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Friday, June 4, 2010

Swingarms Are Better Than IRS!

Yeap, it's true!

I bet that got your attention, eh? Well, now let me jab you one more time! The only reason IRS is so popular is because consumers like you(!) demanded IRS because they(you!) thought Independent Rear Suspension systems were better. Huh? You bought ATVs with IRS rather than swingarms so manufacturer’s all needed to make ATVs with IRS so you would be competitive and you would also buy their’s!

Now let me explain myself. First of all there are no utility ATVs or UTVs than have optimized swingarm suspensions to use as a comparison, whereas IRS systems have undergone several years of improvement.

Now let’s also look at the fact that most IRS systems have huge sway bars that restrict the ‘actual’ independent travel of each of the rear wheels tremendously. Don’t believe me? Go out to your garage and put a jack under one rear wheel and jack it up. (Yeah I know that will require that you first jack up the ATV to get the wheels off of the ground so that you can then put a jack under just one of the tires. And yes I know you may need to sit on the ATV to put some weight on it to ‘try’ to make it move. And yes that might just be another problem here). So, did you do it? Then you know that there was little or no movement. Amazed? I know, it’s an amazing thing. If one rear wheel goes up, the other does too. It’s only independent depending on what you think ‘independant’ means – if you know what I mean….

So why is this so? Because completely independent rear suspension travel does not work on an ATV! If you disconnected the anti-sway bar you’d find that the high center of gravity of an ATV would cause the independent travel of the rear wheels to be a horrific problem, causing the ATV to lean tremendously in the corners, and fall over every time the terrain was uneven.


Let me explain a bit further. If you have one end of a vehicle with the wheels working independently of each other, the other end of the vehicle needs to be an anchor to keep the machine’s wheels below the rest of the machine (in other words it’ll fall over!) Hence a stable rear suspension system that can either be dual a-arms with a swaybar connecting them together, or a swingarm system with a solid rear axle.

Need some examples? How about racing ATVs. Or the ultimate off-road speedster, the ‘Trophy Truck’. Now if you checked out trophy truck suspensions you probably noticed that they are a unique blend of individual trailing arms with a solid rear axle. Arctic Cat had a very similar system many years ago that worked incredibly but was not accepted by consumers so AC switched to what was demanded – an IRS system with tons of ground clearance! And you guessed it, you lost again ;-)

You see, you need the stability of a solid rear axle for the ultimate in stability and handling. But don’t think that just because it’s a swingarm that it can’t have great travel. (refer once again to the comment regarding sport quads and trophy trucks). Why not set up a swingarm rear suspension on a Prairie or Rubicon with 12” of wheel travel? They do it on the sport quads and the trophy trucks…..Oh yeah, I said that already ;-)

So I contend that consumer demand for independent rear suspension systems have made ATVs handle worse than if we would have spent the time to develop better, longer-travel swingarms on our utility ATVs (and UTVs!)

Do I doubt my comment? No, I just got back from riding my tricked-out, Elka-equipped, Kawasaki KFX 700. And if I need more proof I’ll take a spin on the project Raptor…


  1. I might actually have to disagree on this one. That would be a real departure for me as well, you see I usually agree with your thoughts on ATVs and riding (not to mention a life philosophy.) "Always say your prayers, and never pass up a chance to ride." (just as an example) While I do freely admit that there is some merit to your a opinion on SRS vs IRS I hold that despite the limitations imposed by a sway-bar, there is still (all be it a limited amount) some independent motion between the rear wheels. However, I do agree that it is an industry standard to make the suspension too firm so as to show good ground clearance numbers on paper. Unfortunately this detracts from any positive that the IRS could give in ride quality. I don't dismiss the quality of a good SRS machine though. The new Rubicon is a real nice machine, especially that it now comes with powers steering, if only it was fuel injected... Justin

  2. Well, I read and re-read your comment and I didn't see any disagreement! Now just imagine that Rubicon with a realistic 10 inches of travel front and rear! Hmmmm?

  3. My disagreement is that I don't believe that a single rear swing-arm is BETTER. My experience has lead me to be quite impressed by the ride of the Rincon and it's IRS. I now currently own a 2010 800 Outlander XT, and with it's suspension dumbed down to it's softest setting (and with the addition of some wheel spacers) I find it to have a very forgiving suspension. I think that an IRS suspension has the potential to give a better ride and more predictable trail ride than a single swing-arm machine. The SRS certainly isn't the monster ride killer that it's made out too be either... And all variants of ATV suspension could benefit greatly from a softer suspension with a more neutral position rather than at continually sitting at the top of its travel range and barely moving.

