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

Donstar · February 20, 2016

I remember asking at a spring shop if a 1.5 spacer kit has any negative impact on front suspension. He assured me that there is no potential for problems. GRN69CHV points out that a similar amount of lift is generated by loading the back of the truck. Again, I agree with GMC-AT that some rake is ideal from both looks and load carrying perspectives. I like to justify my modifications with some practical purpose. I never was fond of fake air-scoops on muscle cars nor do I care to make my 6cylinder people mover into something it is not. It left the factory designed to accommodate miscellaneous loads for commercial or personal uses. I do not need my truck to be always at the ready for a heavy load so, for me, looks trumps brawn!

GRN69CHV · February 22, 2016

Was able to grab a picture of mine with the 1" front end lift. Excuse the appearance, it's still winter here. Ground has a slight slope, not real bad, but you can get a nice look at the relationship between the front and rear tires/wheelwells. Pic in my signature was a year ago when it was sitting stock ride height. 1" difference doesn't seem like a lot, but it does make a difference. Personally, don't think anyone can go wrong with 1" - 1.5" increase in front end ride height.

Edited February 22, 2016 by GRN69CHV

Donstar · February 22, 2016

Was able to grab a picture of mine with the 1" front end lift. Excuse the appearance, it's still winter here. Ground has a slight slope, not real bad, but you can get a nice look at the relationship between the front and rear tires/wheelwells. Pic in my signature was a year ago when it was sitting stock ride height. 1" difference doesn't seem like a lot, but it does make a difference. Personally, don't think anyone can go wrong with 1" - 1.5" increase in front end ride height.

Stance looks perfect. The 1" is noticeable to those who appreciate such things. My wife called my truck a tank today and belongs to the group of people who don't appreciate the finer aspects of truck ownership! That's the great thing about these forums! BTW, what size tires do you have?

GRN69CHV · February 22, 2016

Tires are the stock Bridgestone Dueller RH-S 265/65-18 (31.56" tall). When these are gone, am considering going up one size to 275/65-18 (32" tall) or possibly even 265/70-18 (32.6" tall) which is what comes on the 2500.

Daryl LBZ · February 22, 2016

Was able to grab a picture of mine with the 1" front end lift. Excuse the appearance, it's still winter here. Ground has a slight slope, not real bad, but you can get a nice look at the relationship between the front and rear tires/wheelwells. Pic in my signature was a year ago when it was sitting stock ride height. 1" difference doesn't seem like a lot, but it does make a difference. Personally, don't think anyone can go wrong with 1" - 1.5" increase in front end ride height.

Looks good. Anything between 1-1.5" is noticeable in my opinion. I've done 1.25" and 1.5" on past trucks and you can see the difference. The truck never rode any different either.

Donstar · February 22, 2016

The diagram on the right shows a dotted "maximum travel" line which is greater than "with Bilstein" shocks but less than "over extended down travel". It would be terrific to know what size spacer will take you to the maximum without going to the over extended zone. Does anyone know if there is a maximum figure or how we could find this out?

GRN69CHV · February 22, 2016

The diagram on the right shows a dotted "maximum travel" line which is greater than "with Bilstein" shocks but less than "over extended down travel". It would be terrific to know what size spacer will take you to the maximum without going to the over extended zone. Does anyone know if there is a maximum figure or how we could find this out?

This is why I only went with a 1"kit. Spacer block is 1/2" thick. When I unbolted the shock at lower mount points and lowered the control arm, there was just enough room to wiggle in the 1/2" spacer.

Donstar · February 23, 2016

This is why I only went with a 1"kit. Spacer block is 1/2" thick. When I unbolted the shock at lower mount points and lowered the control arm, there was just enough room to wiggle in the 1/2" spacer.

Very interesting! This sounds almost too logical. I was hoping a 3/4" spacer (1.5" level) would make the safe zone!!

robvas · February 23, 2016

The diagram on the right shows a dotted "maximum travel" line which is greater than "with Bilstein" shocks but less than "over extended down travel". It would be terrific to know what size spacer will take you to the maximum without going to the over extended zone. Does anyone know if there is a maximum figure or how we could find this out?

