Question....

Will adjusting ride height (using the suspension bolts) affect the alignment settings? Specifically the Toe setting?

I put lowering bolts put on the rear and went all the way down with it. I had it aligned...and now want to raise it up a tad.

I really cant see how that would effect toe but thought I'd ask.

A technical answer from anyone in-the-know would be appreciated vs. "I'd have it re-aligned".

 

This may not be a technical response, but it is a fact that anytime you change the ride height you affect the suspension geometry. It does require re-alignment. I ended up lower by about 1/2" due to Koni FSD installation and the alignment was substantially off on both camber and toe.

Good luck.

 

Now's your chance to be the guy with the technical answer. Do you still have the reults from your last alignment? If so, take it with you and have them verify the settings. Then adjust or not and then report back. It's your assignment

 

sorry not a technical answer but... the answer is yes.. i changed the height of mine in the rear with those same bolts as little as 3/8 of an inch and my allignment was out of factory specs from that alone.

 

This is only "proof" if you had the car previously aligned and not just going off the factory alignment specs because it is well known that these cars come from the factory with numbers all over the place. Some are good but many, if not most, are off.

 

point taken.. but then that is all the more reason to get an allignment after changing the height of the car.. there is no question that changing the height of the car changes the allignment. so bringing it in for an allignment is the only way to be 100% sure it is right.
tks, dal

 

 

Regarding the toe setting specifically, adjusting the ride height will not have any impact on it. The suspension geometry incorporates "zero bump steer" into the design meaning you have zero toe changes as the suspension goes through its' travel. All Corvettes since the C4 ('84-present) are like that. If you look at your suspension, you'll see the centers of the tie rod connections/joints at either end are the same height above the centers of the lower control arm connections (the ball joint and control arm bushings) making it parallel to the lower control arm. We have an SLA suspension meaning short/long arm in reference to the upper and lower control arms respectively. If you scale the lengths of the control arms to the height of the tie rod above the lower control arm, the tie rod will be the same length. With the tie rod parallel to the lower control arm and scaled to the proper length, any movement of the control arms (and spindle) during suspension travel causes the outer tie rod joint to follow an arc that results in zero "rotary" motion of the spindle or zero toe change.

However, due to the SLA suspension, you will have camber change during suspension travel. That's actually a good thing and is the design advantage of the SLA. At the stock ride height, the "long" lower control arm (at the ball joint) is below parallel and the "short" upper control arm is almost parallel with respect to the ground. As the suspension compresses, initially the arc of the lower arm "pushes" the spindle outward just a small amount and the upper arm does the same thing but to a lesser amount with the net effect of a slight amount of negative camber gain. As you go further through the travel, the lower arm starts to pull in but not before the upper one does and the more the suspension compresses, the more the affect is exaggerated giving more and more negative camber gain which is what you want during hard cornering. As the suspension initially extends, the lower arm "pulls" in as well as the upper arm but again the upper pulls in but not as much giving a slight amount of positive camber gain. As you go further through the travel, the upper arm pulls in more and eventually you get negative camber gain. The end result of this is you get very small amounts of camber change with small amounts of wheel travel at the factory ride height which acts to keep the tire flat on the ground over small bumps. As you build cornering speed and compress the outside wheel suspension, you gain camber that counters the lean of the car to help keep the tire flat on the ground.

Since you've lowered the car and are no longer at the factory ride height, the above does not apply to you as you have taken the car out of its' designed optimum camber curve. Your lower control arm is most likely parallel to the ground or maybe above even. When you raise it a "tad", you'll start losing negative camber immediately. If you had the alignment set to the extreme limits towards the negative camber end of the range, you'll probably be ok with camber as long as you don't go more than 1/2" up. Just monitor tire wear on the outside of the tire closely for signs of insufficient negative camber but don't let it go too long because you can't reverse a wear pattern by correcting the cause, you can only stop it. You can always learn to do your own alignments and check/make changes yourself...it's actually fun and pretty easy, I haven't been to an alignment shop over 30 years.

