BMR Suspension's New S550 Rear Upper SHOCK MOUNTS: SM760 - Design Finalized!

[aleccolin]

Here's a little better picture of it without the fender liner, it looks like it's a little bigger piece than I was thinking, and definitely spot welded to the body in a lot of places so you'd probably want to use a spot weld cutter to get it out clean. It's also seam-sealed so that's a PITA

It's pretty thin gauge steel for what it is, maybe 18 ga at best. I think the simplest solution might be to Tig some rounds of similar gauge to the face and the tie it in on the ID to the nut. Would take a small torch and some patience, but beats taking the whole thing out.

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[shogun32]

ma pull the trunk liner and see if the backside of it is accessible.

it's supposed to be though it's not a big hole.

Just gotta figure out how so the load is transferred to structure that can handle it and not create a new failure point.

Look at RIdeTech's bracket. The important thing is to make damn sure you're not crashing hard parts into their limits and the force curve of the impact is 'squishy' and not a sudden spike.

It's pretty thin gauge steel for what it is, maybe 18 ga at best.

I agree it was way too 'over optimised' Instead of cheating by molding it into thin sheet metal it should have been a press-braked bracket attached (bolted or welded) to a substantial substrate.

Ford really needs to put out a PSA - do not use a non-sacrificial mount on any lowered car or with in-line coil-overs. Without very careful consideration.

And if Ford had spent any effort not cutting corners, they would have designed a sacrificial (if need be) mount that had a proper gimbal on it to pivot with wheel movement.

 

[Grimreaper]

No free lunches here. Large one piece side brackets square up the package tray down to the floor pan and completely block the area of the bolt holes. Have to go at it from the outside.

A bracket like ridetech would certainly be a simple and seemingly effective solution.

Wonder if BMR would be game to fab up something similar instead of the current back plates?

 

[S550Whipple15]

No free lunches here. Large one piece side brackets square up the package tray down to the floor pan and completely block the area of the bolt holes. Have to go at it from the outside.

A bracket like ridetech would certainly be a simple and seemingly effective solution.

Wonder if BMR would be game to fab up something similar instead of the current back plates?

I sent all this to bmr about ride tech and they said they’re looking into the etc they. Made changes to mounts but idk. Also made the comment they didn’t want to require so much work during install etc.. I just wish they extended new mounts and made it touch in the dips to help spread the load instead of 1/2” gap..

 

[BmacIL]

Every day

 

[S550Whipple15]

Not sure what your problem is... but this whole time you’ve bashed and or tried to make moog point these issues... It’s cool you support bmr... it’s cool you’re a fan boy.. it’s cool man but for you to bash/distort postings isn’t cool man.. I’m simply bringing the issue to light that even bmr admitted it could be a design flaw and that’s why they rushed a redesign..

 

[Roadway 5.0]

the OE is a sacrificial mount. It blows the rubber out and not intended to be fixed, just replaced. The PP bounce has nothing to do with the mount. It's the lousy damping.

Well said. I decided to use OEM mounts when installing my new Bilstein shocks. The ride and handling have never been better. I had used Steeda mounts for two years prior and didn’t have issues, though in the end I think aftermarket mounts are a moot point if you select a great damper in the first place.

 

[aleccolin]

Well said. I decided to use OEM mounts when installing my new Bilstein shocks. The ride and handling have never been better. I had used Steeda mounts for two years prior and didn’t have issues, though in the end I think aftermarket mounts are a moot point if you select a great damper in the first place.

Yeah at this point I'm just going back to stock mounts the ones that came with the FRPP shocks.

The BMR mounts take away wheel clearance and while I like the idea of a spherical rod end being used correctly (radial loading), I have serious doubts about the overall design now even after going through the effort to add two more bolts to the system.

The Steeda mounts are I think a better design, but you're still using a spherical bearing in axial load which they may be capable of, but it's not really meant for that. They do make spherical thrust bearings, but that doesn't appear to be what Steeda is using - if I'm wrong somebody please let me know what bearing they use. Assuming it's a typical spherical bearing, the axial load capacity is only about 10-20% of the radial load capacity. Again, that may be enough for this application, but it's not ideal. Couple that with the lack of a good way to keep grit and gravel from collecting on top of the bearing and doing damage over time (their caps are not a solution) and I have doubts about the longevity of that bearing. It's nice that it gives you 1/4" more clearance, but that's not really enough to justify the cost.

