wheels

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Hi,

just trying to mod my fourtrak, its now got 2" shackle lifts,my question is whats the biggest tyres i can put on her without cutting wheel arches etc
at the moment i am running on 255 x 75 x 15 with a set of 1" spacers

would it stand a set of 31" tyres?

thanks,
Phil

you are running 31" tyres

sizes as follows 255/75 r15 = 31-10.5-15
235/75 r15 = 30-9,5-15

meanings - first number i.e 255 is the width in mm of the tyre, second number is the profile width, this is a percentage of the tyre width, i.e /75 means 75% so it will be a tyre wall thickness of 75% of 255mm,the higher the percentage the thicker the profile, r15 means rim size (15").
You wont be able to go any bigger on tyres sensibly, the gearing just wont work so well, with 31" tyres there is a strain on power as it is.

Full of ideas but no time to do them!!

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tyres

Hi,
thanks for the reply but iam confused, the dia of the tyre is some 28"
am i reading this wrong?

Phil

psi

how soft is the tyre on the vehicle???? its squashing it pehaps???

Full of ideas but no time to do them!!

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wheels

HI again,

we have been off roading now for a couple of years now, in suzuki sj

yes the pressure was around the 20 psi mark but would that make that much diff?

phil

I have run 31's on both an

I have run 31's on both an F80, and an F78. Both couped fine. No modification required on the F80, and with the front suspention wound up slightly (so the front wheel arch was the same hight from the road as the rear) on the Indi.

Towing the F80 suffered a little, needing 3rd in stead of 4th for some hills. The F78 pulled just as well as befor. The F80 suffered a slightly worse MPG, about 2 less than on 215/15's. While the F78 lost more due to the engine working harder to maintain the same speed as on smaller tyres. Basicly you could fit a feather to the fule needle, and use it as a fan as it went up and down so fast...

If you want the diff hight without the higher gearing you could change the transfur over. They have diffrent ratio out puts for the diffrent engins. 2ltr petrol lowest, then 2.8 NA Diesel, followed by 2.8 TD. There are other, though I'm not sure which are higher or lower of those. I belive ?? the LWB pick up truk has the lowest transfure ratio. All these transfures will fat any 4trak gearbox. The diffrenct that can couse probs is if your transfur is manual 4x4, or a switch on the dash. Also the compleat gear / transfure box can be swaped out. Bare in mind though that the bell housing and primary shaft on the petrol is diffrent, but can be swaped over with little effort.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

wheels

Hi,

ok thanks will look into tyre sizes, my F75 1991 has a 2" lift so i am hoping that will do the trick

Phil

tyre size

well im running 33 inch tall tyres on my 4 track without any problems but yes it does mess with the gearing a bit and will prob drop to 31,s with the next set