Autocross R-comp tire wear issues

Hey guys, I am curious about some ideas on tire wear on my car. I know that front wheel drive cars tend to be hard on front tires, but I get the feeling as though mine is a bit excessive. I am running Kumo V710's. 225/50-14's on some 14x6 rims. My car is a V6 powered mazda 323. It weighs in around 2200 - 2300lbs.. I have a build thread going here on the site for it with various different videos including some of my front and rear suspension in action.

After this weekends double header I noticed a fair bit of wear on the inside half of the tread on my front tires.. In 8 runs today I figure I went threw about .5 - 1/32 worth of tread. It was a very noticable amount of wear.

alignment wise I run 5.25 deg caster, 3.25 deg camber, very little toe out in the front.. In the rear I run 2 deg camber with 0 toe..

I am sure some of it has to do with over driving, but I am not sure what kind of life I should be expecting out of V710's, or if I should reduce some of my camber/caster.. At this rate of tire wear I can't afford to keep running this car with r-comps..

Rotate front to rear after each event? And/or flip the tires on the rim to move that wear to the outside?

Assuming those tires haven't seen anything else other than autocross runs, here's a few ideas.

1.) Did you use tire temps to set the camber? If not, I'd start there. While -3.25 degrees doesn't sound excessive, it's possible.

2.) How much toe is "very little"? With that much camber it doesn't take much toe to really chew up the inside edge.

3.) What bushings are you using? Could there be enough deflection to cause significant dynamic toe, and thus accelerated tire wear?

Do you have serious wheelspin issues? That can really wear the inside edges with that much negative camber.

Spoolpigeon wrote: Rotate front to rear after each event? And/or flip the tires on the rim to move that wear to the outside?

I have been rotating front to back after each event..

petegossett wrote: Assuming those tires haven't seen anything else other than autocross runs, here's a few ideas. 1.) Did you use tire temps to set the camber? If not, I'd start there. While -3.25 degrees doesn't sound excessive, it's possible. 2.) How much toe is "very little"? With that much camber it doesn't take much toe to really chew up the inside edge. 3.) What bushings are you using? Could there be enough deflection to cause significant dynamic toe, and thus accelerated tire wear?

1) I haven't used a temp gun yet... Its on my very short list of tools to add to my tool box for next season.. Specifically for the reasons you are getting at...

2) 1/32 - slightly less... I have not had any issues with my street tires showing signs of toe wear or excessive camber wear with this alignment set up.. I have put about 10,000km's daily driving on the car with this set up..

3) My front control arms have custom milled sleeves with spherical bearings installed... I did a video yesterday of my front suspension.. It didn't show any flex in the control arms but my front subframe is flexing.. looks like I need something better then the factory tie brace..

Jim Pettengill wrote: Do you have serious wheelspin issues? That can really wear the inside edges with that much negative camber.

I have a KAAZ lsd in the transmission and it feels like its working great... I am not getting any noticable wheel spin when getting on the gas on corner exit...

Have you ever checked the bumpsteer?

Knurled wrote: Have you ever checked the bumpsteer?

No I haven't... I have never checked bumpsteer on a car before...Not to sure if I under stand the best way to do it either..

I understand that I would be looking for steering angle changes as the suspension cycles up and down.. I understand that if my lower control arm and tie rods aren't moving up and down in the same arc parallel to one another that this can be a cause for bumpsteer issues... but thats about as far as my working knowledge goes on the issue..

As far as I can tell my car isn't having any bumpsteer related issues... The steering feels smooth as the car rolls over when entering a corner.. I don't have to add or take away any steering effort to keep it under control.. mid corner if I hit a bump the car stays planted and controlled.. The car doesn't has no odd tendancys related to steering control..

Any other idea's or info on things to look for would be great though..

With that much caster, run less camber. Caster increases the negative camber on the outside wheel. Turn your wheels 15 degrees to the right or left and measure the camber.

Thanks guys for the idea's... Next event is in a little over 2 weeks.. So I'll try making some alignment changes and probably update my build thread with the results..

Any more idea's or discussion on the issue or suspension set up in general is welcome..

Hey guys, bringing this thread back up now that I am home from holidays...

I took the car down a local alignment shop I deal with and had them check things out.. I happened to work at this shop for a little while, so I know all the guys there and get to be hands on helping set things up..

The rear springs had settled a little bit causing some light toe out in the rear, but the front had pretty much stayed the same... We checked the front camber curve on turn in.. My camber went from 3.25 to just over 3.5 deg.. It stayed at just over 3.5 until about 20 deg, then it started to drop in camber...

I have to disassemble the front struts in order to change caster, so for now I decided to remove some camber up front.. In the end I decided to make a bit of a drastic change and went down to just over 2.25 deg camber... Front toe ended up getting set up at just under 1/32 so essentially 0 toe up front.. we also reset the rear toe to 0...

We'll see how the tires do at the next event on july 27th.

iceracer wrote: With that much caster, run less camber. Caster increases the negative camber on the outside wheel. Turn your wheels 15 degrees to the right or left and measure the camber.

