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

Reply
 
LinkBack Thread Tools Display Modes
Old 05-03-2013, 12:45 PM   #1
Opposed to Subie Burble
 
Overdrive's Avatar
 
Join Date: Mar 2007
Location: Central CT
Posts: 1,197
Garage
Guessing I need an alignment...?

Sorry if the pictures come out gigantic to where you can see the micro-organisms living on my tires. I just wanted some input from folks on these scallops on my front tires:












I have been running 36psi all the way around for about a year now, and this is the first time I've ever seen my tires do this. The rears are fine, and while I can't say it definitely, I don't recall seeing the tires look like this after autocross a few weeks back. Since then it's just been regular daily driving, and I just saw this 2 hours ago.

It looks like some of the pics rotated and may appear to be upside down or sideways, sorry about that.

I'm running Michelin Pilot Sport A/S Plus tires that have maybe 8 or 9k on them at this point, and the alignment was done maybe about a year ago. Maybe autocross last year ran it out sooner than expected?
__________________
-O/D

1997 Arctic Silver Boxster, 5-spd
IMSR + RMS
Robbins glass window top
Overdrive is offline   Reply With Quote
Old 05-04-2013, 04:25 AM   #2
Registered User
 
Join Date: Jul 2009
Location: Arlington Heights, IL
Posts: 1,557
A yearly alignment is not such a bad idea. For sure after new tires. But, from those pictures, to me, it looks normal, from hard cornering (that's why it on the fronts only, and not showing on the rears). Which is what you should be doing.
Flavor 987S is offline   Reply With Quote
Old 05-04-2013, 04:42 AM   #3
Registered User
 
mountainman's Avatar
 
Join Date: Jun 2012
Location: Little Switzerland, north carolina
Posts: 550
Garage
I automatically get an alignmet every time I get new tires which works out about yearly. I drive hard on twisty mountain roads about 60 percent of the time and my fronts never get like that. An alignmet may be a good idea.
mountainman is offline   Reply With Quote
Old 05-04-2013, 05:05 AM   #4
Homeboy981
 
Homeboy981's Avatar
 
Join Date: Jan 2012
Location: Sherman, TX
Posts: 663
Garage
36psi ALL the way AROUND? Isn't it supposed to be 29 in the fronts? …unless you "squared" your setup on all the same rims and tires.

Again, that is for COLD tires pressure AND regular driving. If you are going on the track or going to drive more aggressively adjust the pressure DOWN - as the tires will heat up alot more more at high speed. Don't know pressures for AX, sorry.

I am getting at least TWICE the mileage out of my fronts and I am in the rear. In fact, I am on my 3rd set for the rear, while the fronts look fine.
__________________
2002 Porsche Boxtser S - Silver & Chrome - Died from IMS failure AFTER IMS was replaced!
Homeboy981 is offline   Reply With Quote
Old 05-04-2013, 06:16 AM   #5
Registered User
 
Porsche Chick's Avatar
 
Join Date: Jan 2013
Posts: 560
Quote:
Originally Posted by Homeboy981 View Post
36psi ALL the way AROUND? Isn't it supposed to be 29 in the fronts? …unless you "squared" your setup on all the same rims and tires.

Again, that is for COLD tires pressure AND regular driving. If you are going on the track or going to drive more aggressively adjust the pressure DOWN - as the tires will heat up alot more more at high speed. Don't know pressures for AX, sorry.

I am getting at least TWICE the mileage out of my fronts and I am in the rear. In fact, I am on my 3rd set for the rear, while the fronts look fine.
I use about 7 lbs over the regular cold pressure.

In the notes for one of our first AX's it said to go to 40 PSI. That seemed like a big jump from my usual 29/31. I was one of the only Boxsters registered, so that made me suspicious. I looked up 911 pressures and 40 would have put them about 7 lbs over normal. Then I did a little digging (some of those racers' websites are pretty funny) and they were recommending going up 7. Long story short (I know, too late for that now) I'm glad I ignored the notes.
__________________
2009 Porsche Boxster - Guards Red/Tan
Speed has never killed anyone, suddenly becoming stationary… that’s what gets you. – Jeremy Clarkson
Porsche Chick is offline   Reply With Quote
Old 05-04-2013, 06:17 AM   #6
Registered User
 
Porsche Chick's Avatar
 
Join Date: Jan 2013
Posts: 560
Overdrive, What, exactly, are we supposed to be looking at in the pictures?
__________________
2009 Porsche Boxster - Guards Red/Tan
Speed has never killed anyone, suddenly becoming stationary… that’s what gets you. – Jeremy Clarkson
Porsche Chick is offline   Reply With Quote
Old 05-04-2013, 06:31 AM   #7
Registered User
 
mountainman's Avatar
 
Join Date: Jun 2012
Location: Little Switzerland, north carolina
Posts: 550
Garage
According to everything I have read when autocrossing or other hard cornering you do need to up the tire pressure somewhat. How much seems to be less clear. According to my wheel guy extra pressure also helps to minimumize wheel damage when we hit the inevitable potholes, etc. As the economy worsens and governments cut back on road maintenance we are getting more road hazards out there. Since I do most of my driving on curvy mountain roads I add about 4 psi to the recommended pressure on both boxsters and my C4 and have found better response and more even tire wear with less wheel damage. Just my experience. Try a few things and do what works for you.
mountainman is offline   Reply With Quote
Old 05-04-2013, 06:33 AM   #8
Registered User
 
