Tyre Pressures?

[The X Man]

Just wondering what tyre pressures members have on their Euro's?

I had some new Sumitomo HTR-ZIII fitted on all corners and noticed immediatley that my car was riding rough and seemed squirmish on the road so i checked the pressures and found the tyre guys has 38psi in the front and 42psi in the rears.

I then let some air out of all 4 shoes to meet the levels indicated on the placard (32psi front, 30psi rear) and the ride is far better.

[tony1234]

Just wondering what tyre pressures members have on their Euro's?

I had some new Sumitomo HTR-ZIII fitted on all corners and noticed immediatley that my car was riding rough and seemed squirmish on the road so i checked the pressures and found the tyre guys has 38psi in the front and 42psi in the rears.

I then let some air out of all 4 shoes to meet the levels indicated on the placard (32psi front, 30psi rear) and the ride is far better.
What do you think of the Sumitomos?I've heard they're not a bad tyre.I've got Conti Sport contact 3s and i run 39-40PSI all round.These tyres and the Eibach/Bilstein combo the car handles and corners like it's on rails.:thumbsup:

[The X Man]

What do you think of the Sumitomos?I've heard they're not a bad tyre.I've got Conti Sport contact 3s and i run 39-40PSI all round.These tyres and the Eibach/Bilstein combo the car handles and corners like it's on rails.:thumbsup:

They are certainly quieter then RE040 and no tramlining as yet. They were only put on Wednesday so haven't had the chance to throw it around a few corners or test wet weather traction yet. I am told by many sources that these tyres are too cheap for the way they handle etc.

[oongie]

I go 42 up front and 40 for the rears...

[lingamair]

Hello! Just wondering, whats the recommended tyre pressure for the 18" CU2 Lux?

[Youngster]

Hello! Just wondering, whats the recommended tyre pressure for the 18" CU2 Lux?

For my CU2, i put 40 front and rear.

[SPO73D]

hmm, Im running 16's and have 40PSI? Thats what I was told by 2 mechanics. Am I over filling?

[tony1234]

hmm, Im running 16's and have 40PSI? Thats what I was told by 2 mechanics. Am I over filling?
If you are happy with the ride leave them at 40PSI otherwise drop them down to 36PSI.

[aaronng]

I'm using 36psi on 16". You can use anywhere between 36 to 40 psi on 17", but it really also depends on your tyre. Not all tyres perform the same like with the Sumitomos being squeamish at ~40psi. I can run 40psi on my RE001 16" with no handling problems. It just magnifies the sound from the pillowball mounts, which is the reason why I go back down to 36psi for the street. On the track, I go back up to 40psi at least.

[Type R Positive]

damn you guys run high pressures. your tyre wear must be bad....

17" CU2: 34 front and back. I ran 36 and had uneven wear.

[Type R Positive]

Actually, it's the otherway round. Lower pressure = more wear and lower fuel economy.
Higher pressure = less rolling resistance = less tire wear, sharper handling and better fuel economy but rougher ride.
um no. correct inflation = better milage.

You get better fuel economy from over inflation due less resistance, wich equals poor tyre handling / performance.

All you're doing is ballooning out your tyres and wearing a strip out of the middle.

This is basic information about over inflation.

[buddah51au]

I run 36 all round in my CU2. It is important to remember that there can be 3 to 4 psi difference between hot & cold tyres.

Over inflation will give you better economy due to less rolling resistance, but will wear the tyres in the center. Under inflated tyres will decrease your economy, run hotter & wear on the outer edges.

[hotout]

Over inflation will give you better economy due to less rolling resistance, but will wear the tyres in the center. Under inflated tyres will decrease your economy, run hotter & wear on the outer edges.

You'd have to overinflate to something like 50 PSI. I've run 42PSI before for > 5000km and never had any unusual wear.

[buddah51au]

You'd have to overinflate to something like 50 PSI. I've run 42PSI before for > 5000km and never had any unusual wear.

If you ran 42 psi for the life of the tyre you would certainly notice uneven wear with the center of the tyre wearing more. >5000km would not necessarily be enough for a noticeable indication of this.

[Type R Positive]

You'd have to overinflate to something like 50 PSI. I've run 42PSI before for > 5000km and never had any unusual wear.If you are unsure, a pyrometer will show you that you'll be wearing the center strip. I just happen to have one such tool, it is handy to have.

