Non run- flat tyre pressures on a car that came with run flats
- Thread starter richardg
- Start date
linnfomaniac83
I bet you can’t wheelie a unicycle!
I belive there is a good reason that minis use run flats and it has something to do with diff windup. A small imbalance in rolling radius between the front wheels can do serious damage apparently.
I don't know the technical details but I'd tread carefully. They are supposed to use run flats, and are supposed to be changed in pairs, never one at a time.
Tony Lockhart
Avoiding Stress, at Every Opportunity
In the years I've been on various forums about cars, ive never heard of a problem with Mini diffs after changing to non-RFTs. As long as the insurance company has no problem, I'd go ahead.
RFTs are quite simply awful things. They're harsh (even the latest imo) and are verging on dangerous at 70mph on wet roads.
RFTs are quite simply awful things. They're harsh (even the latest imo) and are verging on dangerous at 70mph on wet roads.
PaulMB
pfm Member
Beautiful pun! (tread)
Don't know about Minis specifically but I've never heard of a car that HAS to have run-flats. It would be a major design flaw given that people might want to use different kinds of tyres in different seasons or conditions.
On any car the tyres should be changed in pairs.
Tony Lockhart
Avoiding Stress, at Every Opportunity
It's the weight of the car that defines the tyre pressure, so use the same pressures as with RFTs.
I used to have an infrared/laser remote thermometer to test the temp across the width of the tread. After a steady drive, test the temps at left, centre and right. Adjust pressure accordingly. However, oem recommended pressures were close enough.
I used to have an infrared/laser remote thermometer to test the temp across the width of the tread. After a steady drive, test the temps at left, centre and right. Adjust pressure accordingly. However, oem recommended pressures were close enough.
linnfomaniac83
I bet you can’t wheelie a unicycle!
It's something my brother told me about. He said it affects Chrysler engined models and that it causes the crown wheel in the diff to fail causing loos of final drive. He says it is a major design flaw.
It's just something to investigate, he may be wrong and the OP's car might not be Chrysler engined but I mentioned because, if my brother is right and the OP's car is Chrysler engined, he could be landed with a big bill.
As for tyre pressures, I don't know, sorry.
It's just something to investigate, he may be wrong and the OP's car might not be Chrysler engined but I mentioned because, if my brother is right and the OP's car is Chrysler engined, he could be landed with a big bill.
As for tyre pressures, I don't know, sorry.
Accuphaseman
Now Lux man
I have a Mini and use Non run flats.Also know of other people that have done the same. The ride is so much better.
HairyHaggis
<((((º>`•.¸¸.•´¯`•.¸.•´¯`•...¸><((((º>¸.
i couldn't agree more. unfortunately, after a recent purchase of mine, and wishing to get rid of these dreadful tyres asap, to remain under warranty, i am forced to buy a set of tyres which, once fitted, will have cost the thick end of £800. still, if i am to get any enjoyment out of the car at all, this is my only chance. the runflats are simply awful beyond words and, under certain conditions, bordering on the downright dangerous! to say i feel aggrieved towards the manufacturer and dealership is an understatement. i feel i have in effect been tricked! shabby!
apropo minis i could be explicit, but if you have the chance, i'd make the move
PaulMB
pfm Member
Regarding tyre pressures, I've found over the years that the recommended pressure is always fine, but that it is OK to set them a bit softer or a bitter harder according to personal preference. Not by much, but if say the manual says 2.5, you can set them at 2.3 or 2.4 for a softer ride, or 2.6 for lighter steering and better response on smooth roads. It also depends on how heavily loaded a car is, from driving alone, or 4-up with luggage. Which is maybe an extra 300 kilos, most of it on the rear wheels.
Tony Lockhart
Avoiding Stress, at Every Opportunity
Tyres are so forgiving and long lasting now. Remember 35 years ago? Shockingly short lived and expensive.
stonehenge
Steve
Wrong and very poor advice based on ? not fact, that's for sure. I have had RFT's on my last seven cars and none have given any problem on wet roads at speed and can't think why they should.
The latest generation tyres are much better and cars softer riding; my wife's latest 4 series has a beautiful ride quality. Mine is fine as well on very low profile staggered 20's.
The only time that I have not liked the feel of the tyres is when I fitted normal walled winter tyres that felt soft and vague. Don't forget that the suspension is tuned for RFT's.
Now add the fact that you can't drive home on normal tyres and have to fit a spare or take a chance. My wife has had a puncture in a 1 series and was very glad of the RFT technology to get her home, then to the garage.
I agree that 1st generation RFT's were hard and BMW M cars using them were not pleasant cars to ride in. They are much better now.
PaulMB
pfm Member
Remember re-treads?
HairyHaggis
<((((º>`•.¸¸.•´¯`•.¸.•´¯`•...¸><((((º>¸.
my 4-series feels and drives like a blancmange on bricks. we must have different models! and i have heard conflicting things from bmw uk - the suspension is tuned for runflats, the suspension isn't tuned for runflats! make of that what you will. coupled with the fact that very few people stock the ones i would need and so the car would be off the road for roughly 24 hours at least (i have checked this). it's worth noting also that bmw do not fit runflats as standard to m cars.
re driving in the wet, i had a scary experience about 2 months ago when i found myself stuttering sideways, out of control, into oncoming traffic after going over a mild bump at around 50mph in an easy left hand bend. it's not something i've ever experienced before and wouldn't wish it again.
Tony Lockhart
Avoiding Stress, at Every Opportunity
We were looking to buy a 235i when they came out. They could be spec'd with either RFT or proper tyres. The suspension stayed the same.
Here you go. My 911 has on the rear 295-30/19 normal tyres. It's more comfortable and just better all round than our 1 Series was on 245-35/18 on the rear.
On one occasion on the A14 near Stowmarket, in the rain, 70mph and a steady accelerator pedal, the bloody amber light on the dash for esp came on for an instant. Why? I'd gone over a small transverse ridge, that was all. Tyre pressures were fine.
RFTs might be better than they were, but they've no place in my life.
Here you go. My 911 has on the rear 295-30/19 normal tyres. It's more comfortable and just better all round than our 1 Series was on 245-35/18 on the rear.
On one occasion on the A14 near Stowmarket, in the rain, 70mph and a steady accelerator pedal, the bloody amber light on the dash for esp came on for an instant. Why? I'd gone over a small transverse ridge, that was all. Tyre pressures were fine.
RFTs might be better than they were, but they've no place in my life.
PaulMB
pfm Member
Ah, and bear in mind that the figure given as "official" is just a compromise. If you were driving in a cobblestoned city at 25 MPH, or on a billiard-table smooth motorway at 140 MPH you would, in an ideal world, choose different pressures. There is not a one and only "perfect" pressure.
Starting off point is the same pressure. The run-flat feature is only in the collapsed state of the shell, requiring the wall to take the load, but the tyre will be exactly the same when fully inflated. The only difference from that point is personal taste and how that applies to the characteristics of the brand chosen.
Diff wind-up is to do with 4x4s, where someone replaces a pair of tyres and puts them on the front instead of the back. 4x4s need to keep all four tyres matched as much as possible regarding wear to prevent this, but if it comes to it, new tyres go on the rear. I have no idea why someone would apply this to a Mini with a single driven axle.
Diff wind-up is to do with 4x4s, where someone replaces a pair of tyres and puts them on the front instead of the back. 4x4s need to keep all four tyres matched as much as possible regarding wear to prevent this, but if it comes to it, new tyres go on the rear. I have no idea why someone would apply this to a Mini with a single driven axle.