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OVERDRIVE P85 PRIMARY

Doc what did you calculate the overdrive % to be on the switch?
 
If machining your primary for more overdrive, but keeping stock gearing (22/37 on my Pro-S), is there any impact to low end and mid range performance? If I understand correctly, there would not be....?
 
Correct, and before you guys jump on trdehmer for not gearing down he is running a different track and drivers.. just saying . He is moving less air underneath.
 
I would like to try gearing down, but I am concerned it will slow me down!
1 way too find out ! lol
Are you getting full shift now ?

90 percent of the guys are not getting full shift , that's when gearing down recommended ..
 
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Not really sure to be honest, never had a real good long run to test it out last season....


1 way too find out ! lol
Are you getting full shift now ?

90 percent of the guys are not getting full shift , that's when gearing down recommended ..
 
If machining your primary for more overdrive, but keeping stock gearing (22/37 on my Pro-S), is there any impact to low end and mid range performance? If I understand correctly, there would not be....?
Your stock gearing has to be 23/37=1.60 a 22/37 is a =1.68, try the OD with the 1.68 ratio
 
P85 clutches will net you 5-10% overdrive from Poo. As you approach 1:1 and especially in overdrive, your cvt gets very inefficient. Most 150hp trail sleds on the trail will not pull very far into overdrive, even with perfect clutching.

I've heard this inefficient comment before when talking about overdrive but it's never been explained. What makes running a CVT system in overdrive inefficient? Inefficiency ususally comes from belt slipping or excessive "grip" (pinch...) on a belt? Are you saying this is what happens in overdrive no matter what or is there something else going on? Just honest questions. Thanks for any insight you can provide.
 
It has to do with the small radius the belt has go around in the secondary when in overdrive.
 
I just machine to get the most out of my clutches and don't worry about what anybody says about inefficiency. I know I get 10+ overdrive, sometimes more .
 
And there are no downsides to being capable of maximum overdrive, even if you don't get there.
Personally, I concentrate on tight corner to corner riding when possible, so I may never achieve the speeds to get into overdrive. Then it's only a 600 switchback too.
 
If you have the money to spend, go ahead and machine for overdrive, it certainly won't hurt anything. If you're looking for bang for your buck, don't waste your money on it, and certainly don't do the machining expecting to bolt it back on see some performance increase...you won't. Even Brock has admitted that he's only achieving around 10% in perfect conditions, a stock clutch will net you that. Waste of money for a trail sled IMO.


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If you have the money to spend, go ahead and machine for overdrive, it certainly won't hurt anything. If you're looking for bang for your buck, don't waste your money on it, and certainly don't do the machining expecting to bolt it back on see some performance increase...you won't. Even Brock has admitted that he's only achieving around 10% in perfect conditions, a stock clutch will net you that. Waste of money for a trail sled IMO.


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In my experience for the last 14+ years . Polaris has made the primary clutch safe and a 1:1 ratio only. It's hard to get even 5% overdrive out of a stock primary. It has to do with the rad, angle at bottom and sleeve bearing
 
If you have the money to spend, go ahead and machine for overdrive, it certainly won't hurt anything. If you're looking for bang for your buck, don't waste your money on it, and certainly don't do the machining expecting to bolt it back on see some performance increase...you won't. Even Brock has admitted that he's only achieving around 10% in perfect conditions, a stock clutch will net you that. Waste of money for a trail sled IMO.


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You just race modded sleds though don't you??
 
We all drive "trail sleds" until we hit the lake beside 2 or 3 buddies. Then a little bit of OD might make you the hero that day! LOL

Your statement assumes stock clutches don't go into overdrive. They do. So if you're looking for a "little bit" of OD, your stock clutch will give you that, no need to machine it. That's been my point this whole time.


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Your statement assumes stock clutches don't go into overdrive. They do. So if you're looking for a "little bit" of OD, your stock clutch will give you that, no need to machine it. That's been my point this whole time.


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It was a joke. I guess I shoulda said a little MORE overdrive!!!

I guess I like the idea of gearing down to accelerate/launch harder and still not losing anything on top. Kinda like putting 4.88s or 5.13 gears in your rear diff and adding 5th gear OD to your transmission.
 


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