Tire wear

NickXX · 4 Mar 2006 at 19:10

Hi all,

I had a look at my tires today and they seem a little worn - do they still look legal to you guys?

Are those 3 bumps the legal wear markers? How many more miles do you think they'll last before they become illegal (they are the front wheels of a RWD car), I've not been pushing them too hard.

The reason I ask is because the rears seem to have a fair bit more tread and I want to get all 4 replaced at the same time.

Cheers,

Nick

NickXX · 4 Mar 2006 at 19:17

Enfield said:
Illegal.

You can clearly see the blocks from the photo.

Really, is it not when the tire wears down to the blocks, or is it when they just become visible?

NickXX · 4 Mar 2006 at 19:39

Ah, ok thanks guys - I have no idea when it comes to tire wear. Really don't want to lose grip in this weather. Will get them sorted tomorrow - didn't realise you could get points from worn tires :eek:

!

Argh, this has been a very expensive month so far..

NickXX · 4 Mar 2006 at 19:50

Here's another pic - it's shows the tread a little better.

NickXX · 4 Mar 2006 at 20:18

Oracle said:
If its the BMW Nick, they are not illegal. Are they the contis!? They dont have much left in them tho, but as it goes they're not too bad. What I can say tho is that you dont have any front camber issues which is a good thing on an E46 (especially an 330d).

Check the inside edge of the rears as the contis like to let go early on the E46s, and will take most of your suspension housing out with them!

Hi mate, I've Got Pirelli PZero's on the fronts and Bridgestone Potenzas on the back. The Potenzas are fine on the back.

I've just gone out to have another check - the fronts don't seem to be worn down the the marker, but there is only about 1mm before the tread will wear down to the same level. Is it when the tread is the same level as the marker that the tire becomes illegal?

I really want to hold out as long as possible, because they do still grip well, and replacements aren't cheap at £160 a corner.

NickXX · 4 Mar 2006 at 20:27

Enfield said:
Two of the blocks look like they've completely worn away!

Ah, no - I've just been out to check, it's just a bad photo. They're still at least 1mm above the height of each of the blocks.

Oracle - Lol

, didn't realise the Pirellis were that bad, but they still grip, so I may just hold out for another few weeks. I'm going to get Michellin Pilot Sports fitted at Costco I think.

NickXX · 4 Mar 2006 at 22:05

Third Opinion said:
Sorry if I am being a bit thick but are they Avons?

They're Pirelli PZero Rossos 18/225/40. Rears are Bridgestone Potenza's 18/225/35

NickXX · 4 Mar 2006 at 22:55

TomO said:
are you sure on those sizes or is that a typo? 225/35 or 255/35?

You're right - just checked. The rears are 255/35, fronts are 225/40.

Does anyone know what the dimensions represent, is it width/profile?

NickXX · 4 Mar 2006 at 22:59

L0rdMike said:
Is it normal to have a lower profile on the rear at all?

Strikes me as odd but I know little.

Hmm, good point - going to double check that..again (stupid tires

).

NickXX · 4 Mar 2006 at 23:01

Yup, 255/35 on the back, 225/40 on the front. Seems odd - anyone know if this is right?

NickXX · 4 Mar 2006 at 23:06

L0rdMike said:
Is it possible your wheels got swapped around?

Fronts put on the back?

Might explain your tyre wear on the fronts?

I don't think so, as the tires on the front would be wider than the ones on the back if they had been swapped which I assume would be wrong.

I guess the previous owner put the wrong profile tires on last time. Maybe it's normal though. I wish the BMW manual was some use, but it doesn't even mention the 18" wheels :rolleyes:

.

NickXX · 5 Mar 2006 at 00:23

Oracle said:
Umm, its not a lower profile! The rears are 255 WIDE whilst the front are only 225!

The 35 and 40 are a percentage of the width, and as the rears are horrifically wider than the fronts, the profile of the rears will be equal to if not larger than the fronts!

This is obvious............ blindingly obvious!

The 225 / 255 is the section width in mm. the 35/40 is the 'aspect ratio' in relation to the width! So for example you could have 285/30R18 on the rear, and the profile would still be larger than 225/40 fronts.

Aspect Ratio
Often referred to as the profile or series, the aspect ratio of a tyre is determined by dividing a tyre's section height by its section width when the tyre is inflated to its maximum recommended air pressure, mounted on the approved measuring rim, and under no loading

Nick, your rears do have a larger profile than the fronts. The fact that they are (what appears to be)5% different is just peoples lack of understanding. Your rears are wider, and the profile is a percentage. So you'll find the rear profile is bigger.

PS, yes it is right!

Brilliant - thanks for clearing that up mate!

NickXX · 5 Mar 2006 at 11:24

That's a great link - thanks Tom