Off-road wheels & tyres - quick sanity check

Based on what you said about the clearance behind the wheels I thought I would check.

There is nothing remotely close at the back and at the front the radius arm is a long way away even on full lock. However, the bracket on the hub where the steering arms mount is only about 15mm away from the existing rims. I know that 16" rims will be further out but doubt there is 24mm clearance.

This would mean ET 0, which only adds an extra 14mm on the inside, at least for the front.

I am just checking with a tyre supplier if they can measure an actual tyre. Someone did send me a link to Insa which shows the actual diameter of all of there tyres, a 205/80 r16 is actually slightly smaller than nominal, but a 195/80 r15 is slightly bigger.

I suppose it depends on what size base tyre they did the remold on, I assume a smaller size to account for the extra tread?

Robin

Robin

OK, a tyre size E.g. 205/70 r15, doesn’t give the overall tyre size but specifies the width, section band rim size, from which a diameter is calculated.

The diameter excludes the tread depth.

So my current tyres are Maxxis 215/75 r15 with 10mm depth, nominal diameter of 704mm so 724mm overall.

From the table in the photo 195/80 r15 Special track are quoted at 689mm, but tread depth is 17mm so 723mm overall, about the same as my current tyres.

The 205/70 r15 are quoted as 687mm and 19mm tread, so this is 725mm again about the same.

Interesting the section width of 195/80 is 199mm and 205/70 is 217mm, quite a bit bigger than standard.

 

On this basis I have decided to get 15” tyres, the 16” are probably going to be too big.  Next job, measure my Maxxis accurately.

Robin

My Maxxis have just measured 795 or 800mm with 6mm tread, so about 788mm, a little under the nominal size of 704mm + tread.

My choice comes down to two sizes 195/80r15 or 205/70r15, looking at the size chart above, both are about the same diameter 687mm, but I think this excludes the tread with is 17 or 19mm deep.

Overall (inc tread) both Insa tyres should be 25mm bigger than my Maxxis.

I am leaning towards the 205/70r15, mostly because it is a Special Track 2 tyre rather than the older design, although I am struggling to find out what they changed.

Given that this tyre is wider than specification, it should be nearly as wide as my Maxxis.

Robin

Just be prepared for some interesting road manners. A mates son had them on their jimny and couldn't get rid of them fast enough but he was daily driving it which you are not. Also you have stability control which will help.