Strut Tower Brace (STB) Connections

Phil Y · 09-03-2006, 04:45 PM

Have read almost all posts on these. My question is, to how many of the three upper shock tower bolts (camber adjustment bolts) do these products attach? Most of the pics in the PP catalog are either unclear or don't show actual the mountings. Am not interested in the triangulated models so these are all the straight across ones.

JM Products Design STB--?

Elephant Light STB--?

Rennline STB--?

Tarrett Strut Brace Assembly--appears to be two rear bolts plus the top of the actual strut.

Weltmeister Cambermeister SB--appears to be two center-most bolts plus the top of the actual strut.

Rennline Truss Mount Strut Brace--at least two center-most bolts, maybe three?

Am leaning toward one of the last three but the Tarrett and Weltmeister both appear to attach directly to the top of the strut. Can anyone confirm this? Appears that consensus in this forum is that this is NOT desirable, in which case, the last will be my choice.

Thanks in advance!

Zeke · 09-03-2006, 05:02 PM

All I can tell you is the Weltmeister uses all 3 and the shock nut, as you already know. Don't use this model unless you cut out the center part and leave the shock part to float. If you look at the design carefully, you will notice that the shock will be cantilevered when the suspension is at either end of full travel. This in turn places a lot of stress right where the shaft is machined to make a shoulder. It can and has broken according to past posts. I used a modified one and was happy for what I got for the overall cost.

I now have a Rennline on the shelf (no car) and it has integral monoballs, so it uses all 3 as well, but allows the top of the shaft to move side to side as the suspension travels. If it weren't for the OEM rubber bushing, the Weltmeister could not work. In fact, the way I see it (and the way Chuck Moreland, owner of Elephant, sees it), if you had monoballs and a Weltmeister, you would snap your shock shafts off in no time due to the binding.

Make sure you understand which of these are designed for use with a monoball and which are designed for use with rubber. Any time I see "appears to be two center-most bolts plus the top of the actual strut," I think they are wanting a monoball installed.

Sorry, I didn't look each one up. Those are some good names in performance parts. With proper advice, I think any of them would be sufficient for most of our purposes.

911pcars · 09-03-2006, 05:53 PM

Phil,
Maybe this is a good time to group all the strut bar designs in one thread. Here's a Weltmeister. As you describe, it mounts with two bolts on the strut tower and also captured by the large strut nut. This one has been modified by it's owner (sorry about the lack of a photo credit) to allow the upper stut to move on its own and not be constrained by the mount. Yellow zinc plated steel bar and hardware.

Sherwood

Here's a version from KLA Industries:

Brey-Krause (stainless steel and CF)

Rennline:

Racing Dynamics:

BertBeagle · 07:25 PM

Is the bar linking the two strut towers loaded in tension or compression during cornering?

It seems to me, after looking at the different offerings, that the Elephant Racing version that triangulates the towers would be the best, at the expense of useful trunk space.

Thanks

AtomicDog · 08:28 PM

Phil Y,

The photos don't show the Rennline 'truss mount' bar. I would guess that it would be a bit better than the Rennline that was shown.

I looked at the Tarrett product line and wasn't impressed. The Weltmeister bar has its issues, as well. Based on my research, I would only consider the Elephant Racing or Rennline units. When I go to front monoballs, I will purchase the Rennline "integrated" style brace.

Bert,

The strut brace is in tension during cornering. The heavily loaded (outside) wheel exerts more force on its corresponding tower (placing the brace in tension) while the lighter loaded (inside) wheel exerts a much smaller compressive force on the brace.

The net effect is a tensile stress, due to the dominant effect of the outside wheel. The bar serves to resist the tendency of the towers to separate under cornering load. By adding rigidity to the towers, the structure deforms less - which allows the suspension to work as it was designed.

Hope this was what you were looking for...

Chris

Nine9six · Nine9six's Garage

AtomicDog,
FWIW, I did the same comparison, and ended up with the same results regarding the Rennline or Elephant Racing units.

Phil Y · 12:41 PM

From the PP catalog, here's the Rennline Truss Mount SB, which appears to use at least two of the three top mounting bolt locations:

Phil Y · 09-10-2006, 03:41 PM

Update: I just ordered the Rennline Truss Mount SB, as pictured above. Decided against the Weltmeister because it just didn't seem right that at the price charged, I'd need to do some machine work to remove the part that attached to the top of the strut. By the way, I ordered the double bar model (same price as single bar). Will let you know how it goes when it gets here.

scottb · 09-10-2006, 04:37 PM

While we're on the subject of identifying strut tower braces, can anyone tell me who makes this one (installed by the PO)?

BertBeagle · 09-10-2006, 04:57 PM

I am going to guess that is home made - with a couple of hex nuts welded to the end of a piece of tubing.

scottb · 09-10-2006, 05:01 PM

Quote:

Originally posted by BertBeagle
I am going to guess that is home made - with a couple of hex nuts welded to the end of a piece of tubing.

That was my original thought, but two things lead me to think otherwise. First, the tubing tapers down to the nuts on the ends...in other words, it's not he same diameter all the way across. This would require some decent metal working skills. Second, it looks like there's a remnant of a label on the tubing. I can't read anything on it, but it may be from a manufacturer.

