Falken Azenis tire pressures for AX Options

[Racer]

So.. I found one of the few sporty tires for 14" rims for my 914. Falken Azenis RT615-Ks. 195-60-14.

So far, I really like them. However, I can't seem to tell a good pressure for them at AX. First even started at 35 cold all around.. felt ok, and kept bleeding down to 35 as they heated up. Car felt good, but did feel as they heated up I was losing grip, hence the bleed downs during the day

Second event, didn't check cold (slow brain) but bleed them down, hot to 32ish. Couldn't really tell if they were better or worse than 35 hot...

My previous 914 and R comp experience was 205-50-15s (smaller sidewall) of Yoke A008, A032rs, Kumho Victoracers, RA-1s. For those, I never ran more than 30hot.

What could be skewing my memory/preferences is the last 3-4 years I ran a stock 1987 944, 215-60-15s Fuzion xxxx's and they really felt good at 35 hot all around.

Thoughts? Should I be closer to 30 hot with these too? Perhaps I fear too much sidewall flex for the 60 series tire...

[wndsrfr]

This won't help much, but I'll pass it along. My son is running the Azenis's on his asphalt 1/2 mile circle track car (FWD Prelude)....cold pressures 40psi right front, 35 left front, 30 right rear & 20 left rear (which is just along for the ride on a left turn only track). So, take your pick! Tires show tread "rolling" & "worms" in the 25 lap heats but seem to be holding up.

[ThePaintedMan]

This is highly dependent on your ambient temperatures, how stiffly the car is sprung, horsepower, weight, etc. But for me, with a stock 1.7 or 1.8, I run in the neighborhood of 23 front and 26 rear, HOT. This may sound rediculously low, but with such a light car with very little power and not super-high spring rates, you want to make the tires do some work. I found with these pressures I was getting a fair amount of rollover on the tire, indicating a pretty good contact patch. On really hot days, I've even gone lower than that. I run a little extra psi in the rear to help coax the rear end around since it's damn near impossible to produce any kind of throttle-on oversteer with a stock motor. Keep in mind this was also with 205/50/15s. But don't be afraid to experiment.

Also, this is a very basic indicator, and isn't as scientific as checking tire temps, but you can check your rollover triangles at the top of the sidewalls of the tire. You will ideally be looking to get the tires wearing right near the top of the triangle if your pressures are right (and you're driving the car as hard as it can go).

[Cracker]

I'm with George...my experience will not help the OP with THOSE tires but...

I run my Hoosiers at 25-27 hot - means going out at 17-20 cold taking into a variety of factors. A tire with lower pressure also provides a larger safety net with how it releases. Again, this may not be helpful to the Azenis but for what its worth.

PS: I go out in my DSR at 10-12 PSI! The cars weight rules the day...then you take into account the other variables.

Tony

[Jetsetsurfshop]

I was told your air pressure should match the vehicles weight.
10lbs for every thousand pounds. Of course its just a guide.
We ran those tires for Chumpcar last year and George worked on the tire pressures during the pit stops. I think our hot pressures were like 22 front/24 rear. I could be wrong, I was on gopro duty.
Never AXed them though.... (IMG:style_emoticons/default/driving.gif)

[ThePaintedMan]

Agree on both counts. Hoosiers on a DSR/SCCA P2 rarely exceed 14-15 psi. It's all about contact patch. I watched the tires we ran on Shane's car and you get a pretty good picture of what they're doing by the rollover, particularly when every driver is pushing their hardest. By the end of the day, the car was HOOKED UP, and is a ton of fun to drive. Shane built a great car.

For you, don't be afraid to take air out - as long as the bead is still holding, you're fine.

[Borderline]

You might try just changing one end of the car at a time. If the car is understeering leave the rear pressures alone and try adjusting the front pressures up/down to see if you can find a better pressure. Also everyone seems to like a 2 psi differential front to rear, run what works for you. FWIW

[Alphaogre]

Is there no general formula that can get you within a good window? This way no matter what tire you run, you could figure a good general setting and then adjust to track temp and feel? I feel like every time I ask someone I get different answers... (IMG:style_emoticons/default/confused24.gif)

Wouldn't you want to factor the side wall height and how much you roll over on your side wall to be a factor too? if you are running a 55 to 60 tire height?

