Grand Sport Wheel Alignment - Camber

[AlHewitt]

I see this subject addressed in various other postings but thought I'd ask my question out right to the group. Excessive tire ware has been reported by many and is said to be caused by (amount other things) negative camber settings. Negative camber, where the wheel tilts inward at the top, can causes the insides of the tires to ware faster than the outsides and many including myself apparently are having this problem. I don't drive my GS to its limits so increasing tire life without compromising most of the performance seems like a good idea and if reducing the negative camber will accomplish this, I'm in. Researching what is the factory setting is where I'm confused as I want to tell the alignment technician what to set it to. The under dash codes for my 2010 GS says it came with FE3 suspension. The 4 part red service manuals address wheel alignment on page 16-99 and it shows the FE1, FE2 and FE3 suspensions all with the same negative camber @ -0.45, +/- 0.60 degrees. The FE4 and FE5 suspensions (Z06 and ZR1 I'm assuming) have published higher negative camber numbers. The local Chev dealer tells me the FE3 suspension is a Sport Suspension for GS and uses a negative camber of -0.75 degrees. No where do I see this value published in the service manual. So as I see this I need to get a reading as to what my actual camber setting is. My question is what should I specify for negative camber for better tire life?
Thanks
Al

 

[Huskerman]

Don't know why the FE3 would be any different but here is a recent thread on the subject.


http://www.corvetteactioncenter.com/forums/c6-technical-performance/133296-alignment-specs.html

 

[Hib Halverson]

Tell the dealer what the Service Manual says for FE3 then ask them why they say -0.75°.

For best tire wear, I'd start with the FSM numbers, monitor tire wear and if you see excessive wear on the inside or outside of the tread, change the alignment as necessary.

If you don't drive the car hard you might want to set the camber more conservative such as 0 to -0.25.

Two adjustments impact tread life
1) alignment
2) tire pressure

Be attentive to both and you should get good tire mileage.

 

[c4c5specialist]

Details

Hi there,

Please lets clarify a few things.

#1, your best camber setting for optimal tire wear is 0.0.

#2, just because you have FE3 DOES NOT MEAN all specifications are -.45. If you have RPO XFA for a tire size in the front, that specification CHANGES to -0.95.

So, as far as service manual does go, GM service is all online and we do not use service manuals any more.

There is no specification for -0.75 in the service manual for ANY suspension system on Corvette for 2010.

If you would like your dealership to print you the document, please ask them for document ID 2588376

Allthebest, Paul

 

[Hib Halverson]

Hi there,

Please lets clarify a few things.

#1, your best camber setting for optimal tire wear is 0.0.

#2, just because you have FE3 DOES NOT MEAN all specifications are -.45. If you have RPO XFA for a tire size in the front, that specification CHANGES to -0.95.

So, as far as service manual does go, GM service is all online and we do not use service manuals any more.

There is no specification for -0.75 in the service manual for ANY suspension system on Corvette for 2010.

If you would like your dealership to print you the document, please ask them for document ID 2588376

Allthebest, Paul

Paul...when you say GM doesn't use service manuals anymore, I wondering if ESI or SI or whatever you guys call it, now, is the same as the printed manuals except that it gets regularly updated on-line, which the paper books can obviously cannot. The latest copy of ESI that I have is 2011 and every time I've checked by putting my paper book next to the laptop it's the same as what's in the service manual.

 

[AlHewitt]

Hi there,

Please lets clarify a few things.

#1, your best camber setting for optimal tire wear is 0.0.

#2, just because you have FE3 DOES NOT MEAN all specifications are -.45. If you have RPO XFA for a tire size in the front, that specification CHANGES to -0.95.

Hmmmm. There is confusion in the cockpit...
I have the FE3 suspension AND I have RPO XFA front tires. The service manual shows -0.95 degrees of camber for the FE4 suspension which I'm assuming is the Z06 specs. If -0.95 degrees is my camber setting it would help explain the ware on the insides of the tires. What is the down side to less negative camber as in closer to 0.0 degrees? I would not be happy changing it and having a car that is less roadworthy. Lastly did all GS's come with RPO XFA or just the ones with manual transmissions in coupes?

 

[c4c5specialist]

Paul...when you say GM doesn't use service manuals anymore, I wondering if ESI or SI or whatever you guys call it, now, is the same as the printed manuals except that it gets regularly updated on-line, which the paper books can obviously cannot. The latest copy of ESI that I have is 2011 and every time I've checked by putting my paper book next to the laptop it's the same as what's in the service manual.

