Street Tire Pressures At The Track?

[Sylvan]

This topic might have been beaten to death already, but please read on for my actual question, since it might spark some new discussion. As you may have read in some of my other posts, I've started tracking my car this year (it's a bone stock 94).

My tires are 215f 245r Kumho ecsta XS tires, stock size. If my memory serves me correctly (I'm at work right now, can't verify), the recommended tire pressures on the door jamb sticker are 33f and 40r. I guess that would be fine for street driving but on the track the tires would heat up and get too greasy for my tastes, especially in the rear.

So following Billy's recommendations, I started out with cold pressures of 32 psi front and rear as a starting point last week at Thunderhill. It was a little cooler than a typical summer day, about 90 degrees. After a 20 minute session, tire pressures were about 38 front and 39 rear.

The car felt like it had lots of grip, and I didn't feel myself losing grip as the session progressed, but the car felt like it was squirming a lot, especially on the back end. Especially on side-to-side transitions or on initial turn-in, there seemed to be some shimmying around of the tire contact patch, and actually someone came up to me in the paddock and mentioned that my car looked "loose" for lack of a better term. It didn't inspire too much confidence, although the car still felt neutrally balanced so I don't think I was losing grip, maybe I'm just not used to the way it feels to be at high slip angles.

I should add that I'm still a novice, I've only done 6 track days total so far. Some pictures taken from the track shows the sidewall rolling and compressing when accelerating out of a turn (I didn't buy the pictures though). Here is a link to the picture thumbnails, you can see some detail: http://www.gotbluemilk.com/web110624/388/index.html

So, my questions are:

Is this a problem? Is there any danger with this much sidewall flex, like, could the tire roll off and cause a blow out? Or am I just inexperienced and this is in reality nothing unusual for track driving?

Is it better / safer to increase the tire pressure, although this might sacrifice some ultimate grip?

So basically I'm just hoping to get some input from experienced track drivers about sidewall flex, tire pressures, and grip. If this kind of stuff is normal, then I won't worry about it. Thanks!

Sylvan

p.s. Here's a video from the middle of the day. I was getting progressively faster by the end of the day. My focus for the day was to not over-brake for turns. It worked, and I had a firm brake pedal all day, and what appears to be faster lap times.

<iframe src="http://www.youtube.com/embed/9HN-hKg78O8" allowfullscreen="" width="853" frameborder="0" height="510"></iframe>

 

[stuntman]

How much experience or track days do you have? Your driving looks pretty good for an novice - solid line, smooth inputs, and you're driving the car pretty quick.

I didn't watch every corner of every lap, but I watched a few and didn't see any moments where the car looked loose to me. If there's a specific spot in the video, point it out.

As far as the tire roll/sidewall flex in the pictures go, that's normal and not very much. I would say there is zero concern there. I might even try shooting for 37psi HOT in the rear and see how that feels during a session. It might 'squirm' around more on the first few laps but might feel better at the end of a session. It's all testing.

Here's 29psi HOT (24psi cold) in a 2,600lb car on Toyo RA1 R-comps (This is only good for a lap or two and I wouldn't recommend it -but your 32-39psi is a non-issue):

Whats your alignment (camber & toe) front and rear? From the photos, it looks like you could use a little more camber front and rear for how hard you're taking the turns. More camber will give you a flatter contact patch when cornering and more grip/stability.

Is your suspension stock?

A wider rear track (wheel spacers) would also improve stability and increase rear grip. Cheap way for more grip.

If coilovers aren't in your near future, I would recommend getting larger swaybars (like the Dali 1" Race or street/race 0.875" bar) to reduce body roll. Even with coilovers I would recommend larger bars.


Billy

 

[Hrant]

I am not familiar with your Kuhmo's but 38 psi on street tires for the front is too hot it will give you oversteer hence why some may have commented it looked too loose.

With relatively basic OEM set up, 33/40 hot is a good benchmark to start with. Try that to see if it "feels" better - not that we want you to time yourself :wink: I was on OEM tires yesterday at the track and I was constantly chasing to lower my tire pressures after each session - by the time I got to 33/40 it felt better but I had some understeer with my aftermarket suspension set up. I haven't tracked on OEM tires for years so it was a good refresher :biggrin:

 

[stuntman]

I am not familiar with your Kuhmo's but 38 psi on street tires for the front is too hot it will give you oversteer hence why some may have commented it looked too loose.

