Thread: maximum tyre size td5 defender

Hi Ben,

I'm going to talk in km/h. 62mph to 100 km/h. With the 235/85's my speedo was incorrect by 5 km/h at 100 km/h. If I recall correctly it was reading 105km/h when the GPS said 100 km/h. With the 255/85's the speedo is accurate to 1%. Tyre wear will alter that as will different manufacturers that have variances between rolling diameter. Thus work on 5% inaccuracy in the speed range.

If you are contemplating 265/75's you might as well buy the 235/85's. The tyre conversation calculator puts the 235/85's at 31.7 inch and the 265/75 at 31.6 inch in the old school measurement. Same height and rolling diameter, thus same inaccuracies in the speedo, in fact worse being marginally smaller. 265/75 is the limit on a 7" rim and you will lose steering lock including rubbing on the rear during articulation. With 265/75's you will need a zero offset rim (+ or - 10 mm) or spacers. You will get some track width being a wider tyre but the expense to make it all work isn't worth the effort to essentially replace like for like on rolling diameter.

As for adjusting the speedo, there is a kit. I haven't made any inquiries about it because my tyres have corrected the inaccuracy. Google is your friend.

cheers MLD

Originally Posted by MLD

...With the 255/85's the speedo is accurate to 1%. ...

I found the same. If anything mine was closer to 0.1% with 255/85s!

You guys are great, thanks. 255/85 is the way to go.