CHANGING RUN FLATS

[T100L]

mixed reports on them, so decided im going to take them off my gp, asked my local dealer, and he said that the car suspension & wheels are set to run on them??
anybody done this , and whats the score with above:question:

[sh@z]

The dealer will tell you whatever they can to keep the runflats, theres no changes to be made when changing to non runflats as the actual size of the tyre remains the same, so 'technically' there is no difference (other than a brick hard sidewall). Only if you get a flat would the runflats do their stuff.

Take the car to an independant tyre place and sort it, BMW will charge you an arm and a leg for a set of tyres.

[T100L]

good shout, normal tyres here i come! just heard there was a lot of minis having front end crashes with them & the non bmw mechaincs i have spoken with have told me to get em off!

[Gorbash12346]

i'm pretty sure the suspension will have been setup to use them but beyond that i'm not going to cast an opinion either way it's your choice

[KenL]

This suspension thing has got to be a myth.

What is the weight of a runflat in comparison with a standard tyre? Even it if it significant, it is unlikely to be larger than the difference in weight of a 15" tyre with a standard tyre!

Oh, there you go. A Cooper can be specced with 15 - 17" wheels, with and without runflats!!!

[ELFMAN]

I'm coming to the conclusion that Runflats are good for safety/convenience/peace of mind reasons, but from everything I've read/heard, the MINI Handles, Grips and rides better on non-runflats. It's swings and roundabouts as to what you fit. See my thread on Tyre Choice - you'll be 'tired' by the time you read it all!

I'm running JCW suspension - which, apart from some aluminium arms I'll bet (I could be wrong!) isn't a whole lot different from the GP setup, and Cooper themselves told me that it works with BOTH types of tyre. So don't just accept what the dealer tells you... As Ken says, if the COOPER can run on anything from 15" standard tyres to 17" Runflats - the suspension must be a constant - as they don't change it if you change the wheels/tyres do they? To be honest, I'm not convinced by big (over 17") wheels anyway, it's aesthetics over performance (harsher ride and no gains in handling/grip) IMHO - maybe you should go to 17's with non-runflats and nobody would see which way your GP went on a good road........

[Big Col]

I thought the suspension set up would have more to do with the rigid sidewall than the weight?

[ELFMAN]

With the 'first generation' NEW MINI and Runflats, it's accepted (Evo mag, and lots of others) that in standard form, the MINI handled better on 16's than it did on 17's or 18's - so if the suspension was specifically set up for stiffer sidewalls, why would the handling/ride improve with the 'lesser' runflat wheels and tyres, and be even better still (according to some NMS members and other MINI tuners) with non-runflats?

On the weight side, a 15" Alloy and non-runflat MUST be lighter than a 17" Alloy with a Runflat, but the smaller/lighter combo worked well with the MINIs 'Sport Plus' setup. Tuners are always trying to reduce 'unsprung weight' of wheels/tyres - hence lightweight alloys etc - to allow the suspension to work better, so if the MINI suspension works better with lighter stuff at each corner, then it probably wasn't set up for Runflat/big wheel weight either.

I reckon the Gen 1 MINI was works better with smaller wheels/non-runflat tyres in its various suspension settings (Standard/Sport Plus) because that's what it was designed to run with. Runflats and big wheels became the chink in the MINIs armour, as they weren't part of the original equation. Because of this, the 'Sport Plus' setup was 'softened' as time went on to improve the ride etc, as the runflats had killed it, especially as more folk were going for the 17" option. Then the JCW suspension arrived, IMO, with good results - but still with room for improvement - which is why I'm looking at non-runflats.

The latest versions of the suspension on the R56 seem to be taking all these factors into account, as are the latest runflat tyres with their more sophisticated compounds and tread patterns - so the whole package should work better than the previous 'mix n' match' approach, which was a case of 'the tail wagging the dog' - or the wheels and tyres dictating the behaviour of the rest of the car. But then again, I have been known to talk rubbish, so I stand to be corrected!

[Big Col]

P!sh! Yer lookin' at non runflats 'cos yer a tight git that doesn't want to fork out the dosh for 'em! :D

[ELFMAN]

Yeah, that's right, I'm so tight a git I've just spent 4K tuning the MINI - and now spend 10K a month on bloody petrol........ Well thought out reply though big man! ps Can I have that 50p back you borrowed to buy your family Christmas presents?

Seriously though, who has info on the Goodyear Excellence 195/55x16 Runflats now fitted as O.E. to the current MINI - they're probably better that my NCT 5's, but I need some confirmation.

[Gorbash12346]

i'll disagree with you on the grip side of things with my 215/35 18's and my coilovers i get seriously large amounts of grip of the same suspension setup with 195/45 r16's

[miniman06]

you may have to reset the run flat sencor. the we yellow/orange light on yer dash my flash if the tyres are changed to non runflats but this can easily be reset with the button under your handbrake........

[Gorbash12346]

thats not because they are no longer runflats thats because the diameter of the tyre has been changed

[KenL]

quote:Originally posted by miniman06

you may have to reset the run flat sencor. the we yellow/orange light on yer dash my flash if the tyres are changed to non runflats but this can easily be reset with the button under your handbrake........


Just like you should if you pump your tyres up or have them replaced.

[ELFMAN]

“i'll disagree with you on the grip side of things with my 215/35 18's and my coilovers i get seriously large amounts of grip of the same suspension setup with 195/45 r16's“

Gorbash - Yes, but you've totally changed the suspension! I was discussing the 'big wheel' issue in the context of the O.E. MINI suspension/JCW setup. If you stick 18's (especially Runflats) on with standard 'Sports Plus', I'll bet it would be much worse than with your coilovers. OK, I'll agree you'll get more outright mechanical grip on a smooth dry road with the big tyres on standard MINI suspension, but the 'S' I tested in '03 on a damp, lumpy Lanarkshire road with sports Plus and just 17's (runflats) was worse than my 16" version in EVERY respect. Your coilovers obviously work better than the standard setup - which is why you changed to them - and the bigger tyres can then be allowed to work properly. Were your 18's non runflats? If so, IMHO we're talking 'chalk and cheese' comparing Coilovers and 18" non runflats with O.E Sports Plus and 18" Runflats.