Making your quad faster is easy. Just bring money. There are endless tips on how to make your motor stronger, your suspension better and your chassis crisper. But by the same token, we have ridden some very expensive machines that feel like junkers because the builder ignored basic setup fundamentals.
Wayne Hinson at Hinson Racing was one of the pioneers in ATV racing and was crew chief for riders like Gary Denton and Doug Gust. He never lets an ATV leave his shop without going over some very basic setup items. Here are a few of the secrets he shared with us.
You won’t believe how much variation there is in tire size. You can have four tires of the proper spec and of the same make with four very different circumferences. When you have different-size wheels in back, you are robbing horsepower as one wheel tries to cover more ground than the other. In front, you can create handling and steering problems. If you go to any auto race, you see that the tires are pre-measured and stacked in sets. You can easily measure your own tires by inflating them to a consistent pressure and wrapping a tape measure around the outer circumference. You can also dab a little grease on one knob, then roll it across the garage floor. The space between grease dabs is the circumference. Do this before you run a new set so that you can return one of the tires and ask for a closer match.
Most manufacturers deliberately deliver the quad with the steering adjusted poorly. The front wheels typically are toed inward slightly. This creates more drag and makes a quad slow down more quickly when the throttle is chopped. Most tuners agree that a free-rolling quad is best.
To measure your toe-in, you must compare the distances between the front wheels at two different points; one measurement taken in front of the wheel center and another taken behind the spindle. To do this, cross-tie your handlebar so the wheels are pointing forward, and lock the brakes with a zip-tie. The idea is to make sure both wheels are pointing in the same direction, so carefully mark a point on the leading edge of both tires and measure the distance between them. Then make marks on the training edge of both front tires, and measure again. If the front marks are farther apart than the rear marks, you are toed-out and will have instability. If they are toed-in, you will have drag. To correct this you will need to turn the tie-rods’ adjuster nut in or out.
When you take your quad for a test ride, there are a number of things you should check. Among them are the handlebar position and the hands-off stability. For the record, don’t really take your hands off; just feel for a pull in one direction or the other. The handlebar should be dead even when the quad is going straight; otherwise, it could cause handling problems or rider fatigue. This can be adjusted at the tie-rods in quarter-turn increments, making equal adjustments on both sides. If the quad pulls one way or the other on flat ground, there are several things you should check. In order of likelihood, check tire pressure, brake drag and suspension adjustment. You should also look for any damage to the A-arms or tie-rods.
Never underestimate the importance of tire pressure. It should be checked every single ride. The proper level varies wildly according to tire construction and soil, so test rides are important. Look for certain symptoms. If the quad has poor traction, decrease the tire pressure. If the quad won’t turn, increase the tire pressure, particularly in the rear. If there’s too much feedback in the bars, decrease the pressure in the front. If you’re concerned about flats, increase the pressure.
PRELOAD OR AIR PRESSURE
Most modern quads offer a wealth of suspension adjustments. Again, test riding is critical. What worked for a 150-pound test rider at the factory probably won’t work for a 200-pounder in the dunes. In general, sand requires stiffer settings. Softer spring-preload and compression-damping settings are best for hardpacked soil. Mud can go either way, but stiffer settings generally work better because it offers increased ground clearance for dealing with ruts, and also because of the additional weight of mud buildup. When adjusting the air pressure in Fox air shocks, always make sure that the wheels are off the ground.
Once you have your suspension set up, it’s a good idea to check your ground clearance in the front and in the rear. Most quads are fairly level across the bottom when unweighted. Then, when the rider is in place, the rear end will be slightly lower than the front. Never set up a quad with less clearance in front than in the rear, and by the same token, try not to have more than a half-inch of difference between the two when the quad is unloaded.
To make your quad roll as freely as possible, both front wheels should go in the same direction. To check your toe-in, start by fixing the bars to point straight forward with tie-down straps.
Before attempting a front-end measurement, be sure to lock the front brake with a zip-tie. Just locking the park brake won’t do this, as it usually doesn’t affect the front wheels.
Find the centerline of the wheel by measuring from the ground to the axle, then make your marks on the insides of the front wheels at this height. Make one mark in front of the axle and another behind it.
Now, measure the distance between wheels at the front marks and compare that to the distance between wheels at the rear marks.
In order to adjust toe-in and to adjust the handlebar hands-free position, make small changes at the tie-rods.
Set your shock preload so that your ground clearance is slightly higher in the front than in the rear with the quad unweighted. This will become more pronounced with the rider on board.