Da Groj

Tire test by Danny Kao at FedEx Field. The following is Danny's post on another forum.

1. Pure data, no personal comments.

2. We started at 4pm and by 6pm I only had the time from Rival-S test due to timing error and course kept on getting blown up; so I rushed the test to get 3 more tire test runs in. I was a little PO'd so I drove with a lot of anger and not as precise.

3. One my "check up runs" with Rival-S, the temp dropped and the lot was covered with shade. Fedex began to seep water from surface cracks so part of the surface is wet; which made the last runs on the Rival-S kind of useless.

4. My first runs on the Rival-S, my tire pressure was 34/30. My checkup runs I ran 29/25. Again the last runs has partial wet spots so the time is probably not relevant. I do like the feel of higher pressure more; but not sure if it's faster.

Here is the data:

Rival-S (34/30) 62.7, 62.2, 61.5 (Sunny, mid 60s)

Federal RSRR (31/27) 62.9, 63.0, 61.5 (timing shows 61.5, but my solostorm data doesn't support it, so re-run), 62.9. (Sunny, low 60s)

RE71R (28/26) 62.3, 61.9, 61.3 (Temp dropping, high 50s and Sun going down)

Rival-S (29/25) 62.4, 62.9 (hit wet spots), 62.1 (Shaded, mid-50s, several wet spots from ground water)

A lot of us did find the time difference between 255/17 Rival-S vs 245/17 Rival-S. I didn't have time to try it. But Shane, Brian Garfield and Larry Casey all found the same gap of time differences on Shane's car. Because of that Shane is doing another test between 255 vs 245 on NC next week. I will try to participate in that test.

That's all I have without getting into personal opinions. I do have one personal comment: Tire testing is hard. There are so many variables and almost impossible to keep it consistent. It will cost so much money and time to get something definitive; so take this for whatever it's worth - at least it's free for the readers.

Here is the video:

https://youtu.be/JxdyzzRsWaQ

I'm assuming the Rival-S at the bottom of the list is the 1.5 version. Even though lower temp/slight wet spots here and there it seemed to get around the same time as the regular 1.5 that was running a little warmer temps. RSRR looks decent and for the price looks to be a great bang for buck. RE-71 looks to still be king as always.

I just did a back-to back test on our GCAC test & tune with similar results. Here's a copy/paste from my post on the the GT86 forum:

I tested the RE-71R's I ran at Dixie against the 1.5's I ran at the Fort Myers Pro.

On our test & tune course, (concrete) I was almost 2-tenths faster on the RE-71R's. (Course is about 32 seconds long.)

Both sets of tires were 225/45-17 on 7" RPF1's.

The 225 1.5's on the 7" wheel feel vague...as if they are pinched on the wheel. (The RE71's, on the same wheel, feel razor sharp in comparison)

I want to test a set of 1.5 215's on the same wheel and see if they do better.

In this particular application, the RE71R's were the faster tire.

I think the 1.5's would do a lot better on a wider wheel (or smaller tire) and with more camber, But I can't get any real camber in stock class and BFG doesn't make anything smaller for my 7" wheels.

jbrannon7 wrote:
A lot of us did find the time difference between 255/17 Rival-S vs 245/17 Rival-S. I didn't have time to try it. But Shane, Brian Garfield and Larry Casey all found the same gap of time differences on Shane's car. Because of that Shane is doing another test between 255 vs 245 on NC next week. I will try to participate in that test.

Here is something else, in another post he did talk about the 245 v 255 test, the results were the 255 was .5 seconds faster than the 245 on a 62 second course.

jbrannon7 wrote:Tire testing is hard. There are so many variables and almost impossible to keep it consistent. It will cost so much money and time to get something definitive; so take this for whatever it's worth.

This is exactly what I've been saying all along, is that i doubt anyone could really tell a difference between any decent tire compared to another on a autocross course. So many variables in a average 60 second run, that its hard to say which tire is or could be better. If the tire were being compared on a road course that would be a different story. The only real comparison is weight, other than that, run what ever tire works the best for you and your set up.

Solar wrote:

jbrannon7 wrote:Tire testing is hard. There are so many variables and almost impossible to keep it consistent. It will cost so much money and time to get something definitive; so take this for whatever it's worth.

This is exactly what I've been saying all along, is that i doubt anyone could really tell a difference between any decent tire compared to another on a autocross course. So many variables in a average 60 second run, that its hard to say which tire is or could be better. If the tire were being compared on a road course that would be a different story. The only real comparison is weight, other than that, run what ever tire works the best for you and your set up.

