[ds968]

I finally found the steering " feel " I'd want in this car ; I took the tires psi down to 20 and drove for about 30 min on various roads, a bit of highway driving as well, keeping it under 80mph and making sure these were roads I knew inside out, avoiding possible nasty surprises like potholes where I can end up with a bent wheel, but that said, the impression : the steering fedback feels absolutely perfect ! For a while there I thought I was driving a real sports car .. Sigh..

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[Rap]

What made you think to go that low?

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[Cloud9...68]

Yeah, 20 psi is top fuel dragster territory, isn't it <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" /> ? Let me check the calendar - it isn't April 1, is it <img src="/forum/images/smilies/968/tongue.png" class="smilie" alt="" /> ? I'd be concerned about tire longevity, rolling resistance, and, as you said, risk to your wheels. It wouldn't hurt to contact your tire manufacturer and run this by them. But if they give you the all clear, and you're OK with the potential compromises, then I guess it's all good...

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[ds968]

Oh, not a chance...there is no way I'm ever going to run tires that low, this was just a brief experiment out of curiosity to see how the car feels.. A couple of years ago, Flash took tire temps readings on my car, both front and rear and for the suspension set up that I have, and with Michelin PS2, the ideal cold psi was deemed to be 29 front and 30 rear. Before the readings I had them about 2 psi higher than that , all around.

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[Cloud9...68]

Ah, so it was just an experiment. I misunderstood; I thought you were planning to leave them at 20 psi.

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[ds968]

Well, did think about it for a second , but then came to my senses ..

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[Cloud9...68]

Did the steering effort increase significantly? I wonder if you would get a similar improvement in road feel by removing the power steering belt. I'm trying to remember if that's safe to do, though. I seem to remember reading about some issue with doing that.

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[flash]

ds968 - remember though that those are not static figures. in winter time in southern california you need to bump up 2-3lbs, and in northern california more like 3-4lbs over what you would run in the summer.

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[ds968]

Bump UP in winter ? ( " winter " in !NorCal relatively speaking ,lol.. with blistering cold mid 60s ..) So if the air is colder outside , you want more air in your tires ? I would have thought it would be the other way around. Now I'm confused , I was under the impression flatter tires heat up faster.



Anyway, the eight months out of the year when the temps in this area usually stay more of less within a 10 degree delta, I have done the chalk test on multiple occasions and it seems the ideal contact , again with PS2s and with my suspension / ride height, etc , was made when at 31 cold. But after the heat test at Bob's house I took them down a notch. Also a number of people at well known tire shops insisted I should keep my tires even lower, at 25 psi, for best performance all around, although they did indicate that would wear the tires out faster and the gas mileage would suffer..but I don!t care about either of those things, so I thought about doing that, if it wasn't for the risk of hitting a huge pot hole ( plenty of them here in the pathetic road conditions of our state ) where I'm not confident that 25 psi is sufficient to protect the rim.



Yes, 20psi felt as if I had no power steering which I really liked, and the car felt more planted then ever both on straight aways as well as in turns ( but I did not take those at really high speed, pushing the car all that much..) . I do remember the couple of threads on removing the power steering belt and I also recall the conclusion was that it would cause a bunch of headaches , but I no longer remember the specifics of what and why... Just that it wasn't as simple as one might think.

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[94SilverCab]

20 psi is beach driving territory...hmmm...968 dune buggy <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[flash]

yes, because the tires won't heat up as much



remember that the target temperature is measured HOT. this is regardless of ambient temp. checking them cold is only anticipating the heat increase based on things like ambient temp and driving. in the summer you will see 4-5lbs increase (depending on how you are driving, with high speeds increasing temps more than low speeds). in the winter you will generally only see 2-3lbs increase.



p.s. i ran 3.5lbs (not 35) in the paddles on my sandrail, and 9-10lbs on the fronts

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[ds968]

got it, thanks.

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[ds968]

• ot, but still related.. the door sticker on our SUV ( Pathfinder ) indicates just 26 psi for tires, all-around <img src="/forum/images/smilies/968/ohmy.png" class="smilie" alt="" /> On a friggin' SUV ?! Isn't such a low tire pressure on a vehiccle with a high center of gravity a huge rollover risk the moment you try to make a sudden or sharper than usual turn / maneuver ? What to do ?
  
  

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[flash]

not really. the denali is only 30. i've tried other pressures too, and 30 is right, unless i'm towing, and then i bump it up a couple of pounds.



there is a lot that goes into determining the correct tire pressure, not the least of which is load capacity and tire expansion

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[bombfactory]

I just installed a set of PS2's (18") last weekend and have them currently set at the 'usual' 36 psi. I've noticed the ride is quite harsh and the road noise is literally deafening - I thought something had gone wrong with my alignment! After reading this I think I'll bleed out a few pounds and see if things improve.

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[flash]

road noise??? those are some of the quietest tires out there. if you have road noise, the pressure could be too LOW, not too high. google it.



harshness could easily be shock or strut settings. they may be too stiff. fixed compression gas shocks and struts frequently have this issue, which is why i hate gas on these cars, especially on the back.

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[bombfactory]

I didn't double-check the pressure, but the guy who mounted/balanced the tires asked me what pressure I wanted and I picked 36 as a starting point. They definitely don't feel soft, as the ride feels a bit harder than with the old tires, which I was not expecting. I need to dial the front struts back to where they were as well.



Flash, I agree - PS2's are fairly soft and should be nice and quiet - I have them on the M3 and they are really quiet and smooth - but the tire noise I'm getting now is crazy loud! I can't hear the engine or exhaust and have to crank the stereo to hear anything. I noticed it right away - as I said, I thought something might be wrong with the alignment. The geniuses (Sears Auto Center) lifted the car up using the rear lower shock mounts and the rear area of the front control arms as lifting points - unfortunately I didn't see this until it was already up.



I was thinking something might have gotten bent, but wheel angles all look fine, and the car handles and steers just like before (well, a lot better actually!), and the noise is coming from all four tires. Hmm...

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[flash]

are the tires directional? i can't remember. if so, are they on right?



are those new? used tires can do weird things, which is why i never use them



could be a separation too

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[ds968]

Something is out of whack, PS2s are dead silent, even after 25k or 30k + miles on them and Michelin ( especially the PS series ) have the highest consistency in mfg / QA of anything on the market, so the chance of getting a bad one or a bad set is one in a million . IMO, has to be something else causing the noise.

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[flash]

lol - yet i think midblu got 2 bad ones



but i'm not knocking michelins. i love those tires, and may put them on the SL550

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