Tow squat and IRS: bad combo?

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Skid51

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Looking to replace my ‘16 Yukon Denali with a new Tahoe or Yukon. I tow a 6500lb trailer and while the levelling rear air shocks on the Denali‘S MRC do help I still get a 1-2 inches of rear squat while towing. This is not a big deal since it has a solid rear axle. But any significant squat _would_ be a big deal on an IRS vehicle. Wheels would camber in and likely toe in and tire wear on the inside shoulders could be a serious issue. I can’t think of any other vehicle that is rated to tow 8000lbs+ and that has IRS. What are experiences out there with tire wear and dynamic alignment while towing heavy on the 21+ trucks? Do you have to use helper air bags to keep it level? And yes, going with the air ride suspension is an option, I raised some questions on that separately on another post.
 

WalleyeMikeIII

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I love towing w/ mine. The guys at TFL truck (YouTube channel) did a max tow w/ a Suburban High Country and and RST. Was not a ton of squat, but some. They like it better than the expedition (also IRS)

You probably should order the Air Suspension if you plan on towing toward the max, and consider weight distributing hitch.
 

DuraYuk

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Your worrying to much. It tows fine. There have been plenty of irs equipped towing vehicles. The previous generation sequoia comes to mind, as well as Mercedes gls, BMW x7, Nissan armada etc. Air bags do help with squat as does a weight distributing hitch.
 

Polo08816

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Looking to replace my ‘16 Yukon Denali with a new Tahoe or Yukon. I tow a 6500lb trailer and while the levelling rear air shocks on the Denali‘S MRC do help I still get a 1-2 inches of rear squat while towing. This is not a big deal since it has a solid rear axle. But any significant squat _would_ be a big deal on an IRS vehicle. Wheels would camber in and likely toe in and tire wear on the inside shoulders could be a serious issue. I can’t think of any other vehicle that is rated to tow 8000lbs+ and that has IRS. What are experiences out there with tire wear and dynamic alignment while towing heavy on the 21+ trucks? Do you have to use helper air bags to keep it level? And yes, going with the air ride suspension is an option, I raised some questions on that separately on another post.

It depends on the type of independent suspension design. A MacPherson strut design experiences far more camber change than a double wishbone setup.
 

dbphillips

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Well, I thought the squat was pretty square, but after 2-4 tire rotations, the only capable American dealer the truck has been to informs us our 22" tires have been wearing on the inside edge. They are pretty even and the camber spec only goes to -0.5 degrees, so I'm guessing camber while loaded adds about at least another 0.5 degrees. Our tires are toast at 30k.

*I asked Chevrolet customer service what they recommended and they gave me the standard "bring it up with the dealer". Three different dealers failed to bring it up and there probably is no TSB, so what are they going to do? Laugh, likely.
 
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EGTroup

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Looking to replace my ‘16 Yukon Denali with a new Tahoe or Yukon. I tow a 6500lb trailer and while the levelling rear air shocks on the Denali‘S MRC do help I still get a 1-2 inches of rear squat while towing. This is not a big deal since it has a solid rear axle. But any significant squat _would_ be a big deal on an IRS vehicle. Wheels would camber in and likely toe in and tire wear on the inside shoulders could be a serious issue. I can’t think of any other vehicle that is rated to tow 8000lbs+ and that has IRS. What are experiences out there with tire wear and dynamic alignment while towing heavy on the 21+ trucks? Do you have to use helper air bags to keep it level? And yes, going with the air ride suspension is an option, I raised some questions on that separately on another post.
First of all, modern IRS with upper and lower control arms maintain constant camber at different loads so that is not an issue.

I tow a 27ft 2021 Airstream International that could weigh up to 7,000 lbs with 2023 Yukon Denali Duramax and Air Suspension. Use a ProPride hitch that eliminates trailer induced sway. Airstream has a 3” lift kit installed. Rig rides perfectly level and is steady on the interstates.
Yukon-Lifted AS 27 w ProPride.jpg
 

dbphillips

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First of all, modern IRS with upper and lower control arms maintain constant camber at different loads so that is not an issue.

I tow a 27ft 2021 Airstream International that could weigh up to 7,000 lbs with 2023 Yukon Denali Duramax and Air Suspension. Use a ProPride hitch that eliminates trailer induced sway. Airstream has a 3” lift kit installed. Rig rides perfectly level and is steady on the interstates.
View attachment 428312
I would expect so, but my tires beg to differ. We'll see what the alignment shop says this week. Taking it to the guys the Porsche and BMW clubs recommend, since they do a good job on my modified Volvo C70, smh. I don't know of any other good shops.
 

dbphillips

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First of all, modern IRS with upper and lower control arms maintain constant camber at different loads so that is not an issue.
Survey says... -0.1 degrees of camber per 100# of load on stock suspension with Tow Max... Empty camber is specified -0.4/-0.5 degrees (but my alignment specialist said GM have like a +/-1.0 tolerance?!), so with a load, we push -1.5 to -1.8 degrees, which I can confirm from direct experience on the Volvo, will chew up the inside edge of the tires.

Someone either screwed up the design, or the bean counters got involved where they have no business being. I could not find a TSB for this in the hundreds of TSBs on the 2022 Tahoe.

*Ooh, these might be the ticket: https://www.belltech.com/products/b...ustable-rear-leveling-coilover-kit-15113.html

Kind of a pain, but I guess jacking up each corner and adjusting the spring stay every towing trip isn't terrible. I found them when I searched up control arms for the Tahoe to reduce camber and it seems Belltech have some, but I'm waiting for a response to see if they will work for that or if they are just for lifting/lowering.
 
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