maximum tyre size td5 defender

Thanks MLD, much appreciated info regarding fuel consumption. On a 265/75, how much would the speedo be off by? Is there a way to adjust the speedo?

It is off now by about 5 mph at low speeds, 9 mph at high speeds.

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

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Originally Posted by MLD

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

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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.

I was able to get a set of Pirelli Scorpions (265/75/16) off of a Chevy Tahoe basically brand new at the tire shop for someone switching to bigger wheels for 200USD total. Seeing as they are 200USD new for one tire, it was a no brainer.

What do you guy recommend for tire pressures? I am doing mostly highway and city driving. Currently I have it at 32psi in the front and 38psi in the back.

I have to bring them in to be balanced as I just had them mounted on the wheels and put them in the back of my other truck (used tire shop...not trusting their balancing from past experience).