Jump to content
SAU Community

Possibly Serial Offender. Do I Keep Pumping Up My Tyres Too Much?

KrazyKong
 Share

Recommended Posts

KrazyKong Proficient

KrazyKong

Posted
Posted

I've always been a person who likes to have their tyres at the right PSI. However I never actually know what is the "right" PSI. Looking at the tyres gives you a MAX pressure number. This can vary from brand to brand and sizes. However most tyre places seem to under inflate the tyres in my view. Like putting in 26PSI when the max is 44PSI. I never go the max, but I would go maybe 38 to 40.

Am I really supposed to go on the PSI listed inside the door, even though I don't have the same rims or tyres that came with the car?

I occurred to me that maybe all these years I've been putting in too much air. Now that I got some new tyres, I think I need to fess up and say, I'm just confused now if I've ever been doing things right.

KrazyKong Proficient

KrazyKong

Posted
  • Author
Posted

One of my current Bridgestones is showing wear in the middle of the tyre so maybe I've had it pumped up too much. I normally go 41PSI as I found out you'd lose 1PSI when disconnecting the hose. So was running in effect 40PSI in the rears, but now think due to that wear patch maybe it was too high. I do like them firm though.

Duncan Grand Master

Duncan

Posted
Posted

Wear in the middle is a good indicator it's overinflated (and that will vary between tyres and sidewall heights)

Higher pressures can carry more load, will use less fuel and will handle better. Downside is they can be harsher (but frankly, if you are running 45 or lower profile tyres you've already decided to accept a harsher ride).

In my experience tyre shops and mechanics tend to go for a low pressure (30 or lower) and I honestly don't have any idea why

KrazyKong Proficient

KrazyKong

Posted
  • Author
Posted

Maybe it's speed. Quicker to fill it up to a lower pressure and thus time is money sort of thing? I have no idea why they under inflate either, but I've always known they have for some reason.

These tyres were used when I got them, so not too sure it was all me with the higher pressure, but I think for this next set I'll go lower. Instead of 40 maybe start at 36/37 and see how that goes.

I like them high, but don't want to wreck the tyres.

V28VX37 Veteran

V28VX37

Posted
Posted

Wear in the middle is a good indicator it's overinflated (and that will vary between tyres and sidewall heights)

Higher pressures can carry more load, will use less fuel and will handle better. Downside is they can be harsher (but frankly, if you are running 45 or lower profile tyres you've already decided to accept a harsher ride).

In my experience tyre shops and mechanics tend to go for a low pressure (30 or lower) and I honestly don't have any idea why

...to get more grip perhaps?

It's probably not as extreme as with semis but I'm pretty sure that the same street tyre will grip better at 32psi than 42psi...?

Duncan Grand Master

Duncan

Posted
Posted

interesting idea, I'd love to see a back to back test. yes lower pressure will give you more rubber on the road but I'm not certain that translates directly to extra grip because each contact patch will move more relative to the wheel

MBS206 Grand Master

MBS206

Posted
Posted

interesting idea, I'd love to see a back to back test. yes lower pressure will give you more rubber on the road but I'm not certain that translates directly to extra grip because each contact patch will move more relative to the wheel

Mythbusters proved it

http://actiontyres.worldsecuresystems.com/latest-news/effect-of-tyre-pressure-on-fuel-consumption

GTofuS-T Grand Master

GTofuS-T

Posted
Posted

FWIW I run 34 all around on 40 profile tyres, and at the moment have a really good alignment (for the first time in my life, i.e. no inner camber wear) and tyres are wearing evenly

No source, but I wasalways under the impression that higher pressure is better for fuel economy, lower pressure for grip, obviously to a point like so:

post-2-1196429733.jpg

niZmO_Man Grand Master

niZmO_Man

Posted
Posted

As usual, it's more complicated than it seems. 32psi is for putting around town with your family. I recommend 36psi for daily drivers, I run 38-40 depending on season/weather/tyre.

Cheap tyres generally need at least 40psi to get some grip out of it.

pol1on1 Mentor

pol1on1

Posted
Posted

My old mate a tyre guy and owner of his own tyre shop. I always bug him with questions which he doesn't like to give up his 40yrs experience......

Now he said not many people do it right dealership like soft gets a better sale softer ride.

Tyres say max.....

Door frame label says complete opposite.....

So on so on

Best is get a smooth flat ground dark as well. Now put some talcum powder on the ground in a line wide as ya finger but longer then ya tyre now push your car over the line keep rolling it 360 degrees so it makes a tyre print.

