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Just bare in mind all the Porsche's recommended adjustments are a compromise. This includes tire pressure, alignment specs and all possible parameters. The fact that you lowered your car and perhaps drive a bit conservatively when it comes to cornering, the weight, load and how you take a line all have direct impact on the tire wear. I would start by decreasing tire pressure, because Porsche 911 rear tires are very wide and any more air pressure tend to load the outside more so than the average sedan.
Just bare in mind all the Porsche's recommended adjustments are a compromise. This includes tire pressure, alignment specs and all possible parameters. The fact that you lowered your car and perhaps drive a bit conservatively when it comes to cornering, the weight, load and how you take a line all have direct impact on the tire wear. I would start by decreasing tire pressure, because Porsche 911 rear tires are very wide and any more air pressure tend to load the outside more so than the average sedan.
Good point - especially when it comes to pressure. If that center rib is worn more than its neighbors, than your pressure has been a little too high. Would not account for the wear on the inboard, but it would provide more even tread contact (and wear). Tires, no matter what, are always a compromise. Finding the best compromise for the given task is what we are all after.
my tire wear isbasically identical to yours, and I got twenty thousand miles out of my Continental all season tires and I just replace them with some Michelin a few weeks ago. I would not be concerned
20,000 miles! Damn, I'd be thrilled if mine had that kind of mileage. I have yet to get more than 8000 miles out of any rear tire...and I drive like Miss Daisy.
20,000 miles! Damn, I'd be thrilled if mine had that kind of mileage. I have yet to get more than 8000 miles out of any rear tire...and I drive like Miss Daisy.
I've got 5k miles on my pilot sports. Perfect wear pattern and tons of life left. I would bet the average person thinks they are new
Just bare in mind all the Porsche's recommended adjustments are a compromise. This includes tire pressure, alignment specs and all possible parameters. The fact that you lowered your car and perhaps drive a bit conservatively when it comes to cornering, the weight, load and how you take a line all have direct impact on the tire wear. I would start by decreasing tire pressure, because Porsche 911 rear tires are very wide and any more air pressure tend to load the outside more so than the average sedan.
Interestingly enough, I ran 40psi (44 recommended) in this set from day one. Every set I've had have worn the centre more than sides, as can be seen in the picture with the straight edge. I was concerned about going much lower in pressure with the low profile of the tires.
I've got 5k miles on my pilot sports. Perfect wear pattern and tons of life left. I would bet the average person thinks they are new
It's comments like this that make me feel like something isn't right. There was a new set of BS S04s on car when I got it. Inside edge to cords in 5000 miles. Replaced with Falken FK453s and had it realigned. That set of rears lasted about 7500 miles. Another set of Falkens, alignment and about 8000kms. Michelin PSS, alignment and this wear and mileage (6800 miles). First sets I stick with factory recommended tire pressures (44psi rear), Michelins I dropped to 40 psi. No drag racing, no significant high speed runs, three track days each year. Majority is city, back road and highway.
It's comments like this that make me feel like something isn't right. There was a new set of BS S04s on car when I got it. Inside edge to cords in 5000 miles. Replaced with Falken FK453s and had it realigned. That set of rears lasted about 7500 miles. Another set of Falkens, alignment and about 8000kms. Michelin PSS, alignment and this wear and mileage (6800 miles). First sets I stick with factory recommended tire pressures (44psi rear), Michelins I dropped to 40 psi. No drag racing, no significant high speed runs, three track days each year. Majority is city, back road and highway.
My cars alignment specs were dead on perfect and the suspension was stock (coilover installed yesterday, wheels on order and fully adjustable control arm will be ordered in ths next few days). Tire pressures are exactly what the factory calls for (36 and 42 if i recall). My rears are perfect and my fronts have very very very minimal feathering.
I can only assume that your issue is due to lowering it and the camber not being able to be put in spec.
Here is my right rear, the left rear looked just like it and my two fronts were not worn at all. These were Continental DWS all season tires. They were on the car for about 18,000 street miles, I run about 34 PSI or so. When you looked at the rears without getting under the car, they looked great....but go under the car and you'll see the inboard shoulder is completely worn compared to the outboard shoulder. I put some Michelin Pilot Sport 4S's on them. They are sticky! But the car is in hibernation.
Here is my right rear, the left rear looked just like it and my two fronts were not worn at all. These were Continental DWS all season tires. They were on the car for about 18,000 street miles, I run about 34 PSI or so. When you looked at the rears without getting under the car, they looked great....but go under the car and you'll see the inboard shoulder is completely worn compared to the outboard shoulder. I put some Michelin Pilot Sport 4S's on them. They are sticky! But the car is in hibernation.
Interesting. This looks very much like my last set of Falkens. Still concave wear with inside shoulder dead. Difference is in the mileage
I was just thinking about tire pressure yesterday.
What's the lowest one can safely go?
I know the front is light and could use less than the tire manufacturer suggest.
Commuter car with nice twisty roads to and from work, down hill in the morning and uphill home makes for a great end of the day.
20,000 miles! Damn, I'd be thrilled if mine had that kind of mileage. I have yet to get more than 8000 miles out of any rear tire...and I drive like Miss Daisy.
Paul's are all-season so 20k sounds normal I don't think any rear summer tires will last anywhere close to 20k.
I was just thinking about tire pressure yesterday.
What's the lowest one can safely go?
I know the front is light and could use less than the tire manufacturer suggest.
Commuter car with nice twisty roads to and from work, down hill in the morning and uphill home makes for a great end of the day.
I'm not going to touch the - how low can you go question. However - I will offer some ideas.
Use an IR temperature gun (or better yet, a tire pyrometer). At the end of a spirited drive (push hard - as much as traffic and road conditions allow) - check the inboard, center and outboard tire surface temperatures. Do this as quickly as possible after stopping. Log the data over several trips and look for trends. Hopefully your drive will have an equal number of rights and lefts. If not, try to look for a mid-point stop that is close to the balance of direction and severity. You can also focus on just one side at a time - take what is learned and apply to the other side.
Once a decent set of data are captured, analyze for ways to equalize the readings. I.e. if the center is warmer than the sides, you can drop pressure. Any changes should be in small increments (unless temp deltas are large). If one side or the other is hotter, than camber change should be considered. It's unlikely you would ever get temps uniform, even after much testing and refining. Just getting things closer will be a good step.
Surface temps will drop quickly. Be sure to note the order in which each tire was checked. Mix this up so enough data is collected with the LF checked first, etc. Then move to a different corner as first up, for additional data-sets. It will probably take a lot of trials - but the more data you have to work with, the more likely a good picture will emerge. Some data sets will be ruined for any number of reasons (rain, cold, speed, etc). Keep the data - but be sure to note what happened and why it should not be used for any calculations. Consistency in testing is key.
Interestingly enough, I ran 40psi (44 recommended) in this set from day one. Every set I've had have worn the centre more than sides, as can be seen in the picture with the straight edge. I was concerned about going much lower in pressure with the low profile of the tires.
Factory spec (44psi) assumes max load, 3-4 passengers, stock tire size does well at about 36psi if normally driven alone.
01-27-2019, 07:36 PM