    What about a rear suspension made more truck like? Not pivoting from a single forward point on the frame but still a solid rear axle? That would provide the anchor and the articulation? Or and improved version of the twin trailing arm suspension in the Outlanders?

    And...I'd love to see a Rubicon with ten inches of USABLE travel. I'd be tempted to buy it if it had some form of front locker and fuel injection.

  4. Your comment about the 'more truck like' rear axle is exactly what I was referring to regarding the older Arctic Cats - articulation and stability.

    But of course you've hit a soft spot as I feel the Outlander's rear suspension is the best in the world! Just a few tweaks on that and some better shocks (maybe only better shocks) and it would be even more incredible.

  5. I believe that the more 'truck like' axle appeared in the old 86' Honda Foreman in the front. The shocks were raked back at about 45 degrees to lessen the abruptness of impact. I think that probably made it very difficult to control though. But then that was back near the birth of 4x4 ATVs or even of four wheeled ATVs. I was just a pup back then so I might be wrong on that one.

    Unfortunately Arctic Cat is the only ATV manufacturer that I've never tried out, test ridden, or sadly even given a second glance to. I grew up on Honda, believing that nothing else of value existed. While I do admit that they are very good machines (I've owned five including the "mighty" 250r) I recently discarded my prejudice, and open-mindedly purchased my Outlander.

    I digress. I too love the rear suspension of the Outlander and until I can justify almost crazy money for a good set of after market shocks, I'll have to be content with the stock suspension on it's softest setting and installing better tires after these wear out. And I find woefully uneducated in Arctic Cat suspensions and unable to comment on their ride... I leave that to your experienced opinion.

  6. First off I'm not an IRS guy and much prefer SRAs for their side hill stability.

    I would be willing to bet that if the swingarm was just a little longer and the shocks on my ATV weren't near verticle that it would ride a whole lot nicer without loosing the stability factor.

  7. Stability is certainly a big advantage to a Swingarm suspension. It never ceases to amaze how well they work in difficult terrain and sidehills. In fact I went riding just the other day with a guy I know and the fact that he rode a SRA machine while I rode a tall IRS machine made him 'appear' to be a better rider.

  8. I want to ride your KFX 700 (insert smiley)

  9. "appear" (insert rolling eyes lol)

    As discussed in an earlier video Doug there is NO rider ability involved as to where my ATV goes; it’s all machine.

  10. I didn't realize that you had posted video's on rear suspensions and had singled out the Rincon and the Outlander! My two favorites in the IRS dept.

  11. No matter what is done to the suspension the ATV will always have the same problem…
    …”Top Heavy”. Truly if you want IRS then the ATV will have to be redesigned to something similar to the Polaris Razer, get the rider in the machine.
    The whole idea of IRS is to have each wheel and tire move independently, this really can’t happen with the current setup of ATV’s as we as riders like to sit tall on our rides, which by the way makes them top heavy.
    ATV’s were designed from motor cycles, don’t believe me just look at a motor cycle and compare that to your ATV, very similar, the only major difference is ATV’s have four wheels (early ATV’s had three wheels).
    To make IRS work then we as riders need to sit “in” the ATV and not “on” it, a whole new design concept to break the mold and start from scratch hmmmm this could be interesting. Perhaps this is what the ATV market needs, a makeover and a reason to have people purchase new ATV’s with a “New” and “Improved” design. However, would the consumer purchase the ATV in this new design or would the consumer want the current design? Who knows, one of the manufactures would have to present a new design on the market and see how the response would be. Very risky but the payoff could be great.


  12. Dan Gurney developed some motorcycles some years ago where the rider sat considerably lower than normal. Strange looking, incredible handling but never caught on.....and that leaves it wide open for us !

  13. A solid swing-arm is better becuase it can tow without the sqwatting of the suspension.It handle better, You are able to hang out the tail easier. And it has less moving parts. Also it is less complicated..

  14. It's probably to late to comment, but I agree with the first comment, solid axles, and swing arms are better. I had 04 Arctic Cat 650 IRS, didn't like it for hauling a trailer, it had the power, it had the speed, but now I'm at the age where I want something more stable, more for working/hauling fire wood. I'm now in the process of looking for the ATV that will go the slowest, and no wider 4', and must have a solid rear axle like the Honda Forman, which means I'm switching to Honda. I'd buy a small tractor, but the tires on front are to small/tiny, which is another one of my pet peeves. The biggest problem I see with IRS is now you have 4 more axle boots that can get cut, more brush guards to fool with/fabricate, and if they are boxed in to much, snow and ice will build up around the boots. Now if they can make axle boots that sticks wont go through, I wouldn't mind a Independent Rear Suspension ATV so much. That's my story, and I' sticking to it.