rceron

Sorry if this is long.

Just got back from a VIR event this weekend. I've noticed that I have been getting wear only on the outside of my khumho's based on 2 VIR and 1 Mid Ohio event. So recently I changed my neg camber to 2.5 and 2.25 front and back, respectively. Incidently, I run 17 X 275s all around and 650 lbs springs in front and ~400 in back. Based on discussions with 2 other FD track junkies I decided to try the aggressive neg camber alignment. Well, my tire wear did not change after this event.

Since this was a test and tune event, there happen to be a RX8 race team there out of Florida. The "engineer" from the team stated that Victoracers and Toyo RA1's have TOO SOFT of a sidewall and that I was rolling the tires. I told him that I ran tire pressures STARTING at 28 and then at 33 on separate occassions with no difference other than seemingly less grip with 33 lb pressures. He stated that race teams who had to use these tires ran neg cambers of 4 degrees. I was shocked. Is this possible? I'm skeptical since there are tons of people running these tires and they can't be all running such high neg camber settings.

Any thoughts, insights to this commentary would be much appreciated.

BTW, I have stock bushings and the pillow "bushings" have been replace. Only for reference, I'm running 2:17 - 2:19s on 10 lbs of boost on stock turbos and brakes.

thanks,

Ramon

DamonB

What width wheel are those 275's on?

When you say outside wear, how much of the tire width do you mean? 1"? 2"? Half the tread width?

What are you calling wear? Is the inner half of the tire not wearing as fast as the outer? You will certainly see marks clear over the shoulder and onto the sidewall if the tire pressures are good but you won't actually wear through it.

In the scheme of things I'd say Victoracers have "average" sidewalls. They are certainly stiffer than the V710 but typically softer than Hoosiers.

I've run several sets of Victoracers at 1.7* to 2* negative camber and have never had wear problems but those were 245/45/16 on stock 8" wide wheels. In my experience your camber settings should be just fine.

If you made the camber change after the tires were already badly worn the tire will continue to wear anyway. If the outers are worn considerably more than the inners flip the tires on the wheels and run them again.

Tire wear issues are always best solved with a pyrometer. Anybody have one you can borrow?

rceron

Thanks for the input. I'm running 10" wheels. Also, the wear is about 30-40% on the outside and the inside looks practically new. I didn't realize that once the tire begins a certain wear pattern it is hard to change. On the outside halves, the wear has not passed the arrow indications on the sidewall so I suspect the tire isn't under inflated.

I heard that some people flip the victoracers. Maybe I'll try that.

Thanks Damon.

DamonB

Can you post some pics of the tread?

rceron

No idea how to paste pics on the forum. If you pm me with your email I can send some once I remove all the gravel off my tires :-)

thx

DamonB

As long as the pics are under 100K you can upload them here. Click on "Post Reply" and then click the grey "Manage Attachments" button. A new menu will pop up and you can browse and select the pictures you want to post from your computer. Click "Upload". Once the pic(s) uplaod close that menu and then click "Submit Reply".

I'll PM you email too.

John Magnuson

Same here.

DamonB

I just thought of something. Have you ever had Victoracers before? When they are brand new if you look at them closely you'll see that the depths of the grooves cut into the tire tread are more shallow on the outside half of the tire than the inside half. This is so that as the tire wears the outer half will essentially become a full slick and the inner half will have what appears to be some "tread" left. As they wear the outer half will be nearly smooth, the inner half will display tread blocks and the extreme edges will still display tread blocks as well. As the tire is continually run through its life the entire tread face will become smooth.

The rubber is the same thickness everywhere around the tread carcass, but it can appear the outer half is more worn if you're just looking at the tread grooves and don't realize the outer and inner tread are molded to different depths. This is just how Victoracers are built and is not a problem.

Look very closely at this pic from Tire Rack. You can see that the outer tread has shallower grooves than the inner tread. Is that what you're seeing?

23Racer

Don't know if it is relevent, but I have always got that severe outside rib wear on my Toyo RA1's. I have tried bumping up my negative to almost 5 degrees and the wear was reduced but braking ability was reduced as well. I have also played with tire pressures and found that the optimum pressure hot was approx 41 pounds. Until the tire gets hot and the pressure builds it will roll over and actually take a fold about 1 inch from the outer edge.

I control it know by trying to start races with about 32 lbs of pressure and not let the car understeer through the slower corners till the pressures build up, about 2 laps. You can tell when the temps come up as the tires become more progressive and the car is less jiggly (or for our Fresh Prince fans, JIGGY).

