Cooper st maxx

Hi

I´m thinking about to buy cooper st maxx in size 305/70/18.

However, stock rim is only 7,5 inch wide and that tire acording to cooper should be mounted on a 8,5 inch rim. Should I go down to next size that is a 295/70/18 ?

According to cooper that size is ok on a 7,5 inch wide rim.

is it dangerous to use a 305 wide tire on stock rim, will road handle be very bad?

I really wanted to go up to 305 wide because that is more or less a 35 inch tire and that is want I want but 295/70/18 is also ok if the bigger size is not to recomend.

Thanks

I would not be concerned.

I have ran 37-13.50s on stock 7.5" rims, they have about 30,000 miles and no problems.

I have also ran 33-12.50 on 7" rims, also for 50,000+ miles with no problems.

Chalk the tires to establish the correct pressure and run it.

Bingobelle said:

Hi

I´m thinking about to buy cooper st maxx in size 305/70/18.

However, stock rim is only 7,5 inch wide and that tire acording to cooper should be mounted on a 8,5 inch rim. Should I go down to next size that is a 295/70/18 ?

According to cooper that size is ok on a 7,5 inch wide rim.

is it dangerous to use a 305 wide tire on stock rim, will road handle be very bad?

I really wanted to go up to 305 wide because that is more or less a 35 inch tire and that is want I want but 295/70/18 is also ok if the bigger size is not to recomend.

Thanks

Click to expand...

I’m by no means a tire expert, but I just recently dealt with the same dilemma.

It’s my understanding that narrow wheels make the tire crown more. This causes the tire to wear the middle out faster than the edges. To negate that you run less tire pressure. Low tire pressure deteriorates gas mileage and can create hazardous conditions at higher speeds in panic situations. This can also increase the risk of losing a bead when aired down.

I recently purchased STT Pro’s 295/70R17 and mounted on my stock 7 1/2” wheels which is narrowest wheel Cooper recommends for this size/type tire.

At 30psi they seemed very stiff so I did a chalk test and found that they were over inflated. I ended up at 25psi which greatly improved the ride and gave a decent chalk wear pattern. I’m pretty comfortable with 25psi, but I wouldn’t want to go much less for daily driving. I also think I should be just fine at 15psi off road.

At this time I’m seeing a 2mpg lose due to the tires.

I wouldn’t recommend using a wheel that is an inch narrower than the minimum requirement, but I’ve seen plenty of people that do it. Heck, I think there is a guy on here that runs 37’s on stock wheels, but that taller profile probably makes for a better situation than a 70 series, maybe?

Hope that helps.

Running those on stock wheels is not a big deal. Tire shops on the other had might not want to put the tires as the stock wheels are smaller. Discount Tire here in the states won't do it while smaller mom and pop shops won't care.

jdofmemi said:

I would not be concerned.

I have ran 37-13.50s on stock 7.5" rims, they have about 30,000 miles and no problems.

I have also ran 33-12.50 on 7" rims, also for 50,000+ miles with no problems.

Chalk the tires to establish the correct pressure and run it.

Click to expand...

This^^. I am running 37x12.5 on stock wheels now and have no problems as a DD. Definitely do a chalk test. Discount Tire also mounted and balanced them for me without issue. Mine are nitto trail grapplers, not coopers.


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ok, need some help.

I have starting to begang to understand that finding tires in my unbelieable boring country called Sweden is harder than I thought. The st maxx is no longer to be found in bigger size and the AT3 XLT is not allowed to be sold in Europe at all!!!

However, as strange as it may be the more aggresive STT PRO is actually easy to find and also is in a realtive good price point. I can buy the 305/70/18 for about 330 dollar a piece.

But, can some people give me a honest answer about how those stt pro is on the high way. Are they much louder than my current st maxx and will they take a lot of more fuel?

Thanks

Bingobelle said:

ok, need some help.

I have starting to begang to understand that finding tires in my unbelieable boring country called Sweden is harder than I thought. The st maxx is no longer to be found in bigger size and the AT3 XLT is not allowed to be sold in Europe at all!!!

However, as strange as it may be the more aggresive STT PRO is actually easy to find and also is in a realtive good price point. I can buy the 305/70/18 for about 330 dollar a piece.

But, can some people give me a honest answer about how those stt pro is on the high way. Are they much louder than my current st maxx and will they take a lot of more fuel?

Thanks

Click to expand...

Here's a good place to start.

https://wayalife.com/showthread.php?t=51537

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