2019 Sierra AT4 level/wheel/tires mod

Razorrick · October 6, 2018

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

sams819 · October 6, 2018

Why are you parked on the garage door? LOL Nice truck, Great info.

f8l vnm · October 6, 2018

Cmon man. 1 damn pic .?

give us more ?

NWI Denali · October 6, 2018

It's the offset on your aftermarket wheels. There is another thread where someone how 35's on the oem denali 22's with just a 2" level. Those 34's actually look small in your wheel well. I would have guessed 33's.

silveradonationfan15 · October 6, 2018

20 hours ago, 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

Do you have a side shot o your truck with the leveling kit? Also what is the frount and rear wheel well heights?

kylant · October 6, 2018

+25 offset would pull wheels in more, making caliper clearance worse

mfbearded · October 7, 2018

i put on 33x12.5 20s the other day with a -12 offset....no rubbing, no trimming, everything fit with room to spare. ur offset my be the issue

Razorrick · October 7, 2018

Jr09country6.2 · October 7, 2018

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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Jr09country6.2 · October 7, 2018

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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Nice truck though. Saw your second pic, I likey.

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Razorrick · October 7, 2018

I certainly am no expert on backspacing. Just repeated what the wheel guy told me.

AJMBLAZER · October 7, 2018

On another vehicle years ago I had issues with wheels not clearing calipers because of how wide the calipers were.

Basically this vehicles factory aluminum wheels had a 1” spacer built in to the back face so the wheel spokes would clear the wide caliper. Made aftermarket wheel fitment a pain.

Could be an issue like that?

shift_grind · October 7, 2018

The Sierra appears to not be able to fit as big of a tire as the Silverado, everything being equal.

Your wheels are +18, with a 1/4" spacer that makes them around +9 or +10. That with a extra wide tire makes your problem. A 285/60r20 would probably work better for you.

Edited October 7, 2018 by shift_grind

Jr09country6.2 · October 8, 2018

The Sierra appears to not be able to fit as big of a tire as the Silverado, everything being equal.

Your wheels are +18, with a 1/4" spacer that makes them around +9 or +10. That with a extra wide tire makes your problem. A 285/60r20 would probably work better for you.

His tires are only 11.7" wide and tires shouldn't be anywhere near the calipers...I dunno, I haven't been under one of these new trucks so I could be completely wrong.

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Payton34 · October 8, 2018

It is the offset of the aftermarket wheels. Your stock wheels would fit the tires better. Icon fit 35x12.5 ridge grapplers on their Icon 17" wheels on leveled silverado which would be the same height as a stock AT$/trailboss. Icon said there was no rub or trimming with the correct offset backspacing and that a 37 nearly fit with trimming. Also these are 1in smaller diameter than GM's standard 18" wheels and they still cleared the brakes.

Edited October 8, 2018 by Payton34