[Type R Positive]

I run about 90k kms a year in my cars, 90% highway (higher speed = accelerated wear), trust me, I notice the difference. ;)

[The X Man]

So it seems most here run an average of 36PSI in their rubber. Still with the stock pressures as per the placard i took the Euro for a long spin today and it handled fine and was actually quite smooth. I'll try 36PSI up front and 34PSI in the rears and see how goes but the way is was before (38PSI & 42PSI) was horrible for a sore back.

[Youngster]

Would inflating the tyres too much make the ride boucy or hard?

[tony1234]

Would inflating the tyres too much make the ride boucy or hard?
Depends on the brand and profile of the tyre.

[ok2]

I run 38 PSI front 36 PSI rear (+/- 1 psi) and the OEM tyres lasted for 55000+ kms with no uneven wear. IMHO 5 or 6 PSI higher

1) is unlikely to invoke uneven wear

2) will give better fuel economy and handling

3) will give a "harsher" ride

4) differences noted will depend on usual variables, tyre make and rim size&profile, driving habits and locale (highway vs stop/start city, smooth vs rough roads).

In any case monitor them regularly and if you have a pyro, epsecially a good non-contact one use it.

[265coupe]

I've done 115,000km on factory 17s and find 38/36 to be ideal for the handling/ride/wear compromise. In fact wear has been the good point with 50,000 evenly worn kms per tyre (including front to back rotation) with a wheel alignment on new tyre fitment.

The original tyres at book pressures wore out at 25,000km and never did impress.

[aaronng]

I run about 90k kms a year in my cars, 90% highway (higher speed = accelerated wear), trust me, I notice the difference. ;)

Makes sense since your driving style puts the majority of wear right in the middle of the tread. For people driving mostly city kms, their wear would be on the shoulder due to the increase amount of corners that they drive through. So for your case, it is a balance between fuel economy and tyre wear in the middle, while for city-drivers, they can pump up to higher tyre pressures since their wear is mostly on the shoulder.

[Type R Positive]

Makes sense since your driving style puts the majority of wear right in the middle of the tread. For people driving mostly city kms, their wear would be on the shoulder due to the increase amount of corners that they drive through. So for your case, it is a balance between fuel economy and tyre wear in the middle, while for city-drivers, they can pump up to higher tyre pressures since their wear is mostly on the shoulder.
I see your point, but roads are not straight champ. Higher speeds accelerate the wear, and just show you the damage you are doing quicker. :)

And people shouldn't mistake a harder / harsher ride for performance. ;)

[aaronng]

I see your point, but roads are not straight champ. Higher speeds accelerate the wear, and just show you the damage you are doing quicker. :)

And people shouldn't mistake a harder / harsher ride for performance. ;)

Still proportionately higher on the middle though as highways tend to curve at high speed and not have corners (that would be frightening, taking a corner at 80-100km/h).

If that is the case, my tyres (RE001) at 36 psi should also show more center wear over the past 2.5 years that I have been using them but they are mostly shoulder wear instead because I do 50-50 of highway and city driving. The wear in the shoulder overtakes the wear in the middle for me.

I tested a range of tyre pressures from 32 psi up to 40psi, and I found 36 psi was a good compromise for steering response, given my alignment settings. I had it at 33 psi for a while and the response was not as good and felt doughy when I was trying to avoid potholes. 38 psi on the other hand was too harsh and I didn't like it at all. 36 psi gives me the steering response I want but without that juddering ride.

[Type R Positive]

yep, agree. Thats a lot different to people running 40+ in their tyres.....

[The X Man]

Hmm, went for a drive to work today and i am thinking the Sumitomo's may of been a mistake. They appear to be louder then the RE040's on course bitumen but whats worse is something is weird with the handling.

Whenever i drive over bumps or potholes (they are everywhere in SA) it feels like the back steps out or something, or rather the car feels like it looses it's balance on the road. Also the noise from running over potholes etc seems to be much more pronounced now.

They did do a full wheel alignment so perhaps they stuffed this up but it certainly doesn't feel like the same car as it was with the RE040's on.

[tony1234]

Hmm, went for a drive to work today and i am thinking the Sumitomo's may of been a mistake. They appear to be louder then the RE040's on course bitumen but whats worse is something is weird with the handling.

