Initially, I thought mushrooming was said to occur when the concave piece in the center of the strut mount gets pushed upward, so it is not longer completely concave. Then, some of the pics posted make me think it is more of a pushing upward of the sheet metal around the strut mount. That's what made me wonder if my driver's side mount is mushroomed (see first pic). The passenger side does not have the same bend in the sheet metal. Both of the center pieces are completely concave and do not seem to be deformed.

Can anyone diagnose this as mushrooming, or am I just overly worrying?

 

That's shroomage. Take a straight edge, such as a ruler, and connect the nuts. The surface should be pretty flat between the edge of the ruler and the strut tower sheet metal.

 

OK, thanks, you've confirmed the dreaded shroom affliction. I'm thinking BFH and then IE fixed camber plates. Somewhere I read that nothing on top of the stut mount really helps prevent bending the metal underneath.

 

I have those M7 strut tower reinforcement plates on the MC and MCS and they are doing a great job protecting against the crappy roads here in Ohio.

 

I'd suggest you do both the camber plates and the M7 top plates or the M7 top plates with the strut bar. And the BFH.
Once you've got the surface flat and sandwiched between the camber plates and the top plates you should be able to forget about mushrooming. Unless you're planning on crossing the Gobi at high speed.

 

Yes, the driver’s side is deformed. I can’t tell definitively from the photo perspective on the passenger’s side but there’s a possibility. When the struts are removed, look at the guide support for any or all of the bolts to be less than vertical, the ear (where the stud mounts) will look turned down a little.

The Ireland Fixed Camber Plates have at least a chance of preventing this from happening again; a pseudo brace from above the strut tower has no chance.

 

[/quote]a pseudo brace from above the strut tower has no chance.[/quote]

One persons opinion. Others may disagree. There are several threads about the M7 SRP (plates)or STR (bar)

 

I just got my M7 SRP's, and will be installing today. (though I doubt our Arizona roads are as bad as those back east. With snow, salt, etc...)

 

I'd say anytime you drive on a "washboard" road, uneven road patches, parking lot potholes, bridge strips or high driveway entrances, you risk falling prey to the dreaded MINI mushroom effect.

 

The posters here https://www.northamericanmotoring.co...ad.php?t=89303 agree there is very little tensional stress on the guide support threads and what little is encountered can be handled by only a few threads purchase by the nut. Yet they and proponents on this thread, feel placing a piece of metal on top with only 25 ft-lb torque on each skinny stud by a little nut holding on to a few threads (tapered studs so the top three threads are not in contact) is going to place a sufficient clamping force to prevent a blow from below causing tower deformation. This is a common contradiction of beliefs held by the purchasers of this product. That point is actually irrelevant because if the plate below the tower isn’t stout enough to resist bending or wide enough to distribute load, it won’t matter how thick, rigid or how tightly held the piece of metal above the tower is.

Users of this product who have not had deformation since installation will say it is correlation proof of performance; I can also say after more than 70,000 miles without the product it hasn’t happened to me and claim a correlation. The law of averages will catch up and the time will come when someone mushrooms on stock guide supports with the brace looking like Oliver Hardy and Stan Laurel’s derbies.

 

The point I have gotten from the M7 plates and STB, is not to completely stop the mushrooming, but more for insurance.

Since my paasenger side was mushroomed so badly, it's safe for me to assume that at some point down the road, when I'm not paying attention and hit a pot hole, then I'll bend my M7 STB's plates. So of you people are lucky. Maybe it was the metal they used, maybe you know how to dodge pot holes, maybe your roads are smooth as a baby's ......, I don't know. The point is, there is a serious design flaw in the strut towers, and this product is insurance against it.

 

It's been pretty interesting the last couple of months to see photos of autos wtih mushrooming strut towers. I say this because there are some people that say it doesn't happen or happens rarely. We all know it should not happen at all. It's a shame that with somehting that costs as much as these autos do that something like this can occur. I've got an M7 strut bars and will add camber plates soon.

 

Inimini, Both towers are bent. All you need to look at is the angle of the bolts from the strut support. They should be vertical to the tower not at an angle. You may also want to check the bearings for cracks.
We have pretty crappy roads here & it's very strange that some cars are more prone to this, mushrooming, & some are not. There is a guy that lives in 1 of the hill towns that drives the snot out of his car ( with sport suspension ) & has no sign of mushrooming, another that has an MC with less than 30k ( a very careful woman ) & this car has fairly bad mushrooming ( without the sport suspension ).
Anyway when you take the struts out of the tower you'll see that the top of the strut is not what you could call "sport driver" quality... then it's bolted through a, not enough, tower.
The mistery is, why are some better than others? Or, do some people have ESP for bumps? Or, are these cars equiped with Rocky & Bullwinkle supplied upsidasium?

 

Thanks SC60. It does seem that both sides are mushed, but the DS is worse. We do have some bumpy roads around here, and like anyone I've hit a few bumps I wish I hadn't. But really, nothing sensationally severe.

Will the dealer typically fix this under warrenty, or do they consider it road hazard stuff like a nail in a tire? If they would at least bend it back in shape, it would save some effort before installing the camber plates.

 

Not mine

 

well, the SRP's would have to "shroom" for the strut towers to mushroom, or more likely, the nuts threads would have to fail, one of the two, right? I see no mechanism how the strut tower could deform in this way short of one of those two things occuring. Given that the plats are about .5" aluminum, I doubt the first failure mode will happen, anybody had their nuts fail/come loose?

Sure, correlation does not equal causation, but I think theres a more than a statistically significant correlation between people who have the plates not mushrooming versus people who don't having mushrooming occur. Your singular instance is a sample size of 1, so its pretty irrelevant, but so far, they have sold many of these plates, without a single person actually reporting nut failure or plate bending (is there another failure mode I'm missing here?), while a very tangible percentage of people without them HAVE experienced shrooming. . .

