Wrong. No welding was done after drilling holes, the standoffs start as solid rod. Obviously, welding the standoffs “pulls” them from perpendicular. So all welding is done before they are put in the CNC mill, then they are drilled: center-to-center, perpendicularity, and diameter is established on a stable, cooled piece.

If you try to tighten one bolt all the way before starting the other, you will have problems because of the tight tolerance of the 2 holes. If you had my supplied instructions, you could have read in step #15, “Install the C5 caliper assembly using the new 14mm bolts. Because of the (intentionally) tight tolerance of the 14mm bolts in the bracket standoffs, you may need to screw them down alternating between the 2 bolts, one revolution at a time. Tighten with 22mm socket to 125 lbs/ft.”

I had my adaptor brackets and C5 brakes on my car almost ONE YEAR before Baer introduced their GTP system. In 1998 I had even requested that Baer make such a system, but they declined at the time. I have never seen or touched a Baer GTP bracket. We started from scratch.

I never quoted anyone the cost of the mounting hardware, but I did reject many bolts on the basis of country of origin. Nothing against 3rd world countries, but I doubt the thoroughness of their certification of metallurgical standards, especially on 12.9 property class fasteners.

QUOTE: “The Al is going to cost more than the steel but at 1/3 the weight it's a better deal.”

But the aluminum is still MUCH WEAKER, and your finished product will cost $250, much more than my stronger bracket. How is that a better deal?

QUOTE: “On top of that why do you need all that heft with the old design? The C5 spindle is made of 6061 and holds all of the braking loads a C5 can throw at it even with race tires.”

Ask one of your engineers to explain it to you. The C5 steering knuckle brake attachment is not cantilevered out; the shear forces are effectively in the plane of the attachment bosses. A “behind the wheel bearing” attachment technique requires that the attachment plane be moved outward to the original C5 attachment plane. This applies significant mechanical advantage (leverage) against the cantilever. It must be stout. If you notice, I use ˝” steel plate. People who have measured the Bear bracket say it is only 3/8” thick, and their standoffs are smaller diameter than the bosses on the C5 pad abutment bracket they mate with. My standoffs are the same diameter as the C5 part. I have no Idea if Baer copied my bracket, and neither do I care.

Bob Bishop

 

Three points why I bought this kit:

1.- Uses off the shelf parts and in my mind better parts (Corvette vs. LS1 calipers) plus bigger rotors I believe (could be wrong on that one)
2.- Bob's brackets. Doing some background on this I realized a lot of thought went into this design and the choice of materials. I believe and am happy that this part is overengineered. It didn't appear to me that Bob was out to make a business of this, but to serve a need he had for racing.
3. Price. For a whopping $825, I have improved my brakes significantly!

I've had the brackets on for almost a year without any problems and, knock on wood, hope to continue not having problems.

YMMV

 

Hey Merim, what's up?

The C5 rotor is 12.8 inches x 1.25 inches, the LS1 rotor is 11.8, the LT1 rotor is 10.8.

The whole kit when I was retailing them was $825....if you bought the parts yourself you could shave like $75 off that price, but Bob's new design is going to bring the price down even further.

At dealer cost, all the GM parts are just a couple of bucks over $500...add in the cost of Bob's Gen II bracket and you're looking at an extremely reasonable cost for the upgrade.

I also like my brake parts overengineered. Technically, the stock LT1 stuff is "adequate", so is the 275hp engine....There is tremendous peace of mind knowing that caliper isn't going anywhere, which is a good thing because it can make some persons nervous to hack on their stock brakes and install a totally new system. As a buyer you want total confidence in the brakes, IMO.

 

Bob,

Not to get into a pissing contest here but:

First, the kit didn't come with any instructions, just bolts and brackets in a box from Nashville Speed. Perhaps the instructions were lost in transit. We used the online instructions which are slightly different in step #15 from what's in your post.

http://www.nashvillespeed.com/

Second, even if the welding was done before the holes were finished, there is still an interference fit, mainly because the holes are tapered (bigger at the ends and smaller near the welded area). I measured the brackets I have vs production C5 steering knuckles (spindles) and C5 caliper mounting brackets.

GM designed the knuckle mounting holes slightly larger than the body of their attaching bolts. There is about .015 total lateral movement so that the threads in the caliper mounting bracket determine the alignment, not the hole in the knuckle. The alignment or squareness of the caliper bracket (and therefore the caliper) to the rotor is determined by the flat end of the boss on the bracket. These need to be parallel and the correct length. According to my engineer, this is standard practice and a tight fit in the steel adapter (or the C5 knuckle) could force the bolts into some bending, as well as giving erroneous clamping loads based on bolt intalllation torque. Production tolerances on the location of the tapped holes in the brackets could make this situation worse. I guess you and my engineeer see this differently.

Just curious. Why only 125 lb-ft? C5 specs are 160 lb-ft for those bolts.

As far as the choice of bracket material, your point about the offset bracket and the bending loads is right on. However, there is more than one way to resist these loads. I have no reason to believe Baer underdesigned their 3/8 thick steel brackets. I just think the 1/2 inch 1018 steel ones are overkill and add extra unsprung weight. The steel/aluminum strength ratio you quoted (about 1.35:1) is approximately the ratio of 1/2 thick to 3/8 thick material. In other words, 1/2 thick 6061- T651 aluminum has about the same strength as 3/8 thick 1018 steel.

Our design, done initially for our own usage, is another somewhat lighter approach than yours. My engineer likes to put material where it needs to be for strength and remove it from the areas where it's not needed. This is a lot easier to do with a CNC mill than a flame or plasma cutter. He also dislikes extra unsprung weight for all the usual reasons. He has referred to the C5 knuckle design as "elegant" for a mass produced car. BTW, his ride is a C5.

As in almost all markets, there are different products available to fill a need. Consumers deserve information about all available products. I tend to get riled up when I'm passionate about a topic. It may be that the brackets we purchased were not yours, but other than being sprayed black, they look identical to the pics on nashville speed's site. If they are knockoffs, and not yours, I apologize.



Bret