I would like to know if the type of lowering springs used has any correlation to the occurrence of Mushrooms on the shock towers.
If you have had problems with mushroom effect can you post what springs you were running.
Has anyone with the JCW setup had mushrooms?
Spring rates can be found on this sticky: https://www.northamericanmotoring.co...ad.php?t=39371

Thanks!

 

Just happened to me yesterday; Megans, 3/4" drop, 280lb/in linear rate springs up front, dampers set 12 notches from full hard (32 way adjustable). The mushrooming was more noticable in the forward most nut/bolt and less so on the inner most nut/bolt with nothing on the outer most nut/bolt. The pot hole was big enough to fit both tires, but the pass. side took the brunt of the hit and was worse than the driver's side. On a positive side, this adds a little more caster to the alignment specs...and perhaps a little less negative camber - I would rather have stronger strut towers, however.

The pot hole was huge and unavoidable. I removed the struts and used a block of wood and a mallet to re-level to strut towers. I installed my H-Sport strut bar after - was not on before hand.

This is not the fault of the new struts, rather that of a somewhat weak strut tower. I've never had this happen to any car in 25 years and some have had 400lb/in springs with custom valved dampers run on public roads. Blame BMW.

 

I would say that the stiffer the springs, the less chance of mushrooming.It's the bottoming out of the struts that causes the damage, not the stiffness of the springs.

 

is right on the money....

Matt

 

Thats an excellent point, I hadn't thought of that. Thanks

 

I recently corrected a mushroomed MCS wearing stock springs, struts, and bump stops. The guide support bushings were torn as well. I’ve replaced my guide supports twice due to the failing bushing (cut down stock bump stops & lowering springs) but no mushroom effect yet. This brings up a couple of questions; does the guide support lose its cushioning effect and then the body work gives at a later time? Since I’ve not seen a mushroomed frame without a torn guide support bushing, are there examples of frame damage independent of a failed guide support bushing?

 

Onasled is correct. However, I believe too little damping control as well as incredibly stiff dampers - not necessarily springs - can cause this; in either case the POINT LOAD is transfered to the three attachment points on strut towers. The Megans have wonderful bound control in my opinion, quite supple really. These also come with a pillowball upper front mounts. The pothole I hit was huge and the combination of all three perhaps allowed these to hit the bump stops with at high velocity.

Here is an update that Megan can make to thier system; cast a plate that fits the contour of the under side of the towers and attach to this the integrated camber perch. With this particular setup - Megan - there is still plenty of room to lower the car. The fix really needs to be made under the strut towers...

 

I was thinking about this when reading up on the M7 strut tower brace. The strength needs to be added below the sheet metal on the strut tower not on top. The tower brace is spreading the load out over more surface area, but it should be done directly where the force is being applied.
The problem with this on the lowered cars is the increase in ride height. I think people may still see mushrooms with a brace applied on the top of the shock tower.
The real fix should be done by Mini.
I am having a hard time believing no JCW cars have had this issue.

 

maybe we should take a poll, who has mushrooming and what they're running...

 

Tend to agree with putting the blame on the design. The mushrooming should never happen. I also agree that bottoming the shock is the decisive blow, but stiffer suspensions will transmit a lot of repeated energy into the chasis, and that can't be good either in relation to the weak tower. Ultimately I think the first generation new MINI was a good first effort, but there's a long list of needed improvements. Hope they get the new one right.

 

That's what this thread is for - as was asked by the thread starter We just seem to get slightly side tracked every now and again.

 

So back to the poll, so far we have Mushrooms on:
Megans - 3/4" drop - 280lb/in linear spring rate - setting: 12 notches from full hard

Anyone else?

How do we get BMW to fix everyone's?

 

all you have to do is buy a new car, and they'll let you have two unmushroomed shock towers!

Matt

 

Lowering will have more, but even stock cars will show it as they get older, and they hit more pot-holes. I think it's in the design, just keep an eye out for it, and if it gets bad enough, just brake out the 2x4 and the real big hammer!

Matt

 

I was under the impression these things happened with one bad pothole.
Is it a progressive fault?

 

And one really bad whap can do it too!

Such is the nature of the beast....

Matt

But it's not something I'd really loose sleep over. IT happens, you beat the crap out of it to bang it back to shape, and life goes on....

 

Exactly! Actually, if it's not bad, jack the front end up to take load off the towers, slip a socket over a stud and hit it. Or a 2x4 - either one works. Just get the load off the front wheels and therefore the towers first...or you'll be pounding against the ground. The ground ain't gonna move.

 

But there is only so many times you want to be doing this. or the metal will get progressively weaker.
If it is a small deflection it may be better to leave it than to straighten the strut tower several times.
Also need to check the mount plate on top of the strut as it may be bent as well, especially if it is stock & not a reinforced camber plate.{should probably check those as well if mushroom is bad}

 

I'm running factory suspension and recently had to replace my torn strut guides and had nasty mushrooming on both sides. The car is 3 1/2 years old and was running run-flats on 16s then run-flats on 17s until January of this year.

 

The torn strut guides again. Maybe we are onto something here...

 

The strut guides looked terrible. The dealership wouldn't touch them under warranty, but when I took them off (thanks a lot to Mark "Smooth Is Quik" Finn) the rubber looked like it was dessicated from the heat/anti-humidity in Vegas.

 

This has been something I've really been intrested in as well. I know the issue of Mushrooming our shock towers does loom in our minds and it has gotten me thinking as well. Meb, that's a pretty good idea, but I gotta find a way to get a mold of the underside of the shock tower. I was thinking of using one of our top-plates and putting 1/8" of washers on the studs between the top-plate and shock tower. And then pouring a foam through the top to make a mold and see if my factory can replicate it. I don't know if they're going to have that ability; but if they can then I think that would be pretty good.

Dampers w/ Camber Plate AND Tower Reinforcment... that's my aim.

 

you may want to have some sort of thin high density material (foam/rubber) reside between this piece and the actual underside of the strut tower to take up any manufacturing variations as well as to eliminate any potential noise.