Suspension Data for Possible Upgrade

[HarvesterUT]

I tried 285 rears once. Don't remember what the issue was (probably rubbing on fender) and they weren't Sport Cups. The wider rear wheel gives me a bit bigger contact patch and 265 is almost perfect to avoid severe roll under in the turns.

Ah OK. I am going to put 19x10 on all four corners and run 275/35 and 285/35. I am considering swapping over the Z06 factory springs and sway bars. Not going to race it, just back road driving.

 

[RONALD34275]

I have a stock 2007 XLR and had the electronic shocks replaced.
I don't do any racing but I am wondering if sway bars will help.
If so, which ones?
Thx, Ron

 

[Gord]

I have a stock 2007 XLR and had the electronic shocks replaced.
I don't do any racing but I am wondering if sway bars will help.
If so, which ones?
Thx, Ron

Hi Ron,

Help with what may I ask?

It seems lots of folks throw on a rear sway bar without really considering all that it's capable of doing and ...undoing!

Here's a bit of reading which you might find helpful: Anti-roll bar - Wikipedia

If your suspension is working as designed and 'fresh' as you describe, one might be a bit hesitant to fidget with a rear bar unless you have a valid complaint or a specific handling desire, and know that everything else suspension-wise is in good condition as well.

Automobile's overall handling is generally defined by the rear axle design (believe it or not), so any change you make with its layout, really should be thought through with some good, clear understanding of what the results / consequences may be.

HTH!

Gord

 

[HarvesterUT]

I don't see any reason not to add a sway bar to the rear of your XLR. In case you don't know, the base XLR only has a front sway bar - the V got a rear one. Since the car is a Corvette chassis, you can use any sway bar that fits a C6. I am currently running Z06 sway bars. I think the best option for you would be install oem V-series sway bars or even the Corvette Z51 package sway bars. Anything stiffer than that is probably overkill for your needs.

 

[IAN]

Hi Harves/Gord.

Depending in your style of driving… it is OK to have the sway bars of your choice. for your front or rear XLR

with good bushings also of your choice.​

I am not a racing type of driver, my choice would be for a single sway bar as per Gord saying in his thread.

The V has a lot more HP and a rear sway bar is a must…. and why not installing one on the base XLR if you like taking curves at hi speed.

Good road enjoy your driving.

IAN

 

[long Tall Sally]

I buy used z06 sway bars off ebay when people put on the larger bars. The z06 is 2 mm larger than the stock V bar and i get them with links and all but the 2 bolts for 100$ .Best hundred you will ever spend on these cars. Gm knew there owners wanted float and not flat so they did not put on rear bars on the base .( already too heavy in the rear). They felt the mag shocks would work to keep the cars flat In turns with the yaw sensors but that worked when new but is one of the first things to loose its ability as the shocks wear out. I have 245 18 on mine ft and rear and wit the 27mm bar I can keep it flat on the ramp at 45 with the 30mm bar I can do it at 55 before tire noise. on the open road you dont know which bar is on the car but you know it sure works well in turns. out of dozens installed I have yet to read of anyone who removed it after installing

 

[HarvesterUT]

I agree, the Z06 suspension parts are a great upgrade for the XLR. The extra weight of the XLR makes the suspension not as harsh as you would experience in a lighter z06.

 

[xlrlist01]

I don't see any reason not to add a sway bar to the rear of your XLR. In case you don't know, the base XLR only has a front sway bar - the V got a rear one. Since the car is a Corvette chassis, you can use any sway bar that fits a C6. I am currently running Z06 sway bars. I think the best option for you would be install oem V-series sway bars or even the Corvette Z51 package sway bars. Anything stiffer than that is probably overkill for your needs.

The simplest reason not to is the risk of causing over-steer. As the back of a car gets stiffer it increases the risk of over-steer. All manufacturers dial (huge) amounts of under-steer into their road cars, however on the XLR this can be unwise as the active suspension can stiffen up mid-curve, causing the problem they are trying to avoid. Over-steer is very dangerous indeed, what it means is the back of the car has taken control of the direction you are going in. As you are aware you control the steering with the front wheels, so the effect is as you turn OUT of a curve, the back turns you IN harder, the exact opposite of what you are commanding. A crash is imminent. If this ever happens to you, turn back into the curve, even though you don't want to. This is why it is called over-steer, the car is steering harder than you are directing. Under-steer is considered much safer as at least the car goes in the direction you are commanding, though not as much as you might like!

When I put a rear anti-swar bar on my X, it had a number of settings. On the stiffest, it induced over-steer, so I moved back a click or two on the setting. Adding the anti-sway bar eliminated the problem of the suspension stiffening up in an 'S' curve, locking it in the wrong part of the roll. (I also fitted the stiffer front anti-swar bar, which also helps to offset over-steer.)

