Bilstein 5100s on a 2013 4WD - alignment "necessary"

mitchntx · May 27, 2014

I already know I'm removing the front strut assembly and having a shop R&R the struts.

I'm not changing the ride height.

Question is will an alignment be necessary?

Or will it be close enough to drive to an alignment shop.

After all, most box alignment shops align within a window and not a specific number.

It's why I always did my own alignments on the race car.

I have toe plates and will document before and after changes in toe.

That should be a good indicator if camber/caster has changed significantly.

Sound logic?

dsmmace · May 27, 2014

I would pay for an alignment than new tires. My alignment was out after I changed my shocks and leaving them at stock heights.

20Silverado11 · May 27, 2014

When I put four Bilstein 5100's on my 2011 Silverado, I immediately got the truck aligned afterwards - literally drove straight to the alignment place. I figured it was part of the equation.

grimmysnr · May 30, 2014

An alignment should not be necessary for changing out shocks. Shocks do not support the vehicles weight and do not alter ride height unless they serve as an auto leveling system similar to the air ride suspension on Yukon Denalis. Shocks are rate reducers so that your suspension doesn't just bounce all over the place. The compressed gas allows them to return to the extended position naturally so that they have positive tension on them. I have changed shocks on several vehicles including trucks without ever jacking the vehicle and I have also done it with Bilstein 5100's. I simply compressed the shock and let it extend by itself until I can install the mount bolt. Never got an alignment and never had an issue. If I did have an alignment issue it was more because I changed tires or was a little rough on it while driving on the back roads. If you were to take it to a shop and they find an issue I would be willing to bet it was pre-existing long before any shock changes. I am sure somebody will come in here with some science and say shocks lifted their truck 2 inches or something, but through my experience this has never happened. Especially since you can compress a shock by hand.

If it is the whole strut assembly and you are not changing the spring at all or adding any spacers then an alignment should still be unnecessary. If adding anything to change ride height then absolutely.

mitchntx · May 30, 2014

If it is the whole strut assembly and you are not changing the spring at all or adding any spacers then an alignment should still be unnecessary. If adding anything to change ride height then absolutely.

Strut assemblies on FWD cars and Mustangs have the upper strut mount serving as the adjustment for camber and caster. R&Ring makes an alignment a no-brainer.

But it looks to me as though the strut assembly on the Sierra serves as a coil-over assembly with a SLA design rather than a traditional strut assembly which has no upper control A-Arm.

With no ride height change (no change in geometry) I question whether an alignment is necessary in a shock change and was going to make that decision after taking before/after toe measurements. In looking, the shock plays no geometric role in the suspension. So changing it would be like changing a sway bar end-link in terms of needing an alignment.

The end game is better control and stability while towing my camper. I can feel the trailer pushing around the rear of the truck. I'm sure shocks will make a huge difference. I'm also kicking around the idea of a rear sway bar.

I'll see how shocks do and then follow that path or not. Rule I learned in setting up a race car ... make incremental changes so specific results can be measured.

Edit:

The reasoning behind before/after toe measurements being my guide is because the distance between tie rod ends is a fixed distance through the steering components. With the steering mounted to the body, movement in the body changes the relative distance between tie rod ends as the front suspension arcs through its range of motion (bumpsteer). Lift the truck and I get more toe-in ... lower the truck and I get toe out.

mitchntx · May 31, 2014

Installed ... took about an hour, not including the trip to the local automotive shop for use of a decent spring compressor.

Toe went unchanged as did ride height as measured from a LCA bolt,

The Harbor Freight POS spring compressor I had looked like the one O'Rielly's had for a loaner. They both appeared way to fragile to compress a spring with the size of coils.I haven't a clue what the spring rate is nor how much preload was on the assembly.

So, to be safe, I had it done.

Initial impressions ... with a short wheelbase, there is some porpoising present at times. That seems to have been diminished quite a bit.

Ride seems smoother for the most part. Abrupt changes in road surface seem a bit more noticeable initially, but smooth out very quickly.

So bump valving seems stiffer and rebound more controlled.

No change in body roll (and didn't expect any). Shocks control motion and are not intended to shift weight.

Next is to hitch up the camper and see if there are any changes in the way the truck reacts before a dive in for a Hellwig rear bar.