More Ground Clearance with Bigger Tyres

More Ground Clearance with Bigger Tyres

There is only 1 way to get the diffs higher off the ground, and that's with larger tyres. When we're using tracks that have been rutted out by larger trucks, they'll often make ruts that are deeper than what a small tyre can get you through. So there are lots of reasons for larger tyres.

I've got for 31"x10.5" tyres. Again, they're Goodride tyres from the super helpful team at Bridgestone Shirley in Christchurch. These guys know exactly what is needed to fit a Jimny, they've fitted wheels and tyres to LOTS of them!

The Challenges:

Clearance

Since I've changed the front bumper for this steel one, there is no issue at the front, there is lots of space. The 2" lift means there is not going to be any rubbing with the rear wheel, either. 

However, there is some rubbing when I'm turning and reversing from the back of the front tyres. It's not lots of rubbing, but could potentially get a whole lot worse. I trimmed a small piece of the guard with a hacksaw blade, and now there is no rubbing at all!

Gear Ratios

This issue is much harder to fix. Probably no issue at all in an auto Jimny, but starting from a stop in first gear takes careful movements on the clutch. It's not terrible at all, it's okay, but the larger tyres definitely mean the clutch is going to be working a little harder. 

In the next few months I'll look at lower diff ratios to solve this issue, which will make it a lot nicer to crawl through rough stuff, too. 

The Benefits

The Drive

Man, this drives so comfortably now. I drive around town with 26psi in the tyres, and it's driving a lot more like a big truck. Even just going from 30" to 31", I feel more stable on the road and the small bumps in the road are smoother to roll across.  This might also be due to the 30's getting down in tread, but they still had about 70% of their life left in them.

The Clearance

Being an extra inch larger in diameter means the diffs sit an extra 1/2 inch higher, at all times. This doesn't sound like a lot, but it makes a big difference for a light truck that can easily find itself bellied in ruts.

The Width

Moving from a 9.5" wide tyre to a 10.5" tyre obviously means about a 10% wider tyre, which is going to ensure we don't sink the same into softer surfaces.

In Summary

Awesome, I can't wait to get up into the mountains to see how these go - and I'll update this blog post once I've tested them.  

It also should be mentioned that the car now looks even better, with a slightly wider, tougher stance.  

Moving forward, lower diff ratios and air locking diffs is going to make this wee Jimny fairly unstoppable!


Questions or Comments?