Lately there have been several mentions of front CV joint problems on this forum and it seems many who’ve experienced this also have lift kits. My ’99 SP500 has about 2200 miles on it now and fully half of those have been with the bike floating a little higher on High Lifter’s kits, both front and rear. I’m turning 26” Mud Runners on stock wheels and no CV problems, yet.

That’s not to say I have no concerns about this setup. The lift kits drastically increase the downward angle of the axles and could theoretically cause premature wear / breakage. When I installed my front lifts I did it with the machine fully suspended on the frame and all the tires off (was doing routine service at the time too). As a “dry run” once I had the lifts installed and before I put the tires back on I fired it up, put it in AWD and slipped it in gear. I was more than a little shocked to find that, in this condition, with no weight on the suspension and the struts fully extended, both front hubs would “jump” at a similar point in each revolution of the axle. I presumed then, and still do, that with no weight on the suspension the axle angle was too drastic for the front u-joints to handle in one spot of the revolution. I blame the u-joints because in my limited experience with systems like these it seems they would be more likely to cause this than a CV joint, but that’s a semi-educated guess. No such problem was noted in the rear.

With the tires on, the bike back on the ground and the suspension compressed no “jump” or “glitch” is felt in the front end at all. Since I’m not a jumper (this thing weights over 800 pounds with my riding gear on it) I haven’t been too concerned about the “problem” I found with the front suspension unloaded. But lately we’ve been doing a lot of riding on sled trails, and after heavy traffic they’re nothing but a long series of whoops. Unless I keep it under 4mph I can’t help but “get air,” especially under the front end. Every time I’m “flyin’ I can’t help but remember what I saw the hubs do in a similar condition suspended on my hoist. Nothing has broken yet but the talk on this forum has given me even more reason to be concerned so I thought I’d pass this along to those of you who are considering lifting your quad. I like the extra clearance the lift kits give my machine but if things start to break I’ll probably remove them, at least for winter riding.

 

Dear Sir:
I have two 2000 Sportsman Polaris with 27" Vamps all around. I have broken the front CV on each machine. Both times I broke the CV, the wheels were in full left or full right and going reverse. Even the slightest amount of throttle under these conditions will cause them to break. The rears in my opinion will never break. But the front are definitly handicapped in that aspect. As for your concern getting air on the whoops. I ride 2wd most of the time I have gotten plenty of air as 4wd and have not seen a problem yet. I really think that the damage will only come to play when the wheels are in either extreme and you go in reverse.

 

That’s very interesting. While you don’t mention it, may we assume that since you’re running 27” Vamps your machines are lifted?

Since AWD engagement occurs at the front hubs, “outside” of the CVs, there really should be no difference between 2WD and AWD because either way the u-joints, axles and CVs are still turning when you’re in gear. At least no difference as it applies to this discussion.

If your machines are lifted I guess we can somewhat safely say that the most potentially damaging thing you can do is back up in an extreme left or right turn. Do I have that correct?

Good info, Thanks.

 

Hey flood,

Have you brought this to the attention of Highlifter? What did they say about the difference in front-end geometry?

 

You are absolutly right. I did neglect to mention that I do have Highlifters lift kits installed. Now that I got that fact in, I want to add to your comment regarding the awd. True, regardless of where the switch for AWD is positioned, the front drive system is rotating. Since there is no force being placed on the CV's themselves there is not problem with turning the wheel full left or right. Once the awd is activated only then will the CV's actualy receive force. That's where you got to be careful on extreme turns. Again I have only experienced failure going reverse and having the wheel in an extreme left or right turn. It makes sense also because when you go reverse and AWD is active the steering actual is forced to go to the extreme by the tires traction. In a forward motion the wheels want to go away from an extreme turn. I hope this sounds right. I can visualize what I am saying I just dont think it is coming across correctly. Anyway this has been my experience.

 

You are absolutly right. I did neglect to mention that I do have Highlifters lift kits installed. Now that I got that fact in, I want to add to your comment regarding the awd. True, regardless of where the switch for AWD is positioned, the front drive system is rotating. Since there is no force being placed on the CV's themselves there is not problem with turning the wheel full left or right. Once the awd is activated only then will the CV's actualy receive force. That's where you got to be careful on extreme turns. Again I have only experienced failure going reverse and having the wheel in an extreme left or right turn. It makes sense also because when you go reverse and AWD is active the steering actual is forced to go to the extreme by the tires traction. In a forward motion the wheels want to go away from an extreme turn. I hope this sounds right. I can visualize what I am saying I just dont think it is coming across correctly. Anyway this has been my experience.

