Have you ever noticed that all of the other riders are getting good traction, but you just can't seem to find the grip that you need? Well this could be because you are running the wrong tire pressure!
Tire pressures can make or brake a race. Get them wrong, and you could end up with loss of traction, a puncture, a pinched tube, and you could even wear your tires out quicker.
In this post we'll look at what tire pressure you should be running to prevent all of these problems. We'll also find out how you can tell if you're running too much, or not enough pressure. And we'll look at what conditions require lower, or higher tire pressures.
Universal dirt bike tire pressure
If you ask other riders what tire pressure they're running, it'll usually average out at 12 PSI. That's because tire pressure should generally be between 8 to 16 PSI, and 12 PSI sits right in the middle. 12 PSI is recognised as the universal tire pressure, or the sweet spot, meaning it will work for most conditions, but that doesn't mean that it's optimal!
So many different things come into play, including rider weight, terrain, type of tire, and your dirt bike. If you ride on different terrain from day to day, and if you want to optimize your grip, it's worth reading on to discover how to adjust your tire pressure to match your setup, and the terrain you'll be riding over.
Before we go any further, I highly recommend you get a good accurate tire pressure gauge. There are some really awful gauges out there that will not be accurate enough to make the important small adjustments that we'll learn about later.
Motion Pro do an absolutely fantastic tire pressure gauge that's incredibly accurate. The gauge is pictured below, and you can check its current price on Amazon here > Motion Pro Tire Pressure Gauge.
Running low tire pressure
If you're riding on loose terrain, soft clay, mud, or rocks, you may consider using a lower tire pressure. This will increase your traction by increasing the tire to dirt contact area; but bare in mind that your inner tube is at a higher risk of a being pinched. For this reason, a super heavy duty tube is recommended, these will be 3 to 4 mm thick.
You can drop the pressure as low as 6 PSI, but this is only recommended for slower riding. At pressures this low it's easy for your tire to hit a large root or rock, and pinch the tube. If you're riding any faster than 15MPH, then a minimum of 8 to 10PSI is recommended.
This is still a very uncommon range, and would normally only be used in enduro extreme, slow rocky type events.
Another thing to consider when using lower pressures is the rim lock. If you've ever noticed a bolt sticking out of your rim and wondered what it is, it's the rim lock. These are fitted to most dirt bikes nowadays, but if you don't have one you really need to install one asap, especially if you're running low tire pressure.
The rim lock will prevent your tire spinning on the rim, if this happens the tube's valve will be ripped from the tube causing a flat. So with this in mind, tighten your rim lock, or get one fitted now.
Tire pressure for motocross and off road riding
Tire pressures for motocross and off road trail riding will mostly be in the 12 to 15 PSI range. But the type of tire you're using could also make a big difference here, so check the recommendation on the tire wall.
For example, a tire that is designed for soft soil with widely spaced tread blocks and a soft casing, will require a pressure in the upper range, to help it dig into the soil.
Similarly, a tire that is designed for harder soil with closer spacing and a rigid casing, will also require higher PSI. But if you were to use this same tire in soft mud, you would need to drop the tire pressure. A lower pressure will optimize the movement of the casing, and help to clear mud from the tread.
Tire pressure for enduro riding
If you're riding enduro then there may be some on-road sections that will require street legal tires. These tires will require pressures in the 15 to 16 PSI range for two reasons.
firstly, these tires won't tolerate lower pressures because of high speeds that are reached on road sections; this can cause significant temperature buildup. There will also be a risk of increased tire roll when cornering, this will deform the tire which can be very dangerous at speed.
Secondly, during an enduro race the type of terrain varies considerably. You would normally expect some fast square edge hits, which could easily cause a pinch flat and ruin your race.
Riding at zero PSI
Many trail and enduro riders will opt for a mousse instead of a regular inner tube. A mousse is basically a foam insert that is used in place of the tube, to eliminate the chances of a puncture.
A mousse requires no inflation, but they are designed to give the rider the same feel as 12 - 15 PSI would feel on a regular inner tube. They don't last very long due to breakdown and shrinkage, so they are only recommended for competition, or times when a puncture could leave you stranded a long way from home.
Another option is Tubliss which is basically an insert that sits inside the tire acting as a 100 PSI rim bumper. It protects the rim from impacts, but also eliminates the need for a tube.