These are RA1's on 15x7 inch wheels and by the way I generate over 1.2G's steady cornering grip on my datalogger on the lower grip, but more durable Toyo's.

ptrhahn

iTrader: (9)

Ramon,
I'm having the same experience with victoracers, having run them for the first time this season, a total of 7 days this year. I was chalking the outer wear up to having the car set to 18" wheel setting (less camber), and having run the car up 1-2 spins on the GC's to get the fronts to stop rubbing (further lessening the camber). I'm running them on 9.5" SSR's, same sizes, 275/40/17. I've only ever run them at 32 psi cold

I'd be surprised if i'm rolling them over, since there's no tell-tale sign of wear PAST the appropriate place on the tread.

rceron

THanks guys. I will try to post a pic but I don't think I can get under 100K.

So, it seems that the "engineer" from the RX* race team is exaggerating the need for neg camber with these tires. This is what I thought since this issue would have surfaced already in this section of the forum.

There is always Michelin Pilot Cups but they are very expensive....

Fritz Flynn

iTrader: (263)

Wider tires require less camber so with that in mind you're running some VERY aggressive settings hehe

Regarding tire pressures just keep checking wear as you come in against the pressure and do the best you can with the settings you have. Increased pressure will only affect grip if you're getting a smaller contact patch. You may have been sliding more based upon a slight increase in speed through the corner because of better traction. That might sound crazy and possibly you had a less tire on the road but usually I find maximum grip with a stiff tire. I try to get my tires up to 43 or 44lbs once fully warm.

This is my motto for most big corners and this should reduce wear on the fronts; go in hot rotate the *** and get back on the gas and RAWK

IOW try not to over brake (go in slow) and push coming out of long turns killing those tires. Any time you're asking those front tires to turn your grinding away at the leading edge.

jrx13

iTrader: (3)

Do you know what toe setting your using? I always find toe wearing out tires faster than negative camber.

-Jack

rceron

Here is my left rear tire. Sorry about all the gravel stuck on the tire.

rceron

Another. Also, I don't think I run any toe in the rear. Minor toe-in for the front.

rceron

Fritz, the aggressive settings in the rear felt awesome in turn 1 and at oak tree.

John Magnuson

I wouldn't worry too much about it. Sometimes wearing more on the outside is sort of inevitable. Just wait until they're half worn down and then have them flipped around.

Icemastr

iTrader: (2)

It is hard to tell from a picture but it looks like the tire is wearing fine to me. You do realize that the outside straight treads are not as deep as the inside zig zags right? Looks like you are getting maybe a tad more wear on the middle 2/3 of the tire from that picture. I have 225/50/15 Victoracers on 15X8's and I love how stiff the sidewalls are and I have gotten nearly perfect wear on them with -2 camber front and rear. Noticeable stiffer sidewall than the 225/50/15 V710s, but not as sticky.

Fritz Flynn

iTrader: (263)

Ramon,
Whatever works is all that counts. If she feels good then don't change a thing.

If you have to flip those tires with those camber settings I'll send you whatever part you need to fix it cause something is broke LOL

DamonB

Those tires are fine. The difference in the molded tread depth I mentioned earlier is tricking you into thinking the tires are wearing funny.

DamonB

With as much negative camber as we all use toe out or toe in will always wear the insides of the tire, not the outsides. You're right though. Toe wears the rubber much more quickly than camber. With zero toe even a cambered tire still rolls freely down the road. As soon as we add toe in or out we are forcing the tires to constantly scrub since they never face in the true direction the vehicle is traveling.

artowar

iTrader: (1)

That's no bug-- it's a feature!!

Get your next set shaved and it will look like a slick on the outer part of the tread.

I'm trying to find some old literature on the BFG R-1, from which I believe the Victoracer was copied. One of the R-1 design features was a negative camber effect to benefit cars with little or no adjustable camber. On a car with more adjustment range, supposedly you would not need as much negative camber as other comparable R-compound tires (of the time).

I also recall that the R-1's wear issue was called the "Evil Groove of Doom" or "EGOD", where the area around the groove just inside the big outer tread blocks would wear out too quickly. If the Victoracer copied the construction of the R-1 as well as the tread design, this may be something to watch out for (I'll post links to EGOD if I can find anything decent). Some autox'r here must have heard of or seen the EGOD...

artowar

iTrader: (1)

Here's a handy Tirerack page for track tires:

http://www.tirerack.com/tires/bfg/bf...ing_gforce.htm

Some old EGOD information:

http://www.audifans.com/archives/1998/08/msg02909.html

http://members.rennlist.com/944sandmore/traktire.htm

Unfortunately, I can't find a picture of the EGOD...

Fritz Flynn

iTrader: (263)

The groove of doom has been passed on to the victos. I'll post some pics of 2 sets I went through in 6 track days. Both sets were slightly used before I put them on my car but the GROOVE OF DOOM is highly visible in all 8 tires.

John Magnuson

Wow... 6 track days on a set of Victos? I've never gotten more than 4.

Edit: Ohhh... do you mean you went through 2 set in 6 track days? (3 track days per set) If so I don't feel so bad.