Polaris XMF XP 900 Build

[tjof1959]

Seen you in the pits yesterday didn't want to bother you before the race with tech questions. Just wondering if you don't mind me asking what year is this thing, your a-arm mounts look much better and different than my 2011.

Real nice car btw.

It is a 2011. This is a plus 3 kit so we can run desert also.

 

[tjof1959]

Bent wheel thats surprising I was trying to figure those out looked like a hyper plastic outer rim with a metal casted center didn't find a mfg name, I bet the metal bent?

Actually it was not the wheel, we lost a rear link arm which in turn rotated the trailing arm and wheel out. We are not sure what happened but XMF is making new ones.

By the way the wheels are from Hiper Technology. We have been using them for 3 years and have not had any issues (knock on wood). We use them for our desert races also.

 

[TNT]

I’m not sure what links your running but if you don’t have uniballs and misalignment spacers(good ones like FK on both ends) you will run into binding and fatigue issues at max (14”) travel that may not be noticeable in the shop static test. There are two arcs those links swing through @ 90 deg to each other, one is 2 foot link the other is about 3 foot arm. Not sure but I think you were running aftermarket arms, if they twist dynamically it will put your links and articulation structure in bending it was not designed for.

What’s confusing me is if you look @ your upper chassis you have 4 a-arm tabs, my 2011 has 2 and my tabs look much thinner than yours. Dragonfire has come up with this kit since some are breaking them off or elongating the holes. Did your kit modify the chassis tabs?

 

[the stripping shop]

i have a question on dragon fire kit. why would you stiffen the lower arm when the top arm is your load bearing arm. The upper arm is one bolt stock. Xmf makes a plate for the load bearing arm to a 2 bolt set up. Xmf kit in my eyes would work alot better. dragon fire more weight and still doesn't fix problem.

 

[TNT]

I never heard of XMF and I tried goggle but don't think I am finding this kit, can someone please post a link to this kit so I can what they have done?

 

[JoeyD23]

www.XtremeMF.com

XMF is one of the top producers of aftermarket UTV suspensions, chassis', and accessories. XMF builds quality, championship winning race machines and it is not too far off to say that XMF has been a part of more UTV race wins then any other aftermarket UTV company in the industry. Jimmy and Scott are not only well respected and well known amongst the UTV race community but they are known to be amazing fabricators and designers of suspensions and other race components. They are also shock experts when it comes to valving and tuning for their specific applications. Outside of Walker Evans Racing, XMF is the most knowledgeable Walker Evans Racing shocks tuners in the industry.

XMF is also sponsors of UTVUnderground and love to take care of our members!

 

[rappy60guy]

Tnt , There are a few manufactures that are working towards the upper arm problem. I am not intending to plug anyone here but Cognito has arms for the xp and they require new tabs to be added and welded onto the stock chassis. I am very happy with the results. Here is a close up of how they have done it on my race car.

 

[rappy60guy]

Dennis who did your wrap it looks Awesome

 

[TNT]

Ok, thanks, hopefully if I get some time tomorrow I will call XMF to point me to their kit, then Cognito, two companies I never heard of don't matter I know structure, to tell them what I think first and make sure I understand their design intent.

Joey said he takes pride in this sites "freedom of speech" without regard to any vendor or member-owner of a product, unlike my experience with RZR.NET so there is my free speech ticket . If the truth hurts RZR.Net mods don't send me another PM now just go ahead and add me to the many members of the "Banned for life" club.

Next my comparison of both these companies design to Dragonfire with tech reasoning I open to anyone to comment to, the good, bad, and ugly lol....stayed tuned.

 

[rappy60guy]

Cognito crew will be out at Worcs glen helen tomorrow may have to call them on monday. Another great thing about Cognito is they are there for racer support

 

[the stripping shop]

Question to TNT if you look at dragon fire and compare to XMF they are doing the same job. Just one company is doing it to the load bearing arm and the other company is doing it to the non load arm.Were do you need the most structure at?

 

[TNT]

I wish I could explain this in a sentence or two but I never can sorry for the long winded answer and I hope it makes sense complicated topic structures designs takes years to be good at…..

Before we can understand structure we need to understand loads and weight distribution, three different things but very dependant on one another. If you understand them your designs will do much better.

