F10 M5 Tyre Size Options??

[W8PMC]

I'm running the standard 19" wheels on my car with the standard fitment Michelin Pilot Super Sport tyres is the following sizes:

Front: 265/40/ZR19
Rear: 295/35/ZR19

What are my sizing options to offer up a larger rubber footprint, without upsetting the speedo readings, any sensors or other setting on the car?

Would i need to reduce the profile if i increased the width, so if i went for 275 front & 305 rear, would 40 & 35 still be the correct profile?

Thanks in advance.

[RichardM5]

You should be OK going up to 275 and 305 with the same aspect and diameter. The rolling radius will be slightly larger which will give about a 1.15% speedo error, 60mph will show as 59.32.

If you change ratio, to 35 on the front and 30 on the rear, to maintain the rolling radius you'd need 295's on the front and 345's on the rear, these would not fit the existing rims anyway and probably would not fit under the arches without significant work.

[W8PMC]

RichardM5 said:

You should be OK going up to 275 and 305 with the same aspect and diameter. The rolling radius will be slightly larger which will give about a 1.15% speedo error, 60mph will show as 59.32.

If you change ratio, to 35 on the front and 30 on the rear, to maintain the rolling radius you'd need 295's on the front and 345's on the rear, these would not fit the existing rims anyway and probably would not fit under the arches without significant work.

Perfect. So moving up to 275/305 will have no affect on the cars settings other than the slight out on the speedo? Would i likely notice a handling difference going that 1 size larger front/rear?

[RichardM5]

I think the noticeable difference would be negligible.

You'll gain about 3mm in ride hight and loose about 3mm in wheel arch gap. I guess there is a possibility you may get rubbing under extreme loads (very hard cornering or with the car loaded up to the max), but I'm pretty sure I've seen posts where other people have gone to 275/305 without problems, I believe DINAN in the US recommend it although with 20 inch wheels.

[W8PMC]

RichardM5 said:

I think the noticeable difference would be negligible.

You'll gain about 3mm in ride hight and loose about 3mm in wheel arch gap. I guess there is a possibility you may get rubbing under extreme loads (very hard cornering or with the car loaded up to the max), but I'm pretty sure I've seen posts where other people have gone to 275/305 without problems, I believe DINAN in the US recommend it although with 20 inch wheels.

Thanks. Will be fitting my H&R Sports Springs, along with RS29 pads at the same time as new rubber

She'll be sitting about 15mm lower with the springs so need to hope the extra 3mm doesn't make any noticeable difference & cause rubbing. Didn't realise a few had already gone 275/305, so that's good to know.

[jon-]

Don't forget to let the insurance know if you're changing to a non-oe tyre size.

Also, make sure they make the Pilot Supersports in your new chosen sizes, or you'll probably end up losing more grip than you gain.

[RichardM5]

Michelin PSS 275/35 R19's are actually easier to get than 265/35 R19s. 305/30 R19 are about the same as 295/30 R19's, often on backorder and quite hard to find.

Always best to notify your insurance company about any modification, however trivial you think it is.

[W8PMC]

jon- said:

Don't forget to let the insurance know if you're changing to a non-oe tyre size.

Also, make sure they make the Pilot Supersports in your new chosen sizes, or you'll probably end up losing more grip than you gain.

Doesn't look as though i can get the Cup Sport 2's in the wider size F&R & am struggling for standard size rears although plenty of fronts.

So looks as though i'll have to stick with OEM sizes & just the benefit of the extra track performance (dry) that the Cusp will offer.

[RichardM5]

I'm not sure I'd like to drive an M5 with Cups on the road if there was heavy rain.

[W8PMC]

Well it didn't go to plan as although getting fronts in either 265 or 275 isn't a problem, Michelin don't appear to make a 295 or 305 in 19" so that's scuppered that.

Any other tyre options that are more focussed towards trackdays but are of course legal on the road? I've heard of 888's but i think they'd be too scary on the road if i encountered rain so am looking for alternatives?