Whenever i drive over bumps or potholes (they are everywhere in SA) it feels like the back steps out or something, or rather the car feels like it looses it's balance on the road. Also the noise from running over potholes etc seems to be much more pronounced now.

They did do a full wheel alignment so perhaps they stuffed this up but it certainly doesn't feel like the same car as it was with the RE040's on.
Sounds to me like it's an alignment issue.Did you get a 4 wheel alignment?If so then i'd get them to check the rear toe.PM aaronng.He has some settings he can give you to take when you go back to get the alignment checked.As for the tyres being noisy on course bitumen my Continentals also tend to be that way as well.As for bumps and potholes don't get me started on that!!Come to Sydney and i can show you some real shit sections of road.:thumbdwn:

[The X Man]

Thanks Tony. Will PM aaron.

[aaronng]

Thanks Tony. Will PM aaron.

Replied your PM. Could you also post up the alignment settings that they used when they did your 4-wheel alignment? They should have given you a printout with the settings they used.

[The X Man]

Unfortunatley they didn't provide a printout - i thought that was weird too. I had to go back there to have them straighten up my steering wheel as it was pointing to 1 o'clock on a straight road. By the sounds they just have no idea what they are doing or the calibration of their machine is just way out.

[aaronng]

Unfortunatley they didn't provide a printout - i thought that was weird too. I had to go back there to have them straighten up my steering wheel as it was pointing to 1 o'clock on a straight road. By the sounds they just have no idea what they are doing or the calibration of their machine is just way out.

The wheel pointing to 1 o'clock means they adjusted for total toe only but not for individual toe. On my specs, I ask for -0.5mm toe out on each side. So they center the wheel and do each side to get it within my setting. But for most places, the computer would tell them "-1.0mm total toe out" which is the same as my setting but does not tell how much on each side. So they can do -0.9mm on the left and -0.1mm on the right and it will still be the correct alignment (add left and right up and you get -1.0mm) but my steering wheel would point to the right to drive straight like in your case.

Next time before the alignment is carried out, let them know that you want a printout. If you know what settings you want, let them know as well before they put the car up.

[tony1234]

The wheel pointing to 1 o'clock means they adjusted for total toe only but not for individual toe. On my specs, I ask for -0.5mm toe out on each side. So they center the wheel and do each side to get it within my setting. But for most places, the computer would tell them "-1.0mm total toe out" which is the same as my setting but does not tell how much on each side. So they can do -0.9mm on the left and -0.1mm on the right and it will still be the correct alignment (add left and right up and you get -1.0mm) but my steering wheel would point to the right to drive straight like in your case.

Next time before the alignment is carried out, let them know that you want a printout. If you know what settings you want, let them know as well before they put the car up.
Aaron please post here or PM me the settings too as i need a wheel alignment soon.

[The X Man]

Well my suspicions about my Euro driving strangley were indeed correct.

I returned from my holiday interstate (hot chicks at St Kilda beach too) and took the car to BTC (as per Aaron's suggestion) and they could see that the rear wheels were way out of alignment when it was sitting on the ground in the carpark.

Adjustments that were incorrect.

Front Axle - (Total Toe)
Was -7.8mm Now +2.0mm (Left was -3.5mm Right was -4.3mm)

Rear Axle - (Total Toe)
Was +13.2mm Now +2.3mm (Left was +8.0mm Right was +5.2mm)

Camber & Castor was OK on front but camber was out a little on the back RHS.

It certainly drives much better now. I really wonder where some of these tyre places find their wheel aligners. They truly stuffed mine up twofold.

[89superstage]

What brand of tyre do the CU2 Euros come with, OEM, in Oz?
Mine came with Bridgestone Turanza's and I've seen a few with Michelin's and perhaps other makes as well, at the dealership. makes me wonder if there is a standard, or just whatevers on hand :eek:

Can the B'stones be inflated safely to over 38Psi?
I keep mine at 35Psi, because the car came with the tyres at that pressure.

Dropped it for maybe 1 tank, to 32psi, with terrible results - handling, mileage overall feel, so back up to 35 it went. Never considered taking it up higher.

thanks
Des

[d_evilz]

recommended PSI for 225/45/18 tyre?

[Bludger]

recommended PSI for 225/45/18 tyre?
what car?

what's it used for?

[d_evilz]

cl9
whats its used for... driving around?

[Bludger]

36ish psi all round.

in my opinion

[mrgu]

I always do 40 psi. confortable ride pressure