I have an 85 Monte Carlo street car with a 350sbc. I’ve got 2 inch drop springs and billstein shocks. In the front im running 18x8 wheels on 245s and in the rear im running 18x8 on 265 tires. What alignment spec should I go for here?
Best alignment specs?
- Thread starter Irishspring46
- Start date
Unfortunately, this can only be solved by someone who has done this for a long time, basically, an old school alignment guy! A few months ago, I took my 87 El Camino to a shop that had this old school guy. He told me that today most alignment "specialists" only know how to follow the lasers and specifications displayed on the alignment machine! They don't correlate (and maybe know) how the laser measurements and adjustments relate to toe-in, camber, and caster and, most importantly, vehicle road performance.
There will be 'specs' for your specific application ('85 Monte Carlo). They'll be a starting target point.
Typically, GM & other OE manufacturers set the cars up to be 'safe' which equals slowing the masses (avg drivers) down where possible. One way of doing so was using specs that cause cars/trucks to push in a steady-state corner (on/off ramp to/from a highway). That push sensation puts fear into the driver & you want to slow down. The zero to +1° Camber target as well as a low +1° to +3° Caster spec will yield that 'push' feeling.
That being said, it's easy to get more out of an alignment. The OE spec of Camber that helps slow people in turns also does not wear aggressively on the tires. You want to go the opposite way & target zero to -.5° Camber. The negative Camber helps keep the tire flatter in a turn @ speed. The car will feel more planted @ higher speed.
Current vehicles use much more Caster vs older stuff. Think of Caster as the vehicles ability to track straight when on straight stretches of roadway. You want it to track straight vs constantly/easily wandering left or right. High Caster targets yield that goal. So you'll want as much Caster as the alignment guy can dial in while maintaining the -.5° Camber goal.
The 3rd alignment spec target that can cause accelerated wear is TOE. The front wheels can be pointed in toward each other aka 'Pigeon-Toe'd' ( / \ ) or out ( \ / ).
Target 1/16" - 1/8" total TOE IN so that as the vehicle pushes forward down the road surface the pressure/friction between the 2 surfaces put the tires even/straight. Tire sizes/width play into this so there's no 'one size fits all' number. Typically, the heavier the tire combo, the more TOE In it might take.
Typically, GM & other OE manufacturers set the cars up to be 'safe' which equals slowing the masses (avg drivers) down where possible. One way of doing so was using specs that cause cars/trucks to push in a steady-state corner (on/off ramp to/from a highway). That push sensation puts fear into the driver & you want to slow down. The zero to +1° Camber target as well as a low +1° to +3° Caster spec will yield that 'push' feeling.
That being said, it's easy to get more out of an alignment. The OE spec of Camber that helps slow people in turns also does not wear aggressively on the tires. You want to go the opposite way & target zero to -.5° Camber. The negative Camber helps keep the tire flatter in a turn @ speed. The car will feel more planted @ higher speed.
Current vehicles use much more Caster vs older stuff. Think of Caster as the vehicles ability to track straight when on straight stretches of roadway. You want it to track straight vs constantly/easily wandering left or right. High Caster targets yield that goal. So you'll want as much Caster as the alignment guy can dial in while maintaining the -.5° Camber goal.
The 3rd alignment spec target that can cause accelerated wear is TOE. The front wheels can be pointed in toward each other aka 'Pigeon-Toe'd' ( / \ ) or out ( \ / ).
Target 1/16" - 1/8" total TOE IN so that as the vehicle pushes forward down the road surface the pressure/friction between the 2 surfaces put the tires even/straight. Tire sizes/width play into this so there's no 'one size fits all' number. Typically, the heavier the tire combo, the more TOE In it might take.
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Do not let a shop set your car up to factory specs. My alignment guy had a 30 min conversation with me on what my intentions, expectations and use of the car was before he chose some numbers. Also must be considered is the suspension and tires. Once that is known. Choosing some numbers then setting them is the next step.
UMI gave me specs with my control arms. They pretty much mimicked what scoti said.
A tiny bit of neg camber. More equals increased tire wear, especially with wide tire but the payback while cornering is huge.
UMI gave me specs with my control arms. They pretty much mimicked what scoti said.
