Changing tyres sizes and more agressive pattern

brokenant

Just wondering if I will have any issues going from 265/60/18 to 255/60/18, and what difference if any it would make.
Also what difference to normal road driving does a more aggressive tread pattern make, I'm looking at General Grabber AT, Yokohama Geolander or similar.
Thanks for any help.

Paradigm

255/60/18 is slightly smaller in diameter so your speedo will overread by a small amount. A more aggressive tread will maybe be a little louder & offer less grip in the dry but will be better in wet/snow.... perhaps

scheming_gypsy

Paradigm wrote: »

255/60/18 is slightly smaller in diameter so your speedo will overread by a small amount.

there's no difference in diameter as they're both 60/18. The 255 is the width of the tyre so it's just 10mm narrower.

Paradigm

scheming_gypsy wrote: »

there's no difference in diameter as they're both 60/18. The 255 is the width of the tyre so it's just 10mm narrower.

255 is the width of the tyre, the 60 is the profile height of the tyre as a % of the width.

60% of 255 is less than 60% of 265 = smaller diameter.

scheming_gypsy

ah cheers, me bad.....

molerat

The size difference is within acceptable tolerances, a 1.55% difference. Your speedo at 60 mph will be reading 60.9 mph.

marlot

I run general AT2 (the predecessor to the latest AT). Great tyres in mud and snow. Snowflake marked. Good on ice. Fine on hot summer roads (but not as good as 'normal' road tyres). They can even be fitted with studs if you're going up to the alps etc.

Gloomendoom

A few things I would be worried about when swapping from a pure road tyre to an all terrain tyre is increased ride harshness, longer braking distances, more road noise and, on wet or dry tarmac, generally less grip all round.

Also, they will very likely have a higher rolling resistance so will increase your fuel consumption.

forgotmyname

Done a lot of offroading and used many different patterns of tyres and the MT types can make quite a din
on the road.

The hum may drive you crazy after a while. Also they will wear fairly quickly compared to a road pattern.

Think about it half the tyre is missing..

marlot

When I switched to General AT2 tyres ...

>> increased ride harshness
No, didn't find that

>> longer braking distances
In the dry, yes. Not noticed any difference in wet. Shorter braking distances in ice/snow

>> more road noise
Only at 40mph, strangely.

>> generally less grip all round.
Yes, that's true - but only marginally

>> will increase your fuel consumption.
Also true - by about half of one mpg

On the positive side, I can tow my caravan off muddy pitches without getting stuck, and I was able to get up all the local hills in the snow and ice. I even towed the UPS van up the local hill.

Overall, I'm very pleased that I made the swap.

Gloomendoom

marlot wrote: »

When I switched to General AT2 tyres ...

>> increased ride harshness
No, didn't find that

>> longer braking distances
In the dry, yes. Not noticed any difference in wet. Shorter braking distances in ice/snow

>> more road noise
Only at 40mph, strangely.

>> generally less grip all round.
Yes, that's true - but only marginally

>> will increase your fuel consumption.
Also true - by about half of one mpg

On the positive side, I can tow my caravan off muddy pitches without getting stuck, and I was able to get up all the local hills in the snow and ice. I even towed the UPS van up the local hill.

Overall, I'm very pleased that I made the swap.

I must admit that I'm getting a set of the AT2's for my Range Rover. I'm still not sure I'd put them on my road car though.