RZR XP Replacement Radius Rods from Racer Tech

[Tony@Racer Tech]

Well, here we go. First new product from our new shop. We've had our XP in house for a while now and we've obviously been crashing UTV's for years now so by using our experience and resources I decided to start with the obvious stuff first. Here's the fix for about the weakest link on the RZR XP 900. These Radius Rods are a direct bolt-on replacement and work with the OEM trailing arm and knuckle/spindle. They are 1.25" dia. 4130 cond. N Chromoly and use 5/8" FK heim joints. The lower rod is designed to be a fixed length by turning the heims all the way in so they bottom out on the nut. This will help reduce issues with setups gone wrong. The upper rods have a little room for adjustments for the inclined rider to tweak the handling a little bit if desired.

We've already bent these and spoke to others who have as well. Heck, I literally bent one by kicking it! We will be releasing these on our website this week yet and posting in our vendor section with the official release including pricing. If you have questions please just give me a call. I'm busy wrecking this thing and designing new parts for it... http://www.rzrforums.net/images/smilies/hihi.gif

BTW, We have a lot of new things coming out for the RZR XP now that our big move is done. If there's something you have in mind there's a good chance we're already doing it. Feel free to email, PM or call if you'd like to discuss some ideas.
http://i91.photobucket.com/albums/k299/spectrumsandsports/Polaris%20RZR/DSC05619.jpg
http://i91.photobucket.com/albums/k299/spectrumsandsports/Polaris%20RZR/DSC05608.jpg
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Thanks! I'll post some pics up of the new shop later when its all organized.

You can find them on our website here (http://www.goracertech.com/products/rzr-xp-900-radius-rod-kit.html).

[Spicoli]

Great job guys. When I saw the XP in person that was one of the first things I noticed as a weak point.

[JimandMelissa]

The cars with trailing arms I'm used to seeing don't have radius arms. I'm trying to understand why they have them on these cars?

Sorry if it's a stupid question.

[mtoma]

Great idea, that always looked like a weak spot.

[Andy@Racer Tech]

The cars with trailing arms I'm used to seeing don't have radius arms. I'm trying to understand why they have them on these cars?

Sorry if it's a stupid question.

It's not a stupid question at all. There seems to be a lot of confusion about the RZR XP rear suspension. What you need to know is just because it has trailing arms it doesn't mean it's a true trailing arm suspension. It's more of a three-link design than anything IMO. The Commander has a true trailing arm design, where the hub truly "trails" the pivots.

[JoeyD23]

bad ass!!! great idea guys!!

[JimandMelissa]

It's not a stupid question at all. There seems to be a lot of confusion about the RZR XP rear suspension. What you need to know is just because it has trailing arms it doesn't mean it's a true trailing arm suspension. It's more of a three-link design than anything IMO. The Commander has a true trailing arm design, where the hub truly "trails" the pivots.

What doesn't make sense to me, is with radius arms set up that way, the wheels will move in and out from the centerline as they travel up and down. I haven't seen an XP up close. It would seem the leading edge of the trailing arm needs to give some how to accomodate this.

Even if it does, I'm still wondering why they did it this way?

If someone has a pic of how the trailing arm connects to the chassis it might help.

[Bajaxp]

Heim joint in the front accomodates the movement.

With a traditional trailing arm you really can't design in track width changes or camber changes. Polaris did this by design for handling reasons and if you have driven an XP you have to admit it handles awesome.

The new radius arms look really nice and I will bet they are lighter. The kick test did crack me up though. Go kick the front steering arms coming out of the rack on a Class 1 car. I bet they bend! Haha...:D

[JimandMelissa]

Heim joint in the front accomodates the movement.

With a traditional trailing arm you really can't design in track width changes or camber changes. Polaris did this by design for handling reasons and if you have driven an XP you have to admit it handles awesome.

The new radius arms look really nice and I will bet they are lighter. The kick test did crack me up though. Go kick the front steering arms coming out of the rack on a Class 1 car. I bet they bend! Haha...:D

Thanks

[07fj]

Heim joint in the front accomodates the movement.

With a traditional trailing arm you really can't design in track width changes or camber changes. Polaris did this by design for handling reasons and if you have driven an XP you have to admit it handles awesome.

