I've got about 37.5K km on the stock tyres, and tread is about 3mm above the tread bars. Should I replace them now, or is it OK to take them all the way down? Tyre noise seems to be increasing. No idea about relative grip levels or performance in rain, since we don't seem to get much these days.

 

That was about the point I decided it was time to replace. Increased noise was a factor for me, but I'm not sure you'll find much in the range of quieter tyres in the size range (225/45 or 245/40). As to how low you wear them...well, to me it's all about risk tolerances....and, everything else aside, ultimately your safe grip on this good earth comes down to the reliability of those four pads. Good tyres are a necessity, not an option

 

i drive very hard daily and am on 48k kms. I'll be replacing soon also and as you can imagine my tires are nearly racing slicks.

 

The best way to tell about replacement is the wear guides. When they are the same level as the tyres then they have to be replaced immediately, Other than that, I started getting a lot of wheel spin on faster take offs and on cornering on round abouts, that is when I decided to get new ones.

 

The decision to replace is a personal one and possibly dependent on how you want to drive your car. Reduced tread depth affects your grip levels in both the dry and wet. Particularly reduced tread depth will lower the speed at which you'll start aquaplaning. If you're prepared to drive your car more carefully and slower in the wet with increased braking distances then you can possibly go lower. I wouldn't want to be driving down the Bruce Highway at 110 when it's bucketing rain with minimum tread and a low tyre pressure though.

I thought this article was a good read on the subject:
http://autospeed.drive.com.au/cms/A_1589/article.html

 

I decided to change mine at 35,000km i could have pushed them a further 3 -5000km however if you are unfortunate enough to be in an accident your insurance will try and get out of the claim as your tyres will be considered worn

cheers
michael

 

I got 40K out of mine and the tread was down to the indicators maybe slightly past, but definately not slicks. I noticed that the grip level in the dry wasnt as good, the tyres felt squirmish under braking and not so stable in cornering, but the deciding factor for me was aqua planing in the wet. To the point that if I hit a small puddle at any speed above 80km/h it would cause the traction control light to "dance on the dash".