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The great pro-runflat manifesto!

2263 Views 20 Replies 17 Participants Last post by  hyprblu
Others may benefit from this fresh perspective, as generally all the posts mention either superior dynamic benefits with non-runflat tires or the practical advantages of running with RFs, not actually the unique handling advantages the RFs may give your Mini.

First of all, top of my priorities is driving experience, I don't care if the car has a stiff ride, a tiny boot or it doesn't have enough coffe holders. Second I perfectly understand the benefits of low unsprung wheight and all the other rules of thumb regarding vehicle dynamics. Truth is, I loved my MCS handling and performance right from the first day, 17" rims and Dunlop Runflat tires included.

Now, having read so much about the dynamic benefits of ditching the runflats for a conventional hifg performance tire, when the time came for a tire change I opted for a set of Pirelli Assimetricos.

I just plainly feel this as been a backstep...

When turning I feel a slight pendulum effect and more body roll. This is noticeable both on zig-zag backroads as well as on long high-speed turns. The car feels more "nervous" now (not on a good way) and less predictable. It flexes before settling and when you zig-zag you can feel momentum building from side to side.

Also the steering feel is slightly more numb on the straight ahead and overly light. With so few Mini in my country I never had the chance to try out a car with a different configuration soI had to try it and see.

So, my conclusion is I much prefer the car with runflats than regular tires. The new tires have amazing grip, are good and progressive but gone is the zero inertia feel my MCS had. I don't mind at all trading the marginal gains I have now on ride confort and (possibly) grip, for the handling behaviour the runflats gave to the Mini.

Don't get me wrong, I still enjoy my cara lot, it's just that it's lost some handlings traits I really liked.

I'm gonna put on my nomex suit now! :D
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Just reminded of this lost post so decided to give it a bump to see if anybody as fresh opinions since then...

BUMP! :D
I agree with your accounts of more tire flex with the asymetrico's. For a car to handle well on quick turns, the sidewall of the tire must be stiff (like runflats). Even though the asymetrico has higher limits, your not going to reach them on fast corners (and when you do, you get snap traction losses). I had to take this into account when I was shopping for non-runflats and came upon the Yokohama ES 100's. I decided to try them and have had them on for the past few weeks. I've found them just a tad bit softer than the runflats but it's only noticeable on the bug bumps and not in corners. Their limits are definitely higher than the [email protected]'s and I actually felt a bit of g-face on a freeway offramp that the [email protected]'a felt like breaking loose. I'm happy with them and if you ever want to try to make the switch again, I'd recommend you try them. [email protected]'s, still, are good tires for that they are meant to be and they compliment the MINI's handling characteristics very well.
While a stiff sidewall generally gives a good turn in it is not a rule. In reply to a question
on RE050 tyres I dug out an old Autocar test of these runflats. Despite a constant mauling
in the magazine about the RE050 tyres ruining the ride quaility of any car they were put
on they were found in back to back testing to be the slowest tyre in the group, prone to
aquaplaning and were the least capable of direction changes. This was done using a
Z4 that according to Bridgestone was optimised for the RE050 tyres. My Pirelli runflat
tyres were plain poor especially in the wet. I certainly won't flame lusomini as it is good
to see another side of the argument :).
I have to agree with a lot of what was said in the first post. I have just changed my 16" runflats for 18" BK299 with Toyo something-or-others (forgive me, I'm not good with technical names).

The ride is actually much softer than with the runflats, despite being told that 18" rims are supposed to be the worst ride, and the car actually seems much quicker, however I have to say that I like the secure feeling that you get from knowing that if the tyre punctures you can still get home. I also don't like the fact that the handling is so skittish.

I do, however, think that the runflats don't do much for the physical attraction of the car and for this reason would probably not change back. What's needed is a normal tyre with runflat properies.... well we can all dream!
i think the skittishness you're feeling is as a result of going from a very heavy wheel/tyre combo to a much lighter one. it still baffes me why people queue up to get 17" s-spokes fitted when they weigh so much :confused:
I don't think you can make a tyre judgement based on going from 16" alloys with runflats to 18" alloys without. The handling characterists will be affected a great deal by a number of factors there, the tyre composition and construction being only one factor of many.
Hat said:
i think the skittishness you're feeling is as a result of going from a very heavy wheel/tyre combo to a much lighter one. it still baffes me why people queue up to get 17" s-spokes fitted when they weigh so much :confused:
I aknowledge and understand all that ;) As I said the Assimetricos are better tires performance wise but I didn't find the OEM Dunlop SP9000 RF's to be crap. Quite good IMHO. It's just down to individual preferences I guess, I never thought my car's behaviour would be altered in what regards to "stiffness". I certainly expected lighter steering feel but not the tire flex factor being so noticeable. As for the S-Spokes, hell, I sucumbed to the looks and buried my form follows function motto just htis once. The 16's make the car look a little bit more "puny", and with the 17"s it stills handle brilliantly :D ...and I don't have the dosh or time right now to buy lighter aftemarket wheels.

