GoLowDrew

The prioritized suspension performance upgrade list (biggest bang-for-buck):
# optimized tire pressures (usually 3-5PSI higher than OEM rating)

http://forums.vwvortex.com/zerothread?id=2486228

3-5 PSI higher cold?

I would be afraid to go 3-5psi higher for DD.

What do you think?

TunerN00b

Higher pressure = reduced contact patch size

Now, increasing the pressure can certainly make the car feel more responsive, as there will be less sidewall deformation as turn in, but max cornering traction and braking distances can suffer if you go too high.

I regularly run higher pressure than Honda specified for an Integra up front. When I ran the recommended pressures, I had underinflated tire wear up front (both shoulders wore faster than the center of the tread). When I auto-x, I run lower pressures than Honda's recommendation, but the pressures I do use were derived from a day of testing with shoe polish on the sidewalls (found the lowest pressure that didn't allow the sidewall to "roll over" under hard cornering). I also use the wrong sized tires for auto-x, and the small stiff sidewall on a 205/40-16 RT-615 Azenis is probably all that allows me to run the lower pressure.

Don't be afraid to adjust pressure in 2 to 4 psi increments to find what works best for your desires, your car, your suspension and tires, and your road conditions. I would recommend not attempting to go lower than 6psi below the recommended pressure, and certainly don't go higher than the tires rated max pressure.

nsxtasy

Keep in mind that Honda varies its recommendations based on their expectations on how the car is going to be used. For example, the Integra GS-R and Integra Type R are both sporty versions expected to handle like a sports car. Honda's recommended inflation pressures of 35 front, 33 rear give the cars very responsive handling. IIRC, the lower Integra models (RS, LS, GS) have lower recommended pressures, in the upper twenties, consistent with their expected mission as economical daily drivers. If you want better handling on an RS/LS/GS, you can easily run higher pressures than recommended; if you want better ride comfort in a GS-R/ITR, you can easily run lower pressures than recommended.

kulo

whats a good setup
im running 35F 32R

TunerN00b

A "good setup" is the manufacturers recommended pressures as a base, with fine tune adjustments based on preference, wear patterns, tires, and driving conditions.

Meaning, you'll need to find those values for yourself.

Besides, without telling us what car (model, sub-model, and year), tires, suspension, and use case (street daily, street spirited driving, track, strip), no one will be able to make any recommendations.

I mean, I have 1 car that is best with 21/26 psi (manufacturer recommended pressures, which sound absurdly low), another at 38/33, and a third at 32/32...

shwanC

iTrader: (3)

^ Truth.

Most times different sized wheels and tires are used on our cars. I've never personally used shoe polish, but I have used cat litter...get the tires hot, and slowly drive over with clean tires to see if any sticks to the sidewalls. This is with 0 degree front camber, very simple. I did this because I didn't know what tire pressure to use on '92 Civic with ITR 16" wheels, 205/45 tire. Around 35 psi in the front is good for me.

1.5Slowmatic

raising 3-5psi will increase your MPG because of the decreased contact patch. if your driving on the highway a lot i wouldn't hesitate to raise it

N.Balauro

Keep in mind that at the track your tires start out cold.... You want to compensate for expansion as the tires come up to operating tempeture (thus increasing pressure since volume cannot change). Cold pressure /= Operating Temp. Pressure.

Also, tire pressures can be used to alter the handling characteristics of your car. A higher pressure, in the front, reduces understeer - decreasing pressuredecreases oversteer. Increasing pressure in the rear decreases oversteer, vice versa.

Finally, increasing pressure in wet conditions reduces the chance of hydroplaning by "rounding" out your contact patch...

BlackDeuceCoupe

I run my tires @ 50 PSI (cold) and they drive just fine.

The only thing you have to watch for is 'cupping'. Rotating them every 5,000 mi is a must!

Sooo, personally, I wouldn't worry about raising your pressure 3-5 PSI. My tire pressure increases that much, when they warm up... even in the winter.

nsxtasy

That's probably more than the maximum pressure indicated on the sidewall, and if so, it's unsafe. They may "drive just fine" right up to the point when they blow out. Don't do it.

Cupping (a scalloped wear pattern) has nothing to do with the pressure you use. Cupping results from a suspension problem, such as blown shocks, worn bushings, etc., which allows play in the tire's movement instead of holding it so it rolls smoothly down the road.

BlackDeuceCoupe

Thanks, nsxtasy, but...

I'm running Ziex ZE-512s. The maximum pressure (cold) is 51 PSI.

SOURCE: http://www.falkentire.com/tires_spec...=400&width=750

Correct (with qualification)!

