Running Oversized Tires On My TV

Looking for some advise. We've decided to keep our 2012 Ford F-350, 4x4, srw, crew cab, long bed. We are currently running Hankook Dynapro ATM LT 325/60R20 tires on stock chrome spoke 8.5x20 Ford wheels.

Discount Tire said they won't mount that size tire on my wheels. They said it puts to much stress on the bead. They suggested 295/65R20. I like the look, stance, and ride of the current tire and size.

Another tire ire shop we use at work for equipment and trucks said they sell the 325/60R20's all the time for TV's that have my wheel size. Im currently looking at the Nitto Terra Grapler with an E load rating. Road Warrior is 15,300 lbs. dry. Pin weight is around 4,100 lbs (correct me if I'm wrong).

Anyone else running an oversized tire on stock wheels? Any reason why I should steer away from my current combination or the Nitto tires?

Thanks, Tim

I think it is more of a liability thing for some tire shops. I have the Nitto Terra Grappler G2's on my 2013 Ram 2500 4x4. I went up to 295/70/17's on my truck and 2 places I had gone to would not order them for me as they stayed they were to large for my truck. I do not have any issues. I really like the ride and the look of them.

A reputable shop tells you no for safety reasons so you ignore that and go to a shop that tells you yes because you like the look of it? I don't get it...


Sent from my PU-36 Explosive Space Modulator.

They were referring to a clearance issue in reference to the tires in the wheel well. As far as safety the tires have better ratings than the stack tires I previously had on my truck.

They also look good on the truck! Lol

Shortest Straw said:

A reputable shop tells you no for safety reasons so you ignore that and go to a shop that tells you yes because you like the look of it? I don't get it...


Sent from my PU-36 Explosive Space Modulator.

Click to expand...

You don't get what? Me asking for advice, Or that you rushed to judgement before reading my whole post asking for advise? Get it?

TxRoadWarrior362 said:

You don't get what? Me asking for advice, Or that you rushed to judgement before reading my whole post asking for advise? Get it?

Click to expand...

I have the same truck and I run 295/60/20 nitto terra grappler g2.325s may be to wide for the stock rim.The sidewall of the tire has to curve back to the rim to much on that size tire.If you like the 325s you may want to run them on a 9 inch wide wheel with a different offset.

The one tire guy was going by the published specs on the tire from Nitto, most likely. The 325's have a suggested rim width of 9 to 12".

Also, you mention pin weight. Between approximately 4,000 lb. of pin weight and a guaranteed minimum of about 3,500 lb on your truck's rear axle without the trailer, you're looking at 7,500 lb. The 325s have a weight rating of 3,750 lb. each at 65 psi (7,500 lb. total). The 295s have a recommended rim width of 8 to 10" and a higher weight rating of 4,080 lb. each at 80 psi (8,160 lb. total).

Though I understand liking the look of the beefier tire, the other side of the equation is the weight rating.

[Specs on the G2 tires]

Donhutch1800 said:

I have the same truck and I run 295/60/20 nitto terra grappler g2.325s may be to wide for the stock rim.The sidewall of the tire has to curve back to the rim to much on that size tire.If you like the 325s you may want to run them on a 9 inch wide wheel with a different offset.

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Good advise. Thank you

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MCTalley said:

The one tire guy was going by the published specs on the tire from Nitto, most likely. The 325's have a suggested rim width of 9 to 12".

Also, you mention pin weight. Between approximately 4,000 lb. of pin weight and a guaranteed minimum of about 3,500 lb on your truck's rear axle without the trailer, you're looking at 7,500 lb. The 325s have a weight rating of 3,750 lb. each at 65 psi (7,500 lb. total). The 295s have a recommended rim width of 8 to 10" and a higher weight rating of 4,080 lb. each at 80 psi (8,160 lb. total).

Though I understand liking the look of the beefier tire, the other side of the equation is the weight rating.

[Specs on the G2 tires]

Click to expand...

Thank you. I reviewed the Nitto tire specs a few minutes ago. I've exceeded the limits using the 325's on my wheels. I didn't mention that I had discount order the 295's Nitto's on Sat. I wanted to double check with ya'll before I pulled the trigger on the narrower tire. Thanks to all for the advice.

