LT305/65 r18 tire on stock rims

[HarryOlson]

I’m planning on either Nitto Ridge Grapplers or Toyo Open Country AT3 tires on my stock 8” rims. The tire company says a 9” rim is needed. Does anyone have experience using a smaller than called for rim?

 

[Regcabguy]

They'll wear down prematurely in the center at 65-80 psi.
Discount won't mount them.

 

[lpennock]

Smaller than recommended rim will cause additional wear in the center of the tread and side to side flex but a lot of people do it.

Why don't you look at the LT285/75-18 and LT295/70-18 Both are approved for a 8" rim, are taller than the 305/65, and are rated slightly higher on load rating.

 

[HarryOlson]

I’m happy with the tire height but want a wider tread on the ground. The 305/65 has a 12” width which is perfect but I see the 295/65 is 11.6” wide. That could be workable, thanks.

 

[Wiredawg]

Wow,

Discount tire mounted 315/75/17s on my stock 8" rims 03 Ram 2500 6 years ago... they just mounted new Nittos same size a couple weeks ago... 90K miles on the old ones, no uneven wear.

Cheers, Ron

 

[Regcabguy]

Wow,

Discount tire mounted 315/75/17s on my stock 8" rims 03 Ram 2500 6 years ago... they just mounted new Nittos same size a couple weeks ago... 90K miles on the old ones, no uneven wear.

Cheers, Ron

The managers have some discretion but company policy is to follow tire manufacturer guidelines. The 8" wheels are the minimum allowable for a 315 for some manufacturers. Mount those tires on a 8.5 or especially 9" wheel and you'll feel the increase in stability.

 

[Wiredawg]

The managers have some discretion but company policy is to follow tire manufacturer guidelines. The 8" wheels are the minimum allowable for a 315 for some manufacturers. Mount those tires on a 8.5 or especially 9" wheel and you'll feel the increase in stability.

I had great wear and incredible stability.

"315/70R17 tires have a diameter of 34.4", a section width of 12.4", and a wheel diameter of 17". The circumference is 107.9" and they have 587 revolutions per mile. Generally they are approved to be mounted on 8-10.5" wide wheels for passenger tires and 8-11" for LT tires."

and from Discount tire website:

RIM WIDTH RANGE 7.5" - 11.0"

No argument here, just real life experience; 8" wide rim plenty stable and wear just fine.

Cheers, Ron

 

[HarryOlson]

Ron, I’m still stopped on the 90,000 miles before replacement! How did you manage that? I do appreciate your help as well as the help from others. Many thanks, Harry

 

[Wiredawg]

Ron, I’m still stopped on the 90,000 miles before replacement! How did you manage that? I do appreciate your help as well as the help from others. Many thanks, Harry

Rotate and balance every 5K miles.. Ran 70PSI in the fronts and 45 PSI in the rears. Nitto are good tires. We live out in rural area, so most miles more highway than city driving. BTW, was on a 2003 Ram 2500 4dr 4x4 SB.

Cheers, Ron

 

[lpennock]

"315/70R17 tires have a diameter of 34.4", a section width of 12.4", and a wheel diameter of 17". The circumference is 107.9" and they have 587 revolutions per mile. Generally they are approved to be mounted on 8-10.5" wide wheels for passenger tires and 8-11" for LT tires."

A LT315/70R17 is rated on an 8" rim but a LT305/65R18 is not as it has a shorter sidewall. The LT305 looses almost 1" of sidewall height (.3" aspect ratio and .5" rim diameter) compared to your LT315. Additional Side wall height allows more rim diameter choices on the 17.

 

[Wiredawg]

According to Discount Tire, a 305 70R 18 WILL fit 8" rim and should work on OPs. Just have to search til you find something that fits.

Cheers, Ron

 

[lpennock]

According to Discount Tire, a 305 70R 18 WILL fit 8" rim and should work on OPs. Just have to search til you find something that fits.

Cheers, Ron

Discount tires web site does not match with the manufactures ratings. I check the rating for a LT305/70R18 from Toyo, BFG and General and they all have a rim range of 8.5 or 9 to 11. Discount tire web site says 7.5" to 10.5.

