Different tyre load ratings front and rear...

[DoubleSix]

Sorry bit of silly question as I'm 99% sure it's a non-issue but want to be sure.

I'm about to order some Michelin PSS in a staggered fitment and notice the load ratings differ front to rear - this is ok right?

[TooMany2cvs]

DoubleSix said:

Sorry bit of silly question as I'm 99% sure it's a non-issue but want to be sure.

I'm about to order some Michelin PSS in a staggered fitment and notice the load ratings differ front to rear - this is ok right?

Look at the VIN plate. It'll have four weights.


First is MAM/GVW - the max weight of the vehicle itself.
Second is GTW - the max weight of vehicle + trailer. If that's blank, you can't tow.
The next two are the front then rear max axle loads.

Halve each of those, because there's two tyres per axle (right?), and compare them to the load rating table.


Are the tyres rated higher? If so, then no problem at all.

[DoubleSix]

Thanks that's great! So assuming all is within those given limits im good to go.

What about adverse handling traits if tyre load ratings differ front to rear axle? Non issue?

[TA14]

DoubleSix said:

Thanks that's great! So assuming all is within those given limits im good to go.

What about adverse handling traits if tyre load ratings differ front to rear axle? Non issue?

It's potentially an issue but it depends on the detail. Most people only end up with minor changes and don't drive like Moss trying to win a race so it doesn't matter. If you had a large difference in a light sports car that you drove on the limit then it would matter.

[TooMany2cvs]

DoubleSix said:

What about adverse handling traits if tyre load ratings differ front to rear axle? Non issue?

Totally.

[nickfrog]

I assume the official rating at the front is 88 - I would advise to go for 92 to give the the outer shoulders a good chance of survival if you lean on the lat grip and / or do track work. The SS have inherently soft sidewalls sadly and 92 helps (a bit).

The problem can be so bad that I am noving to Yoki Advan 105 (92) as MPSS in 92 are discontinued.

[jon-]

M135i by any chance? I wouldn't just blame the tyres, the front geo scrubs the outside quite badly.

[jon-]

Regarding the load ratings, it's normal to have different front and rear for staggered sizes.

From an insurance point of view, you need to meet the minimum specified, so if the manufacturer specified at 92, you can't fit a 91. You can however fit a 95.

You can go up and down on speed ratings.

[nickfrog]

No Jon, this was a E82 running 1 deg of neg camber thanks to the pin mod. (which is a 10mn job on a 130i too) and some Goodwood track abuse starting at perhaps too low a pressure - but you're quite right it's not just the tyres. I am eventually fitting the M4 lower control arms this week on the M135i to get 2 degrees but will deffo switch to 92 Yoki as part of the strategy to mitigate the issue you highlighted.

[DoubleSix]

Sorry for being a div but I can't find a 'plate' on my 130i that gives the info above.

The manual has the following info but I'm im unsure which number I should be using tbh

[DoubleSix]

Presumably one takes the 920 and divides by 2 for fronts but that just seemed too low...

[gowmonster]

seems logical to me, 81 rating and above? if you weren't halving it, it would be a rating of 105, which is a bit nuts, so it must be right.

[DoubleSix]

True enough.

It's just the 920kgs is massively different to the VAG numbers above that nade me question myself I think.

[TA14]

Does the manual suggest 89 as per the Michelin web site? http://www.michelin.co.uk/tyres/car-tyres#type=typ...

What rating are you wanting to fit?

[gowmonster]

it probably need to include the gross weight, if the car was loaded up. dunno about vag figures though, depends if it's a phaeton or not

[DoubleSix]

TA14 said:

Does the manual suggest 89 as per the Michelin web site? http://www.michelin.co.uk/tyres/car-tyres#type=typ...

What rating are you wanting to fit?

As above, the manual says 920/2 = 460 so load rating of 81 or above, just seemed low to me...

The PSS I'm about to order are 89Y front 92Y rear so no real issue it would seem.

[DoubleSix]

Looking at your link those are 17's

The internet seems to be awash with mis-info about these fitments because BMW changed the rim widths by half an inch on the facelift models so it makes searching for info difficult...


I've settled on the following:
2
Michelin SuperSport Pilot Michelin Super Sport -
215/40 R18 (89Y) XL TL Fuel Eff.: F Wet Grip: A NoiseClass: 2
Noise: 71dB
2
Car / Michelin SuperSport Pilot Michelin Super Sport -
245/35 R18 92Y XL (*) TL Fuel Eff.: E Wet Grip: B
NoiseClass: 2 Noise: 71dB

Edited by DoubleSix on Monday 25th January 12:58

[TA14]

DoubleSix said:

Looking at your link those are 17's

The internet seems to be awash with mis-info about these figments because BMW changed the rim widths by half an inch on the facelift models so it makes searching for info difficult...


I've settled on the following:
2
Michelin SuperSport Pilot Michelin Super Sport -
215/40 R18 (89Y) XL TL Fuel Eff.: F Wet Grip: A NoiseClass: 2
Noise: 71dB
2
Car / Michelin SuperSport Pilot Michelin Super Sport -
245/35 R18 92Y XL (*) TL Fuel Eff.: E Wet Grip: B
NoiseClass: 2 Noise: 71dB

Those would appear to be a very good choice of tyre.

[nickfrog]

Many many people upgrade to 225 front on this chassis. IE M135i sizes. Neutralises the car a little.

Have a check on babybmw.net : far more experience of this particular subject.

[DoubleSix]

nickfrog said:

Many many people upgrade to 225 front on this chassis. IE M135i sizes. Neutralises the car a little.

Have a check on babybmw.net : far more experience of this particular subject.

Yeah, I've heard/read that but suspect it's more to do with the availability of the 215 section which can be a bugger to source. Can't see 10mm making much difference personally.