The new radius arms look really nice and I will bet they are lighter. The kick test did crack me up though. Go kick the front steering arms coming out of the rack on a Class 1 car. I bet they bend! Haha...:D

come try and bend mine, I bet they don't.

and I doubt, the RT arms are lighter than stock POPO.

[Tony@Racer Tech]

Our arms are a little heavier than stock the complete kit weights in at 12.7 lbs. Not sure on the exact stock weight. We also have the HD tie rods complete and will give you guys a 1st peek at those when I get some pics.

[Andy@Racer Tech]

Yeah, you can't kick-bend the tie rods on our Class 1 cars either... :D

The Racer Tech Radius Rods are not lighter than the OEM ones. They weigh 12.7 lbs. as a full set including the spacers and all. I have yet to weigh the OEM ones but I'll try to today. Bottom line though, I don't think it's possible to make something strong enough to fit the application our rods do and still weigh as little as the OEM twigs...

[tatum]

Maybe if you made them out of aluminum foil.

[07fj]

Maybe if you made them out of aluminum foil.

lol :)

For Andy, many peeps are worried about the lower rod catching on things, any reason you did not put a bend in them and bring them up near the wheel? does it cycle that same ( camber) if you did or not?

nice pieces BTW.

[Bajaxp]

The point is the radius rods were designed to take compression and tension loads not shear or a bending moment...just like a tie rod. So kicking at them proves nothing. As I said before, the Racer Tech rods look really nice. Good work!

[Andy@Racer Tech]

lol :)

For Andy, many peeps are worried about the lower rod catching on things, any reason you did not put a bend in them and bring them up near the wheel? does it cycle that same ( camber) if you did or not?

nice pieces BTW.

Thank you, and that's a good question. I have addresses this on our website a bit HERE (http://www.goracertech.com/products/rzr-xp-900-radius-rod-kit.html). But I will also give the elaborated version as well; A lot of people have asked about our stance on bent lower rods for better ground clearance and why we haven't offered them. Here is where we stand on the subject; the issue with any bent / trussed/ etc. design (beside the inherent weakness added by having a rod that's already bent) is the additional leverage applied when something does try to wrap around the bar and tug on it. When it's a straight tube there is only a two dimensional push/pull on the rod. If it's a bend of any kind it's a three dimensional situation and the center to center axis of the ends becomes a fulcrum point for the bent tube to rotate about while it's being pulled or pushed. Essentially, the rod will just try to flop around. The biggest issue with this particular application is the ends need to be a form of a spherical joint to work with the motion of the suspension. If this was some sort of a bushing/sleeve application the bent rod would be no problem. These new rods are going to be very hard to bend or break even if they do hit something.

While using a "bent" design rod won't change anthing about the suspensions geometry, (Because the suspension only cares about the imaginary lines from point A to point B.) We feel there isn't enough advantage gained from using a bent rod to outweigh the disadvantages gained at the same time.

[Andy@Racer Tech]

The point is the radius rods were designed to take compression and tension loads not shear or a bending moment...just like a tie rod. So kicking at them proves nothing. As I said before, the Racer Tech rods look really nice. Good work!

Thanks!

I do have to disagree with you about the kicking test however... The fact that I can kick a factory rod and bend it does have some bearing on the debate in my opinion. You are very much correct in the statement that these rods are designed for compression and tension loads, however the issue comes in to place when the loads are not 100% directional or when the load overcomes the mechanical strength of the rod. At this moment, something has to give. By kicking a OEM rod and bending it, I think it proves the lateral forces needed to bend the rod is small and far less than what will be incurred on many drivers normal day out. By installing our HD Radius Rods the force required to bend them is exponentially higher which overall makes the rear suspension way stronger.

I should also point out that I feel this point in itself should add some validity and another layer to the reasoniong why we don't believe in "pre-bent" radius rods even if they do gain clearance...

[JimandMelissa]

By strengthing the rods which might act as a sort of fuse link on the suspension, is the potential stress being moved to a more costly part in the event of a rock strike?

[Andy@Racer Tech]

Good point, but I don't believe in "fuses" in suspension systems. I believe there is always a weak link, but deciding what weak link you want to leave and how weak it really is makes the most sucessful performance and durability. The fact that these things are bending so easy tells me the weakest link is too weak yet. To answer you're next question, the next weakest link after the radius rods is the rear diff. plate which the radius rods mount to. We've already got that fix in the works... :D

[JimandMelissa]

Good point, but I don't believe in "fuses" in suspension systems. I believe there is always a weak link, but deciding what weak link you want to leave and how weak it really is makes the most sucessful performance and durability. The fact that these things are bending so easy tells me the weakest link is too weak yet. To answer you're next question, the next weakest link after the radius rods is the rear diff. plate which the radius rods mount to. We've already got that fix in the works... :D

Do you think having the adjustability in the geometry is worth the potential downside of this design for the average user? I can see it in a racing app but not sure "average Joe" will ever change his camber or width.

