So was working on motor mount replacement and had my head in the RF fender well. Noticed this sad state of affairs:



RF upper spring pad, part number 31336852465 if I have it right.

Car is creeping up on 98K miles, 2017 F56S. I’m the second owner, purchased around 74K miles in mid-2021. Car has been in the southeast US its whole life.

Is this normal for an F56? Guessing yes since this part seems to run between $10 and $17 out there (the labor is another question), this is clearly (by price and feel) a cheap piece of plastic. But, um, wow.

LF side is not similarly injured, at least not on the front edge. Dunno about the rears.

 

Normal.

I ended up replacing these on my wifes F56 Cooper around 100k, along with springing for new Bilstein B4s all around because... 'while you're in there' disease wouldn't let me just replace the bellows.

 

Well now dang. Guess I'm in "while you're in there" mode again. I'm just winding down that mode from digging around the serpentine belt and upper motor mount, lol

Away we gooooooo

 

While you're doing those, I saw a set of BRAND NEW NM Springs for sale in the marketplace!

 

That is just the dust boot. Pretty normal for those to start tearing with higher mileage. In theory, you can run without them. So, unless you feel the need to remove and disassemble the shocks, I would just keep an eye on them until you need to replace the shocks.

 

Yes, just the dust boot. If the shock isn’t leaking then it is still acceptable as-is. If you are good with the ride/harshness, then you can just leave it.

Just a thought for future consideration, if this was an R53 or R56 MINI, I would say the shocks were shot at 30k miles. The MINI shocks on those MINIs, in comparison to the Bilstein or KONI FSDs, were very harsh when new and just got worse over time, and had poor control over the suspension dynamics. This is the way it was on both of ours and what I have read over the years of ownership. On my F56, the base JCW shocks seemed to be better than what was on the previous Gen MINIs when new, but I changed them for the JCW Pro suspension so I can’t say how they might have lasted. On the previous Gen MINIs a switch to the Bilstein B4s, or in my case the B6/B8s (my R56), or the KONI FSDs (our R50) was always reported as being a huge improvement in ride and suspension control. For the Bilsteins the B4s are a better than OEM ride; the B6/B8s are more aggressive toward handling. The replacement effort is far less than what you just went through for the motor mount.

 

Appreciate all this info.

So for context, the reason I was so thrown by this is that my 1995 Subaru Legacy wagon with over 350K miles has original dust boots on original shocks/struts in the front end and they have shown no sign of this sort of deterioration. The difference that I also just figured out: they're plastic (and not cheap BMW-underhood cracks-if-you-touch-it plastic ). The ones on the MINI, though, are rubber. D'oh. No wonder it looks like dry rot.

Moving on from that, I had not thought about the Bilsteins. On my down-the-road radar are front and rear sway bar replacement as suspension upgrades, but I honestly hadn't gotten as far as thinking about the shocks/struts. Hmmmmmmmmmmmm...

 

Flying in the face of conventional wisdom…. Go you…
”Conventional” wisdom being to just change out the RSB, which I am not a fan of.

Are you planning to track your MINI?

I am a big fan of the front and rear sway bars upgrade. I did this on my R56 for the track. This mod retains the balance of the car while flattening out the ride. A huge improvement in handling, without wanting to swap ends as can happen with just a big RSB. Also, camber in corners improves, which these cars desperately need. The down side is ride takes a hit. If you do go ahead with replacing these, take the opportunity to also change out the bushings for the front lower control arms with with the PowerFlex ones that add a bit of caster to the suspension. Caster becomes camber when you turn the steering wheel for a corner. These are parts that will be “available” for replacement when you dig in to access the front sway bar.

However, depending on your objectives, shocks/struts might provide you with what you want. Maybe add a set of JCW springs*….

As for the Bilstein shocks, the B6 and B8s are their “sports” shocks. These are a good improvement on handling, with minimal effect on ride. They may actually improve ride in some respects. The B6 are for stock springs and the B8s are for lowering springs, although I put B8s on stock springs on my R56 which seemed to work fine.

I will offer up my experiences based on the suspension mods on my R56, which is my street/track MINI and all of which would translate to the F56.

Just remember there is a really big rabbit hole to slide down once you start down this path….

None the less, think about starting a mod thread for your MINI and let us know about it.

*I just happen to have a set laying around

 

Cool info and insights -- thank you.

Not planning to have the MINI on the track as a matter of routine. That kind of fun is on my "one day" list, lol. JCW springs also sound fun but I have to take care of other stuff on this funmobile first.

