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Post by Letitroll98 on Oct 10, 2004 22:22:05 GMT -6
Also let us know what pressure you use. I've been running a rear bias with 32lbs in the front and 35lbs in the rear, cold pressure. This tames a lot of the understeer in this front heavy car.
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Post by omegaic on Oct 10, 2004 23:08:46 GMT -6
30/30 just like the sticker told me.
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Post by JimW on Oct 11, 2004 6:45:23 GMT -6
35/30 with the 55 series tires.
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Post by SupaStealth on Oct 11, 2004 8:00:05 GMT -6
38/38 for me
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scottydl
Super Moderator
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Oct 11, 2004 8:19:32 GMT -6
I stick with the factory sticker recommendations as well. The car is track-tested and rated that way for a reason, I figure.
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dred98
Aurora Driver
Posts: 470
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Post by dred98 on Oct 11, 2004 8:24:38 GMT -6
I stick with the factory sticker recommendations as well. The car is track-tested and rated that way for a reason, I figure. Me too - I don't think I'm qualified to second guess the factory recommendations..
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Post by Aurora40 on Oct 11, 2004 9:46:26 GMT -6
I run 33/31. I always put a little more air in than the factory recommends because the tire will always lose air, but rarely gain pressure.
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Post by Marc on Oct 11, 2004 13:18:36 GMT -6
Same as SupaStealth. _______________ GM!!! BRING BACK OLDS!!!
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Post by Letitroll98 on Oct 11, 2004 15:10:41 GMT -6
Very interesting. No one running a rear bias except me. Both classic and 2nd gen are very much weighted to understeer. With a front driver rule of thumb is to either lower the front pressure or raise the rear pressure, something that goes against common sense. This really helps balance the car.
Also, as far as track tested goes, does anyone test their tires with a grease stick, i.e. put a stripe an inch up the sidewall and run some cones to see what rubs off? You can fine tune the pressure setting for maximum efficiency this way. (I cheat and just use the lines in an empty parking lot)
Thnx so much for the input guys, how 'bout the girls?
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Post by stevensolds on Oct 11, 2004 17:06:25 GMT -6
i keep mine at recommended level. although i agree with what letitroll said to keep the rear a little higher to tame understeer, i dont go 90mph around bends anyway. i only go that fast on straight highway. if only it would stop overheating once i go fast, that would be great
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Post by Aurora40 on Oct 12, 2004 7:39:27 GMT -6
I put more in the front because of the huge weight difference on the front wheels. Having a higher pressure for a heavier load is safer for the tire.
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Post by kobalt on Oct 12, 2004 8:47:23 GMT -6
I too run rear-biased. 27front 30rear. I experience better ride quality this way too. But it may change once I put new tires on.
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Post by Rocketv8 on Oct 12, 2004 16:14:55 GMT -6
33 front/ 31 rear... i dont know about anyone else but the front tires on my 97 always look awful low, even when the gauge says they are ok....i think its because the car is so heavy up front, either that or i need shcoks/springs up there
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Post by Letitroll98 on Oct 13, 2004 12:39:10 GMT -6
Quite right Aurora40, under inflated tires can be a hazzard. That's why you also have the option of increasing the rear tire pressure. As for "factory recommendations" how many of us are riding on OEM tires? These are the same guys that designed every single thing that has broken down on your car. I'll go by the tire manufacturer's recommendation range and my own testing thank you very much.
RocketV8 (and others) you can reduce that "heavy" feeling of the front end by raising the pressure of the rear tires relative to the front tires. I know, I know, it sounds really wierd, but it is founded in standard handling setup for rally with front wheel drivers. Just as the opposite works for rear wheel drive.
You can set you base pressure with a grease pencil. Make a stripe 1 inch up the sidewall from the tread. Run some handling course as fast as you want to drive. If you rub off half of it, pressure is about right. Too much off, increase pressure, opposite for too little rubbed off.
How about all you doubters giving it a try and report on your results. Would be a great way to shut me up if I'm wrong. ;D
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Post by Aurora40 on Oct 13, 2004 15:00:51 GMT -6
How about all you doubters giving it a try and report on your results. Would be a great way to shut me up if I'm wrong. ;D I don't think anyone was doubting you. We just don't run the same pressures as you.
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Post by Letitroll98 on Oct 14, 2004 17:24:32 GMT -6
Ok, Ok, I get the hint, sorry to preach. I'll shut up now.
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Post by kobalt on Oct 15, 2004 0:14:33 GMT -6
Rear biased tire pressure does make sense as BMW and Mercedes runs most of it's sedans this way - these Germans do know something or another about handling; my 530i did handle better than any other car I've owned and that's with 160k miles on the odometer and suspension that needed serious work. Granted, the weight distribution was 50.5/49.5 and RWD, but it was a sedan of similar dimensions and just as heavy as the Aurora
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Post by JimW on Oct 15, 2004 5:42:57 GMT -6
Wouldnt the rear wheel drive impact this "rear biased" air pressuring? Overall I am less then impressed with the Aurora suspension (pre 98). Its not built for going around corners, once a suspension upgrade occurs and I have wider summer tires I may have to try this rear biased setup. Great thread folks
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Post by kobalt on Oct 15, 2004 16:36:19 GMT -6
Wouldnt the rear wheel drive impact this "rear biased" air pressuring? I can't argue that one Jim I must add an observation of mine, however. My Aurora seems to respond favorably to rear biased tire pressure. Could it be because of Oldsmobile using independent parallel trailing arms in the rear suspension, a designe favored by BMW to perpendicular lower control arms AND one commonly found in other FWD sedans? It makes one think...
