[Dave_3]

Just driven back to Scotland today and had my Brother get me a quote on some Michelin PS2 ZPs for my E92 335D. Running the original Bridgestones that came with it in November 2006 - need a change.

Just checking that these are OK for Michelin PS2 Zps :

Front : 225/40 18 88W
Rear : 255/35 18 90Y

The rears are Y not W, I take it that that is just a higher speed rating ? I know some have mentioned a BMW kite mark - is there any way of determining this from order/part numbers etc ? Do you get this dimension of tyre for many other cars - seems quite a specific size ?

Prices very good, but would like exactly the correct spec. Free mounting

D.

[E92Fan]

Originally Posted by Dave_3

Just driven back to Scotland today and had my Brother get me a quote on some Michelin PS2 ZPs for my E92 335D. Running the original Bridgestones that came with it in November 2006 - need a change.

Just checking that these are OK for Michelin PS2 Zps :

Front : 225/40 18 88W
Rear : 255/35 18 90Y

The rears are Y not W, I take it that that is just a higher speed rating ? I know some have mentioned a BMW kite mark - is there any way of determining this from order/part numbers etc ? Do you get this dimension of tyre for many other cars - seems quite a specific size ?

Prices very good, but would like exactly the correct spec. Free mounting

D.

Hi Dave

Both speed ratings are fine - 168mph+ ! And the sizes are correct too, as are the weight loadings. I think these tyres come with the BMW * mark anyway as they are only really used in ZP fitment on BMWs...

Oh, and I think you're going to be suitably impressed! Be aware that the Michelin's are very sensitive to the light point of the tyre matching the valve placement on the wheel - this will help to ensure an easily balanced wheel.

[willhollin]

Originally Posted by E92Fan

Oh, and I think you're going to be suitably impressed! Be aware that the Michelin's are very sensitive to the light point of the tyre matching the valve placement on the wheel - this will help to ensure an easily balanced wheel.

How do you determine the light point of a tyre?

[Dave_3]

Thanks Tony

I'll get them ordered tomorrow. Probably fitted Monday.

Is the light point of the tyre marked ? Little coloured dot ?

It's been over 20 years since I used to fit tyres. Using the old pneumatic clamp and a muckle big iron bar I was a dab hand at it. Nightmare having to break the ice on the old bath out the back in winter to check for slow leaks though ....

All a bit nore high tech now ... will leave it to the lads.

D.

[E92Fan]

Originally Posted by willhollin

How do you determine the light point of a tyre?

The light point of the tyre is where the yellow or orange dot is located on a new tyre sidewall. This dot denotes the lightest point and is supposed to be located at the same place as the valve position on the wheel (which is the heaviest part of the wheel's rotational mass).

[E92Fan]

Originally Posted by Dave_3

Thanks Tony

I'll get them ordered tomorrow. Probably fitted Monday.

Is the light point of the tyre marked ? Little coloured dot ?

It's been over 20 years since I used to fit tyres. Using the old pneumatic clamp and a muckle big iron bar I was a dab hand at it. Nightmare having to break the ice on the old bath out the back in winter to check for slow leaks though ....

All a bit nore high tech now ... will leave it to the lads.

D.

The light point, not the heavy point, is marked with the coloured dot... I changed my wording around from what I originally wrote so that it's easier to understand...!

[willhollin]

Originally Posted by E92Fan

The light point of the tyre is where the yellow or orange dot is located on a new tyre sidewall. This dot denotes the lightest point and is supposed to be located at the same place as the valve position on the wheel (which is the heaviest part of the wheel's rotational mass).

Learn something new every day, cheers!

I will be sure to check when I pick mine up tomorrow, is this true on all new tyres??

[E92Fan]

Originally Posted by willhollin

Learn something new every day, cheers!

I will be sure to check when I pick mine up tomorrow, is this true on all new tyres??

Yes... it's the same on all tyres. Reason is that no tyre is perfectly balanced due to the construction of the steel belts inside, so in order to keep as few balancing weights off the wheel (which negatively affect handling) the idea is that the dot corresponds to the location of the valve. In practice a lot of tyre fitters are lazy and don't bother to do this as they know they can balance a wheel regardless... irritating to me as it normally requires unnecessary additional weights...