+1 for this. Static negative camber is the worst kind of negative camber, use less.

Also did you say you're running 225 wide tires on 6" wide wheels? Did you need some kind of hydraulic press to squeeze those on there? You should be using at least 8" wide wheels with those unless they're cantilevered.

GameboyRMH wrote: Static negative camber is the worst kind of negative camber, use less.

Why do you say this?

Even on cars like Miata's with decent camber curves and dual-A arm setups, the really fast guys are approaching -4° static camber in the front, even though the car picks up more under compression.

Static negative camber isn't ideal for driving in a straight line, it's that simple. The best way to get negative camber is dynamic camber through a good camber curve (not too easy to change after the car's been designed), the next best way is to get more when the wheels are turned with caster.

Not saying you can't have a fast car running a ton of negative camber...but it's far from an ideal setup in the grand scheme of things.

GameboyRMH wrote: Static negative camber isn't ideal for driving in a straight line, it's that simple. The best way to get negative camber is dynamic camber through a good camber curve (not too easy to change after the car's been designed), the next best way is to get more when the wheels are turned with caster. Not saying you can't have a fast car running a ton of negative camber...but it's far from an ideal setup in the grand scheme of things.

Unfortunately, this is a BG chassis car with MacStrut suspension. Static camber is what he needs, and lots of it. Then the trick is to make the suspension not move enough so it doesn't change much.

Camber itself won't cause a ton of extra wear, even when driving in a straight line.

I think there's something else going on here, and if my car were up and running, i'd be able to give some more useful input, but it's not, so i can't.

I'm thinking he should try maybe -2.5. I know quite well that with macstruts you don't really have a choice but hard springs + static negative camber to make the car handle...but running big caster and exhibiting the classic symptom of excess negative camber, he should dial it down.

GameboyRMH wrote: I'm thinking he should try maybe -2.5. I know quite well that with macstruts you don't really have a choice but hard springs + static negative camber to make the car handle...but running big caster and exhibiting the classic symptom of excess negative camber, he should dial it down.

Thats what I have done... in my last post I talked about checking my camber curve with the wheel turned...

I dialed the front camber back down to -2.25" deg...

Here guys... If you haven't seen them in my build thread.. Here are some videos of my front and rear suspension in action...

Rear suspension... http://www.youtube.com/watch?v=UuZYAAWCEb8&list=TL6V9ZWRZFfO8

Front suspension.. http://www.youtube.com/watch?v=i43xkRD3p6w&list=TLq3sJ6d-f3rA

Whoops, shoulda checked the date of the first post haha

GameboyRMH wrote: Also did you say you're running 225 wide tires on 6" wide wheels? Did you need some kind of hydraulic press to squeeze those on there? You should be using at least 8" wide wheels with those unless they're cantilevered.

in stock class this is quite common (you have to use OEM size rims)

a former national champion in D Stock (Integra Type R) was cramming 275's (as best as I can remember) on stock sized rims ( 6 1/2" maybe 7" )

Hoosiers are fine like this ... street tires don't do so well pinched

GameboyRMH wrote: Static negative camber isn't ideal for driving in a straight line, it's that simple. The best way to get negative camber is dynamic camber through a good camber curve (not too easy to change after the car's been designed), the next best way is to get more when the wheels are turned with caster. Not saying you can't have a fast car running a ton of negative camber...but it's far from an ideal setup in the grand scheme of things.

On the average road course, or auto-x, you spend more time turning than you do on the brakes. So it's a worthy compromise.

On my ZX2SR I ran 2.5 degrees neg. camber , about 4 degrees caster and 0 toe. I ran 205/50 Hoosiers on 7" rims. I ran Hoosiers suggest pressures, forgot what that was. at a track day tire temps were even all across. Heavy rear bar so it didn't lean much.

crazycanadian wrote: ... The rear springs had settled a little bit causing some light toe out in the rear...

This bothers me... it means there's a lot of bumpsteer in the rear suspension, which can be a real bear. Bumpsteer at the front is an annoyance, but bumpsteer at the back can cause serious handling problems (spinning, mostly), and odd tire wear if there's a lot of it.

kb58 wrote:

crazycanadian wrote: ... The rear springs had settled a little bit causing some light toe out in the rear...

This bothers me... it means there's a lot of bumpsteer in the rear suspension, which can be a real bear. Bumpsteer at the front is an annoyance, but bumpsteer at the back can cause serious handling problems (spinning, mostly), and odd tire wear if there's a lot of it.

I am not to worried about it.. I haven't had any problems with the rear of the car doing funny things...The only time I have a hard time with the car being loose is when I lift off the throttle while trying to make a quick transition(When I have over driven an element).. Or if I over drive the car on cold tires...

If I do have bump steer issues in the rear then its from the factory TTL design,

Might as well post up pics of my tires... These were not brand new tires when I picked them up.. but they were evenly worn...

LF.. The course was more right hand corner heavy... This is why the LF has the most ware...

RF..

LR tire.. both rears were evenly worn..