As they promised, Grassroots Motorsports has tested some popular street touring and R-compound tyres against each other at Tire Rack's autocross-like facility at South Bend.

It's in the August issue, which just hit, so keep your eyes peeled for your NASA complimentary copy in your mailbox, or see if you can get your hands on it.

Overall fastest street touring was the Falken ST 615, and the fastest R Compound was the Kumho V710. I'm just mentioning that because I know you're going to ask. You should read the article, though, because there could be more to your future purchase than just the fastest time.

Some of us will be disappointed the RA1 was not in the test, but Toyo has always said that the RA1 was not suited for short autocross situations, anyway.

 

Which other tires were included in the test?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">Which other tires were included in the test?
</TD></TR></TABLE>

R Comps:
Yoko A032R S
Kumho Ecsta V710
Hankook Z214
Hoosier A3S05

Street:
BFG G Force T/A KD
Yoko Advan Neova
Hankook RS2 Z212
Falken Azenis RT215
Falken Azenis RT615
Kumho Ecsta MX

 

What did they say about the Hankook? Was the RT615 that much better?

 

Scan the pages George :D

I'd like to see how they rate the Hankook z212 as I currently have them on my car. In my own cheapo (butt dyno style) testing, I prefer them over the RT 215

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SMZ GSR &raquo;</TD></TR><TR><TD CLASS="quote">Scan the pages George :D

I'd like to see how they rate the Hankook z212 as I currently have them on my car. In my own cheapo (butt dyno style) testing, I prefer them over the RT 215 </TD></TR></TABLE>

Ditto here!!

 

Where can i get this mag from???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Team Bukkake!!! &raquo;</TD></TR><TR><TD CLASS="quote">Where can i get this mag from???</TD></TR></TABLE>

A really good newsstand should have it. The magazine section of big bookstores like Borders or Barnes & Noble might have it, too.

The magazine's website address is - believe it or not - http://www.grassrootsmotorsports.com.

 

so what did the best?

 

Could you list them in the order that they ranked? For both R Comp and S Comp.

Also How did the Hankook Z212 compare to the Kumho Mx?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jordo@KAP &raquo;</TD></TR><TR><TD CLASS="quote">so what did the best?
</TD></TR></TABLE>

Among the R comps, the Kumho V710 was on top. Among the street tyres, the Azenis RT615 came out on top.

There's a lot more to it than that, however, and you should read the article. It's possible that the best performer wouldn't be the right tyre for you. There are also some big differences in prices, and that might skew your decision toward a lower ranked tyre.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITR#132 &raquo;</TD></TR><TR><TD CLASS="quote">Also How did the Hankook Z212 compare to the Kumho Mx?</TD></TR></TABLE>

They referred to the Kumho MX as "old technology" and preferred other tyres. The MX was the slowest tyre.

The Z212 did well, but their comments were close to what others of us might have said now that some of us have been on road courses with them.

The sidewall of the Z212 is soft compared to most of the competition. This will cause you to want to put more air in it to stiffen it up a bit, but then the tire will not roll correctly and you will reduce overall grip in most situations.

The situation seems to call for just putting up with a squirmy feeling. The worst it was for me was in the bowl at Shenandoah. If you try to get through the bowl at about 55, there is an uncomfortable squishy squirmy feeling that might cause you to doubt that you're going to make it...but you will. I have an N1 suspension, so the carcass squirming probably became a focal point.

The other problem with the Z212 seems to be that Hankook over reacted to the criticism of the RT215's water channeling capabilities. The Z212 is so good at channeling water that there might be less rubber on the ground than there could be, lessening overall grip just because you're not putting as much rubber down as other tyres in the same size.

Having said all that, however, since the Z212 could be $20/ea cheaper than the same size RT615, I am sure they will sell tonnes of them to us.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jordo@KAP &raquo;</TD></TR><TR><TD CLASS="quote">so what did the best?</TD></TR></TABLE>

Reading comprehension is your friend. From the first post in this topic:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">Overall fastest street touring was the Falken ST 615, and the fastest R Compound was the Kumho V710.</TD></TR></TABLE>



<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITR#132 &raquo;</TD></TR><TR><TD CLASS="quote">Could you list them in the order that they ranked? For both R Comp and S Comp.</TD></TR></TABLE>

<u>Street Tires</u>:
1. Falken Azenis RT-615
2. Falken Azenis RT-215
3. Yokohama Advan Neova
4. Hankook R-S2 Z212
5. Kumho Ecsta MX
6. BFGoodrich g-force T/A KD

<u>Track Tires</u>:
1. Kumho Ecsta V710
2. Hoosier A3S05
3. Hankook Z214 C70
4. Yokohama A032R S

(These are based on average times. Basing it on the fastest clean run would put the Hankook Z214 above the Hoosier.)



