2018 Silverado Wheel and Tire Upgrade

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May 1, 2012
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Indiana
2018 Silverado 3500 WT with 6.0 Gasser

I just took the factory 18" steel wheels off and installed 20" polished aluminum wheels from a 2022 High Country.

I love the upgraded wheels. The old 18" tires were 265/70-18 BFG KO2's. They went 80,600!! That's amazing milage!!

The tires on it now are 275/65-20 BFG KM3 Mud Tires. They look amazing and there's really not that much road noise. There's a bit of a howl from 20-40MPH, but that's to be expected.

I'm attaching pics before and after the wheel install and up close pics of the KM3 tire treads
 

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Not bad. I actually went down from the stock 20" wheels on the LTZ to the stock 18" wheels from either another LTZ or High Country, I forget which. Ride is much better.
 
Tires were obviously more expensive with the 20" wheels, but I like the look.

These 275/65-20 (factory sized tires for 2022 HD models) KM3's just BARELY fit in the wheels well on this 2018 and just miss hitting the fender liners when turning lockout to lockout. The these tires are about 1.5" taller than the tires that came on the truck originally (265/70-18).
 
Using a speedometer calibration calculator found on the interwebs, I'm only off 3 MPH. If the speedo reads 65, I'm actually now going 68 MPH. That's not enough to worry about.
That's pretty good. My speedo is over 16% off because of a transfer case swap. So im always doing some math so I know how fast im going.
 
Totally transforms the look of the truck. I’m glad to hear the aggressive treads are finding ways to settle down some.
 
Update: So last night, in the rain, I decided to brake hard, turn/swerve at speed, etc. so I had a feel how these MT's would react.

I was surprised when the truck felt like it was "floating" when I swerved. The truck was always very responsive and "tight" with the stock tires and the KO2's. But now the truck sways because of the large lugs. I wasn't expecting that.

I imagine if I was in a serious maneuver, especially if pulling a trailer, the truck could get away from me, especially at highway speeds.
 
Update: So last night, in the rain, I decided to brake hard, turn/swerve at speed, etc. so I had a feel how these MT's would react.

I was surprised when the truck felt like it was "floating" when I swerved. The truck was always very responsive and "tight" with the stock tires and the KO2's. But now the truck sways because of the large lugs. I wasn't expecting that.

I imagine if I was in a serious maneuver, especially if pulling a trailer, the truck could get away from me, especially at highway speeds.
Is there a sway bar on the rear? Get one. What are the maximum PSI of your tires? Fill them all the way up. Get some Rancho 9000 adjustable shocks & crank them up to keep the wheels planted to the road.
 
Update: So last night, in the rain, I decided to brake hard, turn/swerve at speed, etc. so I had a feel how these MT's would react.

I was surprised when the truck felt like it was "floating" when I swerved. The truck was always very responsive and "tight" with the stock tires and the KO2's. But now the truck sways because of the large lugs. I wasn't expecting that.

I imagine if I was in a serious maneuver, especially if pulling a trailer, the truck could get away from me, especially at highway speeds.
Tbf, you're using KM3s, which are a mud tire..........
 
Is there a sway bar on the rear? Get one. What are the maximum PSI of your tires? Fill them all the way up. Get some Rancho 9000 adjustable shocks & crank them up to keep the wheels planted to the road.
Too much air will shrink the contact patch (which isn't always a bad thing) and wind will push the car around more. The steering will also be lighter
 
Too much air will shrink the contact patch (which isn't always a bad thing) and wind will push the car around more. The steering will also be lighter
Their issue is sway. They upgraded to wider tires so contact patch is no issue. Low PSI for the tire's rating will cause flexing of the sidewall. Full PSI Stiffens the sidewall to prevent the extra sway. Nothing wrong with lighter steering effort.
 
MT tires are not going to treat you well for on road maneuvers. They are not siped right for pavement grip. They are set up with big knobby lugs for thick, nasty gnarly trails and rocks. If this is primarily a pavement truck, watch your stopping distances as they age, specifically in the rain, and even more in the cold rain.

i used to self-justify all-terrains due to the occasional off highway use I did with my jeeps, but the pickup doesn’t do more than campground gravel and fields. I’ve been moving to the highway-side of all terrains, Revos, continental, and g015. They still give some road grip.

i would not run more than 38-40psi in these. If you need more than that, you may end up with other issues. Also, they should wear in a little and firm up some as the rubber gets broken in. Some do this more than others - I’ll bet it’s a decent bit with those tall blocks.

as long as you aren’t an aggressive driver on road, these will probably be fine, especially if you spend time on hardpack and a little gnarly stuff. If this is really more highway oriented and you drive hard and quick, I’d trade them for something else.
 
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Meep.... These are E-Load rated tires. I'm running 80psi in the rears, 60psi in the front.

I bought the MT because I take this truck through some stuff and now that I'm driving my car everywhere, the truck will mostly sit until I need a truck.... which for me mostly means pulling a trailer or putting 2 tons of material in the bed. I'm hoping I didn't make a mistake with these tires.

I loved the KO2's. But I was willing to experience these KM3's. Time will tell. I did read on several forums that the tires should stiffen up over time.
 
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Their issue is sway. They upgraded to wider tires so contact patch is no issue. Low PSI for the tire's rating will cause flexing of the sidewall. Full PSI Stiffens the sidewall to prevent the extra sway. Nothing wrong with lighter steering effort.
I know, but sometimes 80 psi is still too much harsh ride. And just because the tread is wide doesn't mean it all touches the ground.
 
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