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Biggest tire possible on stock 20's

143K views 35 replies 25 participants last post by  14vern 
#1 ·
Like the title, what is the biggest tire i can put on the stock 20 inch rims
 
#2 ·
Depends on if you level or lift it. With no level or lift you can run a 34 inch tall tire. With spacers and a level you can run 35x12.5 tires. With a six inch lift and spacers you can run a full 37 inch
 
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#3 ·
I just had a set of BFG KO2s in 285/65/20 installed on my 2016 Bighorn - no lift (2" drop springs in the rear to improve stance, but irrelevant for this discussion) - and they aren't all that close to rubbing anywhere. I would guess that a 295/65/20 would also fit, if such a beast exists.

Tires are like shoes though, a given size can vary from one manufacturer to the next so the same size tire in a different product line may or may not fit.

I buy all my tires at Discount Tire. When I'm playing with tire sizes they're good about test fitting one before you get locked in. I've had them do this for me several times on different vehicles. In this case they mounted and test fitted one on the front, checking for steering function. No worries about rubbing, even at full lock and under suspension compression.

I am told that these are roughly equivalent to a 34.5" tire but I'm not sure.
 
#34 ·
I just had a set of BFG KO2s in 285/65/20 installed on my 2016 Bighorn - no lift (2" drop springs in the rear to improve stance, but irrelevant for this discussion) - and they aren't all that close to rubbing anywhere. I would guess that a 295/65/20 would also fit, if such a beast exists.

Tires are like shoes though, a given size can vary from one manufacturer to the next so the same size tire in a different product line may or may not fit.

I buy all my tires at Discount Tire. When I'm playing with tire sizes they're good about test fitting one before you get locked in. I've had them do this for me several times on different vehicles. In this case they mounted and test fitted one on the front, checking for steering function. No worries about rubbing, even at full lock and under suspension compression.

I am told that these are roughly equivalent to a 34.5" tire but I'm not sure.
Where did you get the 2” rear drop from ?
 
#4 ·
I think it also depends which 20 inch rim you have? The Chrome Clads are 9 inches wide, the others are 8.5. With an 8.5 inch wheel you can may be run 295/60/20, that translates to 33.9X11.6. Remember too, the stock wheels have somewhere around +18/+19 mm offset, which brings the wheel in more.
295/65R20 = 35.1x11.6x20

The 20 inch chrome clads run really close to the upper control arm, the 8.5 rim not so bad. You can try by sticking your finger in between the A-arm and the tire see how much space you have.

FYI, 285/65/20 =34.6x11.2x20
285/60/20 = 33.5x11.2x20

*the sizes can vary by manufacturer.
 
#5 ·
I think it also depends which 20 inch rim you have? The Chrome Clads are 9 inches wide, the others are 8.5.
Good point - I mounted the 285s on the factory chrome clad wheels. The gap between the tire and the upper control arm is about the same as it was with the narrower stock tires. The BFGs are 10-ply and they have a much more square shoulder than the stock SRAs. Both means that they "squat" less than the SRAs did and I think this how and why the sidewall on the wider tire isn't any closer to the UCA.

I don't know for sure, but they do fit without any rubbing anywhere.
 
#6 ·
From what I have read in the past 285's on stock 20X9's is really the way to go. That size tire is a little pricey, and not too many options, however the result is very worth it.

Not to forget, those will last you a while.

Terry, do you happen to have a pic with the 285's, very interested.
 
#13 ·
I ran 35x12.50x20 Firestone Destination M/T, with no spacer, and Bils set at 2.8. I had no rub but opted to put on the hubcentric/wheelcentric 10mm spacers I ordered simply to have a bit more fill out in the factory fender flares.
 
#15 ·
I went with the 285-65-20 BFG KO2's, truck has air ride with 2" lift, same as level kit. No rubbing at all, since i added fender flares i am thinking of going with wheel spacers either 1", 1.25" or 1.5" to push them out even with flares but can't pull trigger to get them yet, i have heard a lot of horror stories with guys using them and failing.
 