Now according to that print you would be able to tell if you need more or less you may need to do a few prints.

Remember front to rear will differ

Hope this help i might try make a video (if we have time ) with him helping me its a bit of an old art thats now days is forgotten.

Robocop2310 Experienced

Robocop2310

Posted
Posted

My old mate a tyre guy and owner of his own tyre shop. I always bug him with questions which he doesn't like to give up his 40yrs experience......

Now he said not many people do it right dealership like soft gets a better sale softer ride.

Tyres say max.....

Door frame label says complete opposite.....

So on so on

Best is get a smooth flat ground dark as well. Now put some talcum powder on the ground in a line wide as ya finger but longer then ya tyre now push your car over the line keep rolling it 360 degrees so it makes a tyre print.

Now according to that print you would be able to tell if you need more or less you may need to do a few prints.

Remember front to rear will differ

Hope this help i might try make a video (if we have time ) with him helping me its a bit of an old art thats now days is forgotten.

Sounds too damn complicated. How about you just tell us what you use on your tires? lol

pol1on1 Mentor

pol1on1

Posted
Posted (edited)

Unfortunately that would not work on your car unless you have a landcruiser with BFGs 265/65 r17 lol BTW dont own a skyline [emoji26] but i wish getting there.....

But yes all it takes is one person to do it then free 4 all

Example : R33 GT-R with Pirelli P Zero with this size ....______..... 36psi

Or with Proxes R888 size .._____.. 38psi

Its very rewarding at the end ;)

Edited by pol1on1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      33 GTR Broken front wheel knuckle

      By MBS206 · Posted

      Let's be honest, most of the people designing parts like the above, aren't engineers. Sometimes they come from disciplines that gives them more qualitative feel for design than quantitive, however, plenty of them have just picked up a license to Fusion and started making things. And that's the honest part about the majority of these guys making parts like that, they don't have huge R&D teams and heaps of time or experience working out the numbers on it. Shit, most smaller teams that do have real engineers still roll with "yeah, it should be okay, and does the job, let's make them and just see"...   The smaller guys like KiwiCNC, aren't the likes of Bosch etc with proper engineering procedures, and oversights, and sign off. As such, it's why they can produce a product to market a lot quicker, but it always comes back to, question it all.   I'm still not a fan of that bolt on piece. Why not just machine it all in one go? With the right design it's possible. The only reason I can see is if they want different heights/length for the tie rod to bolt to. And if they have the cncs themselves,they can easily offer that exact feature, and just machine it all in one go. 
    • Bennym35
      New guy

      By Bennym35 · Posted

      The roof is wrapped
    • Duncan
      R34 GT-T cycling ABS pump

      By Duncan · Posted

      This is how I last did this when I had a master cylinder fail and introduce air. Bleed before first stage, go oh shit through first stage, bleed at end of first stage, go oh shit through second stage, bleed at end of second stage, go oh shit through third stage, bleed at end of third stage, go oh shit through fourth stage, bleed at lunch, go oh shit through fifth stage, bleed at end of fifth stage, go oh shit through sixth stage....you get the idea. It did come good in the end. My Topdon scan tool can bleed the HY51 and V37, but it doesn't have a consult connector and I don't have an R34 to check that on. I think finding a tool in an Australian workshop other than Nissan that can bleed an R34 will be like rocking horse poo. No way will a generic ODB tool do it.
    • GTSBoy
      33 GTR Broken front wheel knuckle

      By GTSBoy · Posted

      Hmm. Perhaps not the same engineers. The OE Nissan engineers did not forsee a future with spacers pushing the tie rod force application further away from the steering arm and creating that torque. The failures are happening since the advent of those things, and some 30 years after they designed the uprights. So latent casting deficiencies, 30+ yrs of wear and tear, + unexpected usage could quite easily = unforeseen failure. Meanwhile, the engineers who are designing the billet CNC or fabricated uprights are also designing, for the same parts makers, the correction tie rod ends. And they are designing and building these with motorsport (or, at the very least, the meth addled antics of drifters) in mind. So I would hope (in fact, I would expect) that their design work included the offset of that steering force. Doesn't mean that it is not totally valid to ask the question of them, before committing $$.
    • Kinkstaah
      R34 GT-T cycling ABS pump

      By Kinkstaah · Posted

      The downside of this is when you try to track the car, as soon as you hit ABS you get introduced to a unbled system. I want to avoid this. I do not want to bleed/flush/jack up the car twice just to bleed the f**kin car.
×
×
  • Create New...