This may be more than what you're looking for but it's fun stuff to me.

 

This is a little off topic but still pertains to the alignment. I am getting some noise from my right front hub/bearing and a little vibration. I started getting this right after my last alignment. Will changing the hub/bearing require another alignment or at least re-check?

 

Dang... Was it something I said?

 

Yeah, no one likes a thread thief J/K

I had to replace one of my front hubs and I did not need to re-align. It shouldn't have any impact on alignment that I can think of.

 

Yeah I hate jumping in but everybody was on a topic I needed to know. It sure killed the thread though, Sorry

Thanks for the info. I didn't see how it would affect it but wanted to be sure before I tore the front end down to replace this.

Robert

 

Robert, I'm not sure what you mean by "tear the front end down" because replacing a hub is only slightly more difficult or entailing than changing out rotors, for the most part anyway. You're really not getting in too much further. They're pretty plug and play. Besides, is there a reason you're not having it done by the dealer under warranty?

 

Glass Slipper that was likely the best technical description Ive ever received. Most excellent Sir!

Since you explained that if I raise it I will be dialing in positive camber I think I will just leave it alone. I live in flat Houston and my settings are okay for my usual driving here. My issue is I get some rubbing when I take the car to the TX hill country and attack the hilly-curvy roads.

I may just crank it up a notch or two when I go there (2/3 times a year) and let it back down when I return. It is good to know that the ride height adjustment does NOT affect the tire robbing TOE setting.

Either way I wanted to say "thank you" for the very thorough reply to my inquery. You are a true asset to the CF community.

Bone

 

Sorry I missed your response. I was just using the term "Tear into" loosely. I changed the hub today and it went pretty smooth. It's amazing how when you buy "Sets" of sockets and wrenches it's always missing the sizes you need. I am just now building up my Metric tools completely and I see the general still likes to mix and match the bolts/nuts with SAE and Metric.

Car is all nice and quiet now. No Warranty on the 08. She's a rebuilt with a warranty block.

 

Good job man!

 

not to dispute your statement (i have heard this before, at least for C6), but if that's the case, why do zip and LG sell bump steer kits for C5 and C6?

 

the problem though is that changing the ride height does change camber, which affects both tire wear and handling. unless you actually want a specific camber setting that goes along with a specific ride height setting, you really need to align the car after changing ride height.

 

Look at their bump steer kit:
http://www.lgmotorsports.com/catalog...oducts_id=1767
The first line in the description says it's for "any C5 or C6 that has modified suspension geometry" and I agree with that. A lowered car does not have any part of the suspension modified therefore the suspension geometry stays the same. Why it says "Especially effective for lowered cars", I have no idea and of course don't agree with that. The factory toe curve is close enough to zero to call it perfect, it's just geometry and there's no reason in this day of computers for any car to have less than good toe curves...it's too easy. There are a lot of things that are used on race cars by race teams/shops that are sold to the public that aren't needed or don't work on street cars. There are plenty of "boy racers" that'll buy it...look at all the coilover setups bought by people that never see the racetrack because "it's what the race cars use so it must be good". After it beats them to death on real roads, they end up taking them off much like a person puts a big race cam in their car only to be hugely disappointed with the serious lack of low end torque and terrible idle quality and ends up back stock. DRM sells a rear trailing arm relocating bracket for C4s to improve anti-squat to get better traction coming off low speed corners. They work great on the race track where the surface is smooth and the springs are stiff already. On the street, they are a disaster because the new angles of the trailing arms cause a significant amount of any bumps to be transmitted directly to the frame mount instead of the spring/shock. The frame mount just happens to be right at the driver's hip and makes for a very harsh ride no matter how soft the spring rate is, it's just geometry. Once again, what works on the racetrack doesn't usually work so well on the street...however, what wins on Sunday sells on Monday.

He acknowledged the camber change with ride height change in his second paragraph.

 

yes, but he also implied that the camber change was not significant to require re-alignment.