Kumho Ecsta PS91 - Sidewall failure - Opinions

[cashmax]

Fitted a set of these to the rear of my F10 M5 last year and the car recently developed a slight vibration at speed. I discovered that the inner sidewall of the offside rear tyre had failed all the way around the tyre. Never seen anything like this before and wondered if it is a manufacturing defect or something else. Its a shame because the tyres are great, with very good grip and progressive in the wet.

Tyres at 37psi, car not been on track, although the odd high speed trip abroad (never more that 150mph) and occasional towing of my caterham race car.

[832ark]

Why are you fitting mid range tyres to an F10 M5 for starters? I suspect you’d have had no issues with SuperSports or 4Ss.

[cashmax]

832ark said:

Why are you fitting mid range tyres to an F10 M5 for starters? I suspect you’d have had no issues with SuperSports or 4Ss.

Thanks for the really helpful and insightful response.

[blade7]

Judging by the wear on the inside edge, I'd guess something is wrong with the geo on your car. Besides that they look like they're overdue for replacement anyway.

[cashmax]

blade7 said:

Judging by the wear on the inside edge, I'd guess something is wrong with the geo on your car. Besides that they look like they're overdue for replacement anyway.

Beemers always tend to wear the inside edges if they do lots of motorway miles. The tyres do need replacing, just shocked at how they appear to have failed.

[832ark]

cashmax said:

832ark said:

Why are you fitting mid range tyres to an F10 M5 for starters? I suspect you’d have had no issues with SuperSports or 4Ss.

Thanks for the really helpful and insightful response.

Well, you certainly get what you pay for. I just can’t understand the mindset of taking a valuable, high performance, driver focused car and fitting sub-optimum rubber. If I went to view an M car on such tyres I’d assume the owner was a tight arse and walk away.

[Ninja59]

blade7 said:

Judging by the wear on the inside edge, I'd guess something is wrong with the geo on your car. Besides that they look like they're overdue for replacement anyway.

More and more cars are coming set from factory with more negative camber it will wear the inside tyres in straight line more but enhances grip in cornering.

[ZOLLAR]

832ark said:

cashmax said:

832ark said:

Why are you fitting mid range tyres to an F10 M5 for starters? I suspect you’d have had no issues with SuperSports or 4Ss.

Thanks for the really helpful and insightful response.

Well, you certainly get what you pay for. I just can’t understand the mindset of taking a valuable, high performance, driver focused car and fitting sub-optimum rubber. If I went to view an M car on such tyres I’d assume the owner was a tight arse and walk away.

Nothing wrong with Kumho tires.

Certainly not sub-optimum rubber, Kumho are OEM for BMW and other manufactures.

https://www.kumho.com.au/why-kumho/original-equipm...

Also have plenty of involvement in motorsport including use on Bac Mono's

https://kumhotyre.co.uk/kumho-news/kumho-shod-bac-...

Not sure what else you need to prove they can cope on a fast saloon? I can only assume you see a brand that isn't Pirelli etc and immediately make an assumption they aren't good..

[DailyHack]

Don't think it is anything to do with the brand of tyre - OP could of hit a pothole or anything. High end tyres can have there flaws.

Some people are so easy to jump on making assumptions about cash strapped owners, this thread will now turn into another tyre snobbery thread.

[blade7]

cashmax said:

blade7 said:

Judging by the wear on the inside edge, I'd guess something is wrong with the geo on your car. Besides that they look like they're overdue for replacement anyway.

Beemers always tend to wear the inside edges if they do lots of motorway miles. The tyres do need replacing, just shocked at how they appear to have failed.

I've got PS2's on my 944 turbo, set up by Center Gravity with a fair amount of neg camber, but they haven't worn like that after 20k. I know some Toyos are criticised for having soft sidewalls, and don't work that well on heavy cars. Maybe the Kumhos are the same.

[rallycross]

That is very unusual damage are you sure its not been driven with low PSi on that wheel like less than 10 psi?

The tread looks like you are several 1,000 miles past replacement time my racing car's semi slicks have more tread depth than that!

[brillomaster]

37psi? I run the rears of my 3 series at 44psi, id expect an m5 to run higher than that given its a heavyweight?