 

[Wiredawg]

Discount tires web site does not match with the manufactures ratings. I check the rating for a LT305/70R18 from Toyo, BFG and General and they all have a rim range of 8.5 or 9 to 11. Discount tire web site says 7.5" to 10.5.

From Nitto website on another tire that works per manufacturer.

Like I said, look until you find something that works. Discount tire sold mine and I'm sure if OP finds something that Discount Tire approves, they'll do it. I can't think of anything else to say about it.

Cheers, Ron

 

[lpennock]

Different size tire than was asked about. Yes you can find other sizes that are rated for 8" rim but that wasn't the original question.

 

[Wiredawg]

Different size tire than was asked about. Yes you can find other sizes that are rated for 8" rim but that wasn't the original question.

Just wanted to help the OP find a tire that works. I appreciate you were helping too. That's what we do here on the TDR.

Cheers, Ron

 

[Wiredawg]

I’m planning on either Nitto Ridge Grapplers or Toyo Open Country AT3 tires on my stock 8” rims. The tire company says a 9” rim is needed. Does anyone have experience using a smaller than called for rim?

Hi Harry,

Just curious what you're thinking about doing. We provided a bunch of info and always good to here what the OP decides to do.

EDIT: Just thought I would mention friend of mine got 112K miles with the Michelins on his 2008 F250 4x4. They were just shy of touching the wear marks, but highlights the importance of proper inflation, regular tire rotation, and keeping the front end aligned.

EDIT AGAIN: Ref the Nitto tire specs I posted above, you'll see approved wheel fitment range, but the one in parentheses is the ideal wheel width recommended, which for that tire is 9.0".

Good luck figuring it out.

Cheers, Ron

 

[Regcabguy]

I'm tall and standing with my feet fairly close I'm easy to sway to the side. Widen my stance by a bit and I become much more stable. Everything's relative. If you haven't experienced an inch wider rim on that same tire you wouldn't know. I have. It's the law of physics. Aired down the narrower rim will pinch the sidewall over a wider rim and give you a better chance of not losing the bead but a slightly wider rim within the manufacturers specs. will yield a more stable tire for street use. It's not rocket science. I've got an 11 shoe size and could probably squeeze into a 10.5. It can be done but my foot works much better in the proper shoe. There was a guy on the Cummins

 

[AEdelheit]

Ive ran 37x13.5 on stock wheels with no issues and no premature wear, just pay attention to tire pressure and rotations.

 

[HarryOlson]

I normally put about 23,000 miles on my trucks annually. 4,000 to 6,000 of that is towing heavy here in the western states and the rest is back and forth empty to Mexico hunting. Without better tires I’m getting stuck on wet grass. It’s very aggravating. I’ve run Toyo Open Country ATII tires and liked them but would be happy with Nittos as well. After reviewing your replies I’m going shopping for a 295/70r18 tire. In the Toyo and Nitto tires, they have increased the ratings to 4,080 pounds. Both are a little taller and a little wider than the current Firestones. Hopefully everything should fit, not rub and provide decent wear. Many thanks for the assistance, Harry

 

[Wiredawg]

I normally put about 23,000 miles on my trucks annually. 4,000 to 6,000 of that is towing heavy here in the western states and the rest is back and forth empty to Mexico hunting. Without better tires I’m getting stuck on wet grass. It’s very aggravating. I’ve run Toyo Open Country ATII tires and liked them but would be happy with Nittos as well. After reviewing your replies I’m going shopping for a 295/70r18 tire. In the Toyo and Nitto tires, they have increased the ratings to 4,080 pounds. Both are a little taller and a little wider than the current Firestones. Hopefully everything should fit, not rub and provide decent wear. Many thanks for the assistance, Harry

Glad to be of help... I love the Internet with all the info available. I can sit in my easy chair and figure almost anything out with online searching. I like the stock trims on my vehicles and like to keep the OEM look and wheel setback. We'd love to see pics of what you get.

Cheers, Ron