Thread: Power loss with new tyres?

what did you have on before??

and whats the PSI

The original tyres were 235 70 16 and as far as I know psi of about 36 in them and the new tyres reccomended buy fitter was 32 psi what should they have in them?

Originally Posted by Rad97

The original tyres were 235 70 16 and as far as I know psi of about 36 in them and the new tyres reccomended buy fitter was 32 psi what should they have in them?

when i had the 33" BF AT on 15" i was running 45 front 42 rear. drop to about 30 on dirt roads if i am doing any distance

The only way to gain back power when you increase tyre diameter is by upping your diff ratio 4.11:1 or more 4.14:1 ,you will also notice the speed which is increased in low ratio which can be damaging entering obsticles ? to get a lower range back you need to get reduction gears installed in your transfer case ,with the slight tyre diameter increase you have neither would really be warranted in my eyes as soon as you start getting to 33" or bigger the above is of great gain
cheers Kelvin

That tyre size difference equates to about 20mm increase in diameter, This will make a fair difference in power. I did this and noticed a loss of power and worse fuel economy, but my speedo is now correct (compared with a gps), but more importantly I get more ground clearance off road.

I'm running 265/75/16 and got a loss of power and worse economy I'm getting around 500 km to a tank but that's towing a trailer nearly everyday

The height and width will take a toll.

You opted to go much wider and now the car has to push a much wider contact area bringing with it more strain and potential wear on steering etc.

Wide tyres look cool and do have their place off road but in general are not much chop anywhere else. Should you venture in the bush, make sure you take plenty of spares as mostly standard width tyres are available.
On a recent trip my mates P38a had of all things 285/50/18's and had to wait 8 days to get a spare as his was punctured already. wait for it --$750.00 later.

Anyhow, soon you will be used to the drop in power but to get a increase in power I presume its a 300tdi, upgrade the intercooler and get injector pump tweaked.
Potentially and extra 15-18Kw's. make sure engine in good shape, clean filters and good injectors etc.
Also get it done with a pyrometer up its exhaust to measure temp do not exceed limit.

Happy travels.