That is exactly what my idea is too.. The runflats dribble on bad roadsurface and fast corners. My old 330Ci Convertible also had 18 inch wheels with michelin tires (non runflats) and it had the grip and settled into fast corners (you could actually feel the tires grip up in these situations, sticking to the road).

I consider myself as a fairly good driver since I had a lot of training on circuits.

 

I really recommend getting a digital device to measure tyre pressure. It's proven very helpful to me as I was getting tyre puncture warnings all of the time, and due to the fact that most petrol station compressors seem quite imprecise.

 

^^^^I wouldn't trust a gas(petrol) station air gauge at all. Digital is best.

 

Exhaust changed: yes. Remapped: no. It would need to be done with some aftermarket tuner stuff (Dinan, etc.). My thought is that it is more important to have the computer remapped when there are modifications on the intake side than the exhaust side. I could be talking out of my ass however.
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The exhaust side affects the intake side, thats my point. More noise doesn't mean more HP. Today with all of the electronics, you can get away with unbalancing the system, the engine even compensates for lower octane fuel by decreasing HP.
Even Dinan does not post HP gains for a exhaust system change only, its in conjunction with software and intake system See attachment.
Anyway, my original point is that even though your car "feels" more stable with Snow than the stock OEM sport tires tires, it is probably not.

 

Good point, but I still think that "remapping" etc. will yeild more gains with some intake side mods than with exhaust. A free flowing muffler will sound better. A full exhaust system, including headers, will help the intake side from being "bottlenecked" and thus may be helped with some new mapping of the program. Mods to both the intake and exhaust side will benefit greatly from new programming. (My Audi went from 250 to 318hp with just a $750 "chip". Although Turbos will benefit MUCH more from software reprograming).

I wasn't looking for any more HP gains with the exhaust... Just the "noise".
I haven't noticed and degredation in performance but who the hell knows.

As for the snows. I think a lot of it had to do with going from Runflats to non_runflats but even moreso going from not much tread to "new" tires.

 

I blame runflats for 'loose' feel on turns, particularly when adding power. If the road is at all irregular, the stiff sidewalls do not conform well and traction is lost despite the bigger tread & footprint. I noted early-on that after engine break-in, when higher rpms were safe, during accelerations in low gear and tight turning, I experienced wheel hop occasionaly. Even on smooth road surfaces; so I couldn't blame the raod. I plan to switch tires even though I don't have road noise issues. Runflats are Bridgestone.

 

are you still on your runflats? if YES then i think they are a big part of the problem. I drove a 520i "loan" car from my dealer recently fitted with non-runflats and whooooa what a difference, for the better I mean!!

i think when my tyres reach their end of life (or maybe sooner!!!!) i will be changing them for non-runflats and buying a space saver spare.

runflats are the achilles heel of the E60's IMO. Just waiting for Kwik-fit todo their buy 3 get one free offer again

is it true that BMW's M division have opted to fit the M5 E60 with non-runflats? if yes....nuff said. maybe in a year or so there will be new model runflat tyres that perform better.

 

yeah, its true that the m5 will not be having run flats

 

northernmonkey

think you might be right, it's seriously tempting to get a set of 18' non-runflats fitted despite only having 4500 miles on my current set. any idea how much this is likely to set me back?

jonboy

 

jonboy, try www.blackcircles.com