[Andy@Racer Tech]

I don't think there's a downside to the user no matter who they are. We obviously hold a place in our hearts for the racers but we also realize that our bread and butter comes from the "Average Joe's". This is why we try to make decent instructions and lay out the facts very clearly about what changes will affect different aspects. Besides, if someone is paying for our parts we assume it means they want best. In our opinion the best includes a degree or two of adjustability.

We designed this kit so there essentially is no adjustment for the lower rods and the upper is the only thing to play with. Our suspension systems we sell for other models are some of the most adjustable in the business and I can't say I've ever heard anyone truly complain about having the option. ;)

[JimandMelissa]

I don't think there's a downside to the user no matter who they are. We obviously hold a place in our hearts for the racers but we also realize that our bread and butter comes from the "Average Joe's". This is why we try to make decent instructions and lay out the facts very clearly about what changes will affect different aspects. Besides, if someone is paying for our parts we assume it means they want best. In our opinion the best includes a degree or two of adjustability.

We designed this kit so there essentially is no adjustment for the lower rods and the upper is the only thing to play with. Our suspension systems we sell for other models are some of the most adjustable in the business and I can't say I've ever heard anyone truly complain about having the option. ;)

Hope I'm not coming off as attacking you or Polaris. You guys do great work and this upgrade makes perfect sense.

I was more questioning what the logic was behind the design from the factory and why it's better than more traditional trailing arms or a-arms for overall function and durability.

[Andy@Racer Tech]

**NEWS FLASH**

So I just weighed the OEM radius rods and they weigh 12.1 lbs complete. This puts the weight gains from switching over to the Racer Tech HD Radius Rods at 0.6 lbs!

[Andy@Racer Tech]

Hope I'm not coming off as attacking you or Polaris. You guys do great work and this upgrade makes perfect sense.

I was more questioning what the logic was behind the design from the factory and why it's better than more traditional trailing arms or a-arms for overall function and durability.

No problem, I actually just started posting here today even though our company has been a sponsor for a bit... I actually enjoy having logical technical questions asked of me. I don't find this as much other places...

I can't say I've seen this design acclaimed to be a reinvention of the wheel, or for that matter as anything better than an A-arm or trailing arm. I really haven't decided yet if I personally believe this three link setup is better than a traditional trailing arm design. My first thoughts were that Polaris just got lazy and did it for packaging, (Obviously a true trailing arm wouldn't work on this model). After using it a little bit and swinging it around on CAD I'm still not convinced otherwise. I think it's a pretty neat packaging solution, and I think we'll be able to do quite a bit with it. I guess I just feel like it shouldn't be getting labeled as a trailing arm just yet... It should be called something else. And only time will be the judge of it's performance and staying power.

With this all said, my final thought on providing adjustability in our replacement rods is that as we release some of the other things we are currently developing for the rear suspension of the XP, this will all make much more sense. :cool:

[tatum]

Awesome info Andy.I am curious if this setup saves weight.It obviously still has scrub during travel.

[Andy@Racer Tech]

I'm not sure yet... We just moved into a new building so I can't find everything at the moment...

RZR XP Trailing Arms - 16.85 lbs. each (no bolts included)
RZR XP Radius Rods (OEM) - 6.05 lbs. for one side (1 upper 1 lower)
RZR XP Rear Knuckle - 4.20 lbs. each assembled w/ bearings

RZR S Rear Knuckle - 4.65 assembled w/ bearings, bushings and sleeves
RZR S OEM A-arms - ???

If someone can fill in the blanks for the OEM RZR S arm weights we'll have our answer on the weight comparison...

Maybe we should start a new thread on this though...

[Andy@Racer Tech]

Taking orders now for the FIRST radius rod replacement kit on the market. :rolleyes:

Racer Tech - RZR XP 900 Radius Rods (http://www.goracertech.com/products/featured/rzr-xp-900-radius-rod-kit.html)