With relatively basic OEM set up, 33/40 hot is a good benchmark to start with. Try that to see if it "feels" better - not that we want you to time yourself :wink: I was on OEM tires yesterday at the track and I was constantly chasing to lower my tire pressures after each session - by the time I got to 33/40 it felt better but I had some understeer with my aftermarket suspension set up. I haven't tracked on OEM tires for years so it was a good refresher :biggrin:

How would 38psi hot in front result in oversteer?

The NSX is designed with a tire stagger and often uses a camber stagger -both of which give more rear grip than the front. Optimizing the tire's pressure (36-38psi HOT) will allow said factors make the car balanced with a slight understeer. As you start to go above 40psi, you start to loose grip on most street & R-compound tires which will result in an oversteering car. Vice versa, if the front pressures go above 40psi, the car will start to understeer more. This is why I really don't like to have the rears near 40psi hot because it's on the verge of loosing grip.

0.02

 

[Sylvan]

How much experience or track days do you have? Your driving looks pretty good for an novice - solid line, smooth inputs, and you're driving the car pretty quick.

I didn't watch every corner of every lap, but I watched a few and didn't see any moments where the car looked loose to me. If there's a specific spot in the video, point it out.

As far as the tire roll/sidewall flex in the pictures go, that's normal and not very much. I would say there is zero concern there. I might even try shooting for 37psi HOT in the rear and see how that feels during a session. It might 'squirm' around more on the first few laps but might feel better at the end of a session. It's all testing.

Here's 29psi HOT (24psi cold) in a 2,600lb car on Toyo RA1 R-comps (This is only good for a lap or two and I wouldn't recommend it -but your 32-39psi is a non-issue):

<picture>

Whats your alignment (camber & toe) front and rear? From the photos, it looks like you could use a little more camber front and rear for how hard you're taking the turns. More camber will give you a flatter contact patch when cornering and more grip/stability.

Is your suspension stock?

A wider rear track (wheel spacers) would also improve stability and increase rear grip. Cheap way for more grip.

If coilovers aren't in your near future, I would recommend getting larger swaybars (like the Dali 1" Race or street/race 0.875" bar) to reduce body roll. Even with coilovers I would recommend larger bars.


Billy

Thanks for the information. As I mentioned, I've only done 6 track days so I'm relatively inexperienced. That's why I wasn't sure what constitutes too much sidewall flex. From the looks of it, and what you say, I guess I don't have anything to worry about. I'll keep playing with the tire pressures a bit to see if I can get an optimum setup.

As far as my alignment goes, it's within factory spec, but I might see if I can dial in a bit more negative camber.

Sway bars sound like a good idea but I'm still at a mental cross roads if I want to do any modifications at all to the car. I'm not doing competitions so I don't yet see the point in doing mods. That's kind of a philosophical debate with me, because I think at this point I want to learn how to drive well and quickly with my car as it is. Mods might make me faster but then it's kind of a crutch. So I might pass more cars, but a modified car passing a stock car doesn't really say much about the driver or the car, except who has put more money into their setup. Like if a (supposedly) inferior car passes me in some turns, then later in the paddock I check him out and he has Hoosiers and coilovers, then I don't feel bad because it was just his $$ that was faster than me, not necessarily his skill or his car's ability. Anyway, that's a whole other discussion in itself, and I'm still going back and forth on mods. I may end up doing some suspension upgrades for next year's track season, after at least a year of stock driving under my belt.

Anyways, thanks for the input. I'll be out there next Sunday tweaking some more and having more fun

 

[NSXDreamer2]

there's a little triangle at the side wall, it generally let us see how much you scrub to the side wall, that usually can determine if you need more camber or if air pressure is at the ball park.

If you not sure, you can take a pic and post here, I'm sure we will all have some opinions on that.

 

[stuntman]

Thanks for the information. As I mentioned, I've only done 6 track days so I'm relatively inexperienced. That's why I wasn't sure what constitutes too much sidewall flex. From the looks of it, and what you say, I guess I don't have anything to worry about. I'll keep playing with the tire pressures a bit to see if I can get an optimum setup.

As far as my alignment goes, it's within factory spec, but I might see if I can dial in a bit more negative camber.

Sway bars sound like a good idea but I'm still at a mental cross roads if I want to do any modifications at all to the car. I'm not doing competitions so I don't yet see the point in doing mods. That's kind of a philosophical debate with me, because I think at this point I want to learn how to drive well and quickly with my car as it is. Mods might make me faster but then it's kind of a crutch. So I might pass more cars, but a modified car passing a stock car doesn't really say much about the driver or the car, except who has put more money into their setup. Like if a (supposedly) inferior car passes me in some turns, then later in the paddock I check him out and he has Hoosiers and coilovers, then I don't feel bad because it was just his $$ that was faster than me, not necessarily his skill or his car's ability. Anyway, that's a whole other discussion in itself, and I'm still going back and forth on mods. I may end up doing some suspension upgrades for next year's track season, after at least a year of stock driving under my belt.