 

I agree with you floodrunner, it only makes mechanical sense of the extended angle of the shafts puts extra tension/pressure on the CV joints. I have been reading these forums for a while, and have bought 4x4 ATVs in the last year or so. I read lots of stuff and spoke with several people through e-mail that had "big foot" kits, or simply tall tires and lift kits from high lifter--or a company like them.

I always wanted a big-tire 4x4 when I was getting my 4x4, but I didnt want the breakeage from lift kits and the such that you hear about all the time. (different brands have more trouble than others some time) So when I got the Magnum 500 (which I have now sold to my father) I bought 25x9.5 Vamps for the front and 25x13 Vamps for the back. With this set-up, I dont need a lift, I dont raise the center of gravity (dont need that on these big boys!) , and I have great flotation cuz of a little wider tire in the back. Plus I dont change the effective gear ratio of my ATV by adding bigger tires, the stocks were 25" tall, just like these. So problems people have burning belts, and the such in sticky stuff with 27" and 28" Vamps--or having to add lots of power mods, I dont really need, keeping the stock height allows me to spin the h@ll out of them if I want to, because the power that the engine gets to the ground has not been compromised due to a different ratio.

But, I have a friend (wjptcs on these forums)that has a 00' Sportsman 500 that he has lifted and has 27" bi/tri claws set up, and a bumper that he has designed to hold his winch--and that thing looks bad-a$$!! Unfortunatly he has already had CV joints go out with only about 80 miles on it--and the dealer wouldnt give him warranty! needless to say he wasnt very happy about that!

have a good one,

Billy Eldred

'00 TRX400EX

 

No I haven’t contacted High Lifter about it. First of all, the “problem” I found can only occur with the front suspension unloaded. Realistically that probably happens in only a fraction of the riding time most lifted heavy utility machines encounter. Like I said, I have over 1000 miles on my lift kits without a problem. If there’d been one you can bet I’d have questioned them about it.

But even then, aftermarket mods are a buyer-beware proposition. We’d hope that companies do their research before bringing a product to market so they wouldn’t intentionally or even unknowingly sell us products that cause damage. But part of that equation is the type of owner who makes these mods is more likely to push their machine beyond what the average rider would. Then the thin line between use and abuse comes into play.

Just for example, take a look at the wheel offset of some of the Bigfoot Kits out there. They increase the machine’s track by up to 8”. And have you ever seen the pic of that SP500 with the dual tire and wheel kit front and rear?!? You can’t tell me mods like these don’t increase stress on the drive train, suspension, frame, you name it.

Anytime we modify a stock machine we have to accept a certain amount of responsibility for the results. That’s not to say none should be borne by the manufacturer. Each of us has our own idea of what desirable performance and acceptable reliability risk is. The trick is to push the envelope without breaking it.

 

Alsfrt, turning torque IS a tough condition to describe in print, but I know what you mean. And you’re right, I was only considering the angles the u-joints and CVs were capable of operating at without load. Engaging the AWD adds the sometimes considerable stress of having to rotate the front tires. I can easily see how this would contribute to breakage. Good point.

 

Yep.. I broke it.. When I broke my front cv joints the machine was sitting fairly flat, but the wheels were turned fully to the left. Every time that the left wheel would spin and kind of bite you could hear the cv joint click. This only happened when the steering was fully turned either direction, and in forward or reverse. It really should not matter how loaded the front of these machines are at the time it happens, because if you have just bigger tires and go fully turned left or right. When those big lugs bite hard and you give it the gas the cv joints are taking more stress than they were designed for. Thats exactly what polaris told me when I contacted them. Even without a lift kit, non stock tires will void the warranty because of the extra stress created on the joints. You will seldom ever have any cv joint problems on the rear of a machine as these joints never turn (left or right) and are not subjected to that type of stress, however I have seen 2 of these twisted out of a machine because the rear tires had a bite and something had to give.

Hey BillyEldred....