I’ve often wondered whether it is necessary, or a good idea even, to deflate adventure bike tires when riding off-road. In a 4×4 vehicle it is common practice to deflate tires on dirt roads to improve the ride. In soft sand it is especially useful in order to increase the length of the tire contact patch. Does the same hold true of an adventure bike? I did some research and here’s what I’ve found:
Most experts advocate running the tire pressures recommended by the manufacturer on big adventure bikes. The air in the tires protects the rims against impacts to avoid damage or a flat tire. In some situations airing down the tires can help get the bike unstuck, but you need to inflate it immediately afterward.
This was not an easy post to write. While the experts mostly say the same thing, not all riders agree and there are many different opinions. Let’s take a closer look at what I’ve found.
Adventure bike tire pressure: the short answer
Most riding instructors and rental companies give the same advice: Don’t air down your adventure bike tires. Adventure bikes are heavy machines. Most weight in excess of 450 lbs on its own without gas. Add your weight, and that of your luggage, and it is not uncommon to ask the tires to carry 800 lbs or more. At the speeds you are likely to travel on a big powerful adventure bike, that heavy weight translates in to a heavy load on the tires, especially on bumpy surfaces.
The air in the tires are necessary to protect the rims against those loads. If there is too little air between the tire and the rim, you risk damaging the rim or gaining a pinch flat (if you are running tube-type tires).
In some extreme situations, when you aren’t going too fast, it may help deflating the tires to get out. If you are riding through very soft sand on street tires, and you know there aren’t any hidden rocks, it will make it much easier to get through if you air down your tires quite a bit. This will lengthen the contact patch of the tire to help with traction. Over very rocky trails, through mud or up hills with a loose surface, a lower tire pressure will help you grip and make it much easier to ride through.
Just remember to take it easy when your tires are deflated. Get out of trouble and immediately inflate it back to the recommended pressure before riding at speed again. This is why it is useful to carry a motorcycle pump with you, like the Slime Power Sport Tire Inflator (available on Amazon). To read more on carrying a pump, read this article I wrote.
In short, just ride on hard tires until you absolutely have to deflate your tires to get out of trouble.
What should my tire pressure be?
You should check the owners manual of your bike. Most big adventure bike manufacturers recommend tire pressures of between 30 and 40 PSI. Usually the rear has a higher recommended pressure since there is more weight on the rear wheel. The rear wheel will also generate more friction due to transferring the power of the engine to the road.
The type of tire will also influence the pressure. Many riders change tires multiple times during the life of the bike. The Michelin TKC 80’s, a popular off-road tire for adventure bikes, has a softer side-wall and therefore requires a slightly higher pressure than something like a Mitas E07 Dakar for instance.
The recommended pressure stated in the bike’s manual is for riding on the road and when the tire is cold. As a tire heats up from the friction of riding, the air inside expands and so the pressure increases. That is why it is important to check the tire pressure in the morning before you start the bike. For this reason, I always carry a tire pressure monitor. Even a cheap one like this will do.
If you check the pressure at the gas station, after a few hours in the saddle, it will almost certainly read higher than the cold pressure. If you are unsure, pump the tires slightly above the desired pressure and deflate it to the correct pressure once it has cooled off. That is why I always carry a tire pressure gauge when going on a long adventure bike trip.
There may be different recommended tire pressures for a bike with a solo rider versus a loaded bike with a pillion. The heavier the load, the higher the tire pressure.
Trade-off: safety versus grip
Running tires at high and low pressures, both have its benefits, it just depends on the conditions. There is a trade-off between the safety of running the recommended, hard pressure and the increased grip offered by lowered pressures. You just need to know when (and how) to use each.
Hard tires equals safety
The manufacturers’ recommended tire pressures are quite hard. The main reason is safety. More air in the tires can carry a bigger load. As the side-walls of tires flex during the loading and unloading of the wheels during fast riding on undulating terrain, the tires get hot. The harder the tires, the less the sidewalls will flex. That will result in a cooler running tire that will last longer and that are less likely to fail during a ride.
If your adventure bike runs on tube-type tires, it is even more important to run the correct pressure. Not only is there the side wall flexing, but the tube can move slightly inside the tire, creating friction. The lower the tire pressure, the more movement there will be, which results in higher friction and heat. If the tire gets too hot, you can have a dangerous blowout which is no fun at speed!
Soft tires equals grip
Deflating a tire will increase the area of the contact with the ground. More specifically, it will increase the length of the tire, much like the tracks of a tank. Distributing the weight of the bike over a larger area will help with traction in soft sand and prevent the bike from bogging down.
On loose rocks or gravel, a deflated tire will conform to the irregularities of the trail and as a result, more of the tire’s surface will be in contact with the ground. This will again improve traction.
Be careful of going too low
Care should be taken to not deflate tubeless tires too much. If a tubeless tire is run at a too low pressure, a sudden impact could ‘burp’ the tire, releasing most of the air instantaneously. If the bead of the tire unseats from the rim you might have a difficult time inflating it again (see my post on tire pumps to read more on seating a bead).
Tube-type tires can be run with less air inside, but be aware of tire creep where the inner tube moves in relation to the outer tire. You’ll notice the tire valve standing at an angle. If it moves too far, you risk tearing the valve. A high impact on a tube-type tire can also cause a pinch flat. This is where the rims and tire squash the inner tube and ‘bite’ a small hole (usually two, like a snake bite) in the tube. This can only happen if there is not enough air in the tire.
What do the experts say?
Bret Tkacs has been a professional motorcycle rider and trainer for decades. Based in Puyallup, Washington, his primary focus is reducing the number of motorcycle-related injuries and fatalities. Bret has traveled around the world by bike extensively, and even wrote Washington’s newest basic motorcycle licensing curriculum. He knows what he’s talking about and in his video on the 9 most common mistakes adventure bike riders make, guess what he mentions first? Tire pressure.