(BTW, over-steer is not a skid situation, powering a car through a curve with the back-end sliding out is a skid situation and is entirely different from true, technical over-steer, though many call that style of driving 'over-steering'. It isn't, it is a controlled power slide/skid. Nor is it 'drifting'. True drifting is when you go round a curve with the steering pointing exactly straight ahead, using the rear wheel power to make the car hold the turn. Drifting through a curve is the fastest it is possible to go and is very skilled, as demonstrated by top drivers. Drifting is a controlled skid and has all four tires on their limit of adhesion and then very slightly more (using the available power) at the back and a tiny bit less at the front. Driving on dirt is different and has different dynamics, four-wheel drive is frequently advantageous for example.)

HTHs

 

[RONALD34275]

Thanks all for your input. This will be on the upgrade list.

 

[Gord]

The simplest reason not to is the risk of causing over-steer. As the back of a car gets stiffer it increases the risk over over-steer. All manufacturers dial (huge) amounts of under-steer into their road cars, however on the XLR this can be unwise as the active suspension can stiffen up mid-curve, causing the problem they are trying to avoid. Over-steer is very dangerous indeed, what it means is the back of the car has taken control of the direction you are going in. As you are aware you control the steering with the front wheels, so the effect is as you turn OUT of a curve, the back turns you IN harder, the exact opposite of what you are commanding. A crash is imminent. If this ever happens to you, turn back into the curve, even though you don't want to. This is why it is called over-steer, the car is steering harder than you are directing. Under-steer is considered much safer as at least the car goes in the direction you are commanding, though not as much as you might like!

When I put a rear anti-swar bar on my X, it had a number of settings. On the stiffest, it induced over-steer, so I moved back a click or two on the setting. Adding the anti-sway bar eliminated the problem of the suspension stiffening up in an 'S' curve, locking it in the wrong part of the roll. (I also fitted the stiffer front anti-swar bar, which also helps to offset over-steer.)

(BTW, over-steer is not a skid situation, powering a car through a curve with the back-end sliding out is a skid situation and is entirely different from true, technical over-steer, though many call that style of driving 'over-steering'. It isn't, it is a controlled power slide/skid. Nor is it 'drifting'. True drifting is when you go round a curve with the steering pointing exactly straight ahead, using the rear wheel power to make the car hold the turn. Drifting through a curve is the fastest it is possible to go and is very skilled, as demonstrated by top drivers. Drifting is a controlled skid and has all four tires on their limit of adhesion and then very slightly more (using the available power) at the back and a tiny bit less at the front. Driving on dirt is different and has different dynamics, four-wheel drive is frequently advantageous for example.)

HTHs

Outstanding - concise post.

May I ask, what diameters (and perhaps brands) are you now running as a somewhat successfully balanced 'set'?

Thanks!

Gord

 

[richardyoo]

When I put a rear anti-swar bar on my X, it had a number of settings. On the stiffest, it induced over-steer, so I moved back a click or two on the setting. HTHs

This was the same experience I had with the Hotchkis bar... too stiff and the rear wanted to swing out, middle setting was perfect

 

[xlrlist01]

This was the same experience I had with the Hotchkis bar... too stiff and the rear wanted to swing out, middle setting was perfect

Yes, I fitted the Hotchkis set front and rear. If there are different grades, I don't recall which I fitted. The front is bigger than stock and hollow, that is all that comes to mind. It was a long time ago. The 'middle' setting on the rear fits with my memory too. I had to use a silicone lube on the bushings as although they claimed to be lubricated, they squeaked.

What I can tell you is I took my X on a track day driving skills course and was caught in a huge, sudden thunderstorm downpour and I discovered that with this setup, my X was perfectly happy going round curves far faster than I would on a public highway without losing its calm predictability and confidence. I was very impressed with the handling in awful conditions.

 

[richardyoo]

I had to use a silicone lube on the bushings as although they claimed to be lubricated, they squeaked.

I have tried everything to get them to stop squeaking, and I have given up... various kinds of silicone lube, teflon tape, grease, etc... it'll work for a few hundred miles and it comes back... it only happens in cold weither (sub 40 deg) so its not a regular issue, but when it does make noise its a bit annoying... during the summer months they are silent... oh well...

 

[RONALD34275]

Installed Z06 shocks with simulators.
The car rides OK but low. I hit the gas station underground tank fill doors when driving out. Some driveway angles are not possible.
Already had to have the body shop repair the rockers from scrape damage.
Dealership says the entire suspension spring and bushings needs replacement to get additional height.
About $2200 parts and labor.
Any advice would be appreciated.