HI there,

ESI, or electronic service information is usually on a disc that is then uploaded to a given computer and used. This is a DIFFERENT system than what is used by GM service departments. This is usually an ACDelco type of access like "techconnect".

GM dealerworld is a broadbased website by which dealerships have access to ordering vehicles, parts catalogs and GM service information. Now, this is ALL internet based and is accessed to the GM servers.

Service manuals in printed form are essentially the same thing, but as you have considered, only not updated regularly.

In truth, they are all the same. However, I do prefer the GM side of things because of the instant updating as well as in depth information not available to general public such as preliminary documents and information back as far as I want to go.

Allthebest, Paul

 

[c4c5specialist]

Hi there,

Please lets clarify a few things.

#1, your best camber setting for optimal tire wear is 0.0.

#2, just because you have FE3 DOES NOT MEAN all specifications are -.45. If you have RPO XFA for a tire size in the front, that specification CHANGES to -0.95.

Hmmmm. There is confusion in the cockpit...
I have the FE3 suspension AND I have RPO XFA front tires. The service manual shows -0.95 degrees of camber for the FE4 suspension which I'm assuming is the Z06 specs. If -0.95 degrees is my camber setting it would help explain the ware on the insides of the tires. What is the down side to less negative camber as in closer to 0.0 degrees? I would not be happy changing it and having a car that is less roadworthy. Lastly did all GS's come with RPO XFA or just the ones with manual transmissions in coupes?

HI there,

I cannot say if all GS came with the XFA option, I do not know the packaging requirements for these options.

However, I would say to you that I have tuned many Corvette alignments to 0.0 camber and NEVER had an issue with negative handling affects on the street. And I have gotten 25000 miles out of a set of front tires without issues.

I do not believe that you will notice any handling difference and I believe you will be pleased with the longevity of your tires.

Allthebest, Paul

 

[AlHewitt]

Yesterday I had an alignment done on the 2010 GS. Here are the before readings and specifications;
LF RF LR RR
Camber -1.31* -1.06* -1.24* -0.93*
Spec. -.45* +/-.60* -.45* +/-.60* -.45* +/-.60* -.45* +/-.60*

It is pretty obvious that Chev has these things set aggressively for better cornering, albeit with greater tire ware.
After the alignment I had all four corners set to less that -.20* camber. I have a road trip coming up in a couple of weeks where I'll experience different road surfaces and can better evaluate what this less aggressive camber setting means. I had the car up to 140+ MPH when new but doubt that will happen again so good tire ware and general good performance seems to be what I want.
Cheers
Al

 

[BigJimZ16]

Yesterday I had an alignment done on the 2010 GS. Here are the before readings and specifications;
LF RF LR RR
Camber -1.31* -1.06* -1.24* -0.93*
Spec. -.45* +/-.60* -.45* +/-.60* -.45* +/-.60* -.45* +/-.60*

It is pretty obvious that Chev has these things set aggressively for better cornering, albeit with greater tire ware.
After the alignment I had all four corners set to less that -.20* camber. I have a road trip coming up in a couple of weeks where I'll experience different road surfaces and can better evaluate what this less aggressive camber setting means. I had the car up to 140+ MPH when new but doubt that will happen again so good tire ware and general good performance seems to be what I want.
Cheers
Al

Similar numbers to where mine was when I had it done two weeks ago. I'm at -.25 now with the new Michelin Pilot Super Sports, and I can tell you the the ride, quiet, and highway manners are FAR superior to what I had before!!

 

[AlHewitt]

Road Trip

Yesterday I had an alignment done on the 2010 GS. Here are the before readings and specifications;
LF RF LR RR
Camber -1.31* -1.06* -1.24* -0.93*
Spec. -.45* +/-.60* -.45* +/-.60* -.45* +/-.60* -.45* +/-.60*

It is pretty obvious that Chev has these things set aggressively for better cornering, albeit with greater tire ware.
After the alignment I had all four corners set to less that -.20* camber. I have a road trip coming up in a couple of weeks where I'll experience different road surfaces and can better evaluate what this less aggressive camber setting means. I had the car up to 140+ MPH when new but doubt that will happen again so good tire ware and general good performance seems to be what I want.
Cheers


