Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Reply
 
LinkBack Thread Tools Display Modes
Old 08-25-2009, 03:58 PM   #1
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Kuhmo XS installed!

I finally got rid of my worn out Michelin PS2's and replaced them with these XS tires. These tires are supposed to be the best/fastest of the new crop of high performance street tires so I'm pretty psyched. C&D tested them and they were a full second faster than PS2's on a 1 minute autocross course. Grassroots Motorsports mag also did a comparo and they came out on top. I'm doing a HPDE down at Gateway in STL this Saturday and several autocrosses in the next month so I'm eager to see how they do. Best part is they cost $773 shipped from Tire Rack in 18" sizes. I'll let you guys know how they compare to the pricier Michelins.

__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg
Adam is offline   Reply With Quote
Old 08-25-2009, 06:24 PM   #2
Registered User
 
Join Date: Nov 2007
Location: Chicago suburbs
Posts: 1,675
Brand new, your tires have a tread depth of about 9/32nds. I would keep a eye on them if you are doing a high speed track event, as you may chunk them.

Tread depth that deep could cause some real premature wear (that's why they shave new tires for track use).

Let us know how it goes...
__________________
JGM
2002 Boxster S
1973 911 Green FrankenMeanie
PCA DE Instructor circa '95
jmatta is offline   Reply With Quote
Old 08-25-2009, 07:15 PM   #3
Registered User
 
Join Date: Jul 2004
Location: Houston, Texas
Posts: 7,240
Adam, be sure to come back to this thread and report on how they're wearing, the grip they provide, and of most interest to me, if they "wagon wheel" when cold like the Kuhmo's I had on my boxster after I first purchased it.

Those Kumho's sucked. I swore I'd never buy the brand again, but I'd love you to prove to me I was wrong and I need to eat those words. My wallet would thank you profusely.
__________________
'97 Boxster (Black Hole for 42,000 Dead Presidents and counting) - 122k
New motor, transmission, suspension, and on and on and on it goes...
RandallNeighbour is offline   Reply With Quote
Old 08-25-2009, 07:16 PM   #4
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Quote:
Originally Posted by jmatta
Brand new, your tires have a tread depth of about 9/32nds. I would keep a eye on them if you are doing a high speed track event, as you may chunk them.

Tread depth that deep could cause some real premature wear (that's why they shave new tires for track use).

Let us know how it goes...
Yeah, I know shaving them would be best, but I just can't bring myself to do that. I'll just hope for the best and try to shave them the old fashion way.
__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg
Adam is offline   Reply With Quote
Old 08-26-2009, 07:17 AM   #5
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Quote:
Originally Posted by RandallNeighbour
Adam, be sure to come back to this thread and report on how they're wearing, the grip they provide, and of most interest to me, if they "wagon wheel" when cold like the Kuhmo's I had on my boxster after I first purchased it.

Those Kumho's sucked. I swore I'd never buy the brand again, but I'd love you to prove to me I was wrong and I need to eat those words. My wallet would thank you profusely.
The grip should be exceptionally high. I can already tell taking a few on/off ramps that these things stick very well. Tire Rack indepently tested these tires with a standard BMW 3 and they got 1.02 G's on the skid pad....highest they've ever had with a street tire. With a real sports car like the Boxster I expect that number to be even higher. I've noticed they pick up sand and gravel off the road quite a bit more than the PS2's. Their tread wear rating is 180 compared to 220 on the PS2's so I know they won't last as long. If I get two seasons or 10,000 miles out of them I'll be happy. This tire should be ideal for someone doing weekend autocross/track, but also drives on the street and doesn't want to invest in a trailer, 2nd set of wheels, or new tires every 6 months.

