RE71-RS Delaminating Center Rib

Hi guys,

First time posting but have been reading for a bit now. I just got a set of RE71-RS to use primarily as an autocross tire and occasionally for road racing (I usually use RC1's). I recently had an issue with my new RE71RS showing some weird wear characteristics. I hope I am not being "that guy" making a post about tire wear, but I am looking for more knowledge and hoping to find out if something weird is about, or for me to use this as a learning opportunity to understand if I did something wrong (tire care or car setup) so that way it doesn't happen to me again.

A little bit of info before proceeding to the delaminating.

Car is a 2012 128i, prepped for SCCA STX. Some people may already know the car from some of the national events it has competed in. Car weighs ~2940 lbs without driver.

This year I got a set of RE71-RS in 245/40/17 primarily for autocross, but I had planned a time attack event in April that allowed me a 200 TW tire. 

I did one autocross locally on these tires, and quickly realized these like to be run at a much lower pressure compared to A052's and RT660's. With that said at this point these tires had 8 autocross runs so far.

This last weekend I traveled down to Vegas to drive in a time attack event. The course was Las Vegas Motor Speedway - Outer Road Course. Temps that day were a peak of 86° iirc.

I wanted to be proactive on managing these tires so I was pretty religious at checking tire pressure and not overdriving them.  I kept them at 28-30psi hot, on day one of the event. After my second session the center rib already started to degrade pretty bad. So I dropped the pressures even more and did one more session and called it a day to save the tires for the next day of the event. I ended up hitting 19 psi cold and 26 psi hot, which seems extremely low. This is what the tire was looking like:

Not sure if its hard to tell by the picture, but that center rib was way lower on tread than the rest. 

The second day I ran with this, in hopes of taking some load off the center rib. I also found a tire pyrometer to borrow. So on one of the sessions, I checked it immediately. Did one hot lap, came in and my temperatures were roughly:

This session got cut short so I wasn't able to put more laps on the tire to get more temp into it. But you think with the temp gradient like this I wouldn't wear out the center anymore. 

The next session I was able to run a few more laps consecutively. (Also I want to add, I tried to only do two hot laps in a row, and then a 6/10ths lap in-between to cool the tire off. This is what I was trying to do all day. ) 

After I parked after this session, I ran to borrow the pyrometer again and just recorded what I logged. The tire did have some time to cool off while I snagged the pyrometer, but not completely. here is the data from running a few more consecutive hot laps:

After this I called it for the day just to give myself time to get packed up and head home.  This is what the tire looked like after day 2:

Car alignment and suspension:

Front: -3.7° camber. 0 toe

Rear: -2.3° camber. .10° toe

Dampers are freshly rebuilt JRZ RS-Pros. Spent the winter refreshing all of the suspension components as well (ball joints, bushings, etc.) 

I want to add one more anecdotal piece to this. I actually had 4.1° of camber in the front prior to his year. With RT660's and A052's, I was wearing the outside shoulders out before anything else. (The reason for less is because I had a delrin offset bushing, but swapped to regular poly due to some other gripes I had with the delrin.)

I want to add, this was happening on all 4 corners. It wasn't isolated to one tire or one side. 

Now my question is, is anyone else experiencing this issue? I noticed an evo at the track with these tires and by the end of day 2 it looked like theirs was starting to do the same thing, just not as aggressively as my car. Maybe this is a normal characteristic and I have nothing to worry about, or maybe I am doing something totally wrong.

The car was wicked fast all weekend. In terms of feel and grip, this is one of the best I have driven on. The car just felt like an absolute weapon on these.

Anyway, thank you for reading through this long winded post. I know there are a lot of people on this forum who have a lot more experience and knowledge than I do, and I am hoping to learn something from this post. Thank you. 

I don't see any delamination, just wear. Your tire temps are saying you need more pressure. These are sticky tires that may wear out quickly. Send it and see how long they stay fast for. If the answer is "not long enough" you'll need to switch to a different tire for your application. 

