[JLWSN]

After looking through dicussions about the observered wear and indicated tread wear of the RE-71, I am inclined to test the newest tires vs their predecessors. I believe testing against other manufacturers would not quite provide the answers many of us would like, so I would mount one brand's newest 200 tread wear tires on the driver's side and their predecessor on the passenger side, then test them on the same course. Overall I want to at least see if these tire manufacturers are following their own tread wear rating standards, and comparing two tires which are marketed as having the "same" wearability might at least highlight any gross inconsistencies. The test itself will take time to conceptualize and plan, and I do not expect any action to be taken because of the results. But I do want us to have a better information for other drivers and maybe the SEB if questions, rumors, and complaints compel them to seek such data.

What are some of your thoughts and suggestions?

 

[Mister_Mino]

Only way to get accurate results would be in a lab to control variables. All other "results" I would take with a grain of salt. I love the idea of a conspiracy in autocross tires however.

 

[JLWSN]

Practical and Laboratory results are not the same. Great starting point but not what I am seeking.

 

[Mister_Mino]

Identical practical results will never happen ...unless you're a robot, lol. You can try to duplicate each run as identical as you can and still get different results in wear on the same tire.

 

[Des]

Interesting idea!
I think you'd have to have two of each, one mounted for each side of the car, then swap back to front after every run to equalize for prominence of left- or right-hand turns and changing temperatures over the day.

 

[JLWSN]

Identical runs are not practical. I want this information as it applies to me. I believe I will be quite pleased with the RE -71R.

 

[JLWSN]

Des, I agree. I could design a course which can be driven both ways (mirror). A enantiomer design...lol

 

[Mister_Mino]

Are you aware that wear ratings are not established from wear a tire receives during an autocross, correct? Further more everyone knows that UTQG is a joke anyways. If you're trying to establish which tire has higher wear for your own information, does it even matter? Sure, anyone would like a "fast" tire that I can get 500 runs out of but the cost of this "test" wouldn't justify any savings in related wear you're suggesting to test.

 

[JLWSN]

I am indeed aware of this, which is why I would like to test these two companies' autocross tires and see if any consistent coorelation can be found between the tread wear rating and how the tire actually wears. Again, only as it applies to autocross, specifically me autocrossing. Obviously, the chances of the new tires and their predecessors having the exact same tread wear number should be an immediate indication of a lack of accuracy from the manufactures themselves. Heck, Hankook all but admitted this last year. Ridiculous....but I really like the RS3 v2s.

 

[jasyatz]

Why? Tread wear UTG readings are arbitrary. (ducking from flames)... All 200 TW means is that a tire when tested under the same exact set of conditions, performed 200% better than subject "control tire". If the control tire was already a soft compound, there's your answer. I believe that ALL tires should be subjected to the same EXACT "control tire" and thus we have a linear sliding scale...

In answer to your question, or response to your statement, no need to test which Stone last longer, the new ones last no where near as long as the old RE-11, There are reports of the RE-71s requiring flipping after just 30 runs...That's Hoosier type wear.. Critics will appeal that if these new batch of street tires wear just as fast as Hoosiers, why the hell did we eliminate "stock". Cost...Even if street tires wear as fast as Hoosiers, they are still 30%-50% less cost to replace thus providing the "low entry cost" into Motorsports (Autocrossing) the SCCA was looking for..

 

[Impala SS AutocroSSer]

Why? Tread wear UTG readings are arbitrary. (ducking from flames)... All 200 TW means is that a tire when tested under the same exact set of conditions, performed 200% better than subject "control tire".

Slight clarification : it really means it performed AT LEAST 200% better than the control tire.

Read that as new tires may be ONLY 200% (or 220%) better, previous generation may well have been 300% better.

(aka : manufacturers legally can...and sometimes do for marketing reasons...put a LOWER number on the tire than reality. They just can't legally put a HIGHER number on the tire).

JLWSN : just got throw a set of RE71Rs on the car, you won't care what number is stamped on the side of an RE11 afterwards .

 

[Joe Schmoe]

You're overthinking it. RE-11 are an excellent tire. The first versions were better cold. The revised version is slightly better than the first but only when good and warm. Not as good cold.

<<doesn't autocross.

 

[Des]

The outer edge of one of my RE71s corded yesterday at 74 runs. My intention had been to flip them after this event. They had about 40 runs on the front of the car.

Not sure if it's a real data point because:

• Course was super bumpy and the right-side edge of the tire came into contact with the fender multiple times -- enough to introduce a cut that became a crack ...
• I should have flipped the tires after Crow's landing, but it probably would not have helped because of the above.
• The 215/45/17 is the tallest tire combo -- I didn't have the issue on the shorter 235/40 Dunlop on morning runs.
• I drive like a d*ck.

Probably for bumpy or squarish lots like Packwood the car should be on 16s; Alan didn't have a rub issue at all, and the rev limiter wasn't a real factor.

All data is good. Some data is more expensive.

 

[Impala SS AutocroSSer]

Given the lack of flip and that a large chunk of those runs were at Crows Landing (someone described it as "20 grit sandpaper"...easily HIGHER wear rate there than at most other concrete sites), I think that wear was reasonable (i.e. NONE of the 200TW tires would exactly be a 200 run tire at Crows Landing).

FWIW, my 205/50R16 RE71Rs have ~55 runs on them at Crows (+5 at Marina, which is less abrasive concrete) and are ready for a flip. I have been rotating F->R so the wear is fairly even on all 4 tires. I expect they'll be good for another 40-50 Crows Runs, which would be probably 75 at about any other concrete site. I think that is completely reasonable for a 200TW tire .

 

[AlanBDahl]

The 205 RE-71s spec at 1" narrower than the 225/45-16 Dunlops (7.5 vs 8.5"). Are they really that narrow and do you really get more grip than the ZII star specs?

 

[Impala SS AutocroSSer]

The 205 RE-71s spec at 1" narrower than the 225/45-16 Dunlops (7.5 vs 8.5"). Are they really that narrow and do you really get more grip than the ZII star specs?

The 205/50R16 RE71R is the exact same width (see other threads with evidence) as the 225/45R16 Z2SS, and tiny bit WIDER than the 215/45R17 RE71R. No idea on the 205/45R16 RE71R, as IMHO it just takes an Achille's heel on the car (short gearing) and does nothing to improve it.

The RE71R is definitely stickier/faster than the Z2SS in my experience.

 

[AlanBDahl]

Tire Rack shows the 205/50-16 RE71R at 6.6" wide vs 8.5" for the 225/45-16 ZII SS. Are you saying their specs are incorrect?

 

[Impala SS AutocroSSer]

Yes, that is exactly what I'm saying. I posted pictures/explanation on the ZII vs R1R thread....somethingsomethingthousandwords

http://fiestast.net/threads/zii-vs-r1r.2064/page-7

(also worth a read on how they measure Section Width, and how it changes with rim width, on the TR website...their explanation is spot on with what I measured)