[Ride 207]

Im thinking about gearing down my 2001 ZRT 600 I want more low end, (I want it to wheely) What do you guys think I should do go smaller on the top or bigger on the bottom, And how much

Anyone got a price range of what new gears cost??
and will I need a new chain too?


Thanks :div20:

 

[81 Hydrostream]

:div20: 20/39 gears, and a 70 pitch chain. If you can find a 97 roller cover, and use the tower extensions, or a pre 98 secondary, you'll have better top end also..

 

[Ride 207]

Originally posted by 81 Hydrostream@Sep 17 2005, 04:51 PM
:div20: 20/39 gears, and a 70 pitch chain. If you can find a 97 roller cover, and use the tower extensions, or a pre 98 secondary, you'll have better top end also..
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[/quote]

I dont know nothing about gearing this is gonna be my first time doin it so if you could exsplain that a little bit more that would be great :div20:


Thanks :beerchug:

 

[drwho17]

Originally posted by Zert Man@Sep 16 2005, 11:17 PM
Im thinking about gearing down my 2001 ZRT 600 I want more low end, (I want it to wheely)  What do you guys think I should do go smaller on the top or bigger on the bottom,  And how much

Anyone got a price range of what new gears cost??
and will I need a new chain too?
Thanks :div20:
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[/quote]
Drop the top tooth to a 22, you can still use the 72 pitch chain fine this way. Will take you from .575 to .550. I don't think you need to change gears though, I can "wheelie" just fine with a mostly stock motor (and my suspension set up badly). I would mess with the clutching *first* that's where the biggest performance gains are for sure.

 

[drwho17]

Originally posted by Zert Man@Sep 17 2005, 06:35 PM
I dont know nothing about gearing this is gonna be my first time doin it so if you could exsplain that a little bit more that would be great :div20:
Thanks :beerchug:
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[/quote]
Changing gears is easy, if you go with the 22 top tooth, just open up the chaincase, and replace the top tooth with the new one, use the same chain, refill the chaincase.Like I said though, I'd mess around with the clutches, a more agressive helix would probably give you more of what you are looking for then a slight gear change will though. I'm not sure what those came with, but I remember mine liked a 57/50 when it had an AC roller, like you have.

 

[128jetsnake]

Not all sleds are the same, so some will respond differently to a gearing change. I don't know about the ZRT, but my brother went with a one tooth bigger bottom sprocket on his 98 ZR600 and it made it slower out to the hole. Just because you gear it down doesn't mean it will be faster out of the hole.

 

[81 Hydrostream]

Like DRWHO said, clutching is what will lift the skis on that sled. The gearing I suggested works well, but there is other things more important. Traction is most important, if you spin there's nothing you do that will lift the skis. I would start there first..

 

[drwho17]

Originally posted by 128JetSnake@Sep 17 2005, 10:45 PM
Not all sleds are the same, so some will respond differently to a gearing change. I don't know about the ZRT, but my brother went with a one tooth less bottom sprocket on his 98 ZR600 and it made it slower out to the hole. Just because you gear it down doesn't mean it will be faster out of the hole.
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[/quote]
That would be expected, your friend went to a taller gear ratio.
Example stop 23/40 = .575, drop the bottom gear one tooth to 39, 23/39 = .589. If your brother wanted more bottom end, he went the wrong way.. He should have dropped the top tooth 22/40 = .550, or went up a tooth on the bottom sprocket to 23/41 = .560.

From tallest to shortest
23/39 = .589 (1.69)
23/40 = .575 (1.73)
23/41 = .560 (1.78)
22/40 = .550 (1.81)

Lowest ratio being better for bottom end, higher ratio for top end mph. For my money a helix makes more difference then slight gearing changes. Remember the centrifugal clutch determines gear ratio also, based on where the belt is on the sheaves, by changing helix angles and spring pressure, you can change the characteristics of how the belt moves in the secondary, effectively staying in a lower gear longer if desired. A typical secondary multiplies from 3.8 - 1, if you steepen your helix, it stays closer to the 3.8 longer if you get what I'm trying to say. A steeper helix essentially makes the clutch shift out slower, meaning the belt rides higher in the secondary, and your gear multiplication is greater.

 

[ready2race]

It's better to change both gears, down on top ,up on bottom, works out to about tooth and a half, and is more efficient, less kink in the chain,you can still use stock chain. Better to see whats left in the clutches first though.

 

[Ride 207]

so clutch it first


OK im not gonna buy a kit Im gonna just buy new weights springs and a helix, do I need any thing else?
An suggestions on what to get?

 

[zr52k]

Originally posted by 128JetSnake@Sep 17 2005, 11:45 PM
Not all sleds are the same, so some will respond differently to a gearing change. I don't know about the ZRT, but my brother went with a one tooth less bottom sprocket on his 98 ZR600 and it made it slower out to the hole. Just because you gear it down doesn't mean it will be faster out of the hole.
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[/quote]
Thats gearing up not down... :doh:

 

[128jetsnake]

Originally posted by DrWho17@Sep 18 2005, 05:56 AM
That would be expected, your friend went to a taller gear ratio.
Example stop 23/40 = .575, drop the bottom gear one  tooth to 39, 23/39 = .589. If your brother wanted more bottom end, he went the wrong way.. He should have dropped the top tooth 22/40 = .550, or went up a tooth on the bottom sprocket to 23/41 = .560.

