Top of strut vs bottom of strut leveling kit

USCGRetiredJosh · March 5, 2015

Is there really any difference between a leveling kit going on top of the struct compared to putting one on the bottom of the strut?

I'm looking at the Ready Lift 1.5" goes on top of the struct or Rough Country 2" that goes on the bottom of the strut.

I don't plan on changing my wheels or tires. I like my 22" wheels and the stock tires. Just like the look of it after reading and looking around on this forum. Also, might look at putting on the Bilistein 5100 shocks.

Btuggle88 · March 5, 2015

2 inch leveling kit that goes under the stut is less invasive and will be your best bet instead of having to drop the strut and cut the bolts on the top of the strut to modify it to put the kit on.

fondupot · March 5, 2015

Do the bilstein 5100 adjustable front coils.

Donstar · February 3, 2016

This topic is exactly what I was once questioning. My dealer recommended the Ready Lift (663085). I thought this was a sharp looking two piece kit that "shares the load". (My concern with this kit is compensating the shortened top struts by supplying narrower nuts.) Since my initial inquiry I have done a great deal of internet research on adding a level kit and believe a top or bottom mount spacer does about the same thing. I can't find a good explanation of what these kits actually do to your truck. Are they pushing the body up or are they pushing the suspension down so that the truck has lost 2 or so inches of suspension travel? Adding Bilstiens or pro comp leveling shocks is an option but substantially more cost in product and labour. I really prefer the looks of a new GMC with only a slight rake. However, I don't want to sacrifice function for looks. I would love to find some literature that supports a level improving or maintaining stock suspension capabilities. Your help is very much appreciated!

wade_660 · February 3, 2016

The only difference I see is ease of install. I can put a bottom kit on in about 30 minutes. Especially on a 2wd

robvas · February 3, 2016

This topic is exactly what I was once questioning. My dealer recommended the Ready Lift (663085). I thought this was a sharp looking two piece kit that "shares the load". (My concern with this kit is compensating the shortened top struts by supplying narrower nuts.) Since my initial inquiry I have done a great deal of internet research on adding a level kit and believe a top or bottom mount spacer does about the same thing. I can't find a good explanation of what these kits actually do to your truck. Are they pushing the body up or are they pushing the suspension down so that the truck has lost 2 or so inches of suspension travel? Adding Bilstiens or pro comp leveling shocks is an option but substantially more cost in product and labour. I really prefer the looks of a new GMC with only a slight rake. However, I don't want to sacrifice function for looks. I would love to find some literature that supports a level improving or maintaining stock suspension capabilities. Your help is very much appreciated!

IMO you're introducing 2 pieces to break if you do both top and bottom spacers. And most people only do both if they want 2.5" in the front which will usually cause you to ride slightly higher in the front, unless you add a rear spacer too.

I did the 5100's because the stock shocks aren't that great anyway so 2 birds with one stone.

After the alignment and labor to install it's not that much more. But a cheaper spacer kit is worth it if you can do the install yourself.

GMC-AT · February 3, 2016

bottom will be much easier. All I can tell you is this - after having 2 of these trucks (2014, and 2016) and trying a variety of level kits ( Rancho Quick Lift, Top of the strut spacer, bottom of the strut, leveling shocks) I like this the best - it's also the cheapest and easiest. It also rides great and sits perfect...

http://www.motofablifts.com/product-p/ch-15lm.htm

Edited February 3, 2016 by GMC-AT

Donstar · February 3, 2016

bottom will be much easier. All I can tell you is this - after having 2 of these trucks (2014, and 2016) and trying a variety of level kits ( Rancho Quick Lift, Top of the strut spacer, bottom of the strut, leveling shocks) I like this the best - it's also the cheapest and easiest. It also rides great and sits perfect...

http://www.motofablifts.com/product-p/ch-15lm.htm

Thank you for this link and your advice. I just got off the phone with a 4x4 shop in Victoria, B.C. (recommended on Bilstein web page) and they confirmed that the better alternative after Bilstein 5100 is a bottom mount spacer. They put no stress on ball joints or other critical parts. Top mount spacers apparently add stress by "pre-loading". I don't really understand this but he sounded knowledgeable. To me, a spacer on top of the shock or on the bottom is essentially reducing factory shock space forcing upward pressure (lift) on the truck body. If a top spacer causes stress on critical parts by reducing spring space, then the same issues should happen using Bilstein shocks. They generate lift through reducing spring space. I find this stuff fascinating. My wife turns colour when I start talking trucks so I truly appreciate this forum!

Johnnynovo · February 3, 2016

Another option is the Rancho Quicklifts. They also have a factory ride.

Jeff5347 · February 3, 2016

Thank you for this link and your advice. I just got off the phone with a 4x4 shop in Victoria, B.C. (recommended on Bilstein web page) and they confirmed that the better alternative after Bilstein 5100 is a bottom mount spacer. They put no stress on ball joints or other critical parts. Top mount spacers apparently add stress by "pre-loading". I don't really understand this but he sounded knowledgeable. To me, a spacer on top of the shock or on the bottom is essentially reducing factory shock space forcing upward pressure (lift) on the truck body. If a top spacer causes stress on critical parts by reducing spring space, then the same issues should happen using Bilstein shocks. They generate lift through reducing spring space. I find this stuff fascinating. My wife turns colour when I start talking trucks so I truly appreciate this forum!