Join Date: Jul 2009
Location: Arlington Heights, IL
Posts: 1,557
Quote:
Originally Posted by Porsche Chick View Post
In the notes for one of our first AX's it said to go to 40 PSI.
Maybe it said 40 hot????
Flavor 987S is offline   Reply With Quote
Old 05-04-2013, 06:43 AM   #9
Registered User
 
Porsche Chick's Avatar
 
Join Date: Jan 2013
Posts: 560
Quote:
Originally Posted by Flavor 987S View Post
Maybe it said 40 hot????
No. Cold. I checked, since it sounded like a bit much.

The thing was written for the 911's, which have a much higher pressure. They forgot about the Boxsters.
__________________
2009 Porsche Boxster - Guards Red/Tan
Speed has never killed anyone, suddenly becoming stationary… that’s what gets you. – Jeremy Clarkson
Porsche Chick is offline   Reply With Quote
Old 05-04-2013, 07:15 AM   #10
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,430
In autocross, the runs are so short that the tires do not build pressure like they do during a 25 min track session so many people start an autocross run with higher or "hot" tire pressures despite the fact that the tires are relatively "cold". This prevents the relatively "cold" tire from excessive roll-over. Of course, proper selection of tire pressure at the start of an autocross run is an art and there is a lot of variability in recommendations but most will say to increase (over stock pressures) as a starting point.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor

Last edited by thstone; 05-04-2013 at 07:18 AM.
thstone is offline   Reply With Quote
Old 05-04-2013, 07:29 AM   #11
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,430
Quote:
Originally Posted by Porsche Chick View Post
Overdrive, What, exactly, are we supposed to be looking at in the pictures?
It appears that the photos show what is called scalloping or cupping of the outside edges of the tires.

Unfortunately, this problem can have several causes but the cheapest and easiest fix is to start with an alignment and then go from there, but you should be sure to have the shop do a full inspection of your shocks and suspension just to be sure.

Once the tires are cupped or scalloped, its nearly impossible to "undo" this wear pattern. Some people will have the tires swapped so the cupped outside edge is now on the inside.

For reference, here is an example photo of what extreme cupping or scalloping looks like. Of course, I chose the most extreme example that I could find to make it easy to see in a photo. In more typical situations, cupping is usually more subtle, so it is best found by running your hand over the tire and feeling the up and down wear pattern than seeing them.

__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor

Last edited by thstone; 05-04-2013 at 07:32 AM.
thstone is offline   Reply With Quote
Old 05-04-2013, 10:23 AM   #12
Registered User
 
woodsman's Avatar
 
Join Date: Feb 2013
Location: Land of naught
Posts: 1,302
Overdrive: new tires, massively stressed look just like that or, tires grossly underinflated and overstressed--slow leak? Either way they don't seem to be rolling over too much and the trailing lip on the edge of the tread blocks is indicative of tread deformation caused by severe loading (hard cornering)...autocross
__________________
Death is certain, life is not.
woodsman is offline   Reply With Quote
Old 05-08-2013, 02:27 PM   #13
Opposed to Subie Burble
 
Overdrive's Avatar
 
Join Date: Mar 2007
Location: Central CT
Posts: 1,197
Garage
Hey folks. Sorry, was away for a bit, but thank you for the discussion and responses. I will be bringing the car in for an alignment soon and having the shop check things out to see if there are any serious issues throughout the rest of the suspension...hopefully not, but if so then maybe I'll have to accelerate my M030 plans...?

The tires are at least a few years old at this point, though they've yet to accumulate 10,000 miles yet (I know, I know, I'm driving it a lot more now than I used to, gosh...). I'm sure autocross is just destroying their lifespan, but this is really the first time I've ever seen them look like this, and I only noticed it going on a few weeks after the event while using it to commute for work the week I posted those pictures up.

Also, to one person's question above, I've run 36 all the way around for some time, and no, I'm not squared up. I still have the 7inch fronts and 8.5 inch rears. The car used to plow with the placard-recommended 29 up front compared to how it drives with 36 all the way around.

I know these are pretty benign scallops compared to what they could be, but since I'd never seen it before I was concerned that something may be up. I'm pretty sure there are no leaks, but will check anyway. These tires have been solid since I got them, so I expect that I'll see the same 36psi I put in them a few weeks ago 10 minutes before I took off for autocross.

