Monthly Archives: December 2019

Increase Subaru Off Road Traction

Hey everyone, Scott from RalliTEK here with another blog about enhancing your off road experience while in your Subaru. I wanted to talk about one of the easiest ways to increase off road traction and that is “airing down” before you hit the trail. Letting some air out of your tires before a trail day increases traction by allowing the tire to be softer so it can grip obstacles better and it also allows for a nice comfortable ride as well. Most Subarus run tire pressures between 30 and 40psi and while this is great for on road handling and fuel economy, this makes the tire stiff and unable to conform to the terrain as well which can lead to lots of spinning and sliding. While airing down before a trail day, it isn’t uncommon for others in the group to ask what everyone will be running for tire pressure and in our RalliTEK Subarus, I typically will air down to about 18psi or so for a general trail day. The pressure that you will choose will depend on a few things, the weight of your car, the size of your tire and wheel and the terrain you will be in. The RalliTEK Outback has 245/65-17 tires and because it is pretty heavy, I felt that 18psi was the lowest I would go for the trails in the Tillamook State Forest, the tires performed great but there were a few times I felt the sidewall try to roll under and I wanted a little more support on some of the bumps so I didn’t risk damaging a wheel. The RalliTEK Crosstrek on the other hand is on 235/75-15 tires so it has more sidewall and is also lighter, 18psi was a great pressure and one could probably go down to 15psi if needed.

18psi, let’s hit the trails!

To air my tires down, I use an ARB E-Z Deflator that I’ve had for a number of years now. I like using it because it is quick and the gauge has been accurate. It screws onto the valve stem and then you unscrew the valve core and move the slide to let air out. It is a little cumbersome for the first few uses but it gets easier to use as you go.

Here you can see the ARB E-Z Deflator letting air out of the tire

When you come to the end of the day, you will need to air your tires back up to street pressure before hitting the highway. There are a lot of different methods to air a tire up and since we have relatively small tires, any of the methods work great! I have a Milwuakee cordless air compressor that I use and it works really well; you enter the tire pressure you want and then hit start, it will turn off automatically when that pressure is reached so you can socialize freely. There are also 12 volt options that you clip onto your battery and air up that way, the 12 volt compressors that plug into the cigarette lighter work in a pinch but are not up to airing up all 4 tires. The last option is a bike pump. These actually work pretty well but you will need some endurance as it took 55 pumps per tire to get our 215/75-15s to street pressure from 15psi.

Airing up with the Milwaukee cordless air compressor is a snap
Here is a great example of a compressor that clips to your battery, this system is pretty quick!
Small downside to this style compressor is you have to stand at the tire you are filling, a fast compressor makes this task easier