Rear tyre wear in middle

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djones
djones
20
Joined: Thu Mar 17, 2005 2:01 pm

Rear tyre wear in middle

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Hi,

Just hoping somebody can help on an issue I have on my BMW 1 Series (125i).

Alignment is perfect (it has been on a Hunter 4 wheel machine) but the rear tyres have worn noticeably more in the centre. After about 7,000 they probably have about 2mm of tread left, but the outside of this more like 5mm.

My initial thought was high pressures, but I always run at the minimum in the handbook (34 PSI I think).

Will it be ok to run lower to stop this happening in future?

Thanks


p.s. the car gets driven quite hard, so the 7,000 miles it not a concern as such, just the strange wear.

Jolle
Jolle
171
Joined: Wed Jan 29, 2014 9:58 pm
Location: Dordrecht

Re: Rear tyre wear in middle

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nah, thats just accelerating too brisk and not enough tough cornering to shave the sides a little ;-)

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rscsr
68
Joined: Sun Feb 19, 2012 12:02 pm
Location: Austria

Re: Rear tyre wear in middle

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djones wrote:
Tue Nov 06, 2018 8:45 pm
Hi,

Just hoping somebody can help on an issue I have on my BMW 1 Series (125i).

Alignment is perfect (it has been on a Hunter 4 wheel machine) but the rear tyres have worn noticeably more in the centre. After about 7,000 they probably have about 2mm of tread left, but the outside of this more like 5mm.

My initial thought was high pressures, but I always run at the minimum in the handbook (34 PSI I think).

Will it be ok to run lower to stop this happening in future?

Thanks


p.s. the car gets driven quite hard, so the 7,000 miles it not a concern as such, just the strange wear.
The pressure is clearly too high for these tyres. The handbook can't predict which tyres you use and it has to assume that the car is full of passengers and still be safe. Additionally more pressure usually means less risk of failure and better aquaplaning properties. So basically from the manufacturers perspective more pressure is never bad, especially when the drivers usually don't check the pressure too often.
So basically as long as you don't have excessive deformations in the tyre shoulder just lower the pressure.

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Big Tea
83
Joined: Sun Dec 24, 2017 7:57 pm

Re: Rear tyre wear in middle

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rscsr wrote:
Tue Nov 06, 2018 9:43 pm
djones wrote:
Tue Nov 06, 2018 8:45 pm
Hi,

Just hoping somebody can help on an issue I have on my BMW 1 Series (125i).

Alignment is perfect (it has been on a Hunter 4 wheel machine) but the rear tyres have worn noticeably more in the centre. After about 7,000 they probably have about 2mm of tread left, but the outside of this more like 5mm.

My initial thought was high pressures, but I always run at the minimum in the handbook (34 PSI I think).

Will it be ok to run lower to stop this happening in future?

Thanks


p.s. the car gets driven quite hard, so the 7,000 miles it not a concern as such, just the strange wear.
The pressure is clearly too high for these tyres. The handbook can't predict which tyres you use and it has to assume that the car is full of passengers and still be safe. Additionally more pressure usually means less risk of failure and better aquaplaning properties. So basically from the manufacturers perspective more pressure is never bad, especially when the drivers usually don't check the pressure too often.
So basically as long as you don't have excessive deformations in the tyre shoulder just lower the pressure.
It has to be pressure, or an outside option, tyres wrong profile for the rims.

(Edited width to profile)
Last edited by Big Tea on Wed Nov 07, 2018 10:15 am, edited 1 time in total.
One test is worth a thousand expert opinions

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strad
265
Joined: Sat Jan 02, 2010 12:57 am

Re: Rear tyre wear in middle

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The pressure is clearly too high for these tyres. The handbook can't predict which tyres you use and it has to assume that the car is full of passengers and still be safe. Additionally more pressure usually means less risk of failure and better aquaplaning properties. So basically from the manufacturers perspective more pressure is never bad, especially when the drivers usually don't check the pressure too often.
So basically as long as you don't have excessive deformations in the tyre shoulder just lower the pressure.
Perfect ... Couldn't have said it better. Are you checking pressure when cold? You should.
Test by rolling thru some water then check the imprint left when you roll onto dry pavement/concrete.
Should be able to see the whole tread if not they are bulging in the center from too high of pressure. IMHO
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

Maritimer
Maritimer
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Joined: Wed Sep 06, 2017 8:45 pm
Location: Canada

Re: Rear tyre wear in middle

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Try running them at 28 and raise the pressure accordingly. OEM spec is too high for any reasonable tire, usually even the ones they come with from the factory.

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strad
265
Joined: Sat Jan 02, 2010 12:57 am

Re: Rear tyre wear in middle

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Hadn't noticed the 34 PSI seems at least a couple of PSI too much. 32 is traditional but it might prefer even less.
I run 30psi on my car and the wear pattern is excellent.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

AnthonyG
AnthonyG
47
Joined: Sat Mar 03, 2012 12:16 pm

Re: Rear tyre wear in middle

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Be carefull that you don’t lower the pressure too much. Those RFT tyres in combination with weak BMW wheels tend to crack them when running over potholes. I managed to break 5 17” wheels on my BMW over the years.
Thank you really doesn't really describe enough what I feel. - Vettel

djones
djones
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Joined: Thu Mar 17, 2005 2:01 pm

Re: Rear tyre wear in middle

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Thank you for all the replies, much appreciated and some great information.

I use non run flats as the car was horrible on them.

I shall run the new tyres at 3 PSI less and monitor the wear. Hopefully that is the answer and I'm now not worried about going under the handbook figures after what people have kindly said.

Wait on... I wonder if the handbook figure is so high as that was for the OEM run flats?

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strad
265
Joined: Sat Jan 02, 2010 12:57 am

Re: Rear tyre wear in middle

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When I looked online the it said the door placard recommended 32 PSI. so the higher figure may have been for the run flats. :wink:
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

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mertol
22
Joined: Tue Mar 19, 2013 9:02 am

Re: Rear tyre wear in middle

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Don't you have this on the door?
Image

Find the pressure for your exact tires