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Old 09-29-2020, 01:07 PM   #1
Igoo65
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Wheel Size For TV 20" vs 18"

Good day Montana owners!
I am about to pull the trigger on buying a 2020/2021 SRW new truck to pull my 3000RK (12,500 GVWR).
I would like to know if it matters which size wheels 20" vs 18" I have when towing. Both sets of wheels have E rated tires and the sidewall profile difference is 5mm (65 vs 70). The big difference is price. The 20" wheels cost $1340 and when I have to replace tires, the 20" tires cost $100 more per tire than the 18".
I would like to get some feedback on my dilemma.
Thanks,
Igoo65
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Old 09-29-2020, 01:18 PM   #2
jetskier
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I think you answered your own question. 20's cost more than 18s both initially and down the road. Other than looks, you can get tires with load ratings up to 4080lbs per tire (LT295 and some LT285s)

FYI, the 65 vs 70 is a percentage, not a 5mm difference.
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Old 09-29-2020, 01:19 PM   #3
mlh
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Yes it definitely does make a difference. There is less sway in the 20 inch tires. You have an inch less side wall. I have had both. I would bite the bullet and get the 20s.
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Old 09-29-2020, 01:21 PM   #4
sourdough
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If you can find the truck you want and get the 18s I'd say go for it. The 18 and 20 inch tires both do the same thing but the 20" wheel pkg. costs up front and tires cost more down the road. The only thing they have going for them is looks in some folks opinion. I've had 20s on the last 3 trucks because the trucks I could find with the equipment I wanted (not 20 inch wheels) all had them.
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Old 10-02-2020, 01:07 PM   #5
rohrmann
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On our 4WD truck, in the manual it said the 20s were not recommended for off pavement driving. The dealership had put after market 20s on our truck and it rode harsh. I had them put the 18s back on before we would purchase it, and the ride was vastly improved.
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Old 10-02-2020, 01:56 PM   #6
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go with 18"
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Old 10-02-2020, 07:19 PM   #7
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That trailer weight isn't an issue with either size. 18s will have a better ride, lower cost, and after 3 months you won't even know the difference with regards to looks.
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Old 10-02-2020, 08:24 PM   #8
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The same tire in 20” will have a couple hundred pounds heavier load rating per tire than the equivalent tire in 18” if that matters to you. Due to the shorter sidewall I suppose.

I used to have a link to Ford published truck specifications for all the various configurations and options and the F350 with 20” wheels had higher payload ratings than the same F350 with 18” wheels. Can’t find that link now.
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Old 10-04-2020, 05:27 AM   #9
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I don't believe there is a practical use difference between the 18 and 20 inch tires. My F350 SRW has 20 inch tires as part of the package ordered by the dealer before I purchased it. I have noticed that the DRW's have 19.5 inch tires in that same year. I guess some engineer decided that was better ratio for that model truck, but I'm not sure you'll know the difference either way. BTW, Ford put an 18 inch spare under my truck with the 20 inch tires, but it is taller so it will be roughly the same height as the 20's.
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Old 10-07-2020, 03:31 PM   #10
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I can't speak to the newer TVs but when I bought mine, with 20" wheels the GVWR was 10,000 lbs but with 18" wheels the GVWR was 11,500 lbs.
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Old 10-07-2020, 05:09 PM   #11
danielm300
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I had 20" wheels on my 2011 2500HD Duramax. 20" tires are hard to come by out on the road if you need to buy them. 18s are a lot easier to come by
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Old 10-07-2020, 06:00 PM   #12
Carl n Susan
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The 20" tires have a slightly higher carrying capacity compared to the 18" ones. I have never had a problem getting replacements. Discount Tire carries the Michelin's and 20" replacement tires can be found at Costco and Les Schwab. Oh yea, my 2015 F350 with 20" wheels has a GVWR of 11,500.
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Old 10-07-2020, 07:10 PM   #13
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Quote:
Originally Posted by laverdur View Post
I can't speak to the newer TVs but when I bought mine, with 20" wheels the GVWR was 10,000 lbs but with 18" wheels the GVWR was 11,500 lbs.
My 2012 F350 SRW came with 20 wheels and 11,500 lb GVWR.
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Old 10-07-2020, 08:43 PM   #14
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Originally Posted by BB_TX View Post
My 2012 F350 SRW came with 20 wheels and 11,500 lb GVWR.
My 2014 3500 Ram SRW came with 18" wheels and 12,300 lb GVWR.
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Old 10-08-2020, 08:02 AM   #15
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Quote:
Originally Posted by Montana Man View Post
My 2014 3500 Ram SRW came with 18" wheels and 12,300 lb GVWR.
The point is that it is not the wheels that determines the GVWR, at least on Fords. What is the GVWR of that same Ram with 20" wheels?
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Old 10-08-2020, 11:32 AM   #16
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Quote:
Originally Posted by BB_TX View Post
The point is that it is not the wheels that determines the GVWR, at least on Fords. What is the GVWR of that same Ram with 20" wheels?
the GVWR is whatever the sticker says. If RAM does not come with 20" from the factory, changing them out for 20" rims changes nothing on the sticker.
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Old 10-08-2020, 12:33 PM   #17
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Originally Posted by BiggarView View Post
the GVWR is whatever the sticker says. If RAM does not come with 20" from the factory, changing them out for 20" rims changes nothing on the sticker.
And again, in spite of the post above, the wheel size does not dictate the truck GVWR, particularly since on same brand/same style tire the 20 will have a slightly higher load rating than the 18. Dont know if the RAWR would be lower for the 18 or not with the tire being rated lower.
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Old 10-08-2020, 01:06 PM   #18
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Originally Posted by BB_TX View Post
The point is that it is not the wheels that determines the GVWR, at least on Fords. What is the GVWR of that same Ram with 20" wheels?
I don't know what the rating is with 20's but all the charts I've seen showed 12300 lbs to be the highest rating for this class/brand of truck. In fact, I've not seen where wheels are mentioned specifically relating to GVWR other than SRW, DRW.
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Old 10-08-2020, 02:30 PM   #19
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I had 20 inch wheels on my 2015 Duramax 2500HD. When I decided to get a fifth wheel I started looking for tires with a better rating than the 3150 pounds that were on there, that was a weak link.
Not easy to find and very expensive. One reason I traded for a dually.

I will not have another truck with 20's on it.
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Old 10-08-2020, 03:58 PM   #20
mlh
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My 20 inch tires are rated at 3750 pounds at 80 psi.
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