Following up on the above;
My 10 GS and another C6 (05 - LS2 w/ twin turbo’s) took an aggressive road trip this month to Eastern Oregon and the Hell's Canyon ride/road. Great country if you've never been there with good roads and little of no law seen... The other Vette had a Valentine radar system on board and led most of the way. I was interested in the handling of my GS after the reduction in camber settings. Our speeds were all over the place (0 to 120+) depending on the roads and when I asked him how many cars did we passed, he said, "All of them". One observation I made when travelling with two cars and faster than the traffic the second guy (me in most cases) is subjected to the effects after the first lead car passes the traffic. If you are doing 100+ and pass someone they'll sometimes gets a little rattled and may swerve a bit unless he's looking in his rear-view mirror and sees you coming. This swerve happens about the same time as the second car is passing the traffic. So getting by the traffic in quick order on a two lane road is needed. The twin turbo is quiet as the exhaust is muffled through the turbo system; mine on the other hand has the dual mode where with the throttle open I'm making noise. This added to the swerve as the traffic could hear me coming.

I noticed no difference in steering with the adjustments to my camber. If it corners any different I can't tell it from my un-professional driving skills. I saw lots of .7 and .8 reading on the G meter with the HUD system so I know I was working it hard. Little or no wheel spin and no over/under steering was experienced.

I did not experience it but the 05 C6 with me had his traction control system constantly interfere with his driving. Especially in corners it would apply brakes and alert him. He may have a wheel sensor problem...

In general the reduced camber is un-noticeable. Making this modification is probably moot as if I drive the car as I did on this trip the tires will not make it to 30K miles. On the other hand if you drive it like you own-it rather than stole-it I don't think you will see much of a performance change, but how fun is that?


Al

 

[the boss]

My zr1 came new whit -.95 on 4 corners and whit these big tires, it was pretty aggressive. I first set it to -.70 on 4 wheels keeping the oe caster and toe whit no difference on the handling but still was reacting a lot to any road imperfection. I reset it to -.25 on 4 wheels and still kept oe caster and toe, only down side is on a hard acceleration, it feels a tiny bit lighter on the steering wheel (most peoples would not notice) but for the rest of the ride it is so much better. It is way more comfortable to drive and tires are wearing evenly.

 

[pkincy]

A degree of negative camber is wonderful for handling at the limit as the outside loaded tire stands up straight and gets all of its tread on the road. The unloaded tire has less of its tread on the ground but than again it is unloaded so who cares.

That is the sole reason for negative camber and a degree is a lot of negative camber. Even on cars that I regularly track and/or autox I would limit neg camber to about -0.8 deg as any more is a tire killer in street driving.

If the spec is neg 0.45 and it has a 0.6 +/- tolerance it means you are still in spec at +0.15 deg. However I would probably align it to around negative 0.25 degrees and have fun. You might lower your maximum G loading to 1.0 from 1.05 but then again you don't care.

If you track your car or autox it you want the -0.45 with the tolerance the other way =-1.05 degree although an active track rat would probably have even a bit more dialed in.

Pick your use and align accordingly.

BTW, some DOT legal road race tires that are used in stock classes have some negative camber baked in since the cars that use them can't get enough negative for the road race use. On the Camaros (both 3rd and 4th Gen) most of us found that anything over -2.25 deg was not an improvement. Remember if your car is knock kneed it doesn't accelerate or brake very well because in a straight line it doesn't have all its rubber on the road. So a compromise is necessary.

Perry

 

[Travelor]

Pfadt Specs

These specifications are from Pfadt Race Engineering for Performance Street settings. I have had these specification on my Grand Sport for 4500 miles and the handling is good and tire wear is uniform - at 6/32" at a total of 6700 miles on GoodYear factory tires.

Front
Camber (deg)
min max
-0.7 -0.9

Caster (deg)
min max
7.5 8.5

Total Toe
min max
-1/16" (0.17°) 0 (0°)

Rear
Camber (deg)
min max
-0.4 -0.6

Total Toe
min max
-1/16" (0.17°) 0 (0°)

Pfadt Performance indicates that these settings will provide good performance and good tire wear.

 

[Tlm2010gsc]

Alignment on GS

These specifications are from Pfadt Race Engineering for Performance Street settings. I have had these specification on my Grand Sport for 4500 miles and the handling is good and tire wear is uniform - at 6/32" at a total of 6700 miles on GoodYear factory tires.