You probably had the old Kuhmo MX tires. Those things weren't all that great and didn't really do anything well, but the price was good. These XS are light years better in the performance dept. By "wagon wheel" are you referring to flat spotting when sitting? I'll note that as well. This XS tire also reportedly doesn't do well in the rain so some people would have to take that into consideration....luckily I don't drive the car much in the rain and I doubt you do down in Houston. Also, you shouldn't drive them in sub freezing temps like most performance tires. I think these tires will wear out too quickly for some, and they're not for everyone, but if your needs are similar to mine then I think you'll be very pleased. I'll report back once I get some more miles on them.
__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg

Last edited by Adam; 08-26-2009 at 07:19 AM.
Adam is offline   Reply With Quote
Old 08-26-2009, 07:26 AM   #6
Registered User
 
Join Date: Nov 2007
Location: Chicago suburbs
Posts: 1,675
I'll just hope for the best and try to shave them the old fashion way

Just remember to be smooth...the more you attack, they more the tires will slide, causing damage to the tread block. I'll be curious to see what you think as I usually use a DOT R compound tire and don't have a lot of track experience with street tires; only what I witness as an instructor (I've brand new tires gone in one track day!)
__________________
JGM
2002 Boxster S
1973 911 Green FrankenMeanie
PCA DE Instructor circa '95
jmatta is offline   Reply With Quote
Old 08-26-2009, 08:29 AM   #7
Registered User
 
Join Date: May 2008
Location: Toronto
Posts: 2,656
I see your point but the XS have pretty decent size tread blocks. Not as big as my Star Spec tho...
ekam is offline   Reply With Quote
Old 08-26-2009, 09:08 AM   #8
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Quote:
Originally Posted by jmatta
I'll just hope for the best and try to shave them the old fashion way

Just remember to be smooth...the more you attack, they more the tires will slide, causing damage to the tread block. I'll be curious to see what you think as I usually use a DOT R compound tire and don't have a lot of track experience with street tires; only what I witness as an instructor (I've brand new tires gone in one track day!)
This is my first HPDE and I have to ride with an instructor so I'll try to just concentrate on smoothness and driving technique. This will hopfully be a better way to break them in over the herky jerky movements and quick transitions of most autocrosses. I'm only going to do one 20 minute lap session and classroom time instead of all day long so I can just get my feet wet. It is only going to cost $55, all day long is $225 and five 20 min sessions. Like Ekam mentioned the tread blocks are on the bigger side and look robust so well see what happens!
__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg
Adam is offline   Reply With Quote
Old 08-26-2009, 09:41 AM   #9
Registered User
 
Join Date: Aug 2005
Location: Ohio
Posts: 380
Garage
Adam--a few comments..

I've had these tires on our 987 in 245/35/18 and 275/35/18 sizes off and on since May. I won these at a club DE last year.

I've done one auto-x and 2 DE's with them.

A few observations:

-I like these sizes on the 2.7L model since it lowers the effective gearing because these are about .6" smaller OD than the stock tires.

-These tires have lot of grip; when hot, they break loose but the slide is very controllable--a very easy tire to drive fast on. Have to say before they got heated up, the combination of these tires and XP8 carbotechs had me braking way early for turn 7 at MidOH.

-Tread wear: I went from 10/32 to 7/32 on the fronts at the 2 day DE; wear was very even. Overall, I think the 9-10/32 tread depth on some of these sizes is a bit much considering the market they are appealing to.

-Tire pressure: I'm thinking these tires like pressures under 40PSI--hot At 38/40 (f/r) the wear was very even, but even then I wasn't quite getting to the little triangles on the side that indicate the how much rollover you're getting; 36/38 might be better.

-In the wet: I drove home in the rain on them about 90 miles and they were OK, but I've heard reports that they can be tricky.

-Noise: Initially, very quiet. after the 2 day DE I could hear them. I'm glad I've got the GY Asym F1's for everyday use.

Overall, I think these are a good value auto-x/DE tire for the Boxster. I don't think I'd want them as an everyday tire after a couple of DE's.

