12-21-2006, 05:42 PM
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to much tyre pressure?
it's raining here in sacramneto....still my car slips and slides...i am running 205/50/16 tyres on my car, front shocks set soft, the rears are still spica, the pressures are 32 psi front and rear.....to much pressure? stock pressure on the 84 spideer for 185/70/14 tyres ae.. front 24 psi rear 26 psi....perhaps i put too much pressure in the tyres?
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12-21-2006, 06:04 PM
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 Quote:
Originally Posted by bianchi1
it's raining here in sacramneto....still my car slips and slides...i am running 205/50/16 tyres on my car, front shocks set soft, the rears are still spica, the pressures are 32 psi front and rear.....to much pressure? stock pressure on the 84 spideer for 185/70/14 tyres ae.. front 24 psi rear 26 psi....perhaps i put too much pressure in the tyres?
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12-21-2006, 06:06 PM
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I don't know about you'res but when I picked up my new, to me, Spider it rode like a buckboard and the handling was spooky. When I checked the 195/60-14 tires they were 35psi and the center of the tread was warn more than the outer edges. Once I lowered the pressures to 25psi all around the handling & ride came back to what I would expect from an Alfa.
Those tires are comming off and I'm going back with 185/70-14. As an added benefit my speedo should be closer to reading correctly.
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12-21-2006, 06:19 PM
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green, nope , brand new only about 1200 miles on them they are hankook 107 tyres, the directional type.may try lower to 30 in the rear, with 32 in the front..a question, because the sidewall are so stiff, that would help with the oversteer i am looking at.
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12-21-2006, 10:47 PM
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Quote:
Originally Posted by bianchi1
i am running 205/50/16 tyres on my car
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i'm with Geezer on this one. try 25 psi. worked better all around for me with similar sized tires.
dont forget, fat tires will aquaplane easier than skinny ones.
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[COLOR="Navy"]Dionisios di Fiflos
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12-21-2006, 11:08 PM
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darth.. i like water skiing, in my alfa  ... not really, i slow down in the rain and keep a lot of space between me and the other cars...and in corners... |
12-22-2006, 02:01 PM
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I respectfully disagree with lowering the pressure in a 205/50/16 to the Alfa Romeo recommended tire pressures. Alfa Romeo gave pressure recommendations for smaller wheel/higher profile sizes that were based on touring based handling. If you want a comfortable ride use the original wheel/tire combo and pressure. If you are going to use larger wheels and low profile high performance tires, then run higher pressure. You can always contact the tire manufacturer for a suggested pressure range. I talked with a Toyo rep about a year ago and he suggested much higher pressures than stock. Based on his suggestion and some playing with pressure to achieve the balance I prefer, I run 32F/30R for everyday driving and 42F/38R when I am planning on doing any "spirited runs." The second set of pressures may seem a bit high but are well within the T1R pressure range and provides for a very neutral setup.
I tried them even all around and found the rear to be less predictable being dificult to get to rotate and other times skittering over bumps. Not saying anyone is wrong but this is my experience and I think bianchi1 is more of a performance oriented driver... I may be wrong 
All that aside, it is important to remain within the manufacturer approved pressure range for your tire.
BTW, I have no unnusual central wear as a high profile touring tire seems to experience with high pressures. I do get the outside edges of the front worn but that is to be expected with -3 degrees of camber.
Anyways, hope it helps. Just my .02
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12-22-2006, 06:18 PM
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i am trying 26 f..28 r. lets see what happends
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12-22-2006, 07:30 PM
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Would not a wider tire use a lower pressure due to a larger surface area?
Given tire design plays a very large role.
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83 Spider Veloce
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12-23-2006, 12:36 PM
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Quote:
Originally Posted by Green Dragon
Not saying anyone is wrong but this is my experience and I think bianchi1 is more of a performance oriented driver...
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Quote:
Originally Posted by Green Dragon
I do get the outside edges of the front worn but that is to be expected with -3 degrees of camber.
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that would cause the INSIDE edges of the tires to wear more. its your driving causing the outside to wear 
Quote:
Originally Posted by Green Dragon
All that aside, it is important to remain within the manufacturer approved pressure range for your tire.
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that's all about liability and the expected cars the tires will be used on. with the large diameter/wide/low profile tires i have run on the Alfa, the pyrometer said to do things different. while it did not seem to change the balance of the car, it did ride MUCH nicer on the street. my thinking behind those results is this : those tires, and their recommended pressure, is based on cars up to 1000lbs heavier. on modern cars, i do run more pressure than recommended, because i also use up the outside edge MUCH quicker than the rest of the tire.
just speaking from experience on a limited number of low-pro tires ( on the alfa ).
in Green Dragon's defence, radial tires have more flexible sidewalls than bias ply, so would theoretically need more pressure ( based on similar sizes and load rating). and i'm sure his experience is at least as valuable as mine. and the manufacturers more so
cheers . . .
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12-23-2006, 12:44 PM
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Quote:
Originally Posted by pillowmeto
Would not a wider tire use a lower pressure due to a larger surface area?
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the tire construction, load, and intended use have the impact on needed pressure.
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12-23-2006, 11:57 PM
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Quote:
Originally Posted by darth dino
that would cause the INSIDE edges of the tires to wear more. its your driving causing the outside to wear ... |
On of the reasons I keep the rear as stiff/pressurized as I do is so that the spider can be rotated with some throttle if I find a corner is sharper than expected or has a double apex. My G-Tech indicated better grip when I increased the pressure but granted those readings are taken on public roads where repeatability is less than desirable. Regardless, a tire pyrometer would definitely be the better way to get info regarding tire response to pressure changes....no argument here. I assume your readings were taken at the track (WS?)
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12-24-2006, 01:18 AM
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so far . 26 front 28 rear feels good. grips well with no oversteer..kind of even front to rear now.and nice ride.
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12-24-2006, 06:33 AM
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Quote:
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i am trying 26 f..28 r. lets see what happends
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12-24-2006, 07:55 AM
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Quote:
Originally Posted by bianchi1
it's raining here in sacramneto....still my car slips and slides...i am running 205/50/16 tyres on my car, front shocks set soft, the rears are still spica, the pressures are 32 psi front and rear.....to much pressure? stock pressure on the 84 spideer for 185/70/14 tyres ae.. front 24 psi rear 26 psi....perhaps i put too much pressure in the tyres?
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with a 205/50/16 you have plenty of tire to flex but if it is a high performance tire you might want to lower the PSI especially in the rain.
24/26 is about right, put 27/29 in and then go down from there. Always add and remove when cold.
Little more tire on the road during rain helps traction and handling. MPG may suffer a but but better than a totaled alfa in a ditch!
I run 31/32 in my 17" on a 164 which is much heavier but it handles and rides 10 times better than at 35/36 range, even though MPG is a bit better.
on the spider I run 25/27
shouldn't you run the front ones at higher pressure than the back ones, given that the fronts have to support the weight of the engine?
Tire pressure results in oversteer and understeer from front to rear. OE spec tire pressures are in place for a vehicle that has not been modified! Even tire size. If you have koni's, springs bars or what not, pressures from front to rear may have to change depending on what you have.
You have to play around with it so your spider feels good and nuetral! Not to much oversteer or understeer.
Ciao!
Last edited by Alfissimo Int.; 12-24-2006 at 08:01 AM.
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