Anyways, thanks for the input. I'll be out there next Sunday tweaking some more and having more fun

I don't really agree with this but its your car and what you're looking to do with it. Improving the stability of a 20yo car that wasn't designed with the types of tires you have on there now, with springs and shocks that are probably worn out and not up to par to what it was when new, and swaybar bushings that are worn out and allow for more body roll than when new - replacing them or upgrading them to improve the stability and balance to match todays modern tires and make the car easier and safer to drive and learn how to push the limits of a car to improve your driving is hardly a crutch.

IMO I don't think upgrading the swaybars, wheel spacers (or wheels), or even going to a coilover suspension is a crutch. I would say this is less so than going to R-compound tires or slicks, or adding more power. I still say improve the handling of the car so it dosn't have a mis-match balance for the grip levels and speed your driving it.

0.02

 

[Hrant]

How would 38psi hot in front result in oversteer?

The NSX is designed with a tire stagger and often uses a camber stagger -both of which give more rear grip than the front. Optimizing the tire's pressure (36-38psi HOT) will allow said factors make the car balanced with a slight understeer. As you start to go above 40psi, you start to loose grip on most street & R-compound tires which will result in an oversteering car. Vice versa, if the front pressures go above 40psi, the car will start to understeer more. This is why I really don't like to have the rears near 40psi hot because it's on the verge of loosing grip.

0.02

We all know that the OEM tires/suspension has some understeer. And for most that is a good thing even on the track unless one is accomplished driver and can drive the car at the edge so a more setting would be preferred.

I hate to burden you, but educate me as to why going to 38 psi on puny front tires is such a great idea? Increasing the front tire on OEM setting from 33 hot to say 35/36 psi will compensate for the understeer, but when you keep adding more psi at the expense of the rears won't you get into oversteer? I agree regarding the rears, ideally it should be no more than 38-40 max.

As I said, I am not familiar with the Kuhmo in question. But yes using most R compounds the NSX is happiest in the range of 36f/38r even with a range of suspension settings - most of us weekend track cruisers don't tweak the suspension for each track and day/condition. And the R tires come with built camber bias and most who use R compound have already done some mods to the suspension and camber - and tend to leave it there.

Given OP's second post, he is all OEM. I fail to understand why in such set-up [ie OEM] you would recommend 38 psi on front street tires - even if you keep the rears at 38 psi.

 

[stuntman]

I hate to burden you, but educate me as to why going to 38 psi on puny front tires is such a great idea? Increasing the front tire on OEM setting from 33 hot to say 35/36 psi will compensate for the understeer, but when you keep adding more psi at the expense of the rears won't you get into oversteer? I agree regarding the rears, ideally it should be no more than 38-40 max.

As I said, I am not familiar with the Kuhmo in question. But yes using most R compounds the NSX is happiest in the range of 36f/38r even with a range of suspension settings - most of us weekend track cruisers don't tweak the suspension for each track and day/condition. And the R tires come with built camber bias and most who use R compound have already done some mods to the suspension and camber - and tend to leave it there.

Given OP's second post, he is all OEM. I fail to understand why in such set-up [ie OEM] you would recommend 38 psi on front street tires - even if you keep the rears at 38 psi.

How would going to 35/36psi hot compensate for understeer and add oversteer?

As I said before, most street and R-comp tires generate the most grip between 36-38psi. Try re-reading my last post since I will just repeat but try to clarify: as you increase the tire pressure past its ideal range, you will reduce grip. At 38psi and higher, the tires sidewall will reduce deflection more and have a more crisp feeling than the low 33psi -but will break away quicker into understeer (this is stability -which is what beginners would like better).

As you lower the front tire pressure from ideal, you will start to roll the tire over due to sidewall deflection (see the 510 pic) which will result in a non confidence-inspiring 'wallowing' feeling, a spongy, non-crisp turn-in. This is why I don't like running 33psi hot up front or recommend it for beginners. If I have an understeering car with heavy front springs/bars, I would probably lower my front pressures to around 33psi to reduce understeer. IMO the 33/40psi will probably make the NSX oversteer more than 38/38psi hot -which most beginners would not like.