Front
Camber (deg)
min max
-0.7 -0.9

Caster (deg)
min max
7.5 8.5

Total Toe
min max
-1/16" (0.17°) 0 (0°)

Rear
Camber (deg)
min max
-0.4 -0.6

Total Toe
min max
-1/16" (0.17°) 0 (0°)

Pfadt Performance indicates that these settings will provide good performance and good tire wear.

I asked the plant guys when I was in Bowling Green about the alignment and they told me all GS ARE SET FOR TRACKING AND AGGRESSIVE DRIVING and that will kill a set of tires pretty quickly. When I got home I had the dealer who specializes in Vettes concur the alignment is not good for anyone who wants any life out of the tires. I had them redo the alignment to what normal alignment should be and it made a big difference in feel as a DD. i then put Michelin pS2 AS run-flat on and that made a world different car. I actually had rear rims modified to handle the largest michelin made at the time that were both AS and ZP tires. Smooth, quite, and no drone at high-speed.
Tadge J told me in an email they had found that the Michelin's were much better all around over the GY and that was why they went to them on the C7. Another issue was that no one made a 12" wide AS run-flat so the rims on the C7 were made a little narrower to make the michelins work without making a whole new tire design just for the C7. So on the C7 you can get AS - PS2's ZP tires all around. The issue was AS tires rather than just summer tires. I did my 10GS and never looked back. The Michelin still look like brand new on the car. The GY's were junk in 8-10k miles.

 

[Huskerman]

Tim...what do you mean by modified your GS's rear rims? I also was unhappy when I could not find AS tires to fit my 10 GS. I ended up with Bridgestone Potenza RFT's with a revamped alignment and I really like them. I am curious what you did to modify your rims.....or did you buy new off the aftermarket? Thanks........

 

[Tlm2010gsc]

Tim...what do you mean by modified your GS's rear rims? I also was unhappy when I could not find AS tires to fit my 10 GS. I ended up with Bridgestone Potenza RFT's with a revamped alignment and I really like them. I am curious what you did to modify your rims.....or did you buy new off the aftermarket? Thanks........

I bought a set of 12" OEM GS rear wheels and had them professionally cut down about an inch and a half off the inner side. This way the offset on the outside is still identical to the OEM GS as manufactured. There is absolutely no difference in looks unless you look for a 12" wide tire from under the car.

 

[Hib Halverson]

(snip)
Tadge J told me in an email they had found that the Michelin's were much better all around over the GY and that was why they went to them on the C7.

You're exaggerating what Juechter may have said.

It is true that, in the C7 tire contract "shootout", done by GM, Michelin and Goodyear during late-2010-to-early-2011, the Michelin submission tire performed better than did the Goodyear, but it's an exaggeration to say it was "much better." GM subjected Michelin's and Goodyear's submission tires to 16 different tests. Half of them tested performance and the other half tested "non-performance" characteristics such as tread life, ride and noise. GM has been unwilling to disclose the actual scores in the 16 tests, however, in April of '13, when I interviewed Jim Mero, the GM develoment engineer who conducted most of the tests, he said that if Michelin was a 10, Goodyear was an 8. While Michelin was noticeably better, it's an exaggeration to say Michelin was "much better".

Another issue was that no one made a 12" wide AS run-flat so the rims on the C7 were made a little narrower to make the michelins work without making a whole new tire design just for the C7.

That statement is inaccurate.
C7 wheels are the same width as C6 base wheels but are more narrow than C6 GS wheels. The reason C7 base/Z51 wheels are more narrow then C6 GS wheels has nothing to do with available tire widths.

In fact, the new, Michelin Pilot Supersport ZP in P245/40ZR18s and P285/35ZR19 (base) and P245/35R19s and P285/30R20s (Z51) was engineered specifically for the 2014 Corvettes and, in fact are...."a whole new tire design just for the C7."

So on the C7 you can get AS - PS2's ZP tires all around.

You can't buy car that way, but you can buy Michelin, all-season tires, in the C7 sizes on an aftermarket basis. Also, according to Michelin, the recommended all-season tire for C7 is the new Pilot Supersport A/S 3 and not the Pilot Sport 2.

 

[Tlm2010gsc]

You're exaggerating what Juechter may have said.

It is true that, in the C7 tire contract "shootout", done by GM, Michelin and Goodyear during late-2010-to-early-2011, the Michelin submission tire performed better than did the Goodyear, but it's an exaggeration to say it was "much better." GM subjected Michelin's and Goodyear's submission tires to 16 different tests. Half of them tested performance and the other half tested "non-performance" characteristics such as tread life, ride and noise. GM has been unwilling to disclose the actual scores in the 16 tests, however, in April of '13, when I interviewed Jim Mero, the GM develoment engineer who conducted most of the tests, he said that if Michelin was a 10, Goodyear was an 8. While Michelin was noticeably better, it's an exaggeration to say Michelin was "much better".