 

If you are thinking camber plates, the towers are a relitively easy fix to do yourself. What ever the strut support is made of & the ammount of interferience with the tower itself is pretty poor. No wonder it bends, you'll see...
Some dealerships will fix the issue but it's the same components and you'll have the same issue down the road ( couldn't resist ).

Plates:
The passenger side is difficult, much more so than the drivers side, just another Mini mistery.
There are quite a few options for the plates. IMHO the MTH plates are the best bang for $$ @ around $300, they are also the easiest to install but might be the hardest to adjust ( not hard for me - but for some they are ).
You may want to read this https://www.northamericanmotoring.co...t=82460&page=2 especialy the K-huevo posts. These are a very good value as well.
If you don't track the car a fixed plate is a good option.

 

If the fastener does not fail the imagined “support” is only good for the shape of the stock guide support, not the shape of that block of metal sitting above the tower. It is the opposite reaction to action that pulls the sides downward away from that block of metal; the thickness or rigidity of that block is irrelevant. There is nothing to keep the tower metal from stretching which is what’s occurring during deformation. The section closest to the engine is the weakest in terms of support and will be the most noticeable when deforamtion occurs. Without augmenting bracing in the form of trusses from a fixed point on the chassis or a tie-in to a lower section of the body/subframe or an arch from a connection with a roll cage to the front modular section, it (SRP or strutbrace) will do nothing in terms of bracing against deformation.

 

hmm, so the metal deforms DOWN in mushrooming? I always thought it deformed up, at least thats how I envisioned it deforming, but I could be totally incorrect. Sorry for the thread jack, but its an interesting conversation.

I bought a set of the SRP's for the wife's car, just as insurance, based on statistical correlation only (not anecdotal evidence, but genuine statistically significant correltation). I'm curious if its a placebo effect (people who care enough to buy the plates are aware of the mushrooming issue and as such are gentle in driving over potholes).

I also figured that any impact would tend to deform the tower up, not down, but maybe I'm not quite understanding the failure mode. Seems to me though that the block would more evenly distribute the impact.

 

The force comes from below traveling in an upward direction, as the center of the tower is pushed upwards the sides are pulled away with that force. I use this explanation from Roland at GTT in the U.K. often because it’s stated in easily understandable terms “...You can make the plate on top 6 inch thick kryptonite,if you like and it will still do very little. If you dont put a larger & stronger plate underneath the tower , then nothing has changed. For every force there is an equal and opposite force,its this 'equal & opposite force' which pulls the tower downwards from the outer perimeter of the tower causing mushrooming. Example ... I have a sheet of hardboard (say 2 feet diameter) and bolted on the FAR side near to the centre of it with 3 bolts is a sheet of paper ,If I then push with my knee in the centre of the hardboard and pull the edge of the hardboard (with my hands ) at the same time the board bends right? Now if we repeat the experiment above but replace the weedy sheet of paper with a 2 inch thick sheet of hardened steel (it can be as big in area as you like,so lets make it 2 feet diameter the same as the hardboard) ......suprise suprise the board bends exactly the same (and as easily) as before. "

 

I wouldn't say insurance... More like a small layer of protection against it.

I had the beginning signs of mushrooming when I put my STB/SRP's on. I couldn't see the damage, but Krut and I installed ours at the same time. His was a 3 month old 06 MCS and mine was a 1 year old 05 MCS. His plates went on flat an even. My plates went on and rocked left and right ever so slightly, but still noticeable.

Now on the passenger tower, I can see the SRP opening facing forward isn't perfectly verticle anymore. It should look parrallel like this ||, but the plate has already bent a bit more like \ / . Not nearly that bad of course, but it's noticeable to anyone examining the plate from in front.

They do not prevent mushrooming. They do help reinforce the tower though.

 

hmm, that example confused the **** out of me and didn't seem all that applicable (although Roland knows his stuff, not trying to question his credibility, I just don't unerstand his example or how it applies)

from what I understood though, that model assumes a point force in the center and uses an artifically large circle to make its point. Consider instead taking a 6 inch circle (closer to the size we are talking about), and push up on the middle 2 inches (more representative of the force on the strut tower, as the strut mount is rubber and applies the force over an area). Now consider the 3 bolts to be at about 4 inch diameter. I still may not be seeing this correctly, but it seems like if you change his model to be a bit more realistic, you can see how the plate on top would help, if for no other reason just serving like a big washer for the 3 bolts.

 

Go to post 30 https://www.northamericanmotoring.com...t=82460&page=2 bottom picture.

The top plate is only as good as the interference from the bottom. So the shock tower would start to gap between the mounting, top plate, between the bolts. If you look at the OE strut mount the amount of surface is not all that much in comparison to the replacement, let alone the material diference. ( again what ever you put on the top is only as good as what's under it ). Once the strut mount starts to bend only the mounting bolts will stay with the top plate.

A top plate could work on smooth surface just as a hefty TB, but, for most of us, they would need many more bolts to spread the load laminateing a larger surface interference well beyond the present, OE, components scope.

I wonder what the 07 towers are like....... & strut mounts...

 

so is this a warranty issue?

 

I think this is what I see the SRP's as doing, spreading the load, just like a washer does in more rudimentary applications.

Maybe I'm just hopelessly confused at this point, but it seems like they are just glorified washers, but they are contoured to fit the unsmooth surface below them to more evenly distribute the forces. I see how better a better bottom plate would be a more effective solution, but it seems like they would still help in putting spreading the strees out and make what bottom plate there is take more of the force.