In my case, the test & tune course has been the same for a couple years, so there was no learning curve to the course. (That could cause the second tire to seem faster as the driver gets more familiar with the course...and the 1.5's went second and were slower anyway. Aside from human error, I accounted for as many controllable variables as possible. Whatever errors I made, I made them consistently enough to produce tight timing groups with both tires. I did three runs on each tire and had a spread of ~two-tenths of a second for each tire's three runs. The slowest RE71R run was still faster than the fastest 1.5 run. (less than a tenth, but faster) Also, the 1.5's (this size tire, on this size wheel) are undeniably vague when driven back to back with the RE71R's.

Solar wrote:This is exactly what I've been saying all along, is that i doubt anyone could really tell a difference between any decent tire compared to another on a autocross course.

I think any experienced autocrosser would be able to rank the tires from best to worst if they tried them all. Many would surely be close though. There is a definite divide between the RE-71 and the older/cheaper tires. I ran RE-71's for a season, they were great. I switched back to RS-3's since they were stupid cheap at the time, figuring there wouldn't be much of a drop off. The difference was huge. On the Mustang; compared to the RE-71's, the RS-3s were a steaming pile of poo.

What puzzles me is how this test (and seemingly most other people running them) get results out of RE71s at such low pressures. The rest of the Miata world is running 25-28 psi, mostly on 6" wheels; any time I drop below 32 psi, the car just gets sloppy, and the outer shoulder temps go out of sight. I put it down to lack of camber, but other stock Miatas have the same issue. That's been true of two sets, now, so it's not just a rogue set of tires, either.

Same here, it seems I can make 30 work but lower than that it seems slower.

AScoda wrote:
I think any experienced autocrosser would be able to rank the tires from best to worst if they tried them all. Many would surely be close though. There is a definite divide between the RE-71 and the older/cheaper tires. I ran RE-71's for a season, they were great. I switched back to RS-3's since they were stupid cheap at the time, figuring there wouldn't be much of a drop off. The difference was huge. On the Mustang; compared to the RE-71's, the RS-3s were a steaming pile of poo.

That was your experience, which was all your own, what I'm saying is that I might find the RE-71's aren't as good as the RS3's because of the way I drive or the set up on my car. All these tests I'm talking about are about new tires being tested side by side in a few runs, not the longevity, or how well they heat cycle over time. What one tire does for one person may not be the same for the other. As far as not telling the difference between good tires, I'm referring to most people, as in average drivers in autocross, in just a couple runs, not the drivers that are far and above better drivers that can make any car go fast, (cough cough, you, Loren), to name a few. To me, a couple 60 second runs doesn't really give a really good overall picture of which tire is "better" than the other, there's just to many variables. Plus, I wonder if these tests were done blind, or if the test drivers knew which tires were on their car ? Some test drivers might just think that a specific brand of tire could be slower, and may just over drive the car to adjust for them ?

To me, those Federal RSR's I was running were as good or better than the RS3's, but this was based on my gut feel over a 12 month period, I have no data to confirm this. Now I'm running those Nexens, and I can't really tell a difference other than the sidewalls seem stiffer, and they have a ton of grip just like the RS3's and RSR's did.

What I feel (and agree with Drew that most people can feel) immediately is the responsiveness and "surefootedness" of a tire. A tire that is more responsive and feels more grippy (whether it actually IS more grippy or not) will be faster for most people because it makes them more confident.

The RE-71 is a mind-blowingly responsive and confidence-inspiring tire. Yes, it's grippy... more grippy than an RS-3 or Star Spec or RS-R? Probably not all that much. But, it FEELS fantastic. You FEEL like you can do stuff. And thus... you do. I think that is a lot of why the RE-71 tends to test around a half-second quicker than most tires, and why it is so popular.

A little more, Andy Hollis says this "all the changes on the 1.5 were inside the tire. Same compound, same mold."

The RS-3s, Nexens and Federals that you have run, Brian, probably are pretty close in performance. Most probably would run about the same on any of those. The RE-71 and the Rival S are definitely a step up that most would feel, and you should totally get a set if you do get back to running regularly. You were on the wrong side of the FASTiva last time.
Step your game up!
Dispel your FASTiva juxtaposition!

When you run a set of those, you will attain clarity and you will know that Drew was right. (Which, is always the case, BTW )

I feel like this smilie is underutilized

AScoda wrote:Dispel your FASTiva juxtaposition!

I think the juxtaposition is in the name of the car.

Perhaps oxymoron is more like it...