If you maximize the tire pressures for peak grip (same pressure F&R), the NSX's tire and camber stagger should be enough to result in a slightly understeering car with good front tire turn-in characteristics that aren't vague. Increasing the front tire pressures beyond 38psi hot will result in more understeer and less front grip by reducing the contact patch like a balloon which should make it more stable and easier to drive than having low front tire pressure with a wallowing steering feeling that rolls over its sidewall.

What do you mean by most R-comps have a 'built in camber bias' ? Both the R888 and RA1 have a symmetrical tread pattern while the NT01 is asymmetrical, but all 3 tires can be mounted in any direction and i'm not aware of any 'camber bias' in the carcass itself.


Billy

 

[docjohn]

Billy's discussion makes sense to me ,that is why I too am a fan of having my RA1 the same hot pressures front to rear,and my pyrometer measurements show pretty stable temps across the tire.To the OP your slight adjustments on street tires won't make a big difference.I do like your attitude though taking the steep part of the learning curve stock,but Billy also has a point,if your susp is original to the car your shocks and bushings are probably pretty worn out.

 

[stuntman]

Billy's discussion makes sense to me ,that is why I too am a fan of having my RA1 the same hot pressures front to rear,and my pyrometer measurements show pretty stable temps across the tire.To the OP your slight adjustments on street tires won't make a big difference.I do like your attitude though taking the steep part of the learning curve stock,but Billy also has a point,if your susp is original to the car your shocks and bushings are probably pretty worn out.

And his camber settings are too conservative for how fast he's driving the car. (ie: he wont be using all of the tire during cornering but rather will be rolling over the outside edges which results in less stability and grip. His outside tire temps would probably be hotter than the insides because the stock alignment wasn't meant for aggressive driving on the track -which his video demonstrates hes more than able to do.)


0.02

 

[docjohn]

I can vouch for that. I have strugled with my front tires having hotter outside temps without maxing the camber and keeping them at 38-40 psi.

 

[Hrant]

Well Billy, I will bail out of this discussion as we are talking across each other rather than with each other by focusing on OP's initial post.

In any response, I look at what the OP is asking rather than start tossing the kitchen sink in the mix. The initial question was about tire pressures with stock OEM suspension albeit he is using Kuhmos. I stand by my comments that for him, he should start with a baseline of 33f/38-40r hot and see whether he likes that better or not and then tinker with tire pressure adjustments - and I agree before jumping into all the other mods.

With all OEM settings, 38 psi on the fronts will make the steering floaty and according to my chassis tuning "cheat" sheet, increasing the front tire psi while keeping all things constant increases oversteer. Perhaps science has changed since this was published. But then again, what do I know, I just putz around with a smile on the track :tongue:

YM- will-V:biggrin:

 

[CL65 Captain]

33 front hot is way too low. He's going to either chunk the tire from over heating them as they role over and really heart up or cord the outside edge t real quick.

I ruined a new set of dunlops because the track was cool and I didn't bump up the initial. 30 cold starting point, gave me 33 hot on the first run of a 50 degree day and the whole outside edge of the left front chunked and delaminated. ruined the tire in one session.

sent from my Evo4

 

[Sylvan]

Thanks everyone for the input. I didn't mean to start any arguments :redface:

Billy, I understand what you are saying about having old, worn out OEM suspension parts. I have 110k on the car and I'm pretty sure all the dampers and bushings are OEM, so they probably have more compliance and slop than they did from the factory, so I suppose that replacing those items would be a good idea for a car that will be seeing some track abuse. And I certainly don't have anything against optimizing alignment settings for the kind of driving that I am doing. In fact this is probably where I will spend most of my time tweaking, eventually.

I suppose part of my dilemma is that I haven't decided yet what my ultimate goal is for the car. If I just keep it as a weekend cruiser, or end up doing time trials or something, that will sort of shape where I go with the car, and where to put my $$. I am on a limited budget so I don't want to buy the wrong parts and regret my purchase later. So whether I buy new OEM parts, or swap them out with something aftermarket, is still up in the air.

CL65 Captain, thanks for the data point about your tires chunking up on a cold day. Around here, the tracks are usually pretty warm (90-100 degrees air temp), and I always do at least one lap at moderate pace to warm up my tires, so hopefully that would mitigate that potential issue. I will keep that in mind.

Ultimately, being a street car, my main goal is not to beat everyone on the track, but to have fun and still be able to drive home safely at the end of the day

 

[stuntman]

Well Billy, I will bail out of this discussion as we are talking across each other rather than with each other by focusing on OP's initial post.