Tim

Hi, Tim

I gather that you are attempting to upgrade your truck to tow the Road Warrior. First of all, dry weight is useless. I always recommend using the GVWR for calculating towing capacity needs. Secondly, Bigger tires or tires with higher load ratings may not be all you need to do to improve the GVWR. Although you can increase the GVWR and the rear GAWR, it will not change the Safety Compliance Certification Label information.

If you want to effectively upgrade your SRW to the capacity equivalent to a DRW, there are some mods that may be required. Mods such as increasing the gear ratio to at least 3.73 will help improve the GCWR. A 4.10 would be even better if you will be traveling over the mountains frequently. You may need to consider the springs as well.

As for wheels and tires, I recommend you visit Rickson Wheel Manufacturing for upgrades.

It is not as simple as it sounds. If you have not done so, consider using the app, RVtowCheck.com to learn your truck’s realistic vehicle towing capacity. That will give you some idea of the extent of mods you may need.

Although it depends on how you load it, the pin weight will most likely be around 3,400 to 3,600 pounds.

Heck im surprised you didnt have rubbing issues with yhe 325 on stock rim from get go.. my 12 is lifted 3 " on nitto trail graps 35x12.5/20 (9"wide custom offset) and even then it rubs in reverse ..the nitto have good load rating...enough in fact to probably exceed your rear gawr.

It does look 10x better..but those tires cost me 2+ mpg towing so in dont go go far on them...put stockers back on (both on srw and dually when i tow long)

Also it will be louder and at 35.4 " tall your spare will not match ..

All things to consider especially when towing..

sent from space via an invisible beam from a flying metal dish

TxRoadWarrior362 said:

You don't get what? Me asking for advice, Or that you rushed to judgement before reading my whole post asking for advise? Get it?

Click to expand...

No I read the whole thing. What it sounded like to me is you did get advice but were looking elsewhere to get the answer you wanted to hear instead. What I do not get is putting that big of a tire on a stock rim for a "look". Why not do it right and get bigger rims as well? But who am I right? I have never seen the need to do what you are wanting to do, much less go off the stock size or buy rims for that matter.

I'm very interested in how this turns out. We just purchased a 3513 and pull with a srw 2016 f-350. I know I'm on the tipping edge of max and I too am looking at the G2 tires. Please post pics when she's complete. I'm most likely also going to do a Carli level kit with bags to smooth out this new 1 ton a bit.

Keep us posted


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Discount has never steered me wrong and has been pretty forthright with advice. If they say they don't like it for one reason or another that really would be enough for me. They have a lot more experience in that area than I do. Consider they are doing this stuff daily and we are not. If you are not sure exactly what they were concerned about, go back and ask.

It's kind of like going into Flight Service for weather and having a more experience pilot tell you "I wouldn't today".

DW_Gray said:

Hi, Tim

I gather that you are attempting to upgrade your truck to tow the Road Warrior. First of all, dry weight is useless. I always recommend using the GVWR for calculating towing capacity needs. Secondly, Bigger tires or tires with higher load ratings may not be all you need to do to improve the GVWR. Although you can increase the GVWR and the rear GAWR, it will not change the Safety Compliance Certification Label information.

If you want to effectively upgrade your SRW to the capacity equivalent to a DRW, there are some mods that may be required. Mods such as increasing the gear ratio to at least 3.73 will help improve the GCWR. A 4.10 would be even better if you will be traveling over the mountains frequently. You may need to consider the springs as well.

As for wheels and tires, I recommend you visit Rickson Wheel Manufacturing for upgrades.

It is not as simple as it sounds. If you have not done so, consider using the app, RVtowCheck.com to learn your truck’s realistic vehicle towing capacity. That will give you some idea of the extent of mods you may need.

Although it depends on how you load it, the pin weight will most likely be around 3,400 to 3,600 pounds.

Click to expand...

DW-

Thank you for the response and information. RVtowCheck.com is very good information. I haven't got to spend the time needed to absorb all the info/advise you gave. Again, thank you. Tim

I'm running:
19.5" X 6.75" steel rims with: Toyo M143Z 245/70R 19.5 LRH front and Toyo M608Z 245/70R 19.5 LRG rear. It may not win any bling awards, but I like them.

For my 2012 F350 SRW, I found that when pulling the BH, the drivers side rear tire was a little over weight, but no other tire position was. The load range E tires were at the top of their load range for a 1 ton truck pulling my BH. At 30k miles, the tires were showing wear despite being rotated every 5k miles.