Ideally in the new design R&D phase, which the aftermarket XP900 still is, loads are developed initially by empirical(existing from other models, past experience) data to develop prototype test units, in some cases several to test inconsistencies. In all industries, the first delivered units are field tested, re-doing loads & redesigns can occur years later. I have been involved and am currently doing cost redesigns of structure 10-30 years old. We all make mistakes especially when there is pressure to get a product to market based on competition or other red tape like SAE.

In the case of the front arms, load comes into the tire patch based on caster, camber, toe alignment. I like to think of load as water flow through a hose that does not like kinks or bends, and at every juncture there has to be structure to make a smooth loads transfer. I mean through the arms, chassis, from the arms to bolts, bushing’s, etc. With that said, the lower arms see the highest loads since they are closets to the tire patch, that is why PoPo put twice as many chassis lugs there than top that are too thin. So if one were to strain gage the upper/lower lugs of the same geometry and found that upper sees half the loads, the lowers are just as susceptible to failure.

Basically loads have several components at any joint or juncture, up/down(vertical), forward/rear(horizontal), in/out(side), and resultant loads or forces. It really does not matter how your orientate the loads axis the resultant load will be the same. Structure can then be designed to take the loads out or not depending on the type of load @ the joint(i.e.: chassis lugs) are seeing(tension(how cracks occur), compression, shear, bearing, fatigue, etc…..

Different shape structure takes out different loads. Flat plate you will see in DF’s design takes it out along or in the same plane as the width/length directions, not that well the thickness direction in bending. If the plate were square it takes it out equally in width and length. Now you can look at DF’s rectangular plate and see what it’s doing to add strength in what direction. Tube is good or better at taking out vertical, horizontal, side loads, best along its length.

If you increase the distance the load is from the center of gravity of certain structure or car by running widening kits it multiples the load(bending moment) by that distance(i.e. + 6) and acts on all structure to a degree.

We usually pad up loads and structure for a margin of safety, once proven by field testing a weight reduction effort reduces the impact to structure.

I leave you guys with that to think about while I'll try and get a hold of XMF today then we can take a closer look at the structure.

 

[JakeJean]

Dennis who did your wrap it looks Awesome

RZR Wraps. He won a free wrap a few months back thanks to UTVunderground. It came out looking sweet, except for one of the letters on the right side didn't fully come out. Can't really complain about free stuff.

 

[Scott@XMF]

Terry feel free to give us a call we dont have a lot of data published out on the kit as of now because when we release product it has already gone through testing on a limited number of cars and we are not quite done with that. As for the front arms we added the upper tabs to eliminate the long bolt that from past expeirence had give everyone troubles we also increased the diameter of the crush tubes and bolts size. We use quality rod ends and monoballs. We dont expect to have troubles with the front arms as they are almost identical to our + 8 kit for the regular RZR (s) we have produced for over three years in fact it was on the first walker evans race car we built and have had mulitple racers using the kit with out arm failure. We are not perfect and can take contructive comments.
You have to keep in mind that by governing bodies and rules we can ony modify the chassis so much and still be legal

Hope that helps much easier to talk to someone than type on the computer hope that helps and feel free to call the shop with any of your question

Thanks Scott
623 465 9689

 

[TNT]

Scott, I called at my lunch left msg feel free to call back any time, or if it’s easier my email is Terrylport@yahoo.com. I can’t for the life of me find a pic of the 900XP front arm kit on your site maybe I am blind. My question is how did you attach your four lugs or two added inners and you used the stock outers? I assume welding like Cognito or bolt on lug fitting's like DF? Also chassis mods to the lower lugs, same questions? I can’t find Cognito’s kit on their site either and no answer must be @ Worc’s.

If you welded like Cognito to the stock chassis my next questions are do either of you know what steel PoPo used, it’s carbon content, and weldabiliity? Also who does the welding you or your customers/racers and do the welds get stress releived? Looking at Cognito customer no stress relief is my guess.

 

[TNT]

Question to TNT if you look at dragon fire and compare to XMF they are doing the same job. Just one company is doing it to the load bearing arm and the other company is doing it to the non load arm.Were do you need the most structure at?

