: How much skuttle shake is normal?
Aug 16th, 2011, 10:22 PM
Just became the owner of an 09 Cooper S convertible (2nd gen) with Chilli pack and 17" wheels, and I am not sure if the level of scuttle shake on broken surfaces is normal.
In other convertibles I am used to feeling a flex from the body, but in the cooper it is not just flex, but a judder / resonance which is transmitted up through the seat and feels like it is coming from the back.
It feels worst when the roof is up, perhaps because the movement is more constrained with the roof trying to provide the missing structure.
For sure the stiff suspension, and running flat tyres are part of the equation, but, Just looking for some calibration from other users if it is normal or not?
I think I will try and get a test ride in a new one at the local dealer and see how it compares, but any comments from the forum users will be worth their weight in gold.
Aug 17th, 2011, 01:46 PM
My 2nd gen convertible has fairly modest scuttle shake. Your description of vibration rather than flex fits my experience - the Mini is actually quite a stiff convertible and so you would expect only higher-frequency shake. The stiffer a structure is (bridge, car, whatever), the higher its natural frequency is. So vibration is a good sign!
I find it seems to wobble empty seatbacks and headrests - but then I only have non-run-flat 16s.
Aug 17th, 2011, 09:52 PM
Thanks for the reply, yes it feels very stiff, and hence a higher frequency.
i do think the runflats may have something to do with it as well, so will follow through with a test drive at the dealers to compare, want to be sure the dampers etc are not part of the problem while i still have the warranty from the dealer.
Oct 2nd, 2011, 08:37 AM
Ok, a bit of an update on the scuttle shake after getting a couple of days loan with a brand new cooper S convertable with 17" wheels.
The shake/vibration tendency was there with the new cars, but it felt more damped.
This observation was further underlined when I took the loan car down some of my favourite biking roads....fast windy A & B roads.... Once here the loan car was much more composed, especially when hitting a bump on one side only when pressing on. In my own car, it can get very scary accelerating down this kind of road, whether straight or in corners hitting a bump will lift one front wheel and the steering will snatch Violently.
To put it in perspective, the example would be that when going for a quick overtake down a slightly bumpy A road in 3rd, I was not will willing to take one hand off the steering wheel to change up to 4th, the steering was fighting left and right off each bump and really need both hands to keep the car on the road!!!
In the loan car on the other hand it was again much more damped and composed, although still a bit flighty, it was much easier to control, and no fear to go 1 handed and make the gear change...looking at the speedo, I think I was about 10mph faster through the bends and not feeling like I was tempting fate!
The garage have done a full alignment check and made changes to both back and front, but it has done nothing for the vibration or the flighty steering on acceleration & bumps.
The feeling is that the springs are too stiff and / or the damping is too soft and the wheels can't stay on the road. Based on this the next change is going to be to swap all 4 wheels with the loan car, as I have now spotted that my car is fitted with Chinese WANLI run flat tyres.
I am not sure if the tyres have a much stiffer sidewall than the stock fitment, but by swapping I can try this out with out forking out for a new set.
If it is not that I am looking at dampers, or? ??
For sure it needs fixing as it is not right.
Oct 2nd, 2011, 10:46 AM
.....I have now spotted that my car is fitted with Chinese WANLI run flat tyres.
My sphincter muscle puckered sharply just reading that sentence, so I don't want to think what driving on them might really be like.
Of course they may be fine and I'm just biased. Hands up those who remember the phrase 'jap crap', or when 'made in Taiwan' meant 'will break in the hand'?
Oct 2nd, 2011, 12:27 PM
Must admit I wasn't too pleased when I realised they were Chinese!
I had a good search on the Internet and even found some good reviews for the type fitted, but some of their other products were being slated especially for wet grip, but these ones are good in the wet...its just bump roads that I can't drive on!
Oct 14th, 2011, 06:11 PM
Second update having now done the tyre swap....:D. Good news, the problem is fixed.
Swapped all 4 wheels with anothr car at the garage, fitted with Dunlop SP sport run flats, and now my car is not a scary death trap on bumpy roads.
So confirmation that the budget run flats were either too stiff, or to heavy and they were combining to overwhelm the damping and allowing the wheel to lift off the road when hitting a bump.
Lesson learned for anybody tempted to save a few ££