One last thing, wear--given the amount of wear so far i see these lasting one full DE season or say 5 2 day DE's.
__________________
2013 Boxster S
2006 Boxster--sold
1999 Boxster--sold
MikenOH is offline   Reply With Quote
Old 08-26-2009, 02:39 PM   #10
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Mike, thanks for your driving impressions and input on these tires especially for track/autocross use. I couldn't find any other mention of these on this board so appreciate the feedback on tire pressure ect. I wasn't sure what these tires liked on our cars. If they like high 30's hot then I'll probably start at 36 rear/34 front cold and see how that works. I let you know how things work out.
__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg
Adam is offline   Reply With Quote
Old 08-31-2009, 11:33 AM   #11
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Ok, I did the DE on Saturday and all I can say is I wish I would've had more seat time, but I had a lot of fun. I only signed for one 20 minute session so I never got too comfortable with the track and finding the proper line, braking points, ect. My instructor basically said I needed to slow it down and concentrate on the fundamentals first, then increase speed later. Like Jmatta said, the focus is on smoothness first then speed later, but with the adrenaline pumping and only 20 min I wanted to go fast! As far as the tires are concerned they worked great and offererd a lot of grip! They held together just fine and didn't chunk up or anything. They reminded me a lot of an R comp tire because at the limit they didn't squeal or make any noise, they just quietly and predictably broke away. I can't wait to see how they do this weekend at the autocross where I'm more in my comfort zone and familiar. Oh, and Mike I ran 34 psi up front and 36 out back cold and that seemed to be almost perfect. The fronts rolled over just enough to hit the triangles on the sides, the back didn't roll over quite as much so I might play with lowering the rear pressure in the future.
__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg

Last edited by Adam; 08-31-2009 at 11:56 AM.
Adam is offline   Reply With Quote
Old 08-31-2009, 05:25 PM   #12
Registered User
 
Join Date: Aug 2005
Location: Ohio
Posts: 380
Garage
Smile

Adam--good for you. Glad to hear it worked out well. I suspect this won't be the last DE you do A few years back we decided to do more DE's than auto-x because of the increase in seat time. They cost more for sure but on a good day you can get close to and hour and a half behind the wheel at speed.

Anyway, at your next auto-x try even pressures--f/r. I tried it with these tires this year and I thought the car was very balanced. One nice thing at an auto-x is that you can experiment a bit more with pressures and not get into much trouble doing it.

All things considered these tires are way better than PS2's for auto-x. A few years back I felt good if I could get within 3 seconds of our club's auto-X champ with a 944 turbo running victoracers. In the only one I've done this year, I was just a hair above 1 second behind this guy on brand new XS tires.
__________________
2013 Boxster S
2006 Boxster--sold
1999 Boxster--sold
MikenOH is offline   Reply With Quote
Old 08-31-2009, 06:29 PM   #13
Registered User
 
Join Date: Nov 2003
Location: Illinois
Posts: 3,033
Quote:
Originally Posted by MikenOH
Adam--good for you. Glad to hear it worked out well. I suspect this won't be the last DE you do A few years back we decided to do more DE's than auto-x because of the increase in seat time. They cost more for sure but on a good day you can get close to and hour and a half behind the wheel at speed.

Anyway, at your next auto-x try even pressures--f/r. I tried it with these tires this year and I thought the car was very balanced. One nice thing at an auto-x is that you can experiment a bit more with pressures and not get into much trouble doing it.

All things considered these tires are way better than PS2's for auto-x. A few years back I felt good if I could get within 3 seconds of our club's auto-X champ with a 944 turbo running victoracers. In the only one I've done this year, I was just a hair above 1 second behind this guy on brand new XS tires.
Thanks Mike! Yeah, I'll definately do another DE, perhaps at Putnam, GIR, or the Autobahn Country Club next year and do a full day next time. I agree about the PS2's, these XS tires are in a totally different league and I'm hoping to be 1-2 seconds faster in A-stock and try to take home some wins finally. There is a guy with a 96 Grand Sport vette with R-comps in the local club who like that guy with the 944 turbo almost always wins in my class and I'd like to be running where he's at. I'm doing two autocrosses this weekend so I'll have a good oppurtunity to play around with tire pressure and I'll try equal pressure f/r like you suggested. Thanks again!

__________________
'03 3.2L GuardsRed/Blk/Blk---6Spd
Options: Litronics, 18" Carrera lights, Bose sound, Painted to match roll bars.
http://i100.photobucket.com/albums/m...Mautocross.jpg
Adam is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 08:22 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page