Outer Limits 4x4 Board

is there any benefit in going from 265 /16 to 285/16

Your going up to a effectivly 33" wheel and will give you more clearance

Look at

http://www.miata.net/garage/tirecalcold.html
Steve

From 32" to 33"..... means 1/2" more clearance under the diffs...

Thats assuming they're both the same ratio at 75....

plus of course another 20mm wider for road and beach stuff......

265s are normally on 7" wide rims, most manufacturers specify minimum 8" wide rims for the 285.

Cheers,

Scott

NJ SWB wrote:265s are normally on 7" wide rims, most manufacturers specify minimum 8" wide rims for the 285.

Cheers,

Scott

That is true, but they usually fit without problems. I have done about 30000km on a set of 285/75x16 MTRs - handling is fine, wear is even across the tread width (except for chunks removed offroad), and the tyre seems to stay on the rim better.

Technically they should be on 8" rims though...

also remembering the overall diamater of the tyre will change, and your speedo will read un-true

chops wrote:also remembering the overall diamater of the tyre will change, and your speedo will read un-true

Only 3% so should not even notice a difference.

This also assumes speedo is correct with 265s.

At 100kph on the speedo, road speed is approx 106kph. (measured by GPS running 285/75x16 MTR's)

ISUZUROVER wrote:

NJ SWB wrote:265s are normally on 7" wide rims, most manufacturers specify minimum 8" wide rims for the 285.

Cheers,

Scott

That is true, but they usually fit without problems. I have done about 30000km on a set of 285/75x16 MTRs - handling is fine, wear is even across the tread width (except for chunks removed offroad), and the tyre seems to stay on the rim better.

Technically they should be on 8" rims though...

What about going to a 255/85/16 instead? At about 33.3" it's a little bigger again 0.3" than a 285/75/16 but is still a 7" rim recommendation.

I went from 265/75/16 A/T's to 285/75/16 M/T's today. Pretty happy with the upgrade. My speedo was showing as slow anyway so now it's only 1-2 km's over or so my GPS says. Added about 6cm to the total height of the truck.

Emo wrote:I went from 265/75/16 A/T's to 285/75/16 M/T's today. Pretty happy with the upgrade. My speedo was showing as slow anyway so now it's only 1-2 km's over or so my GPS says. Added about 6cm to the total height of the truck.

Emo, is that sposed to read 6MM? 32 inch tyres to 33 inch tyres equals only one inch gain not over two....

265/75 is less than 32" and 285/75 is normally over 33". If they were worn right down versus brand new (with say 17mm tread depth each side) then a 6cm tyre size increase might be possible.

6cm total height sounds a bit high... that's suggesting n increase in tyre diameter of 12cm or almost 5 inches.

Beastmavster wrote:265/75 is less than 32" and 285/75 is normally over 33". If they were worn right down versus brand new (with say 17mm tread depth each side) then a 6cm tyre size increase might be possible.

6cm total height sounds a bit high... that's suggesting n increase in tyre diameter of 12cm or almost 5 inches.

Emo said that "it added about 6cm to the height of the truck" which led me to believe that the tyres were in fact larger by 12cm!!

265/75/16 = 31.6"x 10.4"
285/75/16 = 32.8"x 11.2


265/75/16 overall diameter = 803.9 mm
285/75/16 overall diameter = 833.9 mm

Remember with tread depth 14mm to 17mm per side (normal for a m/t) then your 803 for 265/75 can end up being 770mm or 30.3"

770 to 833 = 6 cm.....


That was my arguement. Still think it's only 6cm larger tyres.


Of course if you can tell us who has 285/75 that are 890mm then we'll all go get a nice legal set

chops wrote:265/75/16 = 31.6"x 10.4"
285/75/16 = 32.8"x 11.2


265/75/16 overall diameter = 803.9 mm
285/75/16 overall diameter = 833.9 mm

chops, the numbers on the sidewall are only approximate
Going by the manufacturer's guides/brochures that I've got, 265/75x16's vary in overall diameter from 804mm (GY ATR) through to 820mm (BFG A/T). While the 285's vary from 840 (GY MTR) through to 852mm (BFG M/T).

Beastmavster wrote: What about going to a 255/85/16 instead? At about 33.3" it's a little bigger again 0.3" than a 285/75/16 but is still a 7" rim recommendation.

Yes but that is an odd size, only made by BFG and cooper (and maybe one other).

MTRs don't come in a 255/85 (otherwise I would have bought them in that size).

Maxxis (bighorn radial) also come in 255/85 but you're right it's a rarer size.