hmmm...tire load ratings

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Eswift
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J30 has an OEM load rating of 93, and it seems most 45 series rubber available for a 17 inch wheel carries a 91 rating. I did find ONE tire with a 94 rating...but that sort of completely limits my choices.

any other people running aftermarket wheels on the J30 using a lower load rating?

i personally would rather stay at or above spec, although i am sure there is a certain factor of safety involved. on the other hand, the J30 could benefit from the biggest safety buffer available...

Dennis/ others, whats your opinion on running a lower load rating? ( I am sure many run below spec without even knowing it, tires seem to have become weaker since the early 90s, or maybe the tests used to monitor actual load ratings have become stricter...)


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When you read all the post concerning the new TREAD ACT you come to realize that the safety factors in tires and the method of selecting a tire -- the load rating leaves a lot to be desired.

In Europe and Japan it is illegal to use a tire with a lower speed rating or lower load index than that which came on the car. The car will be impounded till brought into compliance [unsafe to be on the road].

In the US a owner is allowed to do anything they want. Those few states that still have annual safety inspections will fail you for your tire choices.

However if something goes wrong with YOUR choice or YOU end up in court [accident] using an inferior tire makes YOU automatically guilty in the eyes of the experts [accident reconstruction specialist witnessses]. YOU lose any rights to sue the tire manufacturer because YOU chose to use an inferior lower rated tire. Even the vehicle manufacturer is of the hook because you redesigned the suspension and handling with a different wheel/tire!

Worse in normal life, tire life and durability is a function of the safety factor - real load vs max load.

The quest for fuel economy has forced tire makers to design tires with low rolling resistances, this requirement is the opposite of that required to build a strong sidewall.

If you are buying a tire that lasts more than 15-17,000 miles [tread compound hardness] always upgrade the load index which is measured brand new and decreases as the tire wears.

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szh
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Hi, Eswift.

I do not know if 245/45-17 is a tire size that will fit your J30 or not, but a number of tire manufacturers make that size in a 95 load rating. I carefully looked at all the choices available for 17" rims before I bought these rims for my Q45. And there were sufficient choices that I felt comfortable in going for it.

Z

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Eswift
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i think it would be a stretch to fit the 245 onto an 8 inch rim...but i will definitley consider it.

maxnix
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Eswift wrote:i think it would be a stretch to fit the 245 onto an 8 inch rim...but i will definitley consider it.
Not at all. It will go on a rim up to 9", I believe. Check the Tirerack specification sheet for your tire.

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AZhitman
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245 on an 8" rim would be perfect, actually.

It's a squeeze on a 7.5.

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Eswift
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i stand corrected, although a 245/45 will make the speedometer show lower than actual, its only about 2%...

just hope 245 isnt going to be too wide

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AZhitman
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I don't think it will...

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Mayhem_J30
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The 235/45/17 for Michelin Pilot XGT H4 have 93 rating. Should be a good fit on the 8" Tire Rack recommends 225 on 8" but they always seem to quote on the small side. Maybe it's for rubbing issues....???

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Eswift
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yeah, i found several 235/45s with a 94 or above rating...think i will go with the kumho 712 i think it is, only found positive reviews of it.

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szh
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AZhitman wrote:245 on an 8" rim would be perfect, actually.

It's a squeeze on a 7.5.


Well ... I am kinda hoping to get 245/45 onto a 7" rim. 'Cause Tire-rack (and others) show a 7.5 to 9 range - I figured that 7" might be okay, albeit a bit narrow.

Z

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Eswift
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i think that might be pushing it.

there might be a significant amount of tire roll with that big of a difference, if it even works.

guess you will have no worries about scratching up the rims on the wheels, though.

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AZhitman
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I have 255's on a 7" rim. Tread was measured with a straightedge at proper inflation to be .1" less than what the specs call for, so it's not rolling up badly at all.

Looks aggressive as all hell, reminds me of the look of the late 80's - early 90's BMW 7series with the fat Michelins.


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