Anything past factory is 'over extended'

Donstar · February 23, 2016

Anything past factory is 'over extended'

Maybe the Bilstein diagram is misleading. My truck is used as a pleasure vehicle and does not need to be raked to allow for hauling heavy loads. I like the looks of a leveled truck however I will not compromise safety. Do you have information that would support why "anything past factory is over extended"? These trucks are designed to operate safely with the front moderately elevated, as this naturally happens when hauling. I don't understand how a 1 or 1.5 inch level can "over" do anything so I'm searching for information and advice from people such as you.

Edited February 23, 2016 by Donstar

GRN69CHV · February 23, 2016

It's physically and mechanically not possible to over extend the factory suspension unless you remove or modify (cut down) the upper bumpstop. Length between the upper and lower control arms is fixed at the spindle and ball joints. Same goes for suspension in full compression, upward travel limit is controlled by the lower bumpstop. I haven't had the shocks out on these trucks, but can tell you from experience, I have never had a suspension apart where the travel limits were controlled by the shock extension or compression with factory bumpstops in place.

PS: When I said there was approx 1/2" wiggle room, that's probably not a good explanation. I had to pry up on the shock to get a little spring compression and a little compression against the upper bumpstop to create the space needed. Didn't need a lot pressure but did need prying.

robvas · February 23, 2016

Maybe the Bilstein diagram is misleading. My truck is used as a pleasure vehicle and does not need to be raked to allow for hauling heavy loads. I like the looks of a leveled truck however I will not compromise safety. Do you have information that would support why "anything past factory is over extended"? These trucks are designed to operate safely with the front moderately elevated, as this naturally happens when hauling. I don't understand how a 1 or 1.5 inch level can "over" do anything so I'm searching for information and advice from people such as you.

Think of it this way. Put your truck up on a lift and let the front wheels come all the way down. Call that "fully extended". Anything past that is "over extended". As in the truck was never designed for the suspension to be pushed that far out/down.

Now install your spacer kit (whether it's a strut tower kit, or control arm spacer kit, doesn't matter). You've just pushed the suspension down another inch or two. You are now past what was "fully extended" and you are now, by definition, "over extended"

The blue drawing in the Bilstein picture is the exact opposite. Imagine you put your front suspension all the way up as far as it can go, under the front fenders of your truck. That's your full range on the compression side. Now stick that one or two inch spacer in there. You just lost some travel. I don't know if you call that "under-extended" or what.

robvas · February 23, 2016

The diagram on the right shows a dotted "maximum travel" line which is greater than "with Bilstein" shocks but less than "over extended down travel". It would be terrific to know what size spacer will take you to the maximum without going to the over extended zone. Does anyone know if there is a maximum figure or how we could find this out?

The whole red area is the 'over extended zone'

Donstar · February 23, 2016

Think of it this way. Put your truck up on a lift and let the front wheels come all the way down. Call that "fully extended". Anything past that is "over extended". As in the truck was never designed for the suspension to be pushed that far out/down.

Now install your spacer kit (whether it's a strut tower kit, or control arm spacer kit, doesn't matter). You've just pushed the suspension down another inch or two. You are now past what was "fully extended" and you are now, by definition, "over extended"

The blue drawing in the Bilstein picture is the exact opposite. Imagine you put your front suspension all the way up as far as it can go, under the front fenders of your truck. That's your full range on the compression side. Now stick that one or two inch spacer in there. You just lost some travel. I don't know if you call that "under-extended" or what.

Are you pushing the suspension down more or are you compressing the spring? I visualize everything remaining in position while on the hoist. I see the extra pressure on the spring pushing the body upward when off the hoist.

Edited February 23, 2016 by Donstar

Donstar · February 23, 2016

It's physically and mechanically not possible to over extend the factory suspension unless you remove or modify (cut down) the upper bumpstop. Length between the upper and lower control arms is fixed at the spindle and ball joints. Same goes for suspension in full compression, upward travel limit is controlled by the lower bumpstop. I haven't had the shocks out on these trucks, but can tell you from experience, I have never had a suspension apart where the travel limits were controlled by the shock extension or compression with factory bumpstops in place.

PS: When I said there was approx 1/2" wiggle room, that's probably not a good explanation. I had to pry up on the shock to get a little spring compression and a little compression against the upper bumpstop to create the space needed. Didn't need a lot pressure but did need prying.

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