It's been a minute since I decided I was eventually going to replace the sway bars, but IIRC my concern was, as you put it, flattening the ride -- I don't like the understeer/plowing effect with the heavier 4-cylinder (vs the 3-cylinder base Cooper) engine in the front, even though I am way better at compensating for it now than before, and I don't like body roll. I figure it's a high-ROI mod, big payoff for an easy and sensible implementation. I plan to change the sway bar end links as well whenever I get around to this, based on some guidance here in the forum, so bushing changes will be part of the effort too.

That said, you have me curious for particulars on this: "The down side is ride takes a hit."

Tell me more? Specifics? I already have to avoid bumps and potholes like the plague with this thing because of what both do to tires (upsizing my tires to 205/50/17 from stock 205/45/17 may have provided partial solution there, but still). Would very much like to know in more detail how the ride changes with the sway bar change.

 

Sway bars are a spring controlled by their torsional stiffness and their spring rate is a function of r^4 power. A small change (ie: 1mm) is a large change in stiffness. What I am familiar with are the MINI sway bars that came on the Gen 1 and 2 MINIs. There were 3 pair (front and rear) that were each 1mm larger than the one next smaller. These were for the base cooper (smallest), the cooper S and the base JCW (largest). A JCW Sports suspension could be had that had bars that were 0.5mm than that on the base JCW. With each larger pair, the proportion of roll stiffness front to rear moves the total roll stiffness more towards the rear of the car that reduces understeer.

I had both a Cooper S and a Cooper S with the JCW base suspension. The difference with the JCW suspension was transformational. Now the JCW base suspension also had stiffer springs and shocks. But body roll is first controlled by the sway bars, then by the springs. The body roll was far less; much flatter ride. Not a big difference in ride quality. That was with only a 1mm change in the size of front and rear sway bars. And some of the ride change came from the springs and shocks. These were likely where most of the ride change came from. I tracked the Cooper S with the JCW suspension for a few years before I upgraded the sway bars to aftermarket bars that are 27mm in the front vs 23.5mm and 22mm in the rear vs 18mm. This was a huge change.

Wtih that change came a big decrease in ride quality, like around town. The side to side stiffness is such that road irregularities from one side of the car to the other are quite noticeable. On the back roads, at speed, this was much less noticeable. Actually quite a pleasure to drive.

I know very little about the bars that come on the F56. It is hard to find out what the sway bar sizes are for the F56 MINIs, as MINI no longer lists this information. RealOEM.com lists 2 rear and 2 front swaybars for the F56. One is listed as “sport” which I assume is for the JCW and the other non-sport is for the base and S models. A guess on my part. However, if I am correct on my assumption, you could change out your S sway bars for the JCW bars and get a pretty good change in handling, with little change in ride. Add a set of springs and it should be pretty nice handling wise.

If you were to go to the aftermarket bars (sorry I don’t know the sizes), I would expect the ride to change similar to what I experienced with my R56. Some people on NAM have done it, and have liked it, but I would hesitate to recommend it if ride is somewhat of a priority. I consider my R56 to be a track/street cave vs a street/track car.

For a street car, that would be track worthy, I would recommend one of the following…
- JCW sway bars and springs with Bilstein B6 shocks.
- your current sway bars with the F56 JCW Pro suspension.
- JCW sway bars with the JCW Pro suspension. This is what I am running on my JCW which I take to the track and it does quit well and it is still nice on the street.

I would also consider the Bilstein adjustable coilovers, but not the non-adjustable coilovers. My reason is ride height. The non-coilovers lower the car too much and that can be an issue with roll center which can hurt handling. The F56 should be lowered only about 3/4”, with an upper limit of 1”.

Hope that helps.

 

I too was an early proponent that larger front bars, along with a larger rear DO NOT promote under steer.
The fact people kept insisting installing only a rear bar, resulted in the F56 having a forced oversteer from the rear bar at higher speeds,
but still understeer at lower speeds.
Rear only was recommended as fronts were not fun to install.
I went with the H&R solid 27mm front and solid 25mm rear, along with H&R springs.
This is no longer a car that is comfortable around town!! But as Eddie07S says, it's fun on back roads. Around here it's long mountain roads.
And it works very well with the Dynamic dampers.

Regarding OEM bars, the "sport bar" is part of the sport suspension package.

If I remember correctly my OEM front was 22mm hollow, and rear 14mm hollow NOT SPORT

 

^^^

22mm and 14mm hollow bars are not much in the way roll stiffness and may make them softer than what came on the Gen 1 and 2 base Coopers. These are also sized in a way to promote understeer…. Ugh Any idea as to what cars got the “sports” suspension and what might have come on the JCW? I may have to measure bars on my JCW.