[ThePaintedMan]

Alpha, sorry I forgot your name. Anyhow, what Shane (JetsetSurfShop) posted above is a pretty good baseline for many tires. 10 lbs for each 1k lbs will work as a decent cold setting for what most of us use our cars for. In general though, there is no perfect "go to". There are too many variables - what is the intended use of the tire? Street? Track? Autocross? Drag strip? Each application requires the tire to do different things, and each tire is constructed differently than the next. As some of the other guys have mentioned, slicks are a WHOLE different ballgame, as are super light cars and when you throw aero into the equation, it gets even more confusing. It's important to be able to at first, visually read the tire. Look for the rollover marks. If you're not hitting them, then your pressures are *maybe* too high, or your are *perhaps* not driving hard enough, or the spring weight on that corner *might* be too low, etc. That's why the engineers get paid so much money - they can determine which is the limiting factor by using onboard telemetry/data. But by reading the tire visually, and when you're ready, buying a pyrometer (to measure tire temps), you'll learn to maximize the work done by the tire.

There are a number of books out there that explain how to setup a car and understanding chassis/tire dynamics. I'll have to dig up a few links for you.

In the meantime, the next time you take your car out, you can bring a piece of chalk with you and mark the sidewall of the tire. By the end of the run, you'll see whether you're rolling into the chalk pretty visibly by how much shorter it gets. To answer your question, yes, there is some consideration for the sidewall height (actually referred to as the aspect ratio), given all other things equal. However, each person has their own tire choice, so you need to learn how to maximize what you're running on your car with you driving it. Don't worry so much about sidewall height, etc. Worry more about getting wear all the way across the tread pattern all the way out to the wear indicator.

Hope this helps.

[Racer]

Thanks for the feedback. Still working on pressures and thoughts. Since I don't carry air I tend to hedge on being able to keep letting air out than having to run out to a gas station to get more.

Car is remarkably stock. It does have some Koni Reds that were put in during the 1970s. Has front and rear factory sways. Stock rear springs. So, she is pretty soft and likes to lean. I am replacing rear sway bar drop link bushings. 1/2 way through the first event one side failed. Ran second event effectively without a rear bar.

Results haven't been too shabby though....

http://live.axti.me/results/VyjIapOub - 8th overall
http://live.axti.me/results/EyihtN4Fb - 12th overall

[914 Ranch]

I'm with George and Tony and I never heard of 10psi per 1K lbs. When setting up my A/X car I was on my own. My car weighs in at 1630 lbs. The last time she was raced we had 14 in the front and 15 in the rear.
It's the rollover (scuffing) on the edge of the tire that guides you to the proper inflation for each tire.
I use a pyrometer to get the tires on the proper contact with the ground, I measured the temperature in 3 places on each tire. I have heard they should all be within 10°.
My car was running with all of them in 130 - 140, I want a little less camber in the front.
Going to grind on the front shock mounts and drop the air another half pound.

Joe Sharp
Team NARP

[SirAndy]

I run my Hoosiers at 25-27 hot - means going out at 17-20 cold taking into a variety of factors. A tire with lower pressure also provides a larger safety net with how it releases. Again, this may not be helpful to the Azenis but for what its worth.

About the same for my GoodYear R250 ...
(IMG:style_emoticons/default/popcorn[1].gif)

[Racer]

In the later events last year I worked down to 30 hot (about 26 cold) and grip was good. Still a month away for my season to begin for 2017. I usually find the car understeers more than I like. Moreso at corner entry than exit. Easy to balance for a long corner with a bit of drift / slip angles, but nothing lurid with such little hp.

The next 2 events from last year (since last post) weren't so bad either:
http://live.axti.me/results/4kPVB6ipZ - FTD hear (but borrowed car (IMG:style_emoticons/default/wink.gif) )
http://live.axti.me/results/Ey6cpSCCb - 3rd overall
http://live.axti.me/results/NkKSsWoef - 5th overall