RS4 chunking....what are we doing wrong??

We ran our 1st enduro of the yr this past weekend,freshly minted civic EG hatch.We won the 7hr by 3 laps and the 8hr by 2 laps so its not a slow car but we averaged laps 8 to 10 seconds slower then its capable of to manage heat,fuel,tire wear etc etc.

 15x9.5 wheels with 245's,K20 power and factory lsd,-3 camber,1/16" toe out and hot pressures mostly at 28 to 30 but we did run a couple stints at 35 hot to see if that helped...no change.

 Judging by the wear its a bit too much camber but not by that much,rest of the tire looks great but the inner 2" is pretty much missing with all the chunks.

 Hoping one of you guys have the answer 'cause clearly we're doing something wrong.

Camber wear is usually pretty even across the face of the tire, it sounds more like too much toe in.

*edit* Generally speaking, you need more toe out as camber increases due to the thrust load generated by the camber angle.

We had a bad time chunking the inner edge of RS4's, but I chalked that up to being a combo of not enough tire, not enough wheel, and maybe not enough pressure. You seem to be fine in all those aspects, so I don't know what to tell you. Plenty of other people don't have this problem, so at least in our experience I blamed myself not the tire. 

What does the pavement look like where you raced?  The difference between WW2 airport asphalt and fresh stuff is amazing.  At Gimli, my tires looked like squirrels had been chewing on them.

In reply to red_stapler :

Agreed, assuming that's 1/16" total, it's probably being pulled to zero or maybe even toe in if it's all stock rubber bushings any time it's on power. Lots of camber and hard braking will always be a little hard on the inner edges of tires as well.

I assume the diff was working, ie no noticeable wheelspin? That's the other easy answer.

red_stapler said:

Camber wear is usually pretty even across the face of the tire, it sounds more like too much toe in.

This plus . . . 

Did you get tire temps?

What are the tire temps across the tire??

We have this issue with pretty much all of the good soft tires.

1 heat cycle before the race has solved this for us.  Whenever I buy new tires, I have tire rack heat cycle them for like 15$.

Also, tire temp could be the other issue.  However, i don't think that would do it.

Was it wet at all?

Properly scrubbed in tires last a lot longer, so +1 on that but without knowing the tire temps your kinda pissing up a rope.

It  was at Shannonville motorsports park in Ontario,mostly old coarse asphalt with a mix of freshly paved sections.

 For sure the diff is working as it should be.

 I've never seen toe in wear the inner edges of a tire.

 Yes 1/16" total toe out.

All poly bushings

 No tire temps to report.

 Dry as a bone,sunny and bloody hot.

 Our crx last yr did the same thing in cold temps so it must be an alignment or pressure thing.

 Poking the net for pressure experiences varies from 25 to 40 as the zone.So thats a bit vague.:)

I don't think this is a pressure issue.

Our tires are happiest at 34 hot with rs4.  However that is not where they are fastest...

I still think this is a new non scrubbed tire issue.

Basically, it "anneals" the rubber and makes it much tougher.

wvumtnbkr said:

I don't think this is a pressure issue.

 

Our tires are happiest at 34 hot with rs4.  However that is not where they are fastest...

 

I still think this is a new non scrubbed tire issue.

 

Basically, it "anneals" the rubber and makes it much tougher.

What pressures do you find are the fastest with the RS4?

If it is alignment then either to much toe out and/or to much camber, those two things would cause excessive wear on the inside edge.

1/16" toe out doesn't sound like a lot to me on a FWD car but I will admit I don't have much experience with them.

-3 of camber does sound like a lot to me but the tire temps would tell for sure.

It is also entirely possible that your current set up produces the fastest lap time possible for that track at the expensive of tire longevity. Decreasing the camber might help the tires but hurt the lap times.

I use one of those cheap infrared thermometers, tire guys may howl but it works well enough to get a general idea of what's going on. 

Here's what kept happening with us (sorry if this pic turns out huge).

In reply to ross2004 :

Thats us but 100 times worse.

 Rest of the tire looks fine.

Have you tried contacting Hankook to see what they have to say? It seems weird that it's chunking the second block on each pair.

I did not, should have, but didn't. I did have other tires where the chunking was on every tread block. 

less camber , more caster, zero toe.

You need temps to see if your pressure is right.

You are working the inside edge too much on the unloaded tire, is my guess.  If you can stand them up a bit, until just before you start doing the same thing to the outside of the tire would be the best compromise.

And compromise is a real word here.  Fastest lap times will not be easiest on tires.

One of my Chump guys has pretty much no idea what a brake pedal is.  Throw it in the corner, and crank the wheel until it slows down enough to turn.  I, on the other hand, am a big believer in the slow in, fast out school of thought. 

I'm much easier on tires.

If you're under driving the car by 8-10 seconds a lap, then you probably don't need-3* camber. Drop that down to -2 or -2.25 and use a pyrometer to test the theory

In reply to iceracer :

We will pull camber out for sure and go to zero toe,castor is maxed with offset upper arms

I have a very similar car in a similar use on the same tires and have never had this issue.  EF Civic, K24A2 (205whp) Civic Si trans with LSD, 15x9 wheels with 225 RS4, raced in Lemons/etc. 

I agree with Rob that you need a heat cycle on these tires, the front tires on these are doing 80% of everything.  We always bring new tires up to temp on testing day and then let them sit and they wear great afterwards. 

You don't need nearly that much camber, and need to do some tire temp testing.  After doing temp testing we are down around -2.5 camber and could go even less, with hot pressure around 32.  

In reply to Sonic :

Thanks,we'll add the heat cycle to our prep.

 Great info

Thanks for the help guys,I knew this bunch would have insights and be willing the share.

In my experience, Shannonville and Sanair are hell on tires. Mosport and Tremblant used to be the same until they were repaved.

Don't know how you Canucks mix your asphalt, but it's like taking an angle grinder to your tires.