My ride is lowered, and (yes) the cupping is due to alignment issues. Actually, I've never seen a CiViC that was perfectly aligned (lowered or not) but that's fodder for a different discussion. The thing is, raising the tire pressure exacerbates the cupping, in my experience.

No big deal, as long as i rotate them every 5,000 miles. If I go much over that, the tires never have a chance to recover. They'll bump and shimmy until they're replaced.

alphalanos

Thats the max pressure the tire can safely hold. That has nothing to do with performance or handling etc. Its much too high.

A Blue Lude

Must have an interesting ride, too.

I've run as much as 50psi (quite) hot in the fronts out of necessity, and that certainly didn't feel ideal...

nsxtasy

Cupping is caused by a suspension component that is allowing play. It is NOT caused by alignment, and it is NOT caused by higher tire pressures.

If you want to eliminate the cupping, get the suspension thoroughly checked out by an expert. Shocks, bushings, and ball joints are common causes.

Yup, exactly. Using 50 psi will give you horrible ride quality, and it will give you WORSE handling (since it reduces the area in which your tires contact the road; it's only two thirds of the contact area you'd have with a normal pressure like 33 psi). But hey, if you want bad ride quality AND poor handling, it's your car, you can do whatever you want with it.

BlackDeuceCoupe

Definitely!

If I can expound...

I actually ended up with 2 sets of OEM alloys for my ride - HX alloys (came with the shell) - and Si alloys (from the donor swap car).

I have Pirelli P3000s mounted on the HX rims - and OMG! - it drives/rides like a go-kart @ 50 PSI. They're rated for 44 PSI max, however, I actually went airborne over a railroad track crossing (Dukes of Hazzard Style) at 130 MPH. My fault... I was racing a guy and didn't see them coming! The other guy (in a shower of sparks) almost endo'ed his ride... but my Vic handled it like a champ!

Yes, the Pirellis @ 50 PSI feel like I'm running on solid rubber farm tires, but they handle just fine - if a little skitterish at times.

I have Falken Ziex ZE-512s mounted on the Si rims, and it's a TOTALLY different experience @ 50 PSI. They drive great! Really! My Vic feels like a little BWM with this combo. They felt/drove like mush @ door-sticker pressures!

Anyway, I'm NOT here to argue the point. I'm just saying that increasing your tire pressure 3-5 PSI isn't going to hurt anything, IMHO...

BlackDeuceCoupe

LoL!

Truthfully, I up the tire pressure to increase fuel economy, lessen rolling resistance, and increase acceleration.

LoL! I gotta hold the world record for B16A2 gas mileage (Lifetime Mileage: 40.44 MPG).

Proof: http://ecomodder.com/forum/em-fuel-l...vehicleid=1291

nsxtasy

Now I know we can trust your advice.

BlackDeuceCoupe

Sorry! That ^%$*er just wouldn't give up...

bsmith100

Try it out and see what you think. It's easy enough to change if you don't like it.

Adjusting tire pressure is the quickest and easiest tuning method there is. It is also one of the most effective.

BlackDeuceCoupe

Thank you!

You've crystallized my thoughts exactly!

LoL!

You know... I've been thinking about this thread...

I wonder how many ppl make tire recommendations, based on how well they work... when they're underinflated!?!?!?!

Truthfully, I H-A-T-E-D my Ziex ZE-512s when I first got them. They felt like marshmallows - and I could see why some ppl were trashing them in the threads (including myself)! But, when I boosted the tire pressure to 40-50 PSI, they felt great!

The fact that they're rated for 51 PSI (cold) indicates that they're designed to run at higher pressures... no?

nsxtasy

No. The pressure shown on the sidewall is simply the maximum pressure for which they can safely be used, and is NOT a recommendation for the pressure to use.

Different tires may vary by a few psi, but the big variable in tire pressure is the car, not the tire.

Your car will almost certainly handle better and ride more comfortably, and the tires will wear more evenly and thus last longer, with tire pressure in the thirties than 50 psi.

BlackDeuceCoupe

Depends on whom you believe, I suppose...

Source: http://www.hybridcars.com/gas-saving...ic-hybrid.html

IMHO, 40-50 PSI is the sweet spot, for a Vic!

nsxtasy

The people who wrote that information are idiots. But there are idiots who post here, too, as some of the posts in this topic demonstrate. You can believe the idiots, or you can believe the experts, such as the Tire Rack.

I've seen some people do things that are pretty darn stupid. Fortunately, I've also seen many more people use common sense as well as the advice of experts. It's your car, and you can decide what to do with it.