I agree with Paul on comparing 16"s to 18"'s plus tire changes, more variables changing so harder to do a proper judgement. As I only changed from RF's to regular I thought it would be a valid oppinion on how it alters the car behaviour.

If I had the chance to try other S's with different setups maybe I would be enlighted but overhere they are a relatively rare sight so have to go by trial and error and live with it.
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I like mine

I didn't really choose it as much as it came with the packages I got but I've been happy with my runflats so far. The handling is as much as I need for aggressive road driving and the ride is better than I expected after reading these forums.
Then there's the whole "runs when flat" benefit.
We were listening to an advertisement this morning on the radio. The DJ was complimenting her car's roadside assistance as she had run over a bunch of nails on the way to work. They changed the tire for her on the side of the road and she was rapidly on her way. My wife and I sort-of giggled at that. Stop? for a flat? Do people still have to do that?
The whole psychological benefit of essentially choosing your breakdown point – particularly if it can then be the tyre shop rather than a dark rainy road somewhere, is extremely comforting.

-Eric
Max said:
Take 2 wheels (the same) one with a RF and one with any ordinary tyre.
Take one in each hand and lift them?
Try not to fall sideways :D :D :red:
Have you actually done this yourself? When I looked at weights of runflats compared to equivalent non-runflats, the difference was typically about 2 pounds. Non-runflats may provide advantages in comfort and handling, but not necessarily in weight. Perhaps runflats have become lighter since the early versions.
I was in the tire store the other day having a runflat with a slow leak repaired and noticed that the Michelin Pilot Sport and Sport A/S are available in a normal version and a Zero Pressure version. Does anyone have any experience with this particular run flat tire? Just wondering if it might be an improvement over the Pirellis or Dunlops.
BTW, I've got about 25K on my [email protected] and my 2 complaints at this mileage are skittishness in the wet and no flex at all.
I'm considering B.F.Goodrich T/A KDWs as the reviews on the Tire Rack site are very favourable.
Rowing with only one oar in the water

I think everyone is missing the boat on this RunFlat vs "ordinary" tire debate. The engineers that designed and built the Mini, making it an outstanding drivers machine, also were the ones who chose Runflats. So the runflats simply are better. Now, lets put both oars in the water and enjoy the ride.
Senior said:
The engineers that designed and built the Mini, making it an outstanding drivers machine, also were the ones who chose Runflats.
The use of run flat tires was dictated by the fact there was no space for a spare tire on the Cooper S.
G
MINIAC said:
The use of run flat tires was dictated by the fact there was no space for a spare tire on the Cooper S.
Yep, as with most decisions on street cars, this was a compromise. The new Porsche doesn't have a spare, but they felt that it wasn't worth putting compromised run-flats on their high performance cars.
Senior said:
I think everyone is missing the boat on this RunFlat vs "ordinary" tire debate. The engineers that designed and built the Mini, making it an outstanding drivers machine, also were the ones who chose Runflats. So the runflats simply are better. Now, lets put both oars in the water and enjoy the ride.
Doesn't every BMW-manufactured car come with runflats, nowadays? That means it could very well be a marketing or a management decision (in fact, it could be when not every BMW came with RF's, it just makes the point a little stronger ;)).

Engineers don't always get their way, just like the marketing deparment or finance department don't always get their way for technical reasons.
An important point which hasn't been mentioned is the different types of run-flat tyre. The original poster said he had Dunlops, same as my old run-flats. These are generally seen as the best of the run-flat family and I was pleased with the performance they gave. I went from the dunlops to Goodyear Eagle F1's and was amazed how differently the car drove. Not all the difference in feel was for the better but overall I consider them an upgrade.
Senior said:
I think everyone is missing the boat on this RunFlat vs "ordinary" tire debate. The engineers that designed and built the Mini, making it an outstanding drivers machine, also were the ones who chose Runflats. So the runflats simply are better. Now, lets put both oars in the water and enjoy the ride.
Yeah, what's the deal with all those aftermarket parts anyway? The car is perfect!
Senior said:
I think everyone is missing the boat on this RunFlat vs "ordinary" tire debate. The engineers that designed and built the Mini, making it an outstanding drivers machine, also were the ones who chose Runflats. So the runflats simply are better. Now, lets put both oars in the water and enjoy the ride.
However when the MINI was first launched did you ever see a press car with the 17" wheels on?

No becuase of the way the bigger wheels and runflats made the car handle. MINI have since (03 models onwards) made changes to the suspension to make the runflats suit the car better, but its still by no means ideal.

After just switching to non runflats the difference is amazing, the ride is the most noticeable thing.
Will any dealers put non run flats on at request or do you have to go to an independent supplier?
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