ATV TEST: Polaris Outlaw 525IRS vs. 525S – blast from the past

When Polaris first introduced their Predator 500 sport quad, it wasn’t a big success. Tranny issues and handling woes kept it from besting its competition. Although Polaris made some very good improvements to the Predator in the following years, they were not good enough to make it a winner. A few years later, Polaris then shocked the ATV world by introducing the first independently rear suspended (IRS) sport ATV. That machine, called the Outlaw 500, featured the same 500cc Predator engine and a chassis that performed very well in rough, rutted and choppy terrain. Weight and gearing issues ended up being that machine’s handicap.

In 2006, Polaris made a strategic business partnership with KTM to share development ideas dealer resources, and started purchasing engines from the Austrian-based company. That relationship allowed Polaris to use KTM’s lightweight and very powerful engines in the IRS equipped Outlaws.


Polaris was so pleased with the performance of the KTM engine in this Outlaw, they developed two more models featuring KTM powerplants bolted into a typical straight axle, sport quad chassis.

One machine features a motocross setup with eighteen-inch tires and a 450cc engine called an Outlaw 450MXR. The other new Outlaw is called a 525S and has twenty-inch tires and a 510cc engine.

With all the new Polaris Outlaw models to choose from, we wanted to see how they rate against each other. For this test, we are comparing both 525 machines head-to-head. The 450 will be compared at a later date heads up to the other six manufacturer’s 450s that are offered for the 2008 model year.

This month we rode each of the Outlaw 525s in the dunes, through the woods and on the track. Basically, the only physical aspect of each machine that is different from one and the other is the rear suspension. However, that major difference has an effect on portions of the ATV not only in construction and handling, but in maintenance and engine performance as well.


The new 525S Outlaw features a standard swingarm setup rear end that utilizes a linkless shock mount with ten inches of movement. Preload, compression and rebound are adjustable.

A strong steel swingarm provides the lower mounting point of the rear shock and houses a hardened, standard width axle that allows for a stock vehicle width of 47.5-inches.
Up front, dual A-arms control ten inches of movement. At each forward corner, the shocks are compression and preload adjustable.

Handling traits are what set these two vehicles apart from one another. On somewhat smooth roads, the S model is very controllable. You can set this machine up for each turn, powerslide through them, and get back on the gas soon to rocket forward. Off-camber terrain is easily negotiable and steering is quick, precise and light.
For carving bowls and jumping off razorbacks in the dunes, the straight axle machine is the better of the two. It’s lighter and zero body roll can be thanked for that. However, the Maxxis Razr tire choice is not ideal for dune conditions. A rounder radial type tire, that is found on the IRS Outlaw, provides better floatation in the sand.

At high speeds, the Outlaw 525S tends to wander in sand or dirt. The twitchy front end reminds us a little of the Kawasaki KFX450.


If the trail turns nasty, that is when the IRS equipped Outlaw shines. It has separate shocks on all four corners that are preload adjustable in the rear and compression and preload adjustable up front. A-arms on all four corners provide ten inches of movement. The rougher, rockier and ruttier the better.

This machine has more ground clearance than any other sport ATV currently offered. This means line selection is not as crucial on the nasty trails that would usually damage or stop a quad in its tracks. The IRS equipped machine had a more planted feel on nearly every trail.

Neither machine works very well on consistent whooped-out trails. The S model’s rear shock tends to pack up quickly so the rider has to back off the gas. The extra weight of the IRS is also a hindrance in the deeper evenly spaced whoops.

Complete suspension and handling action is better on the IRS machine in almost every type of terrain. For a trail quad, the Outlaw 525IRS is the favorite of the two. If you are not an aggressive jumper or dune carver, the 525IRS feels at home in the sand dunes. It works better than most quads at soaking up choppy sand, and you can still throw a good roost with this machine.


The powerplants on both 525 (510cc) machines are nearly identical. In fact, the Outlaw 450MXR utilizes the same engine. A smaller bore measurement on the 450 is the only difference between them. KTM’s four-stroke ATV engines feature a single overhead cam, four-valve design. However, they do have a dual overhead cam, four-valve dirtbike engine. All KTM/Polaris ATV engines use a 39mm Keihin carburetor for fuel distribution.