[SoYank]

Originally Posted by Dave_3

Thanks Tony

I'll get them ordered tomorrow. Probably fitted Monday.

Is the light point of the tyre marked ? Little coloured dot ?

It's been over 20 years since I used to fit tyres. Using the old pneumatic clamp and a muckle big iron bar I was a dab hand at it. Nightmare having to break the ice on the old bath out the back in winter to check for slow leaks though ....

All a bit nore high tech now ... will leave it to the lads.

D.

Wow, Dave, you were spoilt with the pneumatic clamp. When I was fitting tyres I had to do it all with a lever action. I ended up ripping the stand out of the floor (by accident) cause one tyre was so damned troublesome. Boss didn't appreciate it too much, either. I still don't know what exactly I was doing wrong.

BTW, those tyre sizes are the same I have on my car. I think the "kite" mark you're referring to is a star.

[E92Fan]

Originally Posted by SoYank

Wow, Dave, you were spoilt with the pneumatic clamp. When I was fitting tyres I had to do it all with a lever action. I ended up ripping the stand out of the floor (by accident) cause one tyre was so damned troublesome. Boss didn't appreciate it too much, either. I still don't know what exactly I was doing wrong.

BTW, those tyre sizes are the same I have on my car. I think the "kite" mark you're referring to is a star.

The "Kite" mark is the "Star" logo on the sidewall. It doesn't actually mean anything important with regards to performance - it only denotes that this particular tyre type was OEM equipment for BMW.

Only Porsche-related markings (N0, N1, N2, N3, N4) are relevant to performance and suitability for a car, and need to be adhered to for best performance.

[Dave_3]

Originally Posted by E92Fan

The light point, not the heavy point, is marked with the coloured dot... I changed my wording around from what I originally wrote so that it's easier to understand...!

It was a vague recollection from 20 years previously. Knew it was a related to a wee dot.

To be fair, I won't be balancing them this time.

D.

[Dave_3]

Originally Posted by SoYank

Wow, Dave, you were spoilt with the pneumatic clamp. When I was fitting tyres I had to do it all with a lever action. I ended up ripping the stand out of the floor (by accident) cause one tyre was so damned troublesome. Boss didn't appreciate it too much, either. I still don't know what exactly I was doing wrong.

The pneumatic clamp was used to prise the tyre off the bead then clamp the rim, the rest was done with a muckle big iron bar and arm action ... and for special occasions, a muckle big iron bar with nylon bushes for alloy wheels.

But a 15" rim was exotic to me back then.

D.

[doughboy]

Originally Posted by Dave_3

Front : 225/40 18 88W
Rear : 255/35 18 90Y

Just curious, why do you want different speed ratings on the same car??

W = 270kph max
Y = 300kph max

Wouldn't it be cheaper to get both in W?

[Dave_3]

Originally Posted by doughboy

Just curious, why do you want different speed ratings on the same car??

W = 270kph max
Y = 300kph max

Wouldn't it be cheaper to get both in W?

All they have at the moment.

Price is very good. I get them trade.

Option B is let my Swiss BMW Dealer fit them (And I checked around and nobody does "discount", even with special company offers). And that price makes me go a bit peely-wally at the gills ....

Besides, those speeds are academic.

D.

[kend]

Originally Posted by doughboy

Just curious, why do you want different speed ratings on the same car??

W = 270kph max
Y = 300kph max

Wouldn't it be cheaper to get both in W?

On the B pillar of my 330i, I only have 'Y' ratings for tyres.
Apart from speed rating is there any difference between 'W' and 'Y' rated tyres or is it marketing hype.

My understanding from many years ago - that there was a constructional difference in the sidewall which was to do with tranmission of extra power to the road surface by higher powered cars, hence on 325i ='W' rated and 330i = 'Y'

Would using 'W' rated tyres pose an issue with the insurance company in the event of an accident?

[Dave_3]

Had the Michelins on for the last 2 weeks and covered a lot of mixed driving.