The Tubliss insert seals against the tire, and creates an air pocket inside the tire that can be set to extremely low pressures. There's no chance of a pinch flat, and if the tire does pick up a puncture, they are very easily repairable within two minutes!
Other things to consider
When you finish riding, reach down an feel the tire, and you will be surprised how warm it gets. This heat is generated because of friction, and as the tire wall flexes under pressure each time the tire spins.
As this heat is generated, the air pressure inside the tube can actually increase as much as 6 PSI on the rear tire, and 3 PSI on the front tire! For this reason, it's a good idea to start out riding with less than optimal tire pressure.
Bare in mind that more heat is generated on hard ground compared to soft ground, and tire pressures will increase more on a hotter day than on a colder day.
Small changes can make a big difference
You may think that 2 or 3 PSI won't make much difference, but you'd be surprised at how much difference it can actually make. Think about a tire with a maximum pressure of 15 PSI, loosing just 3 PSI equals a massive 20 percent change to the tire pressure.
With this in mind, a tiny 1/4 PSI can make a difference to your traction. In fact, top racing teams are well known for making such small adjustments to their riders tires.
Front tires may require more pressure
The front tire has a much smaller cavity, meaning it has much less air volume than the rear tire. This means your front tire is much more susceptible to a puncture due to pinching.
This may be even more of a problem on 4-stroke dirt bikes due to the heavier front end. So if you ride a 4-stroke you may consider a special 4-stroke front tire which has a more rigid side way to help protect the tube.
Whatever dirt bike you have, it's worth running 1 or 2 PSI more in the front tire just to be safe. But always follow the warning signs covered below to check for under and over inflation.
How to know if your tire pressure is wrong
When your dirt bike tire pressures are too low, you will notice a very unstable feel during cornering, and the front tire will refuse to stick in the turns. Before changing your suspension clickers it's better to increase your tire pressure first. This will likely be caused by tire roll, and if left unchanged could even damage your tires.
Also watch out for damage to your rims. I learned the hard way when going from motocross tracks to trails without changing my tire pressure. The result was a huge dent in my rear rim, and I eventually had to buy a new wheel.
When your tire pressure is too high you'll experience loss of traction during acceleration, and wheel spin on loose terrain.
I'd say running a tire pressure that is a little too high is safer than running low pressure. You reduce pinch flat puncture risk, and you won't smash your rims up so easily.
What about rim clean?
Rim clean is another great way of telling if you're running too much tire pressure. Rim clean refers to the shiny polished edge you see right at the top edge of the rim. This is caused by the tire rolling over the edge of the rim as you ride, and cleaning the dirt from it.
If you get back from riding and you don't see any rim clean, you're most certainly running too much tire pressure. A good amount of rim clean is around 4 mm, if you have any more than this the tire pressure may be too low.
Avoiding punctures and pinched tubes
Punctures can be super annoying, they ruin your race, leave you stranded, and they're a pain to fix. If you don't want to use a Mousse or a Tubliss insert, but you really want to avoid punctures, the best thing to do is run higher tire pressures.
Higher tire pressure won't protect you from things like nails, or sharp object slicing through your tire (I've had that too!), but they will prevent pinched tubes. Pinch flats are the most common way to get a flat tire, I've been through heaps of them and know how easy they can happen.
If you're riding on rocks, roots, logs, or if you expect any square edge hits, it's always better to simply add a couple more PSI to both tires. Although this may cause a few issues as mentioned earlier, it's much better than dealing with a puncture. 16 PSI should work OK, but if you still have issues you may wish to try as much as 18 PSI.
Finding the right dirt bike tire pressure may take a bit of trial and error. As previously mentioned, 12 PSI is somewhere in the middle, so start with the 12 PSI and work your way up or down by using the tips you've learned.
Remember that no two riders are the same, so a tire pressure that works for one person, may not work for another. Be patient, get your pressures set right, and you'll be amazed at how much of a difference this will make to your riding.
One last thing to note is the weight that your dirt bike is carrying. Your body weight will make a difference, but so will any extras you're carrying with you. Overall weight can make a big difference to the tire pressure while riding, so if you're carrying more weight than you normally do, you may need to make small adjustments.