Thanks again, and I'll throw an update up here if there are any discoveries or changes.
__________________
-O/D

1997 Arctic Silver Boxster, 5-spd
IMSR + RMS
Robbins glass window top
Overdrive is offline   Reply With Quote
Old 05-08-2013, 03:20 PM   #14
Registered User
 
Join Date: Jul 2009
Location: Arlington Heights, IL
Posts: 1,557
If those tires are more than 5 years old, they are ready to become a swing.

Why are you autocrossing old tires, and old tires that are all season tires?
Flavor 987S is offline   Reply With Quote
Old 05-08-2013, 03:49 PM   #15
Registered User
 
Perfectlap's Avatar
 
Join Date: Nov 2004
Location: New Jersey
Posts: 8,696
^ sounds like he doesn't want to get summer tires let alone an autocross set of wheels/tires.

Probably not a good idea to start autocrossing (assuming the OP is new at it) on expensive summer tires though. Worse to go out and buy ax tires before you've learned the ropes. Better to tear up what you already have first and get all the mistakes out of your system. Coming to think of it, in these parts that's probably what all season tires are best for... tearing up. They suck in snow deeper than an inch and they are big compromise in summer for such an excellent car.
__________________
GT3 Recaro Seats - Boxster Red
GT3 Aero / Carrera 18" 5 spoke / Potenza RE-11
Fabspeed Headers & Noise Maker
BORN: March 2000 - FINLAND
IMS#1 REPLACED: April 2010 - NEW JERSEY -- LNE DUAL ROW
Perfectlap is offline   Reply With Quote
Old 05-08-2013, 04:55 PM   #16
Registered User
 
BYprodriver's Avatar
 
Join Date: Oct 2008
Location: O.C. CA
Posts: 3,190
Garage
[QUOTE=Homeboy981;340926]36psi ALL the way AROUND? Isn't it supposed to be 29 in the fronts? …unless you "squared" your setup on all the same rims and tires.

Again, that is for COLD tires pressure AND regular driving. If you are going on the track or going to drive more aggressively adjust the pressure DOWN - as the tires will heat up alot more more at high speed. Don't know pressures for AX, sorry.


Porsche specs lower psi in the front tires because there is less weight on the front tires.
If you install larger tires on the front you should reduce psi because the larger tire has a larger volume of air, thus same psi in a larger tire = more air than you had before supporting the same amount of weight. Temporary spare is a good example, smaller tire needs 60psi to properly support the vehicle.

In all situations too much psi is a minor problem, normally only ride comfort is "impacted". Too little psi is always a problem, as every Ford Explorer driver should know!
BYprodriver is offline   Reply With Quote
Old 05-08-2013, 09:29 PM   #17
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Cucamonga CA
Posts: 3,644
Garage
I agree with this from another website. Scalloped tires usually mean worn or bent suspension or possibly out of balance tires.

"Tire is scalloped:
when the tire is scalloped or cupped across the tread it is usually caused by bad shocks or struts. This can also be caused by out of balance tires. Jounce the front end to see if it oscillates and test drive the vehicle to see if it floats and leans excessively around corners. Bad struts are the number one cause of cupped tires."
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor
Topless is offline   Reply With Quote
Old 05-09-2013, 09:27 AM   #18
Opposed to Subie Burble
 
Overdrive's Avatar
 
Join Date: Mar 2007
Location: Central CT
Posts: 1,197
Garage
Interesting. Though they're talking about the scalloping being "across the tread". Am I correct in assuming that means that they mean "across" as the full width of the tread? If so, the only area I'm seeing this happen is the outer shoulder of the tread that I've shown in the pictures. The rest of the tire appears to be fine (of course now I'm going to go double check now that the seed of doubt has been planted).

The suspension is all original as far as I know, but it doesn't feel like it's hurting or doing anything strange. I don't float on bumps or get extra bounces that I can notice while driving.

Either way I'm going to have the tires rebalanced and the alignment done because it's likely needed anyway, and I'll have the suspension checked while they're there. Hopefully I won't get bad news.
__________________
-O/D

1997 Arctic Silver Boxster, 5-spd
IMSR + RMS
Robbins glass window top
Overdrive is offline   Reply With Quote
Old 05-09-2013, 12:46 PM   #19
Registered User
 
Join Date: Jul 2009
Location: Arlington Heights, IL
Posts: 1,557
Quote:
Originally Posted by Overdrive View Post
Either way I'm going to have the tires rebalanced
Don't waste your money if the tires are near 4-5 years old. Buy new. What are your DOT code dates?
Flavor 987S is offline   Reply With Quote
Old 05-09-2013, 12:51 PM   #20
Opposed to Subie Burble
 
Overdrive's Avatar
 
Join Date: Mar 2007
Location: Central CT
Posts: 1,197
Garage
The tires are around 2 years old as far as how long they've been on the vehicle, and were made only a few weeks before I had them mounted on the car, so they're between 2 and 2.5 years old, no rot or cracks in them at all.
__________________
-O/D

1997 Arctic Silver Boxster, 5-spd
IMSR + RMS
Robbins glass window top
Overdrive 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 01:40 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, 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