If you are looking for a definitive yes/no answer, I have none to offer, except to say with dynamic imbalance that involves flexible structure/material stranger things can happen. While I wrote much about the possibility being the tires, I also listed others.

One thing that I have not list is possible engine problem, like one cylinder that is not pulling its weight. Burnt valve or excessively low compression. Not being able to experience the ride and perform a few simple test trying to help troubleshoot over the forum the odds of miss is higher than hit. Do consider the possibility of a bad harmonic balancer too, though on the base Mini I infer it has much lower mass than the one on the S.

Additionally, some symptom can be the precipitation of more than one cause.

 

I completely understand. Just wanted to poll and see if anyone has a shake at acceleration and found it to be a tire issue.

..if it were a misfire would I see a dip in RPMs?

 

So now I've got the wheels rotated and the ride feels the same. I inspected them too and didn't notice them being obviously out of true.

I noticed the rear suspension is rickety, but still most of the vibration feels like it's coming from the front of the car still.

The front suspension feels pretty tight overall.

The axles do have a very minor bit of play in them (left and right axles). They've got maybe 1/16 inch play in them in all directions, and in and out. slight click noise when I push and pull them perpendicularly. I'm thinking this is normal since both sides do it.

The shake doesn't care about rpms. high rev second gear has very minor shaking but as I shift into third it likes to shake a lot more. No loss in power when it does.

I tried testing accelerating around bends, but it doesn't seem to have any affect on the behavior. I also noticed that even when very very lightly accelerating, I get a vibration. When I stop accelerating, vibration persists and mostly felt in the gas pedal. When slowing down it seems to go away completely.

I've still got to check out that harmonic balancer and maybe look at the plugs.


If this gives anyone ideas please let me know. I'm pretty much ready to try anything and open for ways I can figure this out.

 

FWIW ...
From the title I'd a said you have loose suspension or lug bolts. Wobble is dangerous - out of balance rotations aren't so much. But the only under accel leads me back to looseness.
Way back when, I had a 911 customer with a steering wheel vibration at 90 mph. It was very small but it was his car. I had to balance the wheels (only one was out) with the axles with calipers in the vertical and lateral direction very carefully before he was satisfied. I.e. not just the road wheels alone would do.
-Mike

 

what do you think about struts being the issue? I'm trying to figure out how to tell if the fronts stuts may be bad. The rubber up top seems to be in decent shape.

im leaning away from a balance issue since I saw no change with rotation.

 

Not technical like these guys, but regarding your poll for "shake on acceleration." Noticed 2011 Clubman S steering wheel shaking after arrival in Houston (350?)miles. Only shook between 20-40 ish mph, didn't pull to side, no visible tire damage, etc. Balance vs Alignment? Took to tire dealer on Saturday, explained problem, asked them to balance tires. Picked up car for return trip after tire store was closed. Steering wheel still wobbled but I had to make the return trip. In Louisiana, went to a different tire shop, front L tire put on balancing machine. With the cover of the machine UP so the tire rotation could be observed, the tire was obviously NOT making a smooth rotation. (Picture an elliptically shaped wheel rolling). one area of tread surface had slight elevation, couldn't see just looking at a parked tire. 2nd tire guy said it was a broken belt within the tire & tire wobble could have been seen if previous person had observed & not just relied on machine to balance. Put spare tire on MINI & steering wheel wobble instantly gone. Back in Houston today & taking defective tire back to dealer in AM. Of note, date on tire indicates manufactured first week of 2012 - something else to discuss with dealer....

 

First thing, wobble that can be felt through the steering wheel goes like this, in order of least money and danger:-
All bolts at correct torque, am sure they are.
1 Front wheel balance (rear would be a fine wobble not through steering wheel, rarely felt)
2 Tracking and alignment
3 Bushings
4 Bearing (but you would hear that on all turns)
5 This is the dangerous one mentioned above - a tyre fail with bulging or rupture.
Do not go changing out expensive suspension parts until you do the cheap things.

 

Thanks Scudder44,

I think I've ruled out most of this. And yes I get your point about replacing expensive parts, but I was able to see these needed replacing, as you can see from previous pictures. The boots in the axles were also shot.

One bearing was making noise I replaced it and noise gone, but shake not.

Wheels were rotated and nothing changed, So I'm thinking about ruling that out.

I had the wheels balanced and alignment done as well.

 

I have a second thread running that was specific to the engine mounts. I posted this video there, but will post here for anyone following this thread:


https://www.northamericanmotoring.co...tor-mount.html

 

If you're already filming like this, why not bring it up smoothly to 40-70 and see what starts shaking? This shows a lot of engine movement on and off the gas, but it's not the same speed (or doesn't look like it) as your problem.

 

CSP,

you are right about that. I don't even know this is a good test although I can say the shake that I feel when doing this is what I feel when driving. I brought it up to third gear and the behavior didn't change so I just ran it in first gear. If I get it up on stands again I think I'll try again.

I also might get a GoPro and mount it down there while driving. Wheels on the ground might provide better data.

thanks again for the input

 

Until I took the mount off, I couldn't tell it was this bad, it wasn't budging when shaking the motor, and visibly looked ok



So I finally got around to changing out the front engine mount, and it was a huge part of the problem. Although there is still a vibration, it happens in a smaller velocity range and is 10% what it was before. The mount was multiplying the vibration X10.

Thanks everyone for your help!

 

 

Just for completeness I want to post a conclusion, now that I've officially found the issue...

So in my previous post I said 90% of the vibration went away... but with time I think that mount and all loosened up again and it came back ( the shake ) almost to full force. I reassessed the forums and came to the conclusion that the symptoms that I was feeling had to be driveline related, and moreover, were most likely the symptoms of a bad axle.

I got under the car again and shook the axles around to see if there was any play, but there really wasn't. They were both equally tight. However, I noticed that the right (passenger) side axle had some rust and markings on it. I remembered reading some forums where people had gotten bad refurbished axles. Mine had fresh boots and was pretty clean except for these minor details (little rust, some dings). I put a brand new axle in there and the shake was gone! So now I've got some nice tight suspension and the ride is as smooth as could be.

 

In another thread I posted a thought on tires that has a little to do with the recent discussions here. You have a round object that is rotating around a fixed point. The issue is that the tire is not round as the weight of the car compresses the tire. It would be logical to assume that not only does this compression have an impact on rotation but also internally on the structure of the tire.

When you rotate a tire it is still spinning in the same direction but now the compression is taking place from the opposite "end". One would think that this change could affect how the internal structure of the tire reacts.