 

[Gord]

Howdy,
First off, what tires are you using?

Unfortunately the 'ride height bolts' (often referred to as 'lowering bolts') come with the springs. From what I understand, there are 'lowering bolts' available most specifically for the Corvette gang, and I don't know if they could handle being used to raise the car or even put it to a stock height, but it's pretty much the only option I can think of at the moment.

Figure, if your ride height bolts are spent (rubber pads on the bottoms), perhaps changing out to a fresh set of even 'lowering bolts' and adjust 'em appropriately. If you can't get enough altitude with them, maybe adding additional rubber pads to where they land on the lower control arms would give you the results you need.

Perhaps as well, you might find some XLR originals that haven't turned to mush and use those, assuming whomever would sell 'em separate from the springs.

US$2200...yikes, they must be replacing the works, and I'd tend to wager this could be solved for under a hundred bucks and a little elbow grease.

Here's pictures for you:



That's from here: 2005 - 2013 Corvette C6 Front and Rear Lowering Bolts (C6, Z06, ZR1, GS) | eBay

The originals as a part of i.e. the front spring. This doesn't show them very well however they're on each end of the spring (#8).



I'd have a good look at what you have right now - see just how worn out they are, as the rubber on the bottom gets grimy and does somewhat 'vanish' or get squished quite a lot.

Fidgeting with these would probably require an alignment - so consider adding what that might cost to the price of said bolts.

Food for thought, hopefully.

HTH!

Gord

 

[richardyoo]

Ride height is controlled by the ride height adjusters... the shocks do not have any influence on ride height.

They are bolts and pads that are attached to the end of the leaf springs on each corner of the car. Often times they are damaged and/or completely broken off. You can buy any corvette adjusters and they will work.

Installed Z06 shocks with simulators.
The car rides OK but low. I hit the gas station underground tank fill doors when driving out. Some driveway angles are not possible.
Already had to have the body shop repair the rockers from scrape damage.
Dealership says the entire suspension spring and bushings needs replacement to get additional height.
About $2200 parts and labor.
Any advice would be appreciated.

 

[RONALD34275]

Thanks Gord

Howdy,
First off, what tires are you using?

Unfortunately the 'ride height bolts' (often referred to as 'lowering bolts') come with the springs. From what I understand, there are 'lowering bolts' available most specifically for the Corvette gang, and I don't know if they could handle being used to raise the car or even put it to a stock height, but it's pretty much the only option I can think of at the moment.

Figure, if your ride height bolts are spent (rubber pads on the bottoms), perhaps changing out to a fresh set of even 'lowering bolts' and adjust 'em appropriately. If you can't get enough altitude with them, maybe adding additional rubber pads to where they land on the lower control arms would give you the results you need.

Perhaps as well, you might find some XLR originals that haven't turned to mush and use those, assuming whomever would sell 'em separate from the springs.

US$2200...yikes, they must be replacing the works, and I'd tend to wager this could be solved for under a hundred bucks and a little elbow grease.

Here's pictures for you:

View attachment 9560

That's from here: 2005 - 2013 Corvette C6 Front and Rear Lowering Bolts (C6, Z06, ZR1, GS) | eBay

The originals as a part of i.e. the front spring. This doesn't show them very well however they're on each end of the spring (#8).

View attachment 9561

I'd have a good look at what you have right now - see just how worn out they are, as the rubber on the bottom gets grimy and does somewhat 'vanish' or get squished quite a lot.

Fidgeting with these would probably require an alignment - so consider adding what that might cost to the price of said bolts.

Food for thought, hopefully.

HTH!

Gord

Thanks Gord.

We lived in Lake George, NY until last August.
Closer to you than NYC.

 

[RONALD34275]

Thanks for your input.

Ride height is controlled by the ride height adjusters... the shocks do not have any influence on ride height.

They are bolts and pads that are attached to the end of the leaf springs on each corner of the car. Often times they are damaged and/or completely broken off. You can buy any corvette adjusters and they will work.

Maybe I won't need to change the entire spring.

 

[05 GRAND DADDY]

You do not need change the springs, in less it is cracked or broken. I had all 4 changed out when switch out my shocks to regulars too! They change them they reset and adjusted the whole car to original specs! It rides and handles better then before, but may be a little stiffer.


Sent from my iPhone using Tapatalk

 

[long Tall Sally]

yeah you need to check the springs .The shocks will not change the height of the car. You can get the thicker adjusters on several sites. I have bought them and they are the same size as the oem when new. The lowering ones shown will work fine to put the car at stock height if again the front spring is not cracked broken or worn out.