The ATVs all get electric starting, liquid-cooling and a five-speed transmission controlled by a hydraulically operated manual clutch. Actually, the KTM powertrain started life as a six-speed; however, as requested by Polaris, KTM engineers removed the sixth gear and replaced it with a simple gear-driven, cable-actuated reverse system.

In our flat road drag race tests, surprisingly the lighter 375-pound 525S was not always the winner. Not only is traction better on the 395-pound IRS equipped Outlaw, weight distribution is far superior. With nearly every start, the 525S would wheelie off the line or spin the rear tires too much.


The IRS equipped machine would hook up and get the holeshot on every run. The lighter 525S front end was even more evident in our hill climb runs. Riders had to do a lot of body weight adjusting to get the right combo of rear end traction and earth contact with the front tires. It took a very long run (over 200 yards) for the 525S to ever recover and make a pass for the lead.

If we were on an episode of Pinks, drag racing for title on almost any dirt trail, we would pick the Outlaw 525IRS as our weapon. It was more of the same in the dunes. The “S” models rear tire would dig in on takeoff and let the IRS machine take the holeshot. Uphill you could pin the throttle on the IRS machine, aim it toward the hilltop and hang on. Throttle control and body position again were crucial on the lighter “S” model.


Shifting is nearly flawless on both machines. However, the shift lever length measures differently on each machine. Neither shift lever is the wrong length, but they just take a second to get used to, especially when jumping from machine to machine.

The footpegs, brake levers and thumb throttles all work perfectly and are well placed. We have had isolated complaints about the rear brake slave cylinder catching on some riders’ boots.

Our biggest complaint about the 525S is that the top shock location in the rear is very close to the backside of the engine. Because of this, Polaris designers had very little room for an airbox. A smaller airbox in most cases limits airflow and horsepower. Not only is this the case on this machine, the airfilter element is very small and difficult to service.

On Doug Eichner’s straight axle race quad we noticed he completely modified the intake system to accept a standard and larger clamp-on filter element.


We came away from this comparison less impressed with the 525S and more impressed with the abilities of the IRS equipped Outlaw. This machine is a great do it all sport ATV. The addition of the KTM powerplant is just what it needed to keep it from falling by the wayside like the Predator did.

The straight axle Outlaw is not a bad machine but it’s not worth the $7199 Polaris is asking for it. A lower price tag will help to make it more attractive. In fact Doug Eichner waxed the competition on his Yoshimura/Roll/Fox modified Outlaw at the last Pismo Beach race.

In stock trim we would easily choose the IRS equipped Outlaw ($7399) for most trail riding situations over the 525S. The 525IRS has been refined over the few years of its existence and is ready to take on the current king of trail quads, the Yamaha Raptor 700. We will bring you that shootout shortly. Hopefully we will be able to include the new KTM XC525 machine in that test as well. Stay tuned.



Engine Liquid-cooled, Liquid-cooled,
SOHC, 4-stroke SOHC, 4-stroke
Displacement 510cc 510cc
Carburetion Manual-clutch Manual-clutch
5-speed w/reverse 5-speed
Carburetion 39mm Keihin FCR 39mm Keihin FCR
Starting Electric Electric
Transmission Manual-clutch 5-speed Manual-clutch 5-speed
w/rev w/rev
Final drive Shaft Chain
Suspension/wheel travel:
Front Double A-arms; 10″ Dual A-arms w/10″
Rear Dual A-arms; 10″ Swingarm, w/10″
Front Hydraulic discs Hydraulic discs
Rear Hydraulic disc Hydraulic disc
Front 20×7-10 21×7-10
Rear 20×10-9 20×10-9
Overall length/width/
height 70.5″/47.5″/45″. 70.5″/47.5″/45″
Wheelbase 50.5″ 50.5″
Seat height 32″ .32″
Fuel capacity 3.9 gal 3.9 gal.
Ground clearance 10″ 5″
Colors Red, white, black Red, white
Price $7399 $7199
Manufacturer Polaris Polaris

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