Someone correct me but I don't think a top mount, bottom mount or combo of the 2 will be a difference in pressure on the ball joint. RC 2.5 is split in to 2 pieces while a motofab 2.5 is one big spacer on top of the strut. The only difference is the RC puts the strut in between the spacer...so in the middle of the suspension and the motofab in essence pushes the strut assembly to the lower end if the suspension. In either case the strut, ball joint ect...all parts are seeing the same level of stress due to a combined 2.5 lift whether or not the spacer is 1 or 2 piece and location. The strut and spacer become "one ". I think the only way to alleviate that stress would be either a taller spindle to make up for the UCA's increased downward angle in which the spindle would bring it back up to spec or the aftermarket UCA that is designed for lifts

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GMCSierra4x4 · February 3, 2016

Is there really any difference between a leveling kit going on top of the struct compared to putting one on the bottom of the strut?

I'm looking at the Ready Lift 1.5" goes on top of the struct or Rough Country 2" that goes on the bottom of the strut.

I don't plan on changing my wheels or tires. I like my 22" wheels and the stock tires. Just like the look of it after reading and looking around on this forum. Also, might look at putting on the Bilistein 5100 shocks.

Yes. "Top mount" different than "bottom mount" different than a combination "spacer and in coil mount". I have run both top and bottom, do not off road and still had issues over steep speed bumps and pot holes. Go here http://www.bilsteinus.com/products/truck-off-road/5100-series-ride-height-adjustable/ and under "Features and Benefits" click on the "Learn More" link. The PDF document should answer all of your questions.

DISCLAIMER: I have not installed Bilstein 5100s, but the explanation is good about the type of issues you may find yourself dealing with using a spacer leveling kit.

Edited February 3, 2016 by GMCSierra4x4

Mack207 · February 4, 2016

A top mount or bottom mount spacer does not add preload. They give lift by extending the overall length of the shock. The shock/coil doesn't compress any additional amount because no additional load is being put on it. They do make spacers that go between the top coil perch of the shock and the spring, which would add preload. The reason that I have found a top mount can potentially be bad is because the suspension moves in an arc around the uca and lca. The shock is the limiting factor in this movement (along with the ball joints). Because the top mount spacer is solid (cannot bend) the action point of the shock changes, which can lead to additional bushing wear. A lower mount spacer doesn't change the action point of the shock because the shock really hasn't moved. All that has happened is that the lca has been pushed down further than stock when compared to the shock.

5100's give lift by adding preload to the stock spring. Some models are longer than stock, which doesn't necessarily add lift, but it can lead to over-extending the ball joints. The settings on the 5100 lift the bottom spring perch higher than stock, which compresses the stock spring into a smaller space, which puts the spring under a higher load. This is also why the suspension becomes stiffer when adding 5100's, along with Bilsteins dampening.

I'm not a suspension expert by any means, so my terminology may be wrong. This is what I have found after working with my personal suspension setups over the past 9 years. I've installed plenty of 5100's on other vehicles, and I feel that I have a good handle on how they operate as far as providing lift.

GMCSierra4x4 · February 4, 2016

A top mount or bottom mount spacer does not add preload. They give lift by extending the overall length of the shock. The shock/coil doesn't compress any additional amount because no additional load is being put on it. They do make spacers that go between the top coil perch of the shock and the spring, which would add preload. The reason that I have found a top mount can potentially be bad is because the suspension moves in an arc around the uca and lca. The shock is the limiting factor in this movement (along with the ball joints). Because the top mount spacer is solid (cannot bend) the action point of the shock changes, which can lead to additional bushing wear. A lower mount spacer doesn't change the action point of the shock because the shock really hasn't moved. All that has happened is that the lca has been pushed down further than stock when compared to the shock.

5100's give lift by adding preload to the stock spring. Some models are longer than stock, which doesn't necessarily add lift, but it can lead to over-extending the ball joints. The settings on the 5100 lift the bottom spring perch higher than stock, which compresses the stock spring into a smaller space, which puts the spring under a higher load. This is also why the suspension becomes stiffer when adding 5100's, along with Bilsteins dampening.

I'm not a suspension expert by any means, so my terminology may be wrong. This is what I have found after working with my personal suspension setups over the past 9 years. I've installed plenty of 5100's on other vehicles, and I feel that I have a good handle on how they operate as far as providing lift.

I am actually considering the 5100s on the middle setting right now. In your experience, how much of a ride difference does it make? Most forums talk about the improved handling and ride characteristics, but I have seen a few about a harsh ride. My rake is 2" using a laser and ruler at each end of the frame to measure the difference, extending the measurements out to match wheel base (153") and some Trigonometry. The engineer in me didn't trust the wheel well measurements.

Edited February 4, 2016 by GMCSierra4x4

Mack207 · February 4, 2016

I am actually considering the 5100s on the middle setting right now. In your experience, how much of a ride difference does it make? Most forums talk about the improved handling and ride characteristics, but I have seen a few about a harsh ride. My rake is 2" using a laser and ruler at each end of the frame to measure the difference, extending the measurements out to match wheel base (153") and some Trigonometry. The engineer in me didn't trust the wheel well measurements.

I don't have any experience with the ride on the newer 1500's with 5100's. Best guess, it will be more firm than stock, but a good firm (lol). Most of the cases with a harsh ride seems to come from the top setting.

GMC-AT · February 4, 2016

5100 are firmer. I would just keep the stock shocks with a bottom strut spacer no more than 1.5in.. The ride is pretty much stock... even with a few inch of rake, these new body trucks looks level.