consequences of a 1.5" level lift on a sierra/silverado 1500

[GRN69CHV]

This makes sense and is a good explanation but there certainly is some conflicting information out there!

There is conflicting information. Nothing against Bilstein, but that diagram showing an overextension is not correct for a vehicle that still has the factory installed metal travel limiters (bump stops) still intact. Don't even need to get under the truck to see, driver side turn the wheel far left, you can see the upper stop plain where it would hit the upper control arm on full extension. Compression stop is at back of lower control arm. For the compression stop you can get Timbren bushings to almost completely limit upward movement. I've used these in the past for plowing.

[Jon A]

The metal travel limiters are not what limits travel with the stock suspension. They are there as secondary stops for safety. They will only touch if you break something or modify the suspension.

 

The length of the shock, with it's internal rubber droop limiting stop limits extension, the rubber bumpstop on top of the body of the shock is what limits compression. Nobody designs a suspension such that the limits of its travel are provided by metal to metal contact between the frame and control arms. Not only would that give a horribly punishing ride offroad, it would break things left and right when driven hard. Other trucks with different suspensions do limit travel with stops for the control arms mounted on the frame but they are made of rubber providing a smooth, soft, gradual engagement.

 

With both front wheels off the ground and the swaybar disconnected, when you unbolt a shock the wheel will drop another ~2-2.5" before UCA hits its stop (it'll vary a bit from truck to truck). This is why you can typically get away with a spacer leveling kit up to 2-2.5". When that stop becomes your droop limiter, the ride will suffer (depending upon how hard you're hitting it). If the shock and spacers have a little wiggle room or allow the limiter to just barely touch the ride will be much better than if the shock is measurably compressed with the limiter holding it back--as will happen if you try a 3" spacer lift, for example.

 

The Bilstein advertising info is just that--trying to sell you something. While their shocks for these trucks are a tiny bit longer, it's not by much so overall travel with respect to the chassis is largely unchanged. While this does avoid the problem listed above, changing the static ride height within the same amount of travel means you gain compression travel but loose extension travel. The shock remains the droop limiter and does completely eliminate any chances of damage or wear for people worried about that, but by reducing available droop travel from static ride height means you hit that limit more often and harder than if the static ride height was closer to the center of available travel. They are cheap and easy to do so for the price they provide decent results, but they're not going to be as good as a spacer/longer shock level that allows you to stay centered in your travel, along with UCA's that eliminate the contact with the droop stop and prevent balljoint bind.

 

 

 

[Donstar]

The metal travel limiters are not what limits travel with the stock suspension. They are there as secondary stops for safety. They will only touch if you break something or modify the suspension.

 

The length of the shock, with it's internal rubber droop limiting stop limits extension, the rubber bumpstop on top of the body of the shock is what limits compression. Nobody designs a suspension such that the limits of its travel are provided by metal to metal contact between the frame and control arms. Not only would that give a horribly punishing ride offroad, it would break things left and right when driven hard. Other trucks with different suspensions do limit travel with stops for the control arms mounted on the frame but they are made of rubber providing a smooth, soft, gradual engagement.

 

With both front wheels off the ground and the swaybar disconnected, when you unbolt a shock the wheel will drop another ~2-2.5" before UCA hits its stop (it'll vary a bit from truck to truck). This is why you can typically get away with a spacer leveling kit up to 2-2.5". When that stop becomes your droop limiter, the ride will suffer (depending upon how hard you're hitting it). If the shock and spacers have a little wiggle room or allow the limiter to just barely touch the ride will be much better than if the shock is measurably compressed with the limiter holding it back--as will happen if you try a 3" spacer lift, for example.

 

The Bilstein advertising info is just that--trying to sell you something. While their shocks for these trucks are a tiny bit longer, it's not by much so overall travel with respect to the chassis is largely unchanged. While this does avoid the problem listed above, changing the static ride height within the same amount of travel means you gain compression travel but loose extension travel. The shock remains the droop limiter and does completely eliminate any chances of damage or wear for people worried about that, but by reducing available droop travel from static ride height means you hit that limit more often and harder than if the static ride height was closer to the center of available travel. They are cheap and easy to do so for the price they provide decent results, but they're not going to be as good as a spacer/longer shock level that allows you to stay centered in your travel, along with UCA's that eliminate the contact with the droop stop and prevent balljoint bind.