Modified by nsxtasy at 12:10 PM 7/14/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">
<u>Street Tires</u>:
1. Falken Azenis RT-615
2. Falken Azenis RT-215
3. Yokohama Advan Neova
4. Hankook R-S2 Z212
5. Kumho Ecsta MX
6. BFGoodrich g-force T/A KD

<u>Track Tires</u>:
1. Kumho Ecsta V710
2. Hoosier A3S05
3. Hankook Z214 C70
4. Yokohama A032R S

</TD></TR></TABLE>

Did they list the actual times? Just curious to know what the margins were.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P Nut &raquo;</TD></TR><TR><TD CLASS="quote">Did they list the actual times?</TD></TR></TABLE>

Yes.

They used two drivers, both champion autocross drivers. They used a 2004 Nissan Sentra SE-R Spec V with NISMO parts for the street tire test. For the R compound test, they used an autocross-prepped 1999 Mazda Miata belonging to one of the drivers.

Each driver got five runs with each tire, and they re-tested the first tire last to show whether it would have ranked any differently due to having more experience with the track (in both tests, it didn't affect the ranking).

They showed the lap times for each of the five runs for each driver, as well as the number of cones knocked over each time. For each set of five runs by one driver, they calculated the average lap time of the middle three runs (runs 2 through 4). They then took those two numbers (average for the middle three for each of the two drivers) and used the average of those two numbers to rank the tires:

<u>Street Tires</u>:
1. 42.984 Falken Azenis RT-615
2. 43.254 Falken Azenis RT-215
3. 43.287 Yokohama Advan Neova
4. 43.511 Hankook R-S2 Z212
5. 43.762 Kumho Ecsta MX
6. 43.855 BFGoodrich g-force T/A KD

<u>Track Tires</u>:
1. 41.008 Kumho Ecsta V710
2. 41.142 Hoosier A3S05
3. 41.217 Hankook Z214 C70
4. 42.428 Yokohama A032R S

 

Thanks, Ken.

 

I wonder which tires are best for linar accerlation, the soft sidewall from the hankooks have to help that.

im mounting my hankooks tonight. hopefully they are nicer then my bald rt215s.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jordo@KAP &raquo;</TD></TR><TR><TD CLASS="quote">I wonder which tires are best for linar accerlation, the soft sidewall from the hankooks have to help that.

im mounting my hankooks tonight. hopefully they are nicer then my bald rt215s.</TD></TR></TABLE>

When people typically say a sidewall is "soft", they are referring to lateral spring rates...think cornering.

The stiffness that comes into play during acceleration would be the tangential stiffness. Based on data I've seen...most radial street tires are very comparable for tangential spring rates within the same size & speed rating.

All of this means - I wouldn't associate a "soft" sidewall in cornering with a tire's potential for good straight-line acceleration.

If we look at a tire's contact patch, the area that is most important for straight-line acceleration (and by default, braking) is the centerline of the tire. The more contact area with the road there is in the middle of the tire, the better acceleration/braking will be.

Hope this helps,

Matt

 

I just filled out the form on your website for a free issue. You think its possible for me to get the August issue? Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboEM1 &raquo;</TD></TR><TR><TD CLASS="quote">I just filled out the form on your website for a free issue. You think its possible for me to get the August issue? Thanks</TD></TR></TABLE>

As far as I know, nobody here works for Grassroots Motorsports.

Just spend a few bucks and buy the damn magazine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">

As far as I know, nobody here works for Grassroots Motorsports.

Just spend a few bucks and buy the damn magazine.
</TD></TR></TABLE>

Sorry I thought George Knighton worked for them.

And I wish I could buy the magazine but I can't find it anywhere near me. I tried many magazine stands and barnes and noble and border books. I guess ill get a subscription from there site.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboEM1 &raquo;</TD></TR><TR><TD CLASS="quote">I just filled out the form on your website for a free issue. You think its possible for me to get the August issue? Thanks</TD></TR></TABLE>

I have filled that out twice and I have never received any GRMS issues.

 

my new hankooks hook pretty well...

they hold 350-360whp pretty darn well.. i mean really well....

they are just very ugly ahah. they look like mudd tires.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by asmallsol &raquo;</TD></TR><TR><TD CLASS="quote">

I have filled that out twice and I have never received any GRMS issues.</TD></TR></TABLE>

That is weird. Call us and we should be able to sort out everything. And hope the tire test helped. Look for "part 2" in the next issue, as the Avons and Nittos were released too late for the big test.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboEM1 &raquo;</TD></TR><TR><TD CLASS="quote">
Sorry I thought George Knighton worked for them.</TD></TR></TABLE>

David S. Wallens and Scott Lear are members associated with GRM.