A tiny bit of neg camber. More equals increased tire wear, especially with wide tire but the payback while cornering is huge.
^^ This.^^
If they tell you this is all they can do, you're @ the wrong place.
FWIW..... The CC Dually in my member avatar is @ these specs:
NEG .5° Camber
POS 6.9/7.4° Caster (staggered for roadway crown)
1/8" TOE In
It will take a turn (on/off ramp) like a single cab sport truck despite using OE size load rated tires.
Answered some of this in the other thread you started Ref: Vibration.
Not to confuse, but I mentioned bringing it more positive camber..., that's based on getting specs closer to where it should be and as the others have said negative .5 seems to be where it should be.
On the vibration issue I didn't get into to toe setting and reading from the above you significantly added to the foot print of the tire. That is the actual section of tire making contact. And yes, toe in is something that needs looked at as well as the increased friction will move the tires out probably more than the original OEM design. If you get too much toe out, you are scuffing the tires as you drive forward, and yes that can cause the vibration. If you get the IR thermometer I mentioned you can see the difference.
Old school days I used a Hunter rack, but even then I used my hand to feel for hot spots. So I would setup per the spec then test drive and adjust until I could feel even heat across the tire, felt by hand. We didn't have the tech we do today. I certified NIASE before it was ASE, and first job specifically hired for alignments. Did several hundred..., hated every one.
On my Caprice I'm finishing I was thinking of similar setup as you have, but looking at cost and other issues, I am going to keep with 7 inch on the front and just increase to 8 on the rear. I had thought about 9s but cost just doesn't justify. I had thought about drop but decided to just stay stock. If I go onto full on show car I'll probably do the same or similar to your setup but then it will be more of a trailer queen, just because of some of the issues you mention.
Not to confuse, but I mentioned bringing it more positive camber..., that's based on getting specs closer to where it should be and as the others have said negative .5 seems to be where it should be.
On the vibration issue I didn't get into to toe setting and reading from the above you significantly added to the foot print of the tire. That is the actual section of tire making contact. And yes, toe in is something that needs looked at as well as the increased friction will move the tires out probably more than the original OEM design. If you get too much toe out, you are scuffing the tires as you drive forward, and yes that can cause the vibration. If you get the IR thermometer I mentioned you can see the difference.
Old school days I used a Hunter rack, but even then I used my hand to feel for hot spots. So I would setup per the spec then test drive and adjust until I could feel even heat across the tire, felt by hand. We didn't have the tech we do today. I certified NIASE before it was ASE, and first job specifically hired for alignments. Did several hundred..., hated every one.
On my Caprice I'm finishing I was thinking of similar setup as you have, but looking at cost and other issues, I am going to keep with 7 inch on the front and just increase to 8 on the rear. I had thought about 9s but cost just doesn't justify. I had thought about drop but decided to just stay stock. If I go onto full on show car I'll probably do the same or similar to your setup but then it will be more of a trailer queen, just because of some of the issues you mention.
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There are DIY kits out there that allow the home guy to do their own alignment. But it's much harder @ home than it is for the guy w/the digital stuff on a rack @ a pro-shop & it can be a PITA for them so pick your path.
I usually put a digital level on the wheel lip/hub to get Camber close & then have some cheap homebuilt stands I use to dial in TOE enough to go get things checked w/a digital/laser set-up. It's Caster that's more difficult to measure & adjusting one area can impact the other two. The higher-end DIY kits have turn plates which are necessary to be more accurate.
unfortunately alignment shops aren't what they used to be(or as prevalent for that matter) and the end result is big box store drive through(set the toe/let it go)mentality so a lot of places aren't actually staffed with personal as much as they used to be that can/would have the mindset taylor the specs for your benefit.do some local checking around,ask at parts stores,machine shops,race tracks,car shows etc where there's a good place to get your OLDER car lined up.that worked out for me.
I DIY'd the alignment on mine, but, this ain't my first roh-day-oh either. I only had enough shims for -.3 camber and have futzed with caster until the car goes straight down the road while making sure camber isn't running away one way or thebother. And of course roughed in toe, final toe will come when I get the steering wheel installed properly as I'll want the wheel centered. IMO setting the toe and getting the wheel centered is the biggest PITA.
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