First thoughts were of greatly improved steering in the straight ahead, now no longer diverted at the smallest change in camber or bump. Much, much better at shrugging off all those little deflections that plagued the Bridgestones and no longer holding on like Yosemite Sam when you encounter lorry ruts.

The ride is also improved. How much of this is down to the fact they are nice new full-treaded tyres I'm not certain. They certainly seem a little more compliant than before.

On the Motorway and at very brisk driving on wildly undulating (laterally and vertically) B roads I found a strange pitching sensation. On the B roads especially the electronics were stepping in. Regular ripples in the road were catching out the damping, .

Looking carefully at my tyres I had inflated the rears to 2.8 bar ... but mine are now Y rated so they should be 2.4 for normal running. After adjusting them it feels a lot more balanced front to rear - so worth checking the exact spec of your tyre.

Don't really drive like a tool in the wet, so can't comment for people who want to door-handle their car in the wet. Traction seems better than the hard Bridgestones.

Overall - much improved over the Bridgestones. But still totally unconvinced by runflats. Just back from a 200 mile round trip to the car markets using an old Escort MK IV Estate car. Had a great time in that. Sure it would eventually go into glassy understeer in the wet and had no power but the way it rode and handled over many surfaces and road types makes the E92 look like a clumsy, crashy fool. E92 = Ultimate Driving Machine my arse. Ultimate Marketing Machine I can believe.

My next car may very well not be a BMW if the 3rd generation of runflats don't improve considerably.

D.

[doughboy]

I had to reduce my PS2's to 2.2/2.4 bar to stop the rear wheels leaving ground over cats eyes or small lateral bumps. On 2.8 bar even middling acceleration, say up an mway slip road, if you hit a repair or a ridge the car will lurch as a wheel lifts, spins and drops again, traction light flashing. They've reduced the damping for comfort to try and cover for the the shocks transmitted from the tyres, but now it can't control the wheel movement.

The new car (09) is markedly worse than my previous E90 (06), which was great, but too 'stiff' for majority buyers who want m-sport looks, but SE comfort. And poncy magazines like autoexpress criticising hard ride, so they soften them all up for a 'wider' audience. Now we get 'performance suspension kit' for those who previously would have been happy with m-sport ride.

Yep, this obsession with RFTs ruins what should be great cars.

Shame, but same with everything when the accountants are put in charge.

Realistically i'm going to have to change the suspension too for it to cope properly with proper tyres...... I can't live with it for 3+yrs otherwise..

[Yahoo]

Doughboy - What tyres are you running on your e91?

[doughboy]

Michelin PS2 ZP runflats on 18" MV3, factory fitment.

[Dave_3]

The last week has pretty much been hovering about 12 degrees with cold, wet to flooded roads. Done a lot of winding B road driving. Undulating, rising and falling, 90 degree turning stuff - following old coast roads.

Have to say that the Michelins are in a different league to the Bridgestones.

I have adjusted the pressure to get a very good steering feel from the car (18" - 2.6 front W, 2.4 rear Y).

While still firm (RFTs spit, spit), they certainly absorb more of a bump than the crashy Bridgestones. No longer clenching my teeth as I see a small pothole.

And driving in the wet is making my confidence come back - the traction and feel is of rubber. The Bridgestones would Brrrrrp up and down over bumps with the traction light flckering like they were made of bakelite rather than rubber (especially in the wet). The Michelins flow much, much better. More predictable and much more secure in the wet. That increase in confidence is marvellous.

Had to perform a very brisk exiting manoeuvre on a wet junction, expecting to have to feather the throttle to prevent the traction control killing power but was very surprised to quite frankly rocket out the junction while even able to push the loud pedal deeper !

Best of all, still a 100% improvement on straight line stability and reluctance to tram-lining. The Bridgestones were dismal at that - fidgeting on anything other than a mirror smooth road, going apoplectic on rutted roads. Tiresome. Ruining the car.

Overall I can full-heartedly recommend the Michelin PS2 ZPs (RFT).

Actually enjoying driving it again - quite playful now

D.