would be that 3/4 area of open throttle were i would get that constant 8,000 rpms but when opening the throttle all the way she would drop to about 7,500 rpm. What can a guy do to get that full snap at full throttle? there is nothing worse than giving it full throttle and not getting full performance.
 

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Not always. Just because you're geared for 110mph dosen't mean you'll reach it.......... :wink_old:

Geared down alot of my sleds and never lost my top speed and in most cases gained

-grover
I geared down and gained a little on my fanner. If conditions weren't just perfect, the poor little guy just couldn't pull the stock gearing.
 

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When you gear down you need to make clutching changes to see the benefits of the change. 1 or 2 degrees less on the helix angle
 

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Why do you want to gear down? Unless your installing a different track I'd leave the 25 top gear in there for better top end.
I'm geared down and I still get to low 90s on the gps, 100 on the speedometer. Not much more to expect from a fully suspended 600.

Right now I'm clutched, geared, studded, aligned, and pretty happy with the results. The sled is way more spunky than it was stock. If the grass didn't appear so green on the 850 side, I would probably be happy for the rest of my time.
 

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Discussion Starter · #19 ·
When you gear down you need to make clutching changes to see the benefits of the change. 1 or 2 degrees less on the helix angle
Do you know what the right primary spring would be for my gearing set up and would that fix the problem? I dont think i want to spend tons on a new helix and stuff.
 

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Fuzzy but not Blue........
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You have a couple of options, first run it after a gear change and see what it does. If its down a little on rpm's you can take a little weight out, spring change with a little more end force or the cheapest would be just a "clicker" change.......

-grover
 
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