Tires, what’s your pressure

August 28, 2008 by Jon Rhodig

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They are out there those elusive tricks to grab an extra horsepower, take a corner faster, make the ride more comfortable all without spending little or no outright cash. Sounds great sign me up! Well unfortunately nothing in life is ever truly “free” but this tip is about as close as you can get when it comes to a free performance enhancement of your ATV experience, proper tire pressure.

Tire pressure is probably one of the most overlooked aspects on an ATV or any vehicle for that matter. In the ATV world many times I see racers and casual riders just unload their machines give a quick thump or kick to the tires and I know in their minds they are thinking “Yep, its got air in it” and thats it. Well duh! of course its got air in it but is it the proper pressure for the conditions your riding or racing in? I bet not. I have also seen both of the extremes. Extremely under inflated and the rider wondering why his quad wallows all around with slow, sloppy handling or extremely over inflated and the rider wondering why hes just spinning and over steering in every corner. I find the problem is that some riders are just ignorant of the fact that tire pressure is an important part of the ATVs performance. There is also a small percentage that knows its important, yet don’t know where to begin. Read on to find the answers!

Analog dial low pressure tire gauge

First before you fire up that air compressor or unscrew the valve stem cap you need a few things. A good quality low pressure tire gauge not your run of the mill $.99 tire gauge found on most parts counters next to the register. These are fine for quick automotive tire checks and to keep in the glove box. A good low pressure tire gauge will run at least $10+ depending on the style and other features that can come with them. I prefer an analog dial type with a bleed off valve (more accurate), but there are pencil type and digital ones available also. Low pressure gauges typically have a pressure range of 0-15 psi.

Keeping good notes is key

The next item you should have on hand is a notebook. A notebook is handy to keep good notes on what tire pressures you find work best for each track, trail or terrain that you ride. Keeping good notes is a must as it can help you tune your tires for the conditions you will be riding in. For example one of my fellow Team MGR racers Chris Flodine is very fickle on his tire pressures and is constantly adjusting them so he can get maximum performance and traction in each and every situation he rides in, keeping good notes on what works and what doesn’t is crucial as it will save you time on future rides and races.

Ok, so we have talked all about what you need to get started. Now where do I start? ATV tires are going to have between 4-10 psi working pressure although the side wall may say 35 psi at “X” lbs load max or something to that effect. All that means is that is the maximum pressure that the tire manufacture says the tire can safely perform at and anything over that it will run the risk of failing. As far as I know there is no situation where an ATV tire would require that high of pressure other than when used for heavy hauling or utility purposes.

A good rule of thumb is to start with all your tires at 6 psi for your baseline tests. To do your testing find a section of track or trail that has a little bit of everything related to that area, for example if the track is mostly hard packed with only a few sections of nice tilled loam use a section that is mostly hard packed, similarly with trail riding if its loose dirt with only a few sections of rocks find a section with mostly loose dirt. This “testing” section should also be a section that is easy for you to ride or navigate thus you can be more in tune on how changing tire pressures affect the ATVs handling, if the section is too challenging you may be distracted from your tires and just concentrating on getting through the section. Now that you have found your test section is time to ride, do some baseline runs keeping in mind on how the ATV and tires are handling. Now with your notebook handy change the air pressure a couple of pounds up or down keeping notes on what changes you make. Ride the section with your new pressures and determine how the ATV reacted either positive or negative taking notes along the way, keep doing this until you find the ideal setup for this particular track or trail and make a note of your location so you can replicate these pressures next time you ride there. Its also common to find that you prefer different pressures in the front and rear and this is ok, but you should never have different pressures left to right. This poses a safety hazard as it will make the ATV vier or pull to one side and this is especially dangerous when jumping.

“Wow, that sounds like a lot of work!” you might say. Well it sort of is. In the beginning as you log more data you will eventually learn what pressures work best for your tires for nearly any given terrain, this is why the note keeping is so important. “Thats fine and dandy, but how do I know which way to, go up or down in pressure?” you ask. Here are some general guidelines to get you started.

Hard terrain: generally use lower pressures. The lower pressure lets the tire deflect and conform to the terrain such as rocks, roots better it also increases the tires contact patch on flat “blue groove” dirt. One thing to keep in mind is too low of pressure with out bead locks run a higher potential of popping the tire off the bead, most tires should not be run under 4 psi. Another thing to note is on sharp jagged rocks or tree roots sticking up can increase the chance of a puncture or pinch flat if running a tube. The tires design and construction is a big contributor in this as well.

Soft terrain generally use higher pressures. The higher the pressure makes the tire resist knob deflection and promotes it to dig into the soil. Although using higher pressures help in these conditions it lessens the tires overall contact patch thus the tires will slide much easier. Also higher pressures usually give a less forgiving ride especially when hitting an occasional hard object they will bounce off it possibly jolting the ride. Again tire construction and design have a big factor in this as well and will be discussed in later articles.

Well there you have it. I bet you didn’t know someone could make inflating you tires such a chore or technical, but considering its one thing that is relatively free and a do-it-yourself “mod” that anyone can get a benefit from it stands to reason it should be an important thing to check before each ride.

On last word, tire pressures are not an exact science and are very subjective no one setup will work for every rider that is why this article is only a guide to aid in the pursuit of extracting maximum performance out of your machine.