Bret’s advice is to ride it hard all the time, and only air down in extreme situations, like getting unstuck from sand. He stresses that you need to immediately inflate it again before riding at speed. Don’t believe me? You can watch him say it in the video below:
According to Chris Birch, the wheelie monster that makes the giant KTM Super Adventures fly, dropping the tire pressure can be helpful when your in a difficult situation. He will deflate the rear tire as low as 12 psi to get out of trouble because it is just easier than pushing a heavy bike. After having a few unsuccessful goes at a hill or some other obstacle, he’ll drop the tire pressure for more grip. He uses this technique for steep hills, mud, sand or anything else that is making progress difficult, as long as he is going slow. Oh, and he also always carry a motorcycle tire pump to inflate the tire before racing off again.
Craig Marshall, founder of Dualsport Africa, has mapped adventure motorcycle routes in Southern Africa, run a bike rental business and guided lots of adventure bike tours for more than a decade. The 10 Yamaha XT 1200 Z’s and 600 R’s of his bike rental business have covered more than 880 000 km in 5 years, and have gone through many sets of tires. His advice on tire pressure of adventure motorcycles?
Craig admits that the correct tire pressure is very much debatable and that it will depend on the overall weight of the rider, luggage, and whether there is a pillion. He suggests a pressure of anywhere from 26 PSI for solo riding off-road on soft surfaces, to between 36 to 43 PSI on tarmac, two-up with luggage.
It seems like the experienced riders that also coach many other adventure bike riders all say the same thing: Ride it hard and only deflate the tires if you really have to. And once you are out of the difficult situation, inflate them back up immediately.
The opinions on adventure riding forums are as varied as the members’ avatars. It is much harder to find consensus among them than the experts. Here are a few examples of what they said about adventure bike tire pressure:
Some agree that the tires need to be properly inflated.
“You can run 20 [PSI], but order a new front wheel now because the rim will be trashed. I run 28-30 [PSI] with a 4-ply tire. With the stock TK[C80] I would run 30-32 [PSI].”KTM 1090 R rider – AdvRiver.com
“I saw a guy on a [KTM] 1290 that had a mangled front tire because it burped when he hit a rock , it had 20 psi. Make sure you got the tire repair thing down.”Unknown bike rider – AdvRider.com
Another rider suggested an interesting method of determining the optimal tire pressure. He suggests you set your rear tubeless tire pressure to 15 PSI and make a mark on the tire and rim with a sharpie. You then accelerate hard on tarmac, stop, and check your sharpie line. If the tire slipped on the rim, the pressure is too low. Inflate the tire a little and repeat until there’s no more slip.
He goes further to say that if you do want to run at pressures below that slippage point, then you will need a rim/bead lock. He ends of with “Lower pressure off road is the only way to go….”
Below are a few more direct quotes from the forum, supporting enough air in the tires:
“Count me as one who won’t run the front tire below 26psi unless I know it’s going to be a slow ride where turning the front wheel into a taco is a small possibility. I saw too many 950/990 front wheels that were wrecked on high speed runs in Baja.”KTM 1290 Super Adventure R and KTM 400 XC W rider – AdvRider.com
“Depends entirely on your riding style, suspension setup, and what type of tire. I’m currently running a TKC80 up front (very soft sidewall) and I run it with a tube at about 26 psi off road. At the rear I run a mitas E07 Dakar (hard sidewall) and turn it down to about 22 psi. This is an aggressive off road pressure for me. I honestly usually keep it around 30/30 because I’m lazy and don’t want to air up and down on my commute to and from the dirt.”KTM 790 Adventure R rider – AdvRider.com
And then a self-proclaimed ‘expert’ weighs in with this controversial post:
“I have a lifetime of experience racing mx and riding dirt. This is some of what I’ve learned; Yes I’ve bent the front rim. That only tells me I needed a stronger rim. I shouldn’t compromise what I KNOW works(psi wise) to compensate for a s#*$ wheel!! That’s the sticking point here. It’s not that the lower pressure is incorrect. It seems everyone is afraid of bending their precious rim which in reality is JUNK… Invest in the strongest front rim money can buy, put a heavy tube in it, drop the pressure and ride like hell with confidence.”Unknown bike rider – AdvRider.com
Many of the comments that suggested lowering tire pressures off-road came from dirt bike riders that are used to light-weight motocross bikes. To round up the comments on the adventure bike tire pressure debate I end off with this quote that probably sums it up best:
“I’d like to find a happy medium that works well enough on the street and in the dirt without having air up and down all the time. I’m super lazy and, let’s face it, these bikes are one giant 500 lbs compromise, so may as well treat the tire pressure with the same attitude.”KTM 690 Enduro R rider – AdvRider.com
Interestingly, in a thread on tire pressures on the BMW GS forum, almost every rider suggests somewhere between mid-30’s PSI to around 42 PSI. It seems like the GS riders either stick to the pavement or they listen to the owner’s manual.
In the end, it looks like you will have to decide for yourself.
Adventure bikes are heavy, powerful machines. Your tires are the only things between your bike and the road, and the pressure they run at will largely determine how reliable your tires are.
Most experts advocate running the tires at the correct pressures recommended by the motorcycle manufacturer in order to prevent damage to the rims and flat tires. The heavier the adventure bike, the more important the tire pressure.
In extreme off-road situations it is okay to air down your tires in order to get out of the mess, but you need to inflate it back up as soon as you are unstuck. I am one of the lazy ones who just run the tires hard and adjust my riding style to the bike and the road conditions.
Whatever you decide, stay safe out there!