Assuming your car isn't bagged, the OE mounts seem like the best option. Yes, it's not perfectly rigid so your dampening isn't quite as optimized as it could be, but due to the aggressive knurling on the back it locks into its mounting position and transfers load more effectively into the wimpy ass sheet metal Ford used, and it acts as a "fuse" in a worst-case shock bottoming situation, both of which will protect said wimpy sheet metal mount. Also the mounts that came with my shocks have a revised plastic cap with a wider skirt, so they should do a very good job of keeping out the gravel.

I considered maybe filling the stock mount with urethane to make it more solid, but I'm going to ride back-to-back on the BMR, then Steeda, then stock mounts and if there's little or no discernible difference, the stockers are staying on there as-is.

 

[BmacIL]

Not sure what your problem is... but this whole time you’ve bashed and or tried to make moog point these issues... It’s cool you support bmr... it’s cool you’re a fan boy.. it’s cool man but for you to bash/distort postings isn’t cool man.. I’m simply bringing the issue to light that even bmr admitted it could be a design flaw and that’s why they rushed a redesign..

Changes were made for wheel clearance improvement. This isn't the only brand of mounts that has had pull-throughs. As has been mentioned multiple times, when you use an aftermarket mount that has no sacrificial design incorporated, this is something that can happen, particularly when you hit an extreme case condition (pothole). The bracket is very rigid, and has plenty of area to distribute load, far more than the stock or similar mounts. It's not about being a fan of one vs the other, it's about knowing anything about structural design vs not.

 

[S550Whipple15]

Changes were made for wheel clearance improvement. This isn't the only brand of mounts that has had pull-throughs. As has been mentioned multiple times, when you use an aftermarket mount that has no sacrificial design incorporated, this is something that can happen, particularly when you hit an extreme case condition (pothole). The bracket is very rigid, and has plenty of area to distribute load, far more than the stock or similar mounts. It's not about being a fan of one vs the other, it's about knowing anything about structural design vs not.

I’m sorry but you gotta be employed or former employee. Or a fake account.. is this Kelly???

I’m sorry but the bracket clearly lacks load distribution.. the lower part area is shorter than stock mounts allowing for flexing and pulling down on the stock mount/bolting area. If they extended just a little more lower and or event made it make contact in-between the valleys of factory mounting points would/could’ve saved all this issues. Imo it’s a failure on there part for not warning/advising it better that this will greatly improve the odds of these ripping out. I’m sorry if you’re ok with seeing these failures.. I’m betting money it’s only a matter of time before more start showing up... I hate saying it but more are coming and bmr will have recourse for it..

 

[shogun32]

shorter than stock mounts allowing for flexing and pulling down on the stock mount/bolting area.

it you look at the pics of failure (or think about it for a minute) you'll realize the uncontrolled force vector is acting upwards, not downwards. You can set the shock rebound to infinite and it won't hurt the metal. You'll just have the wheel suspended in mid-air (or the car pivoting over into a tripod stance). It's the shock loads of compression energy having no place to go having reached mechanical limits that overwhelms the tear-resistance of the material. If the shock pick up point was WITHIN the valley then you'd be dealing with almost pure sheer and it would sustain higher loading but eventually it too would fail by ovalization.

The factory did the next best thing by making the mount sacrificial. However, I'd wager it would make more sense (and cheaper) to put a medium to high durmeter solid rubber bumper in the undercarriage near the LCA spring mount that acts as the limit of travel.

damn it. now that I look at it I don't see an really good place to put a suitable bump stop except within the spring column itself. At least that area is designed to take serious loads. It was still an engineering error IMO to put the limiter on the shock at all, let alone not beef it up since it's not exactly rare for people to lower Mustangs or use coil-overs.