 

 

 

This is great information! Thank you! I have read it over several times and, if I understand correctly, spacers providing two inches or less of levelling have little or no potential to cause problems. The suspension will work safely within the limits of the stock shocks.

[GRN69CHV]

There is a mechanical stop built in. I was surprised there was no rubber stop, but that's how it is. When I disconnected the sway bar ends and the shocks I fully expected the control arms to drop, that was not the case, downward travel was limited by upper control arm hitting that stop. Of all of the hundreds of cars and trucks I've had apart over the past 40 years of working on them, I honestly can't think of one front suspension where the shock travel was less than the suspension travel. Especially in this design, you'd be creating an extreme stress point on those two lower shock bolts. Both the upper and lower stop are factory drilled to add a rubber snubber if desired. And to be clear, if I were inclined to run my truck hard off-road, I'd be inclined to do the Bilstein shock install. Lower control arm has that pocket forged in to help prevent lateral force load. Spacers eliminate that and transfer lateral load to the bolts. That's why a 1/2" spacer was the limit of what I was willing to go.

Edited February 24, 2016 by GRN69CHV

[Donstar]

Thank you for another informative post! I think the conclusion for me would be the same. Spacers creating less than 2" of lift will not exceed normal suspension function. The "lateral force load" does add a new caution. I am sure that this grandpa will never achieve the force necessary to upset the spacer, however, I do not want to add an option that is weaker than stock.

[Jon A]

When I disconnected the sway bar ends and the shocks I fully expected the control arms to drop, that was not the case, downward travel was limited by upper control arm hitting that stop.

 

Your truck must have been well out of the norm then. Did you happen to snap a pic? The pic you posted clearly shows a gap. The gap does not need to be large--there's around a 10:1 motion ratio there so a gap under 1/4" could provide 2" of wheel movement--so it might actually look like they're touching at first glance when there's plenty of clearance.

 

If what you are saying was correct, people would have a really hard time installing the typical 1" spacers under the shock with a leveling kit--they'd need to compress the coilover a full inch, requiring ~2000+ lbs of force. Enough of us have done this that we know it's simply not the case.

 

 

Of all of the hundreds of cars and trucks I've had apart over the past 40 years of working on them, I honestly can't think of one front suspension where the shock travel was less than the suspension travel.

 

Honestly, if you've mis-diagnosed the one right in front of you, you probably mis-diagnosed those as well. It's really the most common way to do it--especially with cars which typcially have much weaker control arms that would crumple or snap (stamped steel crumple, thin cast aluminum snap) under the 10:1 prying moment of the method above. It's much easier to limit compression with a bumpstop mounted on the frame that can contact the arm farther outboard of its pivots to put less of a bending moment on it than it is to limit extension without using straps or something like that. You'll find limiting straps in the aftermarket and on custom builds, but not on a whole lot of OEM's. But by all means, if you can't think of a single one that doesn't limit extension in an alternate manor, you should be able to post plenty of pics of those that do. I'd like to see some.

[GRN69CHV]

Jon, wish I had taken pics, had mine apart a year ago. I had to pry up on the shock to get the spacer in, that's all I can tell you. Can also tell you it doesn't take 2000# force. Those springs are probably 500-600# rate, using a 2' long prybar would only take 25-30# leverage.

 

Any conventional front coil spring car/truck where the shocks go in from the bottom, the shock is always longer than length of travel and gets pushed up to make contact with the LCA. Too cold and wet here now, when the weather warms up, things dry up and I get my spring chores done, I'll make an effort to pull the wheels and take another look just to put this to bed if it's that important. In the meantime, Happy Trucking!

[mracer]

Jon, wish I had taken pics, had mine apart a year ago. I had to pry up on the shock to get the spacer in, that's all I can tell you. Can also tell you it doesn't take 2000# force. Those springs are probably 500-600# rate, using a 2' long prybar would only take 25-30# leverage.

 

Any conventional front coil spring car/truck where the shocks go in from the bottom, the shock is always longer than length of travel and gets pushed up to make contact with the LCA. Too cold and wet here now, when the weather warms up, things dry up and I get my spring chores done, I'll make an effort to pull the wheels and take another look just to put this to bed if it's that important. In the meantime, Happy Trucking!

