Thread: DIIA tyre sizes

245/75-16 are a great size..

I am currently running 245/70/16 Micky Thompson ATZ P3 hybrid mud/AT tyres and the speedo is out the same as it was with the 245/70/16 Yokohama Geolanders I had on before.
I am towing a 1.5t boat that is pretty high which is creating a lot of wind resistance and is making the V8 struggle a bit So maybe I should have fitted lower profile tyres but i have no idea if that would make any differance or not.
At the moment i am cruising at 85 to 90 and the temp sits on 93 to 95 but if i go up to 100 the temp sits in the high 90"s due to the wind resistance created by the boat.
Without the boat hooked up i can sit on 110 all day long and the temp sits on a steady 91.
I have found that the 245/70/16 tyres are very well suited to my D2a with plenty of flex when you need it and enough floatation for sand as well So regardless of the brand of tyre chosen the 245/70's are my personal choice.

Standard size is better for towing, both engines go better with a few revs under their belts,,

Originally Posted by Pedro_The_Swift

Standard size is better for towing, both engines go better with a few revs under their belts,,

Good point Pedro. Tho' we always tow in 4th with the 300Tdi manual and plan to tow in 3rd lock-up with the Td5 auto.

Haven't checked exactly but I think the Td5 will have slightly higher rpm in 3rd lock-up than the Tdi in 4th. If that's right then the slightly taller gearing of 245/70 or /75 should be OK for our usage.

One must ask, why do you require larger tyres at all?
If you're only travelling on the road, dirt or not, the std size tyres should be fine. There really is no good reason I can think of to change tyre size unless you have an off road camper trailer you're planning to take down tracks.

I believe the idea the engine may use less fuel because the gearing is higher is actually incorrect in this scenario. The motor will use more fuel because it is under more load at lower revs. The end result is likely no gain in fuel economy and more stress on the vehicle.

I'd argue with the std size tyre you maybe able to tow just fine in 4th locked at 100 km/h, you may only have to change down to 3rd locked when climbing a hill.

Just my 2 cents worth. I run 265 75 R16 but i'm not towing, have 3.8 ratio diffs, V8 torque converter, Tune and go 4WDing a lot.

We towed 2.5t of boat with 265-75-16s on stock gearing without issue.

I’m running 240/70 R16 LT tyres on Charlie. No problems and he pulls my 1.8t van nicely.

cheers

Steve