 

[S550Whipple15]

it you look at the pics of failure (or think about it for a minute) you'll realize the uncontrolled force vector is acting upwards, not downwards. You can set the shock rebound to infinite and it won't hurt the metal. You'll just have the wheel suspended in mid-air (or the car pivoting over into a tripod stance). It's the shock loads of compression energy having no place to go having reached mechanical limits that overwhelms the tear-resistance of the material. If the shock pick up point was WITHIN the valley then you'd be dealing with almost pure sheer and it would sustain higher loading but eventually it too would fail by ovalization.

The factory did the next best thing by making the mount sacrificial. However, I'd wager it would make more sense (and cheaper) to put a medium to high durmeter solid rubber bumper in the undercarriage near the LCA spring mount that acts as the limit of travel.

Everyone even Viking/BMR/etc all agree the force and ripping is from downward pull if it was upwards it would the mount would rip from bottom side?

 

[Bluemustang]

I’m sorry but you gotta be employed or former employee. Or a fake account.. is this Kelly???

I’m sorry but the bracket clearly lacks load distribution.. the lower part area is shorter than stock mounts allowing for flexing and pulling down on the stock mount/bolting area. If they extended just a little more lower and or event made it make contact in-between the valleys of factory mounting points would/could’ve saved all this issues. Imo it’s a failure on there part for not warning/advising it better that this will greatly improve the odds of these ripping out. I’m sorry if you’re ok with seeing these failures.. I’m betting money it’s only a matter of time before more start showing up... I hate saying it but more are coming and bmr will have recourse for it..

I'm sorry, dude. But this is just uncalled for. I know @BmacIL personally and he is a good and fair dude. And he is not employed by BMR nor was he ever and does not receive any compensation from BMR for anything whatsoever. He is also a former engineer for Ford and is a lead engineer for a major truck manufacturer. That said, he does not deserve this kind of backhanded accusation. He responded to you politely and was, I'm sure, happy to debate the engineering merits of this topic. Try not to let emotions get to you. It makes people say stupid things.

 

[shogun32]

Everyone even Viking/BMR/etc all agree the force and ripping is from downward pull

if the suspension is extending in an uncontrolled fashion and it's motion is being stopped (topped out) via internal bumper (which it should have) and/or the rod mount (which in BMR's case is a fair bit outboard) then you'd have a point. However rebound is a 'smooth', slow, relatively low energy motion and rarely a source of structural problems.

Remember the spring and damper is trying to absorb a ~80lb mass traveling at something around 2 meters/second all within 3 or less inches of travel. (have to go find my calculator for more accurate numbers). When you lower the car by 1" you're now asking borderline "the impossible".

Tuning, trimming, or selecting bump stops and their effects on bumps, or hitting pot holes is entirely a compression stroke matter. Hard bump stops like the Ford OE don't dissipate enough energy before they go 'solid' which drives the rest of the energy into the wheel well sheet metal in an effort to lift 900lbs of car at those 2 bolts. That is why the sacrificial direction of the OE mount is to blow out the top, not the bottom of the assembly.

For best suspension action you want the longest possible travel with the lowest possible spring rate but modified by expected force profile (2" square bumps being the typical max for calculation purposes). If you fix travel at 3" and rate at 400lb/in, at 2" you need 600lb/in to balance. The problem is the 600 spring will give a poor ride under less stressful profiles and so you go for a 450 and then use a bump stop to artificially increase the spring rate as it nears the limit of travel and also design the mount so that should you run out of room, it can take the blow.

 

[S550Whipple15]

I'm sorry, dude. But this is just uncalled for. I know @BmacIL personally and he is a good and fair dude. And he is not employed by BMR nor was he ever and does not receive any compensation from BMR for anything whatsoever. He is also a former engineer for Ford and is a lead engineer for a major truck manufacturer. That said, he does not deserve this kind of backhanded accusation. He responded to you politely and was, I'm sure, happy to debate the engineering merits of this topic. Try not to let emotions get to you. It makes people say stupid things.

This whole process I’ve been down played and insulted “here and other forums via forum/PM’s” the whole time I’m trying to bring this to light that’s it.. it’s clearly an issue but people press on.. I’m not getting emotional. Simple stated I’ve dealt with bmr/Viking/and out side sources on these failures. More will happen but the moment anyone brings up something remotely “against a company nowadays” they get slandered etc nothing I did resulted in this failure. In a few pages back it was pushed like I did something wrong by several people.

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