[rallycross]

brillomaster said:

37psi? I run the rears of my 3 series at 44psi, id expect an m5 to run higher than that given its a heavyweight?

what tyres / wheel size? I have owned many 3 series never run anything like that high before, your cold/wet grip will be affected and the tyres will wear out in the centre too from over inflation.

[TonyTony]

Kumhos were terrible on my Leon, I can't imagine how bad they are with another 300+ horses going through them!

[Tankrizzo]

832ark said:

Well, you certainly get what you pay for. I just can’t understand the mindset of taking a valuable, high performance, driver focused car and fitting sub-optimum rubber. If I went to view an M car on such tyres I’d assume the owner was a tight arse and walk away.

Do shut up, there's a good chap.

[cashmax]

rallycross said:

That is very unusual damage are you sure its not been driven with low PSi on that wheel like less than 10 psi?

The tread looks like you are several 1,000 miles past replacement time my racing car's semi slicks have more tread depth than that!

Never been driven with low pressure - the monitoring system is pretty good in the M5 and I know for sure that I haven't done that. Re tread depth, that tyre is at 2.3mm.

It's very hard to get tyres to wear evenly on every M car I've owned. A few PSI too much and they wear in the centre, bang on and the camber gets them. I've had cords showing on the inside before when the rest of tyre has 5mm left.

[cashmax]

blade7 said:

cashmax said:

blade7 said:

Judging by the wear on the inside edge, I'd guess something is wrong with the geo on your car. Besides that they look like they're overdue for replacement anyway.

Beemers always tend to wear the inside edges if they do lots of motorway miles. The tyres do need replacing, just shocked at how they appear to have failed.

I've got PS2's on my 944 turbo, set up by Center Gravity with a fair amount of neg camber, but they haven't worn like that after 20k. I know some Toyos are criticised for having soft sidewalls, and don't work that well on heavy cars. Maybe the Kumhos are the same.

Perhaps it's that simple. Did a few long trips with the trailer (500 odd miles) and perhaps that was enough to tip them over the edge.

[cashmax]

832ark said:

cashmax said:

832ark said:

Why are you fitting mid range tyres to an F10 M5 for starters? I suspect you’d have had no issues with SuperSports or 4Ss.

Thanks for the really helpful and insightful response.

Well, you certainly get what you pay for. I just can’t understand the mindset of taking a valuable, high performance, driver focused car and fitting sub-optimum rubber. If I went to view an M car on such tyres I’d assume the owner was a tight arse and walk away.

LOL - If I was selling my car, I doubt you'd come and view it because I probably would have priced it reasonably, so it would not make your shortlist. Having said that, it sounds like most vendors would have you figured out for the tyre kicker you are and march you off the premises long before you got your chance to walk away, shocked that they didn't fit the most expensive boots.

[anonymous-user]

ZOLLAR said:

832ark said:

cashmax said:

832ark said:

Why are you fitting mid range tyres to an F10 M5 for starters? I suspect you’d have had no issues with SuperSports or 4Ss.

Thanks for the really helpful and insightful response.

Well, you certainly get what you pay for. I just can’t understand the mindset of taking a valuable, high performance, driver focused car and fitting sub-optimum rubber. If I went to view an M car on such tyres I’d assume the owner was a tight arse and walk away.

Nothing wrong with Kumho tires.

Certainly not sub-optimum rubber, Kumho are OEM for BMW and other manufactures.

https://www.kumho.com.au/why-kumho/original-equipm...

Also have plenty of involvement in motorsport including use on Bac Mono's

https://kumhotyre.co.uk/kumho-news/kumho-shod-bac-...

Not sure what else you need to prove they can cope on a fast saloon? I can only assume you see a brand that isn't Pirelli etc and immediately make an assumption they aren't good..

People who slate Kumho can't have tried them.

Just because they are priced as a midrange doesn't mean they are in terms of performance.

I love 'em and have had them on an F80 M3 and Z3M coupe and they are utterly fantastic

[gazza285]

Too much nose weight when you are towing your Caterham perhaps? With the camber as it is, you'll have a lot of weight on the inner sidewall if you get it wrong...