Got a chance to talk to XMF, I have all the info I need to answer this early next week. Let me think how to put it together to not step on any toes. Ugly situation any way you look at it, best easiest solution if Pol had just thickened up the tabs maybe a bigger bolt to prevent such headaches making it more race ready. Don't know what thier Engineers were smokin! Same kinda designs can cause manufacturing cost issues making it far more difficult than it needs to be, perhaps in part the reason the MSRP is so high.

 

[Mitch G]

www.XtremeMF.com

XMF is one of the top producers of aftermarket UTV suspensions, chassis', and accessories. XMF builds quality, championship winning race machines and it is not too far off to say that XMF has been a part of more UTV race wins then any other aftermarket UTV company in the industry. Jimmy and Scott are not only well respected and well known amongst the UTV race community but they are known to be amazing fabricators and designers of suspensions and other race components. They are also shock experts when it comes to valving and tuning for their specific applications. Outside of Walker Evans Racing, XMF is the most knowledgeable Walker Evans Racing shocks tuners in the industry.

XMF is also sponsors of UTVUnderground and love to take care of our members!

XtremeMF.com Is the best !

 

[TNT]

Got a chance to talk to XMF, I have all the info I need to answer this early next week. Let me think how to put it together to not step on any toes. Ugly situation any way you look at it, best easiest solution if Pol had just thickened up the tabs maybe a bigger bolt to prevent such headaches making it more race ready. Don't know what thier Engineers were smokin! Same kinda designs can cause manufacturing cost issues making it far more difficult than it needs to be, perhaps in part the reason the MSRP is so high.

im not sure why tying 2 "crappy" design tabs together solves any problems, wouldn't a far better solution be to just weld a mount over top of the existing one?

There is no doubt box structure or strapping lugs together will keep concentrated load away from a single lug and help keep them from bending. Give DF a call I think they have proved it on the race track. Sorry if I got confusing in explaining how, as you can see structural design is complicated if not done correctly can develop issues.

You can try and weld and if you understood what I have written you know what you are trying to accomplish in your design. By doing so forget any warrantee claims if you have an extended. I think you will very likely go down a road you don’t want to travel. If you look at those large tubes POL has in the chassis that is because this highly loaded area. Welding as you may know stresses the material primarily at the transition area between the bead and original material. You can loose up to 40% of its strength if not stress relieved. If you don’t know the type of steel POL used and its weldability, or whether it has high carbon content, or where to place your beads, you can easily develop hydrogen cold cracks that will be difficult to repair. Your choice then would be to weld or bolt on doublers and repeat the cycle leading to a new chassis.

But suit yourself; DF has the best bolt on solution on the market so far. Good luck!

This is the answer I gave when comparing welding to Dragonfire. I assumed he was asking about welding washers/doublers over the two stock upper end chassis lugs, not adding two additional inner ones as Cognito and XMF have. The degree of residual stress and knock down factor to material strength depends on a lot of factors, mainly thickness of the chassis which this one is thin, alloy or carbon content of the chassis which is unknown, how much the joint is constrained in this case primary structure seeing a lot of load, all of which can vary from previous models. Four welded lugs are better than two if you can keep the new welds away from existing welds which is difficult. There is no way around a strength reduction even if stress relieved. At the factory welds are stressed relieved by submersing the entire frame in a heat solution bath, but 100% of the strength is not restored. After market drilling holes in the frame is not better than welding making this a tough situation.

Question for DF is how interchangeable their design is and how well it will distribute load. Looks like they boxed themselves into four hard points. I’d hope PoPo jig located these lugs, just a matter of which side is the tooling surface(assuming inner) with the least location tolerance.

So to answer the question, pick your poison worse being to keep the upper arms and weld to two stock tabs, next DF or other bolt on and four welded lugs(two stock) XMF/Cognito probably have the same chance of survival more testing will tell.

As I said easiest most economical solution is PoPo thicken up the tabs to begin with. I’ve seen this before in the quad industry, gusset kits swapping arms to race, then the OEM’s starting fighting for “Race Ready” off the show room floor, now most don’t need gussets/new arms more can afford to race. Well that was until the aluminum frame showed up by Can-am DS450 in 2008..J/K! Had some weak spots but overall very strong and light bolted w/permanent swaged on high strength aircraft fasteners(hi-locs) no welding, extruded rectangular shapes nice job! Aluminum is a challenge to weld too, 6061 is best, but the stock extrusions were more than likely 2024-T3.