285/75/16 OR 305/70/16 for mi Mitsu Gen II

[caxtrol]

Hi friends

I am traying to buy a new set of tires for my Mitsu Gen II, with a 4.90 diff.

I have new rings 16/8 with a +12 positive offset, but I need some help with the size of the tire, I have 2 options

285/75/16

or

305/70/16

This new set of tires is for my day to day use, and will be an AT tires (for sand, mediun travels, and street)

Somebody has expirience with 285/75/16 or 305/70/16

Thanks

CAXTROL

[Drujba]

Now I understood your question in the other topic
First is equivalent with 33X11,5 second is 33X12,5

Original size is 29,6, so your tires will be 11% bigger than standard. Not good.
Your speedometer will read less than your actual speed, it will overcome the normal speedometer error, and will actually show you approx 6 to 7% less than your actual speed. But your biggest problem is that you will loose traction, and if you have a weak engine, like I do you will immediately notice that.
But if you have a mighty V6, you will hardly notice the difference. Only the fuel consumption will increase.

The best way if you want to go for that size is to change the diff gears to 5,29

As for the tires, on 8J rims as you have the 12,5 tire will look funny. For that you need 9J or 10J rims. I would go for the first one, and as you mentioned that you are planning to use that also on sand, I would go for an even more narrow tire, something like 33X10,5 or in radial size 265 80 R16

[-Scott-]

For a few years I've been running 285/75R16 on zero offset 16x8" rims, with a 2" body lift. It's been inspected and passed by registration authorities here in Australia, which means they didn't notice where the tyres rub.

The V6 copes OK, (and crawler gears help offroad) but as Drujba noted, fuel economy suffers. With a 24 tooth speedo gear and 4.875 diffs my speedo is within 1km/h at 60, 80 and 100.

[caxtrol]

Scott

I know that you have a experience with 285/75/16, but you will recomend me a 305/70/16 or it is enough with 285/75/16 ???

Thanks

CAXTROL

[-Scott-]

Caxtrol

I've not had 305/70 tyres, so I can't really advise either way.

Theoretically the lower profile should handle a little better, but in reality the sidewalls of both tyres are about the same height, so I don't know that the difference would be significant. When I was looking for my tyres there didn't seem to be a large selection in 305/70, so I was happy to stick with 285/75 - but tyre selection may have improved now.

Your +12 offset would put the centreline of your rim further towards the middle of the vehicle, and the wider tyres will move the inside wall further in again - nominally 22mm. I would check clearances carefully, particularly if the 305 tyres have very square shoulders - my 285s are much less than 285mm across the tread face, so a true 305 tread face would be worse again.

Also, be aware that as you move up in tyre height the point where your steering axis hits the ground moves out, which affects your scrub radius. By moving your tyre centreline in the opposite direction (+10mm offset to +12mm) you're going to change your scrub radius even more, which can increase steering load & "kickback".

I guess I'm not a lot of help.

[caxtrol]

Thanks Scott

Any other opinion about it ???

Thanks

CAXTROL

Caxtrol

I've not had 305/70 tyres, so I can't really advise either way.

Theoretically the lower profile should handle a little better, but in reality the sidewalls of both tyres are about the same height, so I don't know that the difference would be significant. When I was looking for my tyres there didn't seem to be a large selection in 305/70, so I was happy to stick with 285/75 - but tyre selection may have improved now.

Your +12 offset would put the centreline of your rim further towards the middle of the vehicle, and the wider tyres will move the inside wall further in again - nominally 22mm. I would check clearances carefully, particularly if the 305 tyres have very square shoulders - my 285s are much less than 285mm across the tread face, so a true 305 tread face would be worse again.

Also, be aware that as you move up in tyre height the point where your steering axis hits the ground moves out, which affects your scrub radius. By moving your tyre centreline in the opposite direction (+10mm offset to +12mm) you're going to change your scrub radius even more, which can increase steering load & "kickback".

I guess I'm not a lot of help.

[jonnyjtop]

285/75/16 are the go mate look fantastic and handel well i put on 16x8 patrol offset (-13) wheels with 2inch body lift and 2inch suspention they fit perfect no rubbing whatsoever i think if they were 305/70s they would scrub because mine only just clear the extra offset also makes the car more stable because they provide more track width...im very happy...

[Grantw]

No difference from my experience. Ran 285 BFG muds for a while and changed to 305 radial claws with no change.
Either way is good. I think a 285 would be a more popular tyre these days.

My 2 cents.