 

What brand spacer did you use for the 1" lift? That's exactly what I'm looking for. Thanks.

[Jon A]

I had to pry up on the shock to get the spacer in, that's all I can tell you. Can also tell you it doesn't take 2000# force. Those springs are probably 500-600# rate, using a 2' long prybar would only take 25-30# leverage.

 

I really think it's more likely you were prying against bushing torque from the bushings in the control arms. The springs on mine were around 850#/" and while I didn't measure their free length, after compressing them enough to swap shocks I estimate they have at least 1-2" of preload when installed on the shock. So yes, if it's less than 2000 lbs it won't be by much and could be a whole lot more.

 

 

Any conventional front coil spring car/truck where the shocks go in from the bottom, the shock is always longer than length of travel and gets pushed up to make contact with the LCA.

 

Yes, I think my '63 Belair was this way if I remember correctly but I don't think I ever verified if it was anything more than bushing bind. I haven't seen too many modern cars with similar suspensions though, especially those with coilover shocks or struts.

[GRN69CHV]

What brand spacer did you use for the 1" lift? That's exactly what I'm looking for. Thanks.

I looked in the history, didn't show it, so may have been just over 12 months ago. Don't recall if it was this company, but this looks the same. FWIW, you don't have to unbolt anything except loosen the sway bar end links. On the 2015, bolts did not want to go in from the top, I put them in from the bottom, was able to reuse the the factory lock nuts (10mm) which I thought were more substantial. Very simple process, JMHOO, takes more time to get the truck up on stands, pull the wheels and get the tools out. Once you remove the factory bolts, you can use a prybar to get enough clearance to get the spacer in there.

 

http://www.ebay.com/itm/SR-CHEVY-GMC-SILVERADO-SIERRA-07-16-FRONT-1-LIFT-LEVELING-KIT-LOWER-MOUNT/301828109682?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35695%26meid%3D308d11cb8df74c9dbd79e7a6be49daea%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D272101221948

[mracer]

Thanks for the info!

[GRN69CHV]

And PS : I used Blue Loctite on the bolts when reinstalled. Could use the Red Loctite which is a more permanent set, but my tube of red was dried out so the blue had to do.

[Shredder15]

On ‎2‎/‎20‎/‎2016 at 7:42 AM, GMC-AT said:

what ever you decide, don't go over 1.5in. These trucks need to maintain 1.5-2 rake in the front to look right. A "true" front to rear level looks like garbage IMO.

Plus, the ride characteristics really start to change when you go higher that 1.5.

 

I have tried every level made between my old 2014 and new 2016 ( top, bottom strut, Bilstein 5100, Rancho Quick lift) I can tell you - 1.5 in under strut with stock socks is the best IMO. ( look and ride)

I have a 2015 Z71 Crew with the Top Gun 2.5" leveling kit, and it's been aligned since install.  I also have an add a leaf on the rear, but all else is standard.  The rake and height are perfect, IMHO, but on uneven pavement there's an annoying noise up front coming from what I'm pretty sure is the struts.  The TG kit has two leveling plates on bottom and one ring on top of the strut to get the full 2.5".  I've also done the 1.5" version with one plate on bottom and the ring and had approximately the same noises from the strut.  Do you think I'd lose the noise if I only do the plates on bottom (only one set of plates and no ring, which would be only a 1" front level)? 

 

I think I'll then have to remove the add a leaf and do a zone 1.5" body lift to get back to where I am.  But I want the factory ride back.

[GravelPitsYew]

Negative of adjustable Bilstein 5100's are that anything other than their stock shock height setting raises issues. The notches for the raised height's can break and your truck will drop wherever you are at. I've also had issues with Bilsteins completely leaking fluid and they claim it's normal for that to happen and won't replace. Done with Bilstein.

[Dave Zirkle]

I put on the Rancho Quicklift assembly and love the way it looks and rides.  I have a 2014 sierra 1500 with 106,000 miles.  I plan on replacing the sway bar end links due to occasional clunking.  My question is, do I use stock OEM end links or longer ones to account for the 1 1/" lift?