911pcars · 09-10-2006, 05:05 PM

Phil,
FWIW, I saw these on an ebay auction (I think). Looks like these might be WM's current strut bar mounting brackets that no longer tie the strut to the mount.

Sherwood
(no affiliation)

sus911 · sus911's Garage

Phil, I just installed the Rennline truss type double bar into my "84.

My understanding is that it precludes the use of mono-balls. For that, you need the integrated system.

Quite an easy installation, once you've got the orientation of the parts figured out. No mods necessary and uses 2 of the 3 mount bolts on each side. You will, however, need to remove the black gunk on top of the srtut tower to give you a clean mounting surface.

I was in a hurry so I just quickly chipped enough off with a small hammer and screwdriver as a chisel being carefull of the paintwork. Others recommend heating with a gun then cleaning off with solvent of some kind. Have a vacuum ready or even better, place a small drop sheet underneath to catch the rubbish from falling into the never never areas.

Take not of the "red dots" which help with the correct orientation of the parts. It nearly threw me because they mention "driver's side", which is the opposite for me!

The installation instructions don't mention it but my suggestion would be to loosely assemble the whole unit first, then install it as 1 piece before torquing up and adjusting the bar tension.

Don't forget to fully screw in the adjustment of both bars before you assemble it. When you're ready to install it in the car, just rotate the 2 bars out together to get the correct width of your strut tower mounts. This is easy as the bars have left hand thread adjusters on one end and right hand on the other so adjustment is is done equally on each end as you rotate the bar.

I installed it at the same time as deleting my A/C and noticed a marked difference in the feel of the car, tighter and more precise, direct and definitely lighter feel. The quality is first class and looks great installed. Already had a few "WOWS"!!

Can't wait to install my turbo tie rod ends and do a full corner balance and alignment.

We'll see at the next track day.

Good luck and enjoy.

Suss

tsuter · 09-10-2006, 05:46 PM

Quote:

Originally posted by scottb
While we're on the subject of identifying strut tower braces, can anyone tell me who makes this one (installed by the PO)?

That is a Starker front strut brace. They're supposed to be really bad. Probably not mfg for 15 years or so. I keep waiting for something bad to happen to mine or the car.....any year now.......

Of course I do have the extra front triangularization support provided by the elastic bra straps!!!!!!!!

scottb · 09-10-2006, 05:57 PM

Quote:

Originally posted by tsuter
That is a Starker front strut brace. They're supposed to be really bad.

What's the story behind the bad reputation?

tsuter · 09-10-2006, 06:01 PM

Quote:

Originally posted by scottb
What's the story behind the bad reputation?

It has to do with the mounting method....the enginerds on this site have beaten it dead....must be 6-8 threads...

scottb · 09-10-2006, 06:11 PM

Quote:

Originally posted by tsuter
the enginerds on this site have beaten it dead....must be 6-8 threads...

I just did a search and couldn't find any threads. Different spelling, maybe?

brett25 · brett25's Garage

i bought the weltermeister strut brace which attaches to the tops of the shock towers. i figure for street use (lower stress driving conditions) the bar should work out ok and i will be getting the benfit of a sort of monoball effect. i dont think i would use it in its unmodified form for any kind of track use. if i had to do it over i would have gone with elephant racings bar

Zeke · 09-11-2006, 12:10 PM

Quote:

Originally posted by brett25
i bought the weltermeister strut brace which attaches to the tops of the shock towers. i figure for street use (lower stress driving conditions) the bar should work out ok and i will be getting the benfit of a sort of monoball effect. i dont think i would use it in its unmodified form for any kind of track use. if i had to do it over i would have gone with elephant racings bar

I have to agree. With the stock rubber bushings, you aren't going to necessarily snap the shock shaft off even though there is a weak point at the shoulder of the shaft that I'm certain was never intended to take any what some of the engineers around here might call vector loads. (Am I right on that?) This has been a good thread on the braces and should be bookmarked or printed by all contemplating these devices.

There was a question above regarding whether the towers spread or came together during stress. It seems I read quite a while back that they tend to move together. Thus, the triangulated brace would do the most good. Further comments?

BertBeagle · 09-16-2006, 08:03 PM

Quote:

Originally posted by milt
There was a question above regarding whether the towers spread or came together during stress. It seems I read quite a while back that they tend to move together. Thus, the triangulated brace would do the most good. Further comments?

I asked that question but I was thinking a strut tower brace would be loaded in compression (towers moving together). My thinking is that if someone were going to purchase one, that the triangulated brace would be the best for that reason. Someone posted that they were in tension (towers spreading apart) under cornering, which makes a case for the single, small diameter, lighter bar.

But either way. they are loaded much less than the lower suspension link and as for up and down loading obviously they only carry the shock absorber loads. I question the real need for a strut tower brace of any kind - unless the car is converted to coil over suspension (coil spring over the strut with torsion bars removed). The towers look stout the way they came from the factory.

Wonder if anyone has done a simple test to determine which way each side tries to move and how much, for a given cornering force, noting whether the car was turning right or left?