15 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHRear tires have bumps, not true anymore ? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Leading reported evidence
Replace rears at grand prix performance
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
Replaced the rears at Grand Prix Performance yesterday.
Rear tires have bumps, not true anymore ? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Read full discussion summary
Leading evidence: 'Replace rears at grand prix performance' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Recommend service life and can experience tread separation issues' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Recommend service life and can experience tread separation issues
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
If your tires are older than 6 years, they are past the recommended service life and can experience tread separation issues.
Rear tires have bumps, not true anymore ? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Replace oem shocks at 50k, i have 54k
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Several sources recommend replacing OEM shocks at 50K, I have 54K on the '98 base model.
Rear tires have bumps, not true anymore ? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Coverage and how to read this overview
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
15 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
986Forum: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T022239Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I started hearing a faint whup-whup-whup at certain speeds. Put the car on the lift and found both rear tires were not completely round, certain spots had-for lack of a better word-bumps.
Bought this '98 with 38k miles and put on another 10k the past two years.
Any idea what caused this ?
Below is a good basic chart to read your tire wear with problems and likely causes/solutions. Which size and model of tire exactly?
HOW TO READ TIRE WEAR
If your tires are older than 6 years, they are past the recommended service life and can experience tread separation issues. Get some new tires before you have a blowout or tread separation, and risk of an accident.
Thanks for the feedback, the tire separation video is great.
The tires are Pirelli 255/40/17 P-Zeros. The "bumps" are on the tread and are too subtle to get a good picture.
Question: Is there a date of manufacture on the tire ?
And, yes I'll replace them.
If the bumps are that small it could be caused by worn struts or the alignment being off.
All tires have a date code at the end of the serial number after the DOT the stamped number is 4 digets & the last diget is the year.
The date code should be at the end of this string;
DOT XT DD 9857
_ _ _ _.
It only has to be on one side of the tire, so it's possible it's on the inside wall.
*edit*
By the way, the four missing digits will be the week of the year, followed by the year.
Serial # is molded onto the tire, date code is stamped after the molded #
Another sign the tire rubber is hardening is cracks in the rubber. Worst place is right next to the wheel rim
The complete string is:
DOT XT DD 9857 1008
So, they are 2008 tires. Thanks for the tips on reading the date code, learned something new.
I bought the car in 2010 with 38K and put 10K on since I got it. Seems like my tire life is pretty consistent with others I've read.
I have had bumps on the tread portion and sidewall of tires before and it is basically some sort of internal structural failure of the tire.
Get rid of those tires ASAP they have failed and could be dangerous to drive on.
Replaced the rears at Grand Prix Performance yesterday. They called it cupping and I had been inflating them to 32 lbs. Tomorrow, they are doing an alignment, the tech said it was close, but better to dial it in.
Several sources recommend replacing OEM shocks at 50K, I have 54K on the '98 base model. It's all been generic driving, no AX, no spirited driving. When I push down on the body -at the corners- the rebound is stiff, and the car never rolls on curves. I assume the shocks are fine....
This is a source reference. Confirm exact model applicability in the original material.
