2019 Sierra AT4 level/wheel/tires mod

[z1boss]

On 10/5/2018 at 9:46 PM, Razorrick said:

Thought  I’d offer my two cents on my mods. First I had a 2” front leveling kit by rough country placed. One gmc dealer refused to put it on. Second dealer no problem. Looks much better. Re aligned. Rides great. Then off for wheels/ tires. Have read 34” and even 35” tires are no problem. I placed nitto ridge grapplers 295/60/20. 33.94 x 11.7. Both fronts rubbed. Trimmed inside plastic flaps. Better, still some rubbing. So people claiming 34/35” clear, not on my truck. Wheels are Gear 20x9” with 18mm offset. Two custom wheel dealers called their reps and were sure they would clear calipers and not stick out past wheel wells much. They would not clear new larger front calipers. Had to add a 1/4” spacer on fronts to clear. Which means these wheels would need about 25mm offset to clear. Love my wheels but a lot of what I found on this forum and wheel/ tire shops I don’t believe to be accurate. I know the 2019 is new and we’re all learning. Just passing on my findings

=

 

The Sierra wheel well will NOT accept the same tire size as a Silverado.  I am running 33.5 x12.5 R20 with a 0mm offset and only have very slight rubbing at full lock and I do NOT have a level.  I have a 19 Silverado Trail Boss and just based on your pic above, the bottom parts of the wheel well look like they curve back in, which make them closer to the tire.  Below are some pictures that I just took.  I have a lot more room on either side of the tire and my wheel wells do not curve back in.  The only part mine rubs on is the plastic mudflap on the back of the tire only (front side does not rub).  If I removed the mudflap it would not rub at all, however I am not going to remove them as they prevent my tires from kicking up rocks onto the body of my truck.  Hope this info helps.

[z1boss]

[Payton34]

 

[MadCaddie]

I'm slightly annoyed that I have to level my AT4.  

 

How do you like the Ridge grapplers?   I want to grab a set of the trusty Ole Duratracs but I've been leaning twords the Nitto. 

[Razorrick]

I hear u about the leveling. As far as the nittos, I wouldn’t buy anything else. Last set of terra grapplers I put 57,000 miles on and still had a lot of tread when I traded in. Ridge grapplers just as quiet but more mud terrain look. You’ll like them. 

[gothp28]

Has any one else put new tires and rims on? Size?

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[StevenStarke]

Razorrick, any pics showing how much they stick out? like looking along the side edge of the truck?

[Razorrick]

Steven they stick out very little. Almost flush. 

[Sierra Dan]

Here is what looks off and strange to me with GMC T1:

 

The Proportions of the Tire to Fender Opening ( RED ) Compared to the Gap between the tire & Fender Rear... Fender/Bumper Front at points 3 & 9 O'Clock

GMC's front leading edge angle ( BLUE ) also makes this lift tire combo very Odd! This is a 6" lift.

Silverado looks much better with a lift due to round openings. Not so much with Sierra.

 

[L86 All Terrain]

^^ So the new bigger wheel-wells are in fact, not bigger and the leveled trucks need to be re-levelled in order to clear a tire we were already clearing on a K2. The wells just look bigger allowing no real improvements for tire size just less metal for GM to use making it cheaper and making it look less "filled out"? Great news. 

[gothp28]

Found this online. Stock 20 in size

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[Ryan Meador]

RC leveling kit did not work for me,  I installed it myself, noticing when fully flexed the 4x4 drive shaft makes contact with the lower shock bolt mount.  RC made a point to let me know the level kit is not for the AT4.  I already aligned my tires and its fine for now on the street, but waiting for someone to release an AT4 level kit.

[JeremyW426]

On ‎2018‎-‎10‎-‎06 at 7:49 PM, Jr09country6.2 said:

this. His comment doesnt make much sense. More negative the offset the more the wheels stick out. Most factory wheels are around 27mm or so, I dont understand how an aftermarket wheel that is 18mm offset wont clear a caliper especially with it being a 20" wheel.

Maybe the tires were hitting the UCA with the 18mm offset and the wheel being 1" wider than factory.

OP, any pics of the clearance issue? I know the calipers are a new design so I could be missing something.

Some random math because alcohol:
-10mm is only ~.39 inches. Difference between factory and aftermarket.
- new wheels are 1" wider so .5" on each side.
- maybe with the wider wheels and tires there is uca contact. I just dont see caliper contact.


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Its not so much the offset that's causing the issue. What's I've seen is that the caliper actually sticks out past the hub a little so any wheel, regardless of offset, that had spokes that run straight out from the hub are not going to clear the caliper. The spokes need to instantly taper towards the outside of the vehicle in order to clear the caliper.

[gothp28]

Thought  I’d offer my two cents on my mods. First I had a 2” front leveling kit by rough country placed. One gmc dealer refused to put it on. Second dealer no problem. Looks much better. Re aligned. Rides great. Then off for wheels/ tires. Have read 34” and even 35” tires are no problem. I placed nitto ridge grapplers 295/60/20. 33.94 x 11.7. Both fronts rubbed. Trimmed inside plastic flaps. Better, still some rubbing. So people claiming 34/35” clear, not on my truck. Wheels are Gear 20x9” with 18mm offset. Two custom wheel dealers called their reps and were sure they would clear calipers and not stick out past wheel wells much. They would not clear new larger front calipers. Had to add a 1/4” spacer on fronts to clear. Which means these wheels would need about 25mm offset to clear. Love my wheels but a lot of what I found on this forum and wheel/ tire shops I don’t believe to be accurate. I know the 2019 is new and we’re all learning. Just passing on my findings

Thanks for posting this. I have a at4 and was planning on ridge grapplers 295x60x20. I do not have any other spacers or anything. Sounds like it will not work.

Anyone else try to go bigger than 33s?

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[1stimeGMowner]

On 2/9/2019 at 11:16 PM, gothp28 said:

Thanks for posting this. I have a at4 and was planning on ridge grapplers 295x60x20. I do not have any other spacers or anything. Sounds like it will not work.

Anyone else try to go bigger than 33s?

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Hello all,

I hope you're doing well. I was able to install LT275/65R20s on my stock AT4. No rubbing and no trimming required. Mounted on OEM wheels. I hope this helps!

 

- ZT

 

 

 

Edited February 22, 2019 by 1stimeGMowner