rwatson5651

iTrader: (5)

So I am about to mount new tires and will do a front end alignment and would like suggestions as to exactly what the best specs would be. My car is a '79 with a respeed rack, coilovers, camber plates, Racing Beat strut tops running 15x7 tires. Mainly street driven, but usually driven fairly hard.

I dont want to just use the stock numbers because it makes no sense to me to run positive camber. Never understood why the stock specs called for it. I do my own alignments and have been running about 3/4 degrees neg camber but was beginning to get some inside tire wear. How much do you guys think I can run without uneven wear? I would also like your thoughts on toe and caster.....

-xlr8planet-

iTrader: (3)

you use 3 or 4 degrees of camber in front?

I´ve only seen use that in race cars

THE most aggressive I´ve seen on the street is 2,5 degrees

rwatson5651

iTrader: (5)

three quarters of one degree.

DivinDriver

iTrader: (15)

I for one would be very interested in knowing the methods/tools you use for DIY caster/camber setup.

rwatson5651

iTrader: (5)

First I used some plastic tubing to measure how unlevel my shop floor was, then I used asphalt tiles under the wheels to make sure the car is level accurate to the mm. Then I made a jig out of square aluminum tubing and mounted a digital level to it. That gives you the camber, good to the tenth of a degree. Then you turn the wheel all the way to the left or right and zero the level and then turn the wheel to the opposite lock, that gives you the caster. Here is a pic:



Then I use a string to set the toe.

Now all I have to do is determine the ideal specs for a re speed front end without ruining a set of new tires.......

j9fd3s

iTrader: (3)

the stock +1 camber is just to make it understeer... if you are seeing some inside wear @-.75 then maybe back it off to -.5?

caster isn't that adjustable, so as much as you can get. stock is about 4. if you can get 5 it should be more stable, its a subtle adjustment, so the difference is probably really small.

toe; since you have the rack that changes things a little, but a good starting point is always zero toe. toe out, should make it turn in better, but it'll be less stable on the freeway. toe in is the other way, its stable, but turn in isn't as good.

on most cars toe is really easy to play with, because you can adjust by flats, but the SA/FB isn't that easy. might be worth to just try it anyways.

camber you can go by tire wear, the toe in/toe out is mostly driver preference

Re-Speed.com

iTrader: (3)

This is what I run in my car:



Now a couple of things to note:

1) Camber will really depend on what tires your use and your intended use of the car. Some tires like more and some like less. Street tires are usually less than race tires. I was running 225/45 R15 tires and thats seems to work best over all, I can snag a picture of what my tires look like now after being done for and you'll notice that its pretty even all across. With me doing a considerable amount of racing, I think that helped out on the wear and it was also daily driven with those tires too, long hauls too. I think I made it out from Ontario Canada to Florida with them. I certainly made it out to Alabama with that alignment setup.

2) Caster, just to correct j9fd3s, with the rack kit since the stock tension rod is taken out the rear lower adjustments allow for a bit more caster than the tension rods. I think that the maximum safest that I was able to get (about 5 threads or so still into the arm)

DivinDriver

iTrader: (15)

Brilliant.

I can invision a dodge where doubling the lower arms so they can clear front/rear of the tires, and then slotting them, would allow two steel tape measures to provide for direct toe measurement by taking their difference.

Off to Home Depot I goes...

Brigdh

iTrader: (9)

Jeez, thats a ton of dynamic caster from your camber. You have nearly even tire temps with that setup in the front?

rwatson5651

iTrader: (5)

What I did to set the toe was first determine the center of the car. I did this by measuring things like the front nose piece and some areas at the rear of the car where body seams let me determine the exact center, then measured an equal distance out to the side that clears the tires by about a half an inch or so and then stretched a string from front to rear and used that as a reference line to check the toe. I havent bothered to figure out how to convert my measurements to degrees. In the day people just refered to toe in inches, now they talk about degrees and I cant corrolate the two in my head. One sixteenth toe is how many degrees? I dunno. I know it depends on the diameter of the wheel, but I havent bothered to convert it. But I digress.

Any way I made some jigs with plumb bobs to hang on the bumpers that let me quickly check the toe without complicated set up.

rwatson5651

iTrader: (5)

I have a question...... Should my street tires tolerate .75 neg camber without inside wear? (Yokahama S Drives)

To get rid of tire wear worries should I run zero or almost zero camber?
I would hate to do that as my front end really sticks with what I have been running, but I do not want to ruin a new set of tires. Thoughts?

Re-Speed.com

iTrader: (3)

I honestly can't answer that, every tire is pretty different. How many miles have you driven on them before noticing the wear? You do have to keep in mind that with more camber you should be rotating your tires also a bit more often just so that it doesn't happen.

As for running zero camber, that will help with wear, but front end grip is also compromised if raced.

Here's a pictures of my tires with those specs. Now you will notice that one tire has heavier wear than all the rest on the edge (Its an outside edge btw and not an inside one) the reason for that is because the one track that I normally go too has all the high speed turns as right hand turns wearing out the one tire more than all the rest. I will admit had I rotated the tires more often at the track it most likely wouldn't be as bad as it is now.