In reply to CrashDummy :

Thats what I am wondering, if this is just expected wear, especially running a super 200 on a road course. I'm not sure if the photos do it justice but the center rib is already at the wear bar while the rest of the tire is above it. I might have to get some photos with tread depth gauge. 

I fell like running low pressures would imply the wear to be inverse of what I am seeing though? 

Agreed.  Pressures too low based on temps.  Camber seems in the ball park.

That is not delam.   That is just wear.  It could be from just not enough physical tire for the weight and speed.

Okay awesome, if that's the case I won't stress it too hard and keep running these for autocross. 

I wish I had temperature data from the first day. I was running about ~4 psi more on day one. 

Yeah not enough pressure for sure. We've found they like at least a few psi *more* than RT660s. DS GR86 so slightly lighter but narrower wheels and less camber, the happy pressure range seems to be 36-37psi hot. Might be a bit less for you but I'd guess at least low 30s.

If you want to see center rib delam, check out the early runs of the Falken RT660. 

That looks fine though I'd argue you'd benefit from more pressure, anecdotally I found that these kind of tires like running ~35PSI hot, +/- 2PSI.

The center rib looks like its wearing due too much slip angle AKA understeer. I wonder if you're so far under the correct pressure that the tire is deforming and causing the weird wear pattern. I'd highly recommend buying a pyrometer and using it on a regular basis. Start with your pressures a little high and work your way down to the sweet spot.  

How long after the last lap did you take the tire temps?

 After my first autocross, with my ES Miata, I noticed that the center rib on one or two of the tires was a little chewed up on the edges. I've got about 40 runs on those tires now, and I do notice somewhat more wear on that center rib, but nothing excessive. 
 

Here's a review I did after that first event with closeups of all four tires. 
 

The grip is phenomenal, so we agree on that. I just ran my civic on a brand new set last weekend, and despite being seriously underpowered for H Street (approximately 60 horsepower less than the FST and SI) I was 18th in pax.

 I haven't had a chance to really evaluate the tires visually yet. I'm going to do another review soon. 

Another question came to mind. What width wheel are you running? Maybe they are pinched and its causing the tread to have a rounded face. FWIW: I'm running a 245 on a 9" wheel.

In reply to CAinCA :

You raise a good point. I'm running a 205/50-15 on six inch wheels on the Miata. The wheels on the Honda are seven inch with 225/50-16 tires. 

In reply to L5wolvesf :

The first measurement was right in the pits, but only one lap on it so I'm not sure if I got enough heat to get it uniform

The second measurement happened ~15 minutes after the session 

In reply to CAinCA :

Understandable, but I will say the car was rotating beautifully all day, a little trail brake in and a touch of the throttle to keep the rotation. Car felt awesome. 

I am running a 245 on a 9" wheel as well.

I guess the hard part for me to understand is I did start at a higher pressure (30 hot) and that's when the center rib wear started. 26 hot it looked like the center rib was still wearing albeit the temps being cooler on the center. 

I will also add in my PB (and record for the class now) was at 26 psi. Albeit that could also be chalked up to me learning a new track.

besimxcars said:

In reply to L5wolvesf :

The first measurement was right in the pits, but only one lap on it so I'm not sure if I got enough heat to get it uniform

The second measurement happened ~15 minutes after the session 

15 minutes after is really too late and 1 lap isn't much. My practice was minimum of 5 hot laps and do the measurements as soon as possible. Having a trained helper do them as you unbuckle is preferred. 

besimxcars said:

In reply to CAinCA :

Understandable, but I will say the car was rotating beautifully all day, a little trail brake in and a touch of the throttle to keep the rotation. Car felt awesome. 

I am running a 245 on a 9" wheel as well.

I guess the hard part for me to understand is I did start at a higher pressure (30 hot) and that's when the center rib wear started. 26 hot it looked like the center rib was still wearing albeit the temps being cooler on the center. 

I will also add in my PB (and record for the class now) was at 26 psi. Albeit that could also be chalked up to me learning a new track.

30 hot was already too low.