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Post by Letitroll98 on Oct 15, 2004 17:37:13 GMT -6
Not really. BMW and Merc recommend rear bias to tame oversteer on their powerful rear drive cars. Front bias would make them twitchy on throttle. The bugaboo with almost all front drivers is understeer, even my GF's Probe GT will understeer at the limit. So although independent suspensions and other factors always come into play, my preferences apply to to the Aurora because it has heavy understeer during normal everyday driving. Connie's Probe needs almost no bias for normal driving because of other factors in it's suspension tuning, but if going out to rally with it I would adjust tire pressures accordingly. (She would kill me if I took it racing) And I said I would shut up.
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Moe2244
Aurora Newbie
Black 95 Aurora
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Post by Moe2244 on Oct 27, 2004 18:17:23 GMT -6
I always ran with 40 psi front and rear. I was afraid that 30 pounds wasn't enough. I'll try 35 first to see if there is a difference.
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scottydl
Super Moderator
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Oct 28, 2004 8:25:56 GMT -6
Just out of curiousity, what would make you think 30psi is not enough... especially if that's what the tire is rated for?
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Moe2244
Aurora Newbie
Black 95 Aurora
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Post by Moe2244 on Oct 28, 2004 12:32:19 GMT -6
Lack of experience I guess.
I thought that if you inflate your tire to 30 lbs, it's possible to loose some of the air pressure do to natural circumstances. A tire down to, let's say 27 to 28 lbs, doesn't seem sufficient for a car so heavy. Hitting a bump or whole in the street at the right speed, may cause some damage to the tire or rim.
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Post by Letitroll98 on Oct 31, 2004 0:56:58 GMT -6
Hi Moe2244. The pressure you set your tires at is partially independent of the biasing issue. In other words you could leave you fronts at 40lbs and increase pressure in your your rears. (Oh, that sounds perverted) Or you could leave the rears at 40lbs and lower the front pressure. I set my base pressure with a grease pencil mark one inch up the sidewall, then increase the rears 3-4lbs over the base I set. I vary the base pressure all the time based on weather, time of year, and my mood that day.
Manufacturers all give different pressure recommendations for different tires. If you check pressure regularly and keep it above mfg minimums, I wouldn't stress a bit. Sustained rally speeds, towing a heavy trailer, a loaded car full of family and luggage driving highway speeds all day? Then stress on your tire pressure. Otherwise I recommend playing with it. A lot, and often. (That also sounds perverted) I started this survey hoping to spark some controversy and get folks re-examaning long held beliefs. Have some fun with tire pressure!
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Post by Aurora40 on Oct 31, 2004 7:51:51 GMT -6
In addition to keeping minimums in mind, tires have a stamped maximum pressure. If you set your base at 40 psi, then raised the rears, you'd be in dange of exceeding the maximum of just about any tire. Some tires have a max pressure of 35 psi, but more common on car tires, especially of a decent speed rating, is 44-45 psi.
Just be aware of that as well. If you set your tires at 40-42 psi or so in the winter, and don't check them until summer, they could easily have raised to over 45 psi.
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Post by SupaStealth on Oct 31, 2004 10:14:47 GMT -6
Just be aware of that as well. If you set your tires at 40-42 psi or so in the winter, and don't check them until summer, they could easily have raised to over 45 psi. That is for those of you who live where it's a lot colder in the winter of course (gotta love Minnesota)
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Post by Aurora40 on Oct 31, 2004 12:37:31 GMT -6
That is for those of you who live where it's a lot colder in the winter of course (gotta love Minnesota) I live south of the Mason-Dixon and would have that problem. Tire pressures will change about 1psi per 10 degrees F of temperature change. Here in Virginia, the temp swings about 65F between highs in summer and lows in winter. Even in Miami, FL, the average temps change by about 25F between the average low in winter and the average high in summer.
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Post by Letitroll98 on Oct 31, 2004 22:19:00 GMT -6
Quite right on both posts Aurora40. Could I add two things? One, maximum tire pressures have a fudge factor built in for heavy loads in that you can safely exceed them by about 6 psi when towing or loaded up with passengers and cargo. Two, anyone not checking their tire pressure for enough time to pass from winter to summer is probably not reading this thread.
It all reminds me of Tom Wolfe's book "Fear and Loathing in Las Vegas" when the protaganists inflate the tire pressures of a rented white Cadillac (the White Whale) to something like 75psi to "improve the handling". ;D
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