In any response, I look at what the OP is asking rather than start tossing the kitchen sink in the mix. The initial question was about tire pressures with stock OEM suspension albeit he is using Kuhmos. I stand by my comments that for him, he should start with a baseline of 33f/38-40r hot and see whether he likes that better or not and then tinker with tire pressure adjustments - and I agree before jumping into all the other mods.

With all OEM settings, 38 psi on the fronts will make the steering floaty and according to my chassis tuning "cheat" sheet, increasing the front tire psi while keeping all things constant increases oversteer. Perhaps science has changed since this was published. But then again, what do I know, I just putz around with a smile on the track :tongue:

YM- will-V:biggrin:

To each their own. I still stand behind my track pressure recommendation even for OEM suspension and tire size to modified suspension and alignments. These are general baselines that I feel are much safer than the stock recommended settings. I've come to these general baselines from years of tracking many different cars, TONS of NSXs, almost every 'high performance street tire' on the market, working with some of the best engineers in motorsports, and doing this for a career.

I've seen many 'cheat sheets' out there that miss a lot of important concepts and have a ton of flaws in them. Many of them draw conclusions for incorrect reasons because they missed a major concept. There are many exceptions to rules and there are always points of no return (moving in one direction will not always elicit a certain response).

At the end of the day, my advice is based on my personal experiences and testing the exact questions at hand and I don't really wish to argue it any further in an e-battle, unless someone's looking for clarification or has new questions.

33 front hot is way too low. He's going to either chunk the tire from over heating them as they role over and really heart up or cord the outside edge t real quick.

I ruined a new set of dunlops because the track was cool and I didn't bump up the initial. 30 cold starting point, gave me 33 hot on the first run of a 50 degree day and the whole outside edge of the left front chunked and delaminated. ruined the tire in one session.

sent from my Evo4

I don't know if 33psi would necessarily chunk a tire, but with stock camber settings (-0.5* front?) -having such little camber and tire pressure will cause the front tires to roll over on the sidewall and could cause excessive wear (and yes maybe chunking too) of the corners of the tread blocks.

Either way, I stand behind the recommendation of adding more front (and rear) camber -1.5* front, -2.5* rear as well as bumping the front pressures up.


Billy

 

[RYU]

A few questions for you guys if you don't mind...

1. What's a good baseline spec for an alignment? I just need a starting point and I can adjust from there. (Billy mentioned front (and rear) camber -1.5* front, -2.5* rear as a starting point for the camber)

2. I know I will want non-compliance for the front and non-compliance toe links for the rears. What alignment should I start as a baseline for this setup?

3. I'm currently at a 4" ride height and 4 1/8" front ride height as measured from the bottom of the lift points. It's got a 1/8" negative rake to it. Any recommendations on a starting point here?

4. I also have a question on corner balancing. My coilovers has a separate spring preload adjustment and a separate ride height adjustment. I know shops that are lazy won't even bother corner balancing by adjusting ride height but instead they mess with the preload perch (it's just easier). Is there a rule of thumb for this particular adjustment? I'm also curious how to measure spring preload.

-------------------------------------------
I left the house for a "shakedown" run up in the canyons yesterday. I'm currently running on my street set 18/19 setup with thin tires. I left the house at 32psi on all 4s and after about 80 miles of perhaps 60-70% hard driving the tires hot were at 47psi! I was wondering why the car felt so skittish. (It was about 90* up at Angeles Crest) I also noticed I am scrubbing a lot of outer front tire. The tire wear on the outer fronts are noticeable - not terrible but definitely measurable. This was how it was at the track on my NT05s 235s also and the car was understeering on high speed turns. I know if got alignment issues to sort out and I probably need much more neg camber. I've also just installed new coilovers so I have lot of settings still to fine tune.


Thanks much gents! Happy 4th to you guys and thanks for the help.

 

[CL65 Captain]

-------------------------------------------
I left the house for a "shakedown" run up in the canyons yesterday. I'm currently running on my street set 18/19 setup with thin tires. I left the house at 32psi on all 4s and after about 80 miles of perhaps 60-70% hard driving the tires hot were at 47psi!

That doesn't sound possible.

On the track with a 90F day, my fronts usually go up +4 to 5 and rear +6 to 8 with a 20 minute session driving HARD. And I guarantee that my track driving is ALOT harder than anything you would ever attempt on a public road canyon drive. Even when I ran an open session for over an hour straight at 100% chasing a Cayman S one day, my tires didn't bump up nearly that much. The highest I have EVER seen my rears is low 40s.