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#20 ·
Hope this helps someone in the future. I read a lot of things and thought for sure I could fit the new tire and wheel combo with no level or lift. Well come to find out not the case at full lock bad rubbing. So I did a leveling kit thought great this is money. Still a little rub nothing major going to have to trim some plastic. My setup is a 2016 Ram 1500 big Horn 2wd. I went down to 17" rims for cost of tires they are a -12 offset. Tires are 315/70R17 which converts to a 34.5x12.5R17 they are falken wild peak ATS. Again hopefully someone can learn from this or if I missed something let me know! Thanks
 
#21 ·
Hello need to know /help!! wish to replace front and rear shocks on my '16 ram 1500. bighorn.already put level kit in front. getting ready to also add 1 1/2 in rear. want to upgrade shocks. Do i need to disassemble front control arms and have truck realigned just for front shocks? Any vids out there to help? Thanks to all you wizards out there with your ram knowledge!! My bilsteins are waiting to to be shipped.These shocks are replacements after the lift. 2.5 in front. and 1.1/2 in rear.
!
 
#24 · (Edited)
Little confusion. You already have a level and you’re adding the front Bilsteins? If so, I assume you have the spacer on top of the strut. Don’t keep that and add the Bilstein for more lift. Take it off and just use the Bilsteins for lift. It’s a much better way to level your truck. Assuming you’re referring to the Bilstein 5100 height adjustable struts of course. You also should get an alignment but it’s not something you need ASAP or you’ll mess things up. I wouldn’t go long without one for sake of your tires though. You have to separate upper ball joint from the steering knuckle, and remove Caliper, lower end link and have a spring compressor handy to disassemble the strut once it’s off the vehicle. It’s in depth but not TOO hard. Rear shocks are a breeze and have about 1-2” more travel than stock.

One thing to note:

If you set the Bilsteins at 2.8, you MAY experience premature ball joint failure when the suspension is at full droop. It’s a Dodge thing. I went with that setting anyway and will address issues as needed. I’ll eventually upgrade the UCA’s with ones that have a better ball joint angle for leveled trucks.
 
#23 · (Edited)
I currently have Bilsteins at 2.8 with 1.5” rear lift. For the past two years on my 2017 I’ve had 305/55/20’s (33.2x12x20) on my factory chrome clads which are a 9” wide rim with a +19mm offset. They have zero rub. Only about a knuckles width between uca and tire though. Next week I’m tossing on 35x12.5x17’s on factory 17” wheels that have a +25mm offset but are an 8” wide rim. We test fit a same size tire at the tire shop and it’s about 1-2mm from the uca. Still no rub. I am getting a small, 1/4” spacer just to put my mind at ease though. Reason for the spacer instead of just getting a narrower tire is that the tires I want (K02’s I’ve ran for years and love) don’t come in a narrower tire for that size. Hope that helps. First photo is the 305’s I’ve ran without a level for two years. Second is the test fit 35” on 17’s with the 2.8” level. ?
 

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#32 ·
i'd agree with you if we're not talking about heavy loads. when you're towing, that larger sidewall isn't optimal. they tend to flex more which, at highway speeds, can translate into trailer sway. how you use your truck, and how you plan to use your truck should all be factored into the tires and tire size you ultimately decide on.
 
#31 · (Edited by Moderator)
There are several sites for offset/tire size calculations and photos to give you an an idea of what the stance will look like that are a one stop info source for everything wheels and tires and many Ram pics at Custom Offsets here - https://www.customwheeloffset.com/wheel-offset-gallery
 
#33 ·
Are the chrome clads the same size as the black wheels they're using on the 2019 Warlocks? Just leased one and curious to know what I'll be able to put on down the road, assuming I opt to keep this truck. Really loving it so far! Not a huge fan of 20" wheels, wish they had used 17" or 18" wheels, but they still look good, IMO. I'd like a bigger sidewall though to fill the big gaps. Not leveled. The Warlock has a 1" lift I believe (4x4 models). Considering using these wheels for winter tires depending on how this truck handles the snow this winter. Then I could go to a 17" or 18" wheel and 33"-34" tall tire for spring/summer/fall.
 
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