Tyre tread depth - when do you change yours ?

[USS Bozeman]

I am getting a couple of new rear tyres fitted tomorrow. The tread is just under 3mm on the tyres. I have a hard weekend of driving coming up so thought its better safe than sorry.

The legal limit is 1.6mm this site - http://www.tyres-online.co.uk/techinfo/tread_depth... suggests that tyres should be changed at 3mm.

What do people think ?

[jb12]

As you mentioned you have a hard weekend of driving coming up, so it’s best to change them just in case. The lower the thread gets the less efficient is your car stopping in the wet.

So it will be safer and you don’t run the risk of going below the legal limit.

[NJH]

I normally change them when the tyres have gone off and have next to no grip left in either wet or dry conditions. For the past 4 years (mostly Toyo tyres) this always happens long before the tyre becomes a slick. The worst case I had 4mm tread left on the outside of the rears and about 2.5mm tread in the middle of the rear tyres.

[rude-boy]

In the summer I tend to let it get to about 2.5mm before I start to sort out some new boots. When we are heading into the winter I'd be a little earlier. I regularly check the tread depth and dobut I've ever had a tyre with less than 2mm on it

[USS Bozeman]

What are peoples opinions on distance for scrubbing in new tyres - I am having them fitted tomorrow then go away Friday, so only have a short time to scrub them in.

[NJH]

USS Bozeman said:

What are peoples opinions on distance for scrubbing in new tyres - I am having them fitted tomorrow then go away Friday, so only have a short time to scrub them in.

Both the Toyo tyres I used to have and the Hankook RS-2 I am on at the moment take about 500 miles of road driving before they really work.

ISTR the advice for scrubbing in on the track is to do no more then a couple of fairly quick but not hot laps, then come in and adjust pressures.

[noumenon]

2.5mm or when the edges look really badly worn from very spirited driving.

[anonymous-user]

when the warning canvas is visible on 2/3 of the tyre

[MogulBoy]

Porsche suggest 4mm to prevent aquaplaning and also that you change all 4 at once.

Threfore, rears down to 4mm and fronts hardly touched, buy a new set! (at OPC prices ideally!)

Acquaplaning is certainly no fun but I like the way my 2.7 Boxster handles when the rears are down to the wearbars (and the fronts are still good) because it gives me the feeling that it's got more power than it actually has!

[USS Bozeman]

Another guy on this trip has a Lotus Exige with slicks on - and rain is forecast most days - oh how we will laugh as he goes spinning past us !! He has been told by the Lotus garage to be "very careful" with standing water.........hope he doesn't hold us all up.

[911fan]

How is the tread measure so accurately please? Is the difference btwm 3mm and 2mm potentially hazardous?

[fido]

911fan said:

How is the tread measure so accurately please? Is the difference btwm 3mm and 2mm potentially hazardous?

think of the gap between the tread as water dissipation capacity - in very simplistic terms, going from 4mm to 2mm means half the amount of standing water that the tyre can get rid of.
i change tyres at 3mm, or at least worry about it if it's less than that!

[DanH]

911fan said:

How is the tread measure so accurately please? Is the difference btwm 3mm and 2mm potentially hazardous?

With a depth gauge its a pen like instrument with a sticky out probe. Or you can just estimate.

Depth isn't necessarily that critical unless you hit standing water at which point you want as much as you can get. Having said that, the tyres can go off and not offer as much grip when worn or excessively heat cycled (more a track issue). Definitely noticeable how grip diminishes as you get near the wear bars.

[noumenon]

http://www.autoexpress.co.uk/videos/featuresvideos...

[BERGS2]

resurrecting this thread as I've got a similar quandry...

having whipped off one failed Michelin Pilot sport tyre and inspected the tread i'm buggered if i can tell how much it has left....

the central 4 main grooves appear to have good depth still (4-5mm) but the outer angled channel reang from 2mm to almost nothing

pic for reference here:




now - my question is this - (the fronts are about the same level of wear..
)
1) should all 4 be replaced at the same time (i've just paid for our wedding, so the timing of this isn't ideal...)
2) can I run continentals on the back and pilot sports on the front, if I do choose to replace just two tyres
3) an i just too pikey to own a porsche?

[Stealth997]

Bergs - I might be wrong here but that outer wear looks seriously wrong to me. The wear on mine is a lot more even. Have you had alignment issues?

[cptsideways]

I'd be far more concerned about the sidewalll lumps = broken down carcass

[LuckyP]

Yeah, I'm with comments so far. If you're in a daily driver, then why wait 'til you have exhauxted every last bit of tread....

....but if you are after trackday grip......well, this is when I changed mine:



Not to be recommended for finding your way back from the track in the rain.

[BERGS2]

cptsideways said:

I'd be far more concerned about the sidewalll lumps = broken down carcass

yeah - this was one that got punctured on the A3 and i had to drive a couple of miles to get off - hence the destroyed carcass.....I reinflated it to try to find where the puncture was...

the wear does seem odd to me as well..... I'll have to get it checked out.

do you guys know if any of those mobile tyre jobbies had the capability to check alignment when they fit tyres?

This is my getting to church car for the wedding in a week or so - i dont want to have the red spacesaver wheel on for that...

[graeme36s]

BERGS2 said:

resurrecting this thread as I've got a similar quandry...

having whipped off one failed Michelin Pilot sport tyre and inspected the tread i'm buggered if i can tell how much it has left....

the central 4 main grooves appear to have good depth still (4-5mm) but the outer angled channel reang from 2mm to almost nothing

pic for reference here:




now - my question is this - (the fronts are about the same level of wear..
)
1) should all 4 be replaced at the same time (i've just paid for our wedding, so the timing of this isn't ideal...)
2) can I run continentals on the back and pilot sports on the front, if I do choose to replace just two tyres
3) an i just too pikey to own a porsche?

personally Bergs I'd stick a new set of Pilot Sports on the rear. Camber has worn the inside edge. If you try and run a new tyre on one side and leave the old on the other it will not feel nice. ie on the motorway hands off wheel boot it and it may pull to the left, back off and it may pull to the right or vice versa. Never be a tight arse where tyres are concerned.