 

[RYU]

That doesn't sound possible.

I have 3 other guys who's jaw dropped the same as mine. All 4 where hot and within 2-3lbs of each other. I also have a Moroso gauge for anyone who's going to say.. your gauge is bad! haha

Any help with my baseline setup questions perhaps Captain? :biggrin::biggrin:

Edit! Typo! It was at 35 psi when I left the house. Anyway, I don't think my psi fluctuations is really all that important. I can adjust that fairly easily.

 

[docjohn]

I'm with the capt no way your street tires could increase 12 lbs from canyon (street) driving. 8-9 is the most I have seen my RA1 at the track .

 

[CL65 Captain]

A few questions for you guys if you don't mind...

1. What's a good baseline spec for an alignment? I just need a starting point and I can adjust from there. (Billy mentioned front (and rear) camber -1.5* front, -2.5* rear as a starting point for the camber)

-1.5 F / -2/5 R
2mm out front toe
2 to 4mm in rear toe (tradeoff is rear stability vs tire wear - higher toe in more wear).

* BUT it also depends on the spring rates of your coilovers and sway bars. But -1.5 is about the most you can get in the front with out going to Comptech's camber bushings.

2. I know I will want non-compliance for the front and non-compliance toe links for the rears. What alignment should I start as a baseline for this setup?

Same as above, maybe relax the rear toe a bit but you don't have to. I'm still running 4mm in the rear.

3. I'm currently at a 4" ride height and 4 1/8" front ride height as measured from the bottom of the lift points. It's got a 1/8" negative rake to it. Any recommendations on a starting point here?

I'm running about 1/4" rake. I remember reading Shad at DA said they use 1/2" at the f/r jack points. I tried that, but it looked like the rear was way too high for my "visual" tastes.

OEM ride height delta is 43mm f/r ( 1.7") but that's at the OEM measuring points per the manual.

 

[Hrant]

Since this is a new RYU question, I will chime ......... if your street tires are almost new with say 10/32 or even 8/32 new, you will get significant tire pressure increase because the more rubber you have the more they will absorb and retain heat. I did get about 12 psi gain on a set of OEM Yoko tires back in 2003 with only 300 miles on them at Infineon; I had no choice as I needed tires and I wasn't going to miss the NSXPO :biggrin: I was chasing tire pressure pretty much all the day

This last Saturday, same track about 90F ambient on OEM Bridgstone tires with about 50% thread life left, I gained about 8 psi.

Don't know your canyons but canyon driving can be aggressive with hard braking and constant switched. Gaining 8 psi is not out of the question but not very likely. As for 12 psi that is kind of questionable indeed. Do try a different gauge and see if the numbers match.

 

[RYU]

Captain - Thanks! I appreciate it. This gives me a starting point. Much better than the best guesses I have now after swapping suspensions/setups a few times already. I like my current hardware setup and it'll stay for a while. Now onto fine tuning.

Hrant - You might be onto to something. My street tires tires are Hankook Ventus V12 with practically no sidewall in 18/19. I'm often hard on the brakes (NA2, Cobalt Friction GT pads) and was scrubbing a lot of outer front tire in the turns. Tires maybe only have 1000 miles on them. Plenty of thread left. I also suspect ambient temps could have been hotter. Anyway... It's neither here nor there.

FWIW.. I just took my tire pressure just now. It's at 25psi cold (F&R) sitting in the garage. I last set my hot psi at 35psi. That's a 10psi swing.

 

[Hrant]

FWIW.. I just took my tire pressure just now. It's at 25psi cold (F&R) sitting in the garage. I last set my hot psi at 35psi. That's a 10psi swing.

If I read this correctly, the last time you set/cehcked the tire pressure it was 35 HOT right? If so then cold it would have probably been 32-33 unless you were driving hard then too in which case more like 31-32. So the actual swing from your current 25 is 6-8 psi which makes more sense :wink:

 

[stuntman]

I can believe a 10-12psi swing. A lot depends on the tread design and tire size. Also if their is water in your tires from condensation it will cause large tire pressure changes. 47psi is WAY too high and I would expect it to be skiddish.

Outer front tire wear might indicate the need for more front camber.

I would loosen the spring perch to just barely touch the spring (no preload compressing the spring) -or even back it off 1/4"so there is a slight gap between the spring and the collar (to increase droop travel). From there use the bottom adjuster with the threaded shock body to set your ride height.


Billy