Optimal speed for economical m'way driving?

AdrianHi

meester wrote: »

My tyre blew out on the motorway at 100mph+, I had been doing sustained speeds of around 100mph (trying to catch flight), I am sure this is why it occured, and it would not have happened at 70mph.

I managed to guide the car off the motorway onto the hard shoulder, it wasn't too bad, probably better because it was 5:30am, and all happened quite quickly, so didn't have time to think about it, unfortunately a tree grazed the door and so I sold the car because it was a bit of a banger anyway, and not worth replacing.

I since check my tyres for damage a bit more often.

For what it's worth 85% of motorway blow outs are caused by tyre pressures not being maintain at their correct level. The higher the speed the more heat builds up in that tyre side wall that is flexing more than it should due to low pressure. Something like 10% are cause by picking up a slow puncture during the drive and only 5% by debris on the road.

I cannot stress how important it is to check and correct tyre pressures every 2 to 4 weeks. As winter draws in I watch my tyres drop from 2.2 bar to 2.1 bar (5%) in just 3 weeks. Pressure loss not so quick in summer. Even 5% affects wet braking distance quite considerably.

This is something I look into before removing run flat tyres from my car (I have a lot of reasons for wanting to do that). Run flat tyres mean you keep control of the car if it looses pressure, in removing these tyres I wanted to know what risk I was bringing back. Not much as it turns out as you can avoid nearly all the causes yourself by maintaining tyre pressures correctly and I have a tyre pressure monitoring system on the car which will warn me if I pick up a slow puncture mid-journey.

meester

AdrianHi wrote: »

For what it's worth 85% of motorway blow outs are caused by tyre pressures not being maintain at their correct level. The higher the speed the more heat builds up in that tyre side wall that is flexing more than it should due to low pressure. Something like 10% are cause by picking up a slow puncture during the drive and only 5% by debris on the road.

Actually I think mine was caused by tyre wall damage due to tracking being bad.

I should buy one of those tyre pressure gauges though...

ihatecharges

AdrianHi wrote: »

This is something I look into before removing run flat tyres from my car (I have a lot of reasons for wanting to do that). Run flat tyres mean you keep control of the car if it looses pressure, in removing these tyres I wanted to know what risk I was bringing back. Not much as it turns out as you can avoid nearly all the causes yourself by maintaining tyre pressures correctly and I have a tyre pressure monitoring system on the car which will warn me if I pick up a slow puncture mid-journey.

What Beemer you driving if you don't mind me asking?

AdrianHi

meester wrote: »

Actually I think mine was caused by tyre wall damage due to tracking being bad.

I should buy one of those tyre pressure gauges though...

Can you remember where on the side wall the tyre shredded?
Bad tracking usually shows up as uneven wear on the tread region and not side wall damage. In the too low pressure scenario the tyre side wall literally melts in area area of greatest flex around half way up the side wall.
There are other ways the side wall can be damaged, my wife caught an "outcrop" of kerb stone on hers once.

AdrianHi

ihatecharges wrote: »

What Beemer you driving if you don't mind me asking?

It is an October 2005 320d SE touring (E91) - new shape.

ihatecharges

AdrianHi wrote: »

It is an October 2005 320d SE touring (E91) - new shape.

Cheers, I prefer the touring to the saloon, very nice.:beer:

greenman7

Pew Pew Pew Lasers - this is my reply from the IAM:
I have a few comments – the first being that the only reason I am responding to this is to protect the reputation of the IAM. Otherwise I do not respond to anonymous mail.

The IAM would appear to have had someone who has gone through our process and has been able to pass the advanced driving test, but who has negative views about the speed limit. Given that about half a million people have taken the IAM’s advanced driving test, I would be surprised if there weren’t a range of opinions amongst them. The individual is not a member, so I have no control, influence, or responsibility for him – and it may well be that the reason he is not one of our members is because of our stance on speed limits. The IAM’s view is that drivers should obey the speed limit. Encouraging anyone to do otherwise is a criminal offence. Individual speed limits may be inappropriate, and there may well be a need to review them – but just because I don’t like the law that says I should not hit people I disagree with doesn’t mean I am free to ignore it – and the same applies to speed limits.

AdrianHi

greenman7 wrote: »

Pew Pew Pew Lasers - this is my reply from the IAM:
I have a few comments – the first being that the only reason I am responding to this is to protect the reputation of the IAM. Otherwise I do not respond to anonymous mail.

The IAM would appear to have had someone who has gone through our process and has been able to pass the advanced driving test, but who has negative views about the speed limit. Given that about half a million people have taken the IAM’s advanced driving test, I would be surprised if there weren’t a range of opinions amongst them. The individual is not a member, so I have no control, influence, or responsibility for him – and it may well be that the reason he is not one of our members is because of our stance on speed limits. The IAM’s view is that drivers should obey the speed limit. Encouraging anyone to do otherwise is a criminal offence. Individual speed limits may be inappropriate, and there may well be a need to review them – but just because I don’t like the law that says I should not hit people I disagree with doesn’t mean I am free to ignore it – and the same applies to speed limits.

They are bound to say this, a good response.
I'm just wondering if it is time to agree to disagree between the parties involved on this point?
It's been dragging on for a while now and it's not really positive any more.

tomstickland

Otherwise I do not respond to anonymous mail.

Why the need for anonymous mail in the first place?

greenman7

They are bound to say this, a good response.
I'm just wondering if it is time to agree to disagree between the parties involved on this point?
It's been dragging on for a while now and it's not really positive any more.

I agree - this will be my last post on the subject.

Why the need for anonymous mail in the first place?

To be honest I did not realise it was anonymous until he pointed it out to me. I was rushing to make an email whilst doing other things.