Brcobrem

Hi 1st Gen Forum,

My 2000 RX300 had new 225/70R16 Michelin's put on about 9 months ago (before I owned it). The valve stems have those green plastic caps that indicate he paid to have nitrogen put in them. I checked them for pressure and they all say 35psi. However, the door sticker says 30psi.

I've talked to a couple people and they say leave it at 35psi. I thought I'd see what the Forum had to say about that.

I look forward to your thoughts.

Regards,
Brcobrem

P.S. Based on my research and the ~$200 it costs to get a tank, regulator, nitrogen, etc, I'm not gearing up for nitrogen here. An in-line water moisture remover on my compressor will be good enough.

hypervish

35 psi is fine, that's what I use in the summer, and anytime I go on a road trip. During the winter I drop them down to 32 psi for better traction, and a smoother ride on salty roads.

Brcobrem

Thanks hypervish. I'll leave 'em alone at 35psi. Point well taken on the 32psi in the winter.

In recent years, I've yet to see a tire wear out in the middle first. This is sort of "old school" and imho: With the alignment good and the tires warmed up, draw chalk lines across the tires, drive straight forward as appropriate (big flat parking lot works good for this), and note if the chalk is wearing evenly across the tire (or wearing off outsides or insides first). Although not right for every situation, that can give a visual clue that they're inflated properly for normal street driving. Just something I remember from days gone by.

Regards,
Brcobrem

Stemmer

Although the OP's question was answered I just wanted to pipe in that despite the door sticker telling me 30 psi, at that pressure my RX would lose traction on wet turns, and squeal around turns at any modest speed. At 35 psi all problems solved.

Brcobrem

More good feedback.

At their current 35psi, they look like they're properly inflated and that's how I'm going to keep them. Perhaps the 30psi on the sticker works for those drivers who want what we used to call a "lead sled soft ride" (ie. "lead" as in the heavy metal).

Thank you Stemmer :-)

lexina

35psi in general is good. however, tire pressure depends on tire brand and model, also if there is burden weights associated with it, not to mention about climate temperature. Different brands, diff models have different sidewall softness. The best is to increase the pressure up until you feel the roughness then decrease it 1.5 psi or decrease it to the point where you feel comfortable with your road environment, then stick with that pressure for that brand for the tire. Of course you will have to watch for the max tire pressure allowed. There is a formula for the tire pressure, but to me that is still just a general rule of thumb.

Brcobrem

Thanks lexina. Many good points made.

I have an older sports coupe that likes to take V rated tires. That's 4 plys on the bottom (2 nylon + 2 steel) and 2 plys nylon on the side. They look like street legal dirt/asphalt track tires. They stick like glue, but are a dry weather tire and not for rain. Before you put them on the rims, the bottom is so stiff that you can barely, deform it by hand. That's actually the tires I "chalk" to get the pressure and wear characteristics right.

The RX300 is my first ride that's not a car and I don't do pickup trucks, so I'm not up on all the peculiarities of this weight class of vehicle. I didn't put the Michelin's on it personally, so I didn't get a "feel" of how these tires were constructed.

Regards,
Brcobrem

trhs75

It's always puzzled me that no matter what tire is on the car, the manufacturer-recommended pressure doesn't change. I would think the ideal pressure would depend more on the tire than on the vehicle, but I'm certainly no expert.

varithms

I bumped mine up to 35 also. It keeps the tires from balding the out sides of the tires.

sktn77a

iTrader: (2)

Same experience. I stuck to the manufacturers recommended pressure for the first 3-4 sets of tire but had premature wear on the inside and outside tread. I run 35-36psi all round now and have even wear!

PaulDaisy

Mine are at 30 psi and wore out evenly. I change tire pressure a lot in my truck as the load changes or if I tow but in the 300 I don't. I noticed that a lot of time higher pressure will gain a bit of fuel mileage but you reduce the compression of the tire so tire works less and suspension works more, especially on bumps. I try to keep tires as low as reasonable and go by even tread wear pattern. Replacing suspension parts is much more PITA than watching the tires, which are replaced regularly anyway.