Like adding the GY tires for the fiver, I wanted a margin of safety the load range E tires cannot offer.

Sorry so long but instead of 2 cents, I'm giving a $1's worth. I don't like tire mods. IMHO, mounting tires on the wrong rims is not an original idea. More likely than not a problem will be introduced into the system. My experience came from a fitment issue when I bought some 20 inch OEM take offs to replace my 17 inch rims on my 2013 Ram 2500. The 20 incher's came off a 2014 RAM 3500 which offered that as an option. There did not appear to be a fitment issue in the beginning but it soon became clear that the 2014 RAM 3500 OEM 20 inch tire rubbed my frame in tight right hand turns (turning into parking spaces). Fortunately it was only enough to hear feel, diminish fuel milage, and polish the frame a little. I made the mod to get around tire loading issues stemming from not having the right tow vehicle to begin with.

With the bigger, heavier tire I suffered about a 10% loss in fuel economy. I went from 19 average around town to 17 (average about 10%). While towing I went from 11 to 9, which is about a 20% decrease in much needed fuel economy and range. The screwed up 4% change in my speedometer indications are annoying also. Let alone the exacerbation of the already too high drive line ratios. I would have to go to a 3:75 diff ratio on both axles (4X4) to compensate. For me the 10% loss in fuel economy adds about $150 to fuel operating cost between fuel filter and oil/filter changes. And that is without towing anything. If I was towing it works out to about $250 on a 4000 mile trip. I realize that a diesel will get 500,000 miles easily, but based on a 250,000 mile life span an extra $5000 in fuel expenditures is required to run those 20 inch tires in place of the OEM 17's.

Ignoring the rim width introduces several performance related issues. Tire rack's website has a comprehensive FAQ on tire/rim issues and tire/rim fitment issues. As far as load ratings, I achieved my goal by installing the 20 inch OEM Firestone tires on the 2500, but ultimately I cured my problem by ordering a 2017 RAM 3500 SRW with 18's which have the same load rating as the higher priced 20's, since I already own a set of the optional 20 inch rims (currently on the 2500), I intend to swap them out and have the 20's on the 3500, and then have the tire size changed in the EVIC. Now I have no fitment issues and no load issues at 4300 lbs payload with the 3500. Original is always preferable when towing 15,500 lbs or more. Mounting a tire on a narrow rim increases the diameter of the tire and mounting the same tire on a wider rim decreases the diameter of the tire. At first glance one might not see the significance of these changes as they are subtle. But if one takes a sharp pencil to it the math will point out the drastic changes caused by tire mods. Did I mention brake system maintenance yet. Remember those brakes have to stop that rubber (tire mass), and your vehicle, a larger heavier tire requires significant brake pressure to accomplish this which translates to heat and wear. In the end the accumulative cost of a tire mod, if identified should preclude anyone thinking of it.

There are so many issues to modifying rims and tires that I would refrain from getting involved in it at all. Stay with OEM sizes, your tow vehicle and your wallet will thank you for it.

End the end advice is worth what you pay for it, and since this is free it's not worth much. Good luck with your mod.

And thats why i ended up with 2 sets of wheels/tires...lol

One set of 6 full vanity,waste of money , because i want to wheels.....

One set of 6 aftermarket rims on stock tire size...

Its hard to find a happy medium when towing gets involved..


But if done correctly its safe and really only becomes a cost issue...like so many other indulgences we all have...

To each their own...

Own it, love it, drive it, !! Its all about the journey!!

Merry day before christmas eve to all!!



sent from space via an invisible beam from a flying metal dish

Jim.Allison said:

Sorry so long but instead of 2 cents, I'm giving a $1's worth.

Click to expand...

I'd say that was more like $2.00 worth . . .

Myself personally I wouldn't run any tires on your TV .LOL BUT I have on my Landmark Rushmore Goodyear g range 110 psi plenty strong

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Thanks for all the responses. Y'all are very helpful.

Jim, that was a good read, thank you.
DW- after plugging in the specs, I'm not within the tow limits of my truck. Close, but not good.
Todster- For what it's worth. I went with the 295/65r20 G2's. When I bought the truck it had the 20' wheels on it.

Thanks again for the advice and wisdom. Merry Christmas!

Tim