What rear suspension and why?

GTXVette wrote: check out a cup car rear end they have a crazy amount of camber and toe,and you can buy em cheap round charolette and Kannapolis

I don't know about crazy amounts. The limit for them is about 4 degrees of combined camber and toe, with axle splines cut to allow the angles. But still 4 degrees in a 'straight' axle is a lot. The rules have been set so that the parts don't get too crazy, because if allowed they would run more and break more often.

gtx: as much as I would LOVE to play with a floater, were at 1k and counting, and the car isn't even starting to go together yet. not in the budget. now, if there's a way to add camber and whatnot to a non-floater, I'm all ears. bend the axle tubes and bevel the inner splines with an angle grinder just doesn't sound like the ticket here....

Crackers wrote: Is it possible to get even tire wear out of a live axle though? Pretty well all the live axle cars I've driven/worked with wore the outside edge excessively. I have been led to believe that it was an inherent quality of live axle cars, but have no real data to back that up.

I recall reading somewhere that optimal grip comes with the tire at half a degree of camber relative to the road. Or maybe it was 1.5. Either way, this figure can't be an absolute because different tire construction and shapes will deflect differently, but there you go.

"But I run -3 on the front of my car and it needs more!" Yes, and you have to compensate for body roll, which a solid axle doesn't care about, just tire flex/compression.

You can get a half degree of negative camber with tweaked axle tubes, more than that and you really need to go with a full floater and barrel splined axles.

Curiously enough, the first RX-7 I had had -.5 degrees in the back, and it was really bad for wearing the INSIDE, no matter how much I "tested the envelope"...

Knurled wrote:

Crackers wrote: Is it possible to get even tire wear out of a live axle though? Pretty well all the live axle cars I've driven/worked with wore the outside edge excessively. I have been led to believe that it was an inherent quality of live axle cars, but have no real data to back that up.

You can get a half degree of negative camber with tweaked axle tubes, more than that and you really need to go with a full floater and barrel splined axles.

Please go on...

In reply to Knurled:

Half a degree of camber relative to the road when? I'm guessing in a corner, obviously, but are we talking under load at full tire flex/compression?

Technicalities aside, that would imply that even tire wear isn't necessarily a good thing wouldn't it?

Crackers wrote: In reply to Knurled: Half a degree of camber relative to the road when? I'm guessing in a corner, obviously, but are we talking under load at full tire flex/compression? Technicalities aside, that would imply that even tire wear isn't necessarily a good thing wouldn't it?

For maximum lateral grip, given that the tire will distort under the wheel.

"Even tire wear isn't necessarily a good thing" is opening a HUGE philosophical can of worms... Given that tire makes maximum grip at a given slip angle, and that given slip angle is also dependent on the vertical load on the tire, and (by definition) the two tires on a given axle aren't getting the same vertical load... How do you set TOE? And then you change the roll stiffness end-to-end and this mucks things up again if you had toe figured out the first time...

Toe affects tire wear waaaaay more than camber does!

I say, hang the sense of it and just do testing and see what works. Or do what the people who go fast are doing as a good starting point.

OK so one more thing .... Heat and air pressure, that is a tale tell way to read tires and what you want is uniform heat across a tire. getting there is not as easy as it may seem

I liked the equal length 3 link I did on the corolla,never played with shorter/longer 3rd link though and kept it parallel with the lowers.No wheel hop or other weirdness so I left it.

I did very much like the idea of a LONG tq arm but I wasn't confident I could make it strong enough at the diff without weighing a ton so went 3 link.

I found most of the rear grip improvement with adjustable panhard mounts(yes both ends need to be adjustable)and a significantly lower RC.

Also it was mentioned earlier in this thread that a solid rear axle is awesome as it doubles as a sway bar....umm no.