From tallest to shortest
23/39 = .589 (1.69)
23/40 = .575 (1.73)
23/41 = .560 (1.78)
22/40 = .550 (1.81)

Lowest ratio being better for bottom end, higher ratio for top end mph. For my money a helix makes more difference then slight gearing changes. Remember the centrifugal clutch determines gear ratio also, based on where the belt is on the sheaves, by changing helix angles and spring pressure, you can change the characteristics of how the belt moves in the secondary, effectively staying in a lower gear longer if desired. A typical secondary multiplies from 3.8 - 1, if you steepen your helix, it stays closer to the 3.8 longer if you get what I'm trying to say. A steeper helix essentially makes the clutch shift out slower, meaning the belt rides higher in the secondary, and your gear multiplication is greater.
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[/quote]

Originally posted by zr52k@Sep 18 2005, 08:59 AM
Thats gearing up not down... :doh:
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:doh: Yup, my bad, I confused everyone. I was supposed to say he ADDED one tooth to the bottom sprocket. Now that I lost credibility on what I'm talking about.

Like I said, I'm sure not all sleds will react the same way to gearing change, depending how they're set up from the factory. But, when you gear your sled down, make sure you have something to compare it to. Like I said, just because you gear it down, doesn't mean your sled will be faster out of the hole. My brothers sled wasn't.

Read my post again but use the words ADD one tooth instead of take one away.

 

[ready2race]

Wouldn't really gain much going up 1 tooth on the bottom, it's only about 1/2 a tooth compared to the top, and I think you need a new chain. Your are right ,each sled reacts differently, gearing up or stock helps more with some sleds, gearing down is not always the answer. depends alot on the conditions and power.

 

[128jetsnake]

^^^^^ Your right it wouldn't be much of a gain, because it lost, by quite a bit. With the stock gearing it was dead even with the test sled. After we added one tooth to the bottom sprocket, made the sled noticeably slower out to the hole, consistently. Believe what you want, but I know what I saw.

 

[ready2race]

Sled must had other problems, that gearing would hardly be noticable, let alone slow it down by alot ,600 is comparable to my 500 and even with stock gears it shoud be decent out of the hole. :dunno:

 

[128jetsnake]

We made a few runs with the stock gearing, runs were side by side. we pulled the sled in the garage, changed the gear on the bottom and ran'em again about hour latter, not much else could change, the sled was only a year old. It wasn't alot slower but about a sled length behind from 0-60 mph. A few inches is a lot, remember this is "hardcore" sledder.

So, like I said. Don't always throw in a set of lower gears and think you will be faster out of the hole, ain't going to happen.

I also seen a drag racer that said he runs a high gear then stock. :dunno:

 

[ready2race]

Yes.. A length is alot to lose, just doesn't make sence. Some racers do gear up but you need a light sled with alot of HP, most go down but you need traction also. I compare the 600 to my 580 ,I went down 2 teeth with that sled and it was a rocket out of the hole, but on soft snow it would get beat by smaller sleds. My bother inlaw had a 95 700ZR and I could beat him in a 1000Ft race maybe more, same as the 600ZRT's(hard packed snow)clutching must also match. I think the ZR 600 and my 580 both had 20/39. That puzzels me, It shouldn't be that much slower to 60, unless it's soft snow, I could see that. Hard to know, the 600 should be a sled to benefit from a gear change on the right conditions. :dunno:

 

[128jetsnake]

Yeah, this test was done on hard pack snow.

It was explained to me a while back on why it works this way and I probably shouldn't try to explain it, I think I would fail. But, it had something to do with, well hell I don't know how to say it, but the with the clutches in the mix it just changes things. Gearing down a sled doesn't always have the same effect as gearing down an old musle car because a musle car doesn't have clutches like a sled.

That doesn't help does it? :dunno:

 

[C-notesnopro]

Originally posted by DrWho17@Sep 18 2005, 07:56 AM
A steeper helix essentially makes the clutch shift out slower
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[/quote]
actually, just the opposite, a ''shallower'' helix makes the ratio stay lower(closer to 3.8) as it ''slows'' the upshift with more torsional resistance as belt fights the friction of the sheave counter rotating against the directional pull of the belt against the spring and ramp angle when combined under load,,,,,,,

a steeper helix acts just the opposite of above,, less torsional force required to let belt ''force sheaves apart'', mostly with side pressure from spring and less torsional friction from less rotating distance necessary to reach bottom of ramp against load of spring,,,,,,

 

[user2]

Our 99 ZRT600 bored to 700 with reeds and bored carbs works great
with a bearcat secondary and 24-39 gears. We use a BLACKMAGIC
belt number 1400. The bearcat helps give the tripple a stronger low
end. Runs with most 800s but not the F7 or the 800HO.