You weren't part of what was discussed so let's leave what you think someone may have said out of this. Shoot-out ? Now there's an exaggeration. These tire companies like all other suppliers are supplying a product with performance spec at a price. There are far better tires for tracking and all around use but there is a balance to what the spec dictates vs the market they were trying to hit. In the end it doesn't matter much what the engineers may chose if marketing has other marketing motives in mind. Along those same lines it was GY these folks thought were great tires for corvettes on prior models. The GY are may be for performance and but don't have any kind of acceptable life span and are the nosiest tires on the market After 13 new corvettes i can agree with what Tadge told me, the michelin were a far better tire for their choice. I have switch to Michelin every time after the OEM just failed to perform. So much for engineers shoot-out concepts.

That statement is inaccurate.
C7 wheels are the same width as C6 base wheels but are more narrow than C6 GS wheels. The reason C7 base/Z51 wheels are more narrow then C6 GS wheels has nothing to do with available tire widths.

This issue came up when another owner asked me how I handled the rim problem with AS tires on A GS not any other car. The z06, ZR1 and GS all cannot have AS ZP tires on their rear wheels by any manufacturer we explored.

In fact, the new, Michelin Pilot Supersport ZP in P245/40ZR18s and P285/35ZR19 (base) and P245/35R19s and P285/30R20s (Z51) was engineered specifically for the 2014 Corvettes and, in fact are...."a whole new tire design just for the C7."

that's a stretch to say the tires are just for the C7. They clearly aren't and are available to any car or rim they will fit. Sure tire tread design and make-up are constantly being re-visited with each manufacturers needs which is how the Manufacturers meet that performance spec that engineering dictates. The PS2 now the PS3 is a good example. Did Jim mention why they went from a wider better gripping 12" to a narrower tire on a faster car? I asked that question and it was once again marketing who decides what gets ultimately chosen. The engineers are only a piece of a puzzle to what gets built. If they had they're way none of us could afford the vette. The high end vettes are not what GM is going after when it comes to the C7 even though the C7 is quite a fast car at any price. I'm a great example of that according to my conversation. The corvette with GY's cannot be driven in colder climates below 45 degrees without major problems with traction and there is NO option for me to buy any any cost to get a AS ZP tire for my car.

All pre-c7 vettes have summer tire only on them. Talk about limiting the market to only warmer climates for DD's. The C7 is trying to break the poor sales showings of recent years and has to reach out to every segment of the country, hot, warm, cold etc. They had to make changes and the smaller rear rims allowed the AS ZP being available by Michelin as an option for me to use my C7 as a DD and not sit in the garage until a sunny warm day shows up. That's not the only reason but was one mentioned once I got into the whole tire design problem for colder climates.

You can't buy car that way, but you can buy Michelin, all-season tires, in the C7 sizes on an aftermarket basis. Also, according to Michelin, the recommended all-season tire for C7 is the new Pilot Supersport A/S 3 and not the Pilot Sport 2.

That is true BUT these are not just AS but also ZP as well and as least now I can buy a C7 and switch to them as an option for colder climate and safer driving of the car. Never had that option before with the GS unless you did what we did to our 2010GS which gets very expensive to say the least. I just that makes me a new buyer who decided that the c7 is my next Corvette. # 14 and counting.

 

[mikeCsix]

Wheel alignment camber

After reading the comments and from my own experience, negative camber numbers are less of a concern for tire wear than toe. too much toe will wear the tires much faster.

I'm an hpde enthusiast, ran six events last year and one event the year before. I run in groups 'B' and 'C'. I'm on my original set of GY Supercars and run -.95 camber in front with minimal toe. I have 14k miles on the car. With the rubber bushings in the suspension, camber jumps all over the place and it will likely be different nearly every time you put the car on an alignment rack. My tires are getting to the point where they need replacement (could do maybe one or two more events) and I have more wear on the outside of the tires than on the inside indicating I need a bit more camber - perhaps -1.2 to -1.5. I also have the pfadt camber plates which lock in the adjustments.

My suggestion is to do the pfadt street performance which is within the FE3 specs with minimal toe (you want a little to aid stability) and you should get good tire mileage.