AT4 Lift Kit + Stock 18" Wheels

BetaX · May 31, 2020

Been contemplating going either with a 1.75/2" ReadyLift w/ control arms or go to a ~4" full kit on my '19 AT4 crew cab.

I've always been a fan of a clean look with stock wheels and larger tires.

I'm noticing i'm not finding any lift manufacturers that advise i can run the stock 18's with their lifts for these trucks and requirements seem vague or sporadic from each lift mfg.

It looks like its likely tie rod clearance due to diameter of the smaller wheel causing the issue. Not wanting to go to the 20's or run large spacers kicking the stock wheels out.

Been searching and searching to see if anyone has found a way to make this happen and coming up empty which is probably not a good sign.

Anyone found a way to keep the 18's with a lift kit?

Thanks

Supercup · May 31, 2020

That is what I did - Ready Lift SST kit - see link to another thread and see my post with before and after measurements and photos of truck after.

Looks good - you will like the look. Only downside is Ready Lift does not recommend use of auto 4wd with this level kit, they have had a few customers have issues with cv axels and front diff when shifting on the fly into auto 4wd - Had I known I would lose that feature - I would have gone BSD coilover kit - but a lot more $. I have used my truck in 4H and 4L without issue, so since the truck is leased I am going to leave as is for now.

Link:

BetaX · June 2, 2020

On 5/31/2020 at 2:26 PM, Supercup said:

That is what I did - Ready Lift SST kit - see link to another thread and see my post with before and after measurements and photos of truck after.

Looks good - you will like the look. Only downside is Ready Lift does not recommend use of auto 4wd with this level kit, they have had a few customers have issues with cv axels and front diff when shifting on the fly into auto 4wd - Had I known I would lose that feature - I would have gone BSD coilover kit - but a lot more $. I have used my truck in 4H and 4L without issue, so since the truck is leased I am going to leave as is for now.

The no auto-4wd is a concern of mine and have run across it mentioned in a few places in my searches. Any feed back of shifting on the fly vs auto or the reasoning behind it? I've been trying to find decent CV angle images for people with the 2" kit on the AT4, the few i've found look fairly steep but hard to judge from photos sometimes to get a good idea.

I did reach out to BDS yesterday to ask if they plan to offer the 2.5" kit without coil overs. At this moment they have no plans. Surprising since it's likely a new spacer and removal of the coil overs with the rest of the kit staying the same.

Supercup · June 3, 2020

17 hours ago, BetaX said:

The no auto-4wd is a concern of mine and have run across it mentioned in a few places in my searches. Any feed back of shifting on the fly vs auto or the reasoning behind it? I've been trying to find decent CV angle images for people with the 2" kit on the AT4, the few i've found look fairly steep but hard to judge from photos sometimes to get a good idea.

I did reach out to BDS yesterday to ask if they plan to offer the 2.5" kit without coil overs. At this moment they have no plans. Surprising since it's likely a new spacer and removal of the coil overs with the rest of the kit staying the same.

Here is photo of CV angle - with SST kit installed with stock tires - 275/65/18.

Reasoning behind Ready Lift note not to use Auto 4wd - I had a discussion with Ready Lift over phone, why the note (after my install) - they indicated they had a number of customer complaints of grinding noises on shifting on the fly and a few customers who said when shifting on the fly had reported loud grinding, then front differential damage (which was not covered under factory warrarnty due to the kit installed). The added angle and the added torque of shift on the fly overwhelmed the system and caused damage - hence their recommendation to "not shift on the fly at all" or use auto 4wd - as you drive at speed using it and that increases forces on the drive line, adding to the risk of damage to CV axel or front diff. As I did my "after the install" research I learned quickly it was common knowledge that after about 2.5" of lift you need a drop bracket for the front diff to not have CV axel angles outside of spec and not have damage to front diff. Given the AT4 and Trail Boss come with 2" of factory lift - they really need a "real" lift kit, with front diff drop bracket to safely use all the features the truck was delivered with.

BetaX · June 3, 2020

I reached out to a supplier that mfg's diff drop's for the pre '19 trucks, they have one in production for the '19+ at the moment, but won't share any other details past that right now. Thinking that might be the way around the 2" leveling kit problem depending on the drop amount.

I'm trying to stay low lift + 35s to still be able to use the truck bed to easily load dirt/trial bikes into the bed. The fact that no one is producing a 4" kit (2" for AT4/TB) while correcting all geometry is surprising. I was hoping Rancho had something in the works as they typically allow stock wheels, but at the moment they're only about to release a 3" for non-TB/AT4 trucks apparently.

Supercup · June 4, 2020

You can get the BDS kit at 2.5" (so 4.5" overall) - has Fox coil overs like the 4" lift kit, but shocks are slightly shorter. Expensive - but your are getting quality set up and great shocks - will improve ride and performance of truck a lot. If my truck wasn't leased I would have gone that route for sure.

BetaX · June 4, 2020

6 minutes ago, Supercup said:

You can get the BDS kit at 2.5" (so 4.5" overall) - has Fox coil overs like the 4" lift kit, but shocks are slightly shorter. Expensive - but your are getting quality set up and great shocks - will improve ride and performance of truck a lot. If my truck wasn't leased I would have gone that route for sure.

After i lifted one of my past trucks and hated it, i became a cheap ass on mods within reason. Or maybe i matured, who knows

I'd entertain the BDS if they had it without the coil-overs but not wanting to drop 5-6k at the moment.

I think i'll just end up with the 1.75" or 2" SST once the diff drop is available and call it a day. The ~4" between the level & tires should be plenty to get me what i want and keep the angles relatively happy.

I had reached out to Readylift over the weekend and finally got a response, may as well share for people who are searching later on about this.

Quote

Hello! Using Auto 4wd is not recommended only because when lifted it is sending too much torque into the front differential thus causing a vibration in the vehicle. With that, we recommend that it is not used. Standard 4H and 4L is completely applicable for the application.You should have no problem shifting into 4H on the fly. The issue with the GM auto 4hi is that it acts like an AWD system and constantly is shifting in and out of 2 hi and 4 hi, which cause a torque vibration. Stock trucks do it. When lifted it seems it is more noticeable for some folks. Therefore we do not recommend using auto 4hi and instead just use standard 4hi when needed.

Casey Nelson · June 5, 2020

I have a 2 inch ready lift with control arms on my truck. I ran the stock 18s with stock tires and had no issues for about 500 miles before getting 20x10s and 33s.