One other thing: Did these get a proper heat cycle before their first event?

https://grassrootsmotorsports.com/articles/why-you-should-heat-cycle-your-tires/

I haven't used the RE71-RS, so I can't say much about them specifically, but some tires seem to like to wear the outside edge of the tread blocks with continuous grooves next to them.  Presumably this is because there's not much support across that groove, so it's getting deformed in a similar way to the outside edge of the entire tire -- it's almost like there's another mini tire there.  Toyo RRs, for example, do this to me every time I run them.

The other thing I'll toss out here is that ideal pressure/temperature for performance is not necessarily the same as ideal pressure/temperature for tread life and you may need to decide which is more important to you.

Echoing what others have said, you need more air.  While these tires can deliver optimal pace around 28psi hot, they are also susceptible to overdriving at that pressure.  Strongly suggest more in the vicinity of 32-34 hot, depending on car setup. 

And to reiterate what Tom linked above...you really want to put a mild heat cycle on these before hammering or you risk edge-peeling that center rib.  RT660's are like this, too.

If you want optimal performance and hammer-time on Day 1, buy them shaved and heat cycled.  See recent test story below: 

https://grassrootsmotorsports.com/articles/how-optimize-tires-quicker-laps-and-longer-life/

PS: To the OP...that's not delamination.  That's graining.

Awesome thanks for all the responses guys, I appreciate them!

To add more info I did a highway drive to heat cycle them before I did an autocross early April. Not the optimal heat cycle but I figured I would get some kind of heat in the tire.

I want to add this, at my local autocross I did prior to the TT weekend, at 37/35 hot it looked like this at the end of the day. I just chalked it up to too much pressure after talking to some people:

So I think the lesson here is that I was too low, and too high, and miss the "just right" mark.

Moving forward, how would I reduce the chances of this? Tire pyrometer and tune accordingly to temps?

And for my clarification, tire graining, that can be caused by either too high or too low of pressure?

Thanks!

That photo looks fine from a pressure standpoint, just some combination of not enough initial heat cycle, overheating, and/or over driving.

dps214 said:

That photo looks fine from a pressure standpoint, just some combination of not enough initial heat cycle, overheating, and/or over driving.

This man speaks the truth.

Graining is uni-directional abrasion, typically caused by overdriving.  Pressure can have some effect, in that it can localize loading, but graining is more often caused by a compound that is not yet cured enough to support the loads being requested.  This is exacerbated by tall tread blocks and sticky rubber.

Y'all need to get a copy of Paul Haney's book, if you can find one at a decent price.  Best book ever on tires in motorsports.

https://www.amazon.com/-/es/Paul-Haney/dp/0768012414

PS: I have a picture of an RE71RS that looks way worse than that one...properly heat-cycled but then hammered hard for six laps for a tire test.

besimxcars said:

Moving forward, how would I reduce the chances of this? Tire pyrometer and tune accordingly to temps?

Yes! Start with a new set of heat cycled tires at reasonable pressures. Use the Excel spreadsheet on this page to figure out which adjustments to make to pressure and camber:

https://nasaspeed.news/wp-content/uploads/2016/04/TireTempCalculator.xls

Looking at your last picture I honestly wonder if you have too much camber in the front. It looks like you're only working the inner 2/3 of the tire.

In reply to Andy Hollis :

Whats a book? My generation gets all of their information from vertical videos in 15 seconds or less.

Jokes aside, I definitely need to get myself a copy, thanks for the responses. 

CAinCA said:

besimxcars said:

Moving forward, how would I reduce the chances of this? Tire pyrometer and tune accordingly to temps?

Yes! Start with a new set of heat cycled tires at reasonable pressures. Use the Excel spreadsheet on this page to figure out which adjustments to make to pressure and camber:

https://nasaspeed.news/wp-content/uploads/2016/04/TireTempCalculator.xls

Looking at your last picture I honestly wonder if you have too much camber in the front. It looks like you're only working the inner 2/3 of the tire.

Oooh thats a good resource. Thank you