Just who signed off on the OE tyres?

T

techathy

Active member
I found out two things today. Firstly my house mate thinks that Dunlop can be spelled Pirelli :roll:... secondly, and some what more importantly, even with temps in the mid to high teens 235/40R18 Pirelli Sottozero 3 winter tyres gives better traction on smooth & fractured tarmac than the 255/35R18 OE rear tyres. Which leads me to the question - who signed off on RFT as a good idea? :rofl:
 
Pretty much all BMWs have RFTs and have done for years. It's to do with weight saving, fuel efficiency on official tests, and production cost reduction, not driving quality...
 
RFTs weigh more than standard tyres so don't think it was a weightsaving idea .
More likely cost cutting & in many cases no room for a spare wheel :wink:
They are terrible on some cars but work well on others .
For a performance car like a Z i would have them off asap & enjoy the noticeable difference
 
What gets me is that many moons ago Potenzas were ace in tests but look at any tyre test now and they don't fair well at all in any test and especially in the wet. It's mental that on some wheels or just specific models you are automatically defaulted to run flats wether you want them or not but the ///M's are now sold with non rtfs, choosing Michelin PSS 3 iirc and the i3 and the hybrid active cars are also sold without RFTs. Just really strange.

On my Mini I had non RFT's and instead BMW supplied some gunk and a compressor. Funnily enough though no jack which really should be used as you should really rotate the tyre when using the glue stuff.
 
techathy said:
I found out two things today. Firstly my house mate thinks that Dunlop can be spelled Pirelli :roll:... secondly, and some what more importantly, even with temps in the mid to high teens 235/40R18 Pirelli Sottozero 3 winter tyres gives better traction on smooth & fractured tarmac than the 255/35R18 OE rear tyres. Which leads me to the question - who signed off on RFT as a good idea? :rofl:
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Which ones do you have? The Bridgestones?
 
Angie4m said:
What gets me is that many moons ago Potenzas were ace in tests but look at any tyre test now and they don't fair well at all in any test and especially in the wet.
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Maybe other manufacturers have moved on since Potenzas topped the tests and Bridgestone havnt done enough to keep up or stuck with what they had.
 
Nictrix said:
Angie4m said:
What gets me is that many moons ago Potenzas were ace in tests but look at any tyre test now and they don't fair well at all in any test and especially in the wet.
Click to expand...
Maybe other manufacturers have moved on since Potenzas topped the tests and Bridgestone havnt done enough to keep up or stuck with what they had.
Click to expand...

That's exactly what's happened. They've stuck with a formula that worked and whilst they weren't looking other companies came and stole their crown. What I don't get is why BMW stick with them? They aren't the greatest tyres for their cars but as not many run flats about it leaves them with not too much of an option unless they want some other company to develop new RFTs which would cost millions and would in turn cost even more than current RFT prices.

Definitely BMW should give people the option of RFT or non RFT. I've actually been in the dealership and heard people ask about the spare wheel not even realising that they have RFTs and when they've been advised they have RFTs and non spare they want to know what RFTs are!!
 
Happens all the time for whatever strange reason.
For a while Yamaha were punting out their sportsbikes with Dunlops on them that were notoriously bad and people were buying the bike and having the dealer swap the tyres before taking delivery, at the buyers cost.
 
mr wilks said:
RFTs weigh more than standard tyres so don't think it was a weightsaving idea .
More likely cost cutting & in many cases no room for a spare wheel :wink:
They are terrible on some cars but work well on others .
For a performance car like a Z i would have them off asap & enjoy the noticeable difference
Click to expand...
RFT tyres all round should be lighter than a space saver + tool kit.

Angie4m said:
What gets me is that many moons ago Potenzas were ace in tests but look at any tyre test now and they don't fair well at all in any test and especially in the wet.
Click to expand...
I agree with this but I wasn't comparing the OE Bridgestones to another summer HPT but to a winter tyre in conditions which were well outside it's optimal zone & getting close to idea for a summer tyre.
 
I think that RFT' are fine on a 45 profile and above, but in a low profile should be avoided especially with OEM potenzas.

The 225/45/17 on my last zed were pretty quite and comfortable, changing to 225/40/18 and non RFT's the ride was pretty similar. The car I test drove had 19" wheels and were pretty noisy on the motorway and uncomfortable around town.

techathy, the winter tyres have a lower glass transition temperature than summer tires, therefore at mid teen temperatures they will be significantly softer than a summer tire and thus give improved traction, the downside is that they won't last long
 
sars, The road I'm thinking of has deep cracks/steps - the tarmac was laid over a concrete road & now the sections have started settle relative to each other & have become miss-aligned. Under these conditions in 6th & 7th gear any meaningful acceleration (maybe 1/3 throttle) would result in the TC light flickering and the rear moving a small amount with the Bridgestones. On the Pirellis I could be fairly aggressive on the throttle in 5th (<80%), also on road expansion joints no flickering TC light on a neutral throttle. However, on a flat smooth road surface I was getting TC intervention & wheel spin at 50-60% throttle in 2nd with the Pirelli tyres, on the Bridgestones WOT in 2nd doesn't cause any TC intervention.
 
Yep - completely agree.

I have 19" 326s on my 35is - with the RFT tyres (plenty of tread left) the traction was skittish as soon as it got cold (below 10 degrees C) in any conditions. In the wet or on a less than perfect surface you had to be feather light on the throttle & pretty cautious on any bend at any speed. TC light was flickering very often.

Switching to super sport 3s improved the grip no end. Still cannot be a lunatic in the cold & wet, but nothing like the RFT tyres - plus comfier & quieter.

Can of gunk & the compressor kit stashed in the boot just in case, but not had a puncture in 20 years so feel pretty comfortable... plus the AA will help out if lightning does strike :)

Matt
 
But it doesn't really explain it. By that I mean the Pirelli tyre doesn't have more traction than the Bridgestone on smooth roads. It's just the RFT carcass can't keep as much tread in contact with road when there are imperfections.
 
But a softer tyre will help with imperfections in road surface, where on a smooth flat surface the wider tyre probably makes the difference less noticable
 
Broken or rough surfaces sure, but not things like 10<30mm steps, 20<50mm wide cracks in an otherwise smooth surface. With things like that we're beyond tread deformation and well into carcass deformation.
 
My M135i came with MPSS as standard although you could spec NRFs as an option. If I go for another will definitely be speccing runflats, I have a love hate relationship with the Michelins but generally fed up with them and never liked the thought of relying on a can of hopeless foam.

Tim.
 
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