Bad Wheel Alignment or is it all Prado 120s ?

[Jacto Senior Member Find all posts View Profile Close Jacto]

Hi bugeyes02

Just a thought......do tyres wear out quicker if they are not at operating temperature????

This might be a bit long winded but here goes and I do have a long history of managing tyres where pressure/temperature relationships are a concern.

Tyres do not wear quicker by not reaching operating temperature. They actually will wear quicker when subjected to higher temperatures, as an example, a tyre's inflation pressure should be set at 25 degrees C and this is the standard industry temperature relationship with pressure in tyres. If there is a variation in temperature either side of 25C the pressure will either increase if the temperature increases or will decrease as temperature decreases. This is why a tyre's pressure increases on a long trip because as the tyre is continually flexing, it is increasing it's temperature and therefore pressure due to friction.

On the other side of the equation if say you are in Alice Springs on a morning where the temperature is 0 degrees C and you check your tyre pressure and it is reading 30psi and you think crap I had better inflate to my normal operating pressure of 36psi, if you do this and then later in the day when the temperature could be 40 degrees C, the pressure is likely to read maybe 42 psi even though the vehicle may not have been driven. I do have all of the figures for pressure/temperature variation back in my office for tyres so if anyone wants to know the variation I can post it for you.

My own GT's have done around 65K now and most of it has been country driving but I have started doing a fair amount of work in Sydney lately and the tyre wear is becoming significantly obvious, particularly with the right hand front inner tread, and yes, city driving does have an adverse effect on tyre wear. Do not take any notice of the tyre pressures recommended by Toyota on the tyre placard and as most others will advise, operate the tyres at around the 36psi cold (25 degrees C) mark to get the best life, rotate them religiously about every 5,000k and keep out of the city

[photoprado Avid PP Poster! Find all posts View Profile Close photoprado]

Suburban driving is hell on front tyres.

Quoted for truth.

I have a friend who runs a newspaper delivery round throwing papers from various econobox wagons and such like. Tyre wear is so horrific that he has adopted retreads to try and put a lid on tyre costs. 99% of the driving is at < 25km/h

[mansour Member Find all posts View Profile Close mansour]

Shudder

bugeyes02

Mate, Keep in mine my Rig is LHD

Keep in mind that our mate Fazza suggested some readings for my rig (which drives on the Left hand side - like the US)

Fazza also suggested some readings for - Aus. Prado (RHD)

Under any case TOE-in=0.0 its a magic formula for edge wear

------ As for the break shudder , Was it usefull to skim the rotor? did the shudder disappear ?

Toyota wanted to do the same for mine ; but my old fella told me that Rotors shouldn't be trimmed before at least 150K or something; other suggested a skim at every brake pad change (I changed my FR ones at 48K without skimming).

I could buy a new rotor for the price that toyota will charge me for two skims ? :P

Cheers

[bugeyes02 Lurker Find all posts View Profile Close bugeyes02]

Thanks Jacto!
Sounds like my 40psi cold is too much. Ill adjust to 36psi - im sure the wife will enjoy the softer ride.
Rotation every 5000kms sounds fine in THEORY but do ppl really have the time to do this.
Mmmmm might have to invest in a Heavy duty trolley jack and car stands

[bugeyes02 Lurker Find all posts View Profile Close bugeyes02]

Mansour,

The brake skim does make a difference, but I found that it reoccured after a few thousand kms. They then replaced the front disks (under warranty) and it had pretty much disappeared UNTIL now. It has come back. Not sure if the shudder is from the front or read. Ill ask them to put a dial guage over all the disks to check, so that this can be done before my warranty runs out next February!

As for skimming every pad change, my Toyota mechanic recommended this but our family mechanic says that this is necessary only if the disk is out. I guess the thinner the disk, the more quickly it heats up and make it prone to warping? The more thickness on the disk the better.

When warranty is finished Ill probably put some DBA rotors on. My experience with them in the sports car sector has been good. The reports on PP about the DBA product seems positive also!

[playdo Junior Member Find all posts View Profile Close playdo]

I guess it depends on the tyres you are running and what pressures you want. I run BFG ATs which are a light truck construction and have no issues keeping them at 40psi (or even higher if loaded)