Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site sunybcs.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!princeton!rocksvax!sunybcs!uggoodjm From: uggoodjm@sunybcs.UUCP (a Model I) Newsgroups: net.auto Subject: Re: tire inflation pressures Message-ID: <1916@sunybcs.UUCP> Date: Fri, 12-Jul-85 20:59:34 EDT Article-I.D.: sunybcs.1916 Posted: Fri Jul 12 20:59:34 1985 Date-Received: Sat, 13-Jul-85 16:39:34 EDT References: <572@hlwpc.UUCP> Distribution: net Organization: WNY TRS80 Users Group Lines: 53 > I just bought new Michelin XH tires for my not-very-sporty > 1980 Chevrolet Malibu, and the guy who installed them told > me to keep the pressure at 34-35 pounds cold. That's the > pressure listed on the sidewall as maximum. I've always > kept my tires inflated to the manufacturer's recommendation > printed in the manual and the door sticker (which for my > Malibu is 26 pounds in front and 29 pounds in the rear) > When I questioned the tire installer about his, he said > in no uncertain terms to ignore the mfgrs. recommendation > and keep them filled to the tire maker's maximum. > > Seems to me the installer should know his tires, but I'm > reluctant to believe him without further comments. > Can anyone confirm or deny this recommendation? > > Carl Blesch Due to problems with the return address at seismo, I am posting this for all of the net to see. To: harpo!whuxlm!whuxl!houxm!ihnp4! Subject: tire pressures\ Did your Malibu originally have METRIC radials. If not, this is the reason for the change in preessure. Metrics have different load capacities than the Alphanumeric series they replace. Another thing to consider, at higher pressure (harder) the tire has a greater load capacity, runs cooler, and often gets the same tread wear or better. The reason is that Detroit (especially GM) has been putting smaller and smaller tires on the same weight car. I have personally seen this as on my 68 Chevy (3800#) the label says 8.85x14 (J78-14). My 72 Chevy (4200#) says G78-15. The tire capacity is determined by the letter, the "higher" the letter, the higher the capacity. The J78 has almost 400# more capacity, yet the 400# more car has the smaller tires. When I bought the '72 I immediately changed to L78-15 on the 72, and run them 2-5# higher than the label pressure. This gives a little harsher ride, but the safety and handling have improved immensely, as has the tire life. All in all, I would stick with the higher pressure, and maybe next time, go one or two sizes larger. Usually one or two sizes won't adversely effect the speedometer, but if it should, your dealer has different size gears for in the transmission case. These are a one bolt job which anyone can do on ramps in their driveway. The dealer can help get the right gear. J. Matthew Good