I suspect the short wheel base and stiff suspension. I bet Mini comes out with a recal and replace the springs with ones of a differant rate.

 

This will be interesting when winter hits and I skip over a bump in the road onto some ice and just start sliding...

 

I think I posted this on other thread too. But just curious to see if any of you experience this: When braking over bumps (ex, coming to a stop), the brake pedal vibrates violently. Some people told me that was the ABS kicking in, and I did some researches online too, and it does seem like it's ABS. But I don't understand why the ABS activates so easily. Because most of the time, I was not driving/braking over bumps in a high speed, and the bumps weren't that crazy either. Sometimes, even small bumps would cause the pedal to beat violently, and I can hear metals too! Not sure if this is normal. Do anyone have the same problem? Thanks

 

Difficult to be sure without being there in person, but the brake pedal vibrating violently accompanied by a metallic sound is almost certainly the ABS engaging because the ABS system is detecting that one or more tires is losing traction. If you are braking moderately to severely and a tire hits a pretty good bump, it will tend to lose traction (versus a tire not hitting a bump) as the tire "unloads" when the suspension (and tire itself) rebound from the bump, and given the unloading of the tire the brake on that tire/wheel starts to lock. If this is the case, the ABS is doing exactly what it should be doing to prevent that tire from locking up and skidding. But this should not be a regular occurance unless you tend to brake hard (which some drivers do) If this is happening often, you should have it checked out. Could be an overinflated tire. Also could be a bad strut that is not dampening the movement of the tire/suspension the way it should. And if you are braking moderately to severely over a bad section of pavement when this happens, the ABS engaging may very well be absolutely normal.

 

Mine did the same thing - "hitting bump triggering ABS", that's normal. To address both the ABS issue & rough/bouncing around on uneven roads I "upped" the tire PSI to 38PSI (from 32PSI) Unbelievably upping the pressure smoothed out the ride. I was skeptical from past vehicles, but as suggested in the forums, upping the pressure made it ride smoother and cut down the ABS issues. Go figure...

 

thanks guys, after reading your responds, i think i was over worrying about the issue, coz the brake's perfectly normal on smoother surface. It is just I've driven other cars, but none of those are that sensitive to bumps. Perhaps it's because the CM's heavier and I'm also on runflats? I guess I just need to watch out imperfections on the road coz i really don't like the feeling when the pedal vibrates, feel like i'm not able to stop the car.
@Mical: Will upping the pressure affect the handling and riding quality? I'm on runflat, and i don't want to get even stiffer ride.

 

Mical, I tried what you are suggesting, and it really is true. But I wonder why that is. Could it be that with the extra 6 psi you are riding more on the center of the face of the tire, and there's more of a flex area between the contact patch and the stiff run flat sidewalls? That makes me nervous, and I re-did the pressure back to what Mini specifies. My concern is that an overinflated tire changes the contact patch as designed, and could cause reduced traction, especially when braking on a wet road. But I'm no tire engineer. What does everyone else think?

 

Note that the tire pressures specified on the door jam include (on a yellow sticker) a pressure setting of 38 psi (cold) to be used if you intend to drive at speeds exceeding 100 mph. You are not over-inflating the tires at 38 psi. Modern radial tires actually have a rather wide range of pressures where safety and traction are not significantly affected.

From my road racing experience I've concluded that running slightly higher than the pressures I use on a dry track may reduce the tendency of the tires to aquaplane at higher speeds.

 

I've not been a fan of the bump-steer in my ALL4 since the beginning. It started getting worse recently and, when I took it in to the dealer for them to look at, they found the RF shock leaking. After replacement and realignment the bump-steer is much less.
Still, it does seem to be a characteristic of the car. I had hoped the suspension would be a little softer and the wheel travel longer (both would help). I'm still on RFTs and they are probably contributing.
I found that increasing the tire pressure reduced the cornering traction and made the issue worse, so until I change to non-RFTs I'll just have to live with it. If I see the bump in a turn, I try to turn to the inside to anticipate the effect.

 

I have the stock RFs and also have the occasional (what feels like) sideways skitter if I hit rough spots...usually when going around curves at a good clip. The first night I drove home I hit the ridges on one of the corners near home and it scared the crap out of me. I was already nervous because he was brand new. Now that I'm used to it, I think it's kind of fun and I usually watch for rough patches so I'm usually ready. Hit some on the freeway this week that I wasn't expecting....thought I was going into the other lane. I should probably slow down.