taguy16

I've been researching my options for upgrading my '89 Camaro's front bakes and most of the budget options using original parts call for using the standard F-body 10.5" rotors cut down into hubs. Of course the problem with this is then you're stuck with the tiny outer (A34) wheel bearings. I found a company online called "bigbrakeupgrades" that sells the 10.5" rotors already cut down into hubs, and for another $100 they'll machine out the outer portion of them to accept the large A3 bearings that the 1LE brakes have. The question I have is how safe this is since you can tell by the way the snout on the 10.5" castings are tapered they were made specifically for the smaller outer bearings. I'm afraid machining out the snouts to accept the A3 races would weaken the hubs in the place they they are the most weak in the first place. In the pictures on them on Rock Auto the snouts of the 1LE rotors look more squared off and beefy to me than the 10.5" rotors like they were made that way to make sure there was an adequate amount of material to keep their strength with the larger bearing race bores.

Seems like if you can't afford some high dollar specialty brake set-up their aren't hardly any good options if you want both bigger front brakes and larger outer wheel bearing like the 1LE option had.

Any thoughts?

sofakingdom

iTrader: (1)

There may well be some brand or brands of replacement rotors that DO have enough meat there. Maybe even ones listed for some other vehicle. Stock ones for these cars exclusively aren't the only choice for raw materials. That'd be a question for BBU though.

taguy16

Aftermarket replacement rotors are made to OEM specs so I doubt there's going to be much difference at all between brands of them. My car came with one OEM and one replacement rotor on the front and they are both the same except for some minor cosmetic differences.

I don't know what good it would do to contact BBU because they are just going to say it's okay to machine out the snout of the rotors. I'm sure their products come with all kinds of disclaimers, and if one of their wallowed out hubs fails it's always the fault of the customer. That's the way way of the world nowadays.

I'll bet I would have a hard time finding a machine shop willing to machine my 10.5" rotors for the large bearings because of either the liability issue or because they would say it makes them too weak. I can only imagine the kind of problems it would cause if the end of a machine out hub broke off.

sofakingdom

iTrader: (1)

1 replacement rotor is a pretty damn small sample size for extending to "all", don'tcha think?

It may well be that there are other brands that might be different. I'd have to see EVERY BRAND before I'd be willing to give up and admit that they're all the same. Since after all, there's not really any reason that the hub area there "has to" neck down. As long as it's smaller than the wheel hub diameter it's a non-issue.

84 1LE

iTrader: (9)

I think Scott (BBU) mentioned using those std hubs with the larger bearing on their autox cars with no issues. Also i have their aluminum hubs with said larger bearing and have had no issues since installing them back in 2018.
You could just have "1LE" rotors turned into hubs for peace of mind.

sofakingdom

iTrader: (1)

AFAIK the 1LE hubs are just ... hubs. The rotor is a separate piece, just like the later systems.

So, yeah... if you could find em, you could just buy 1LE hubs, and be good to go.

LAFireboyd

iTrader: (3)

I remember when Scott (BBU) came out with this modification. I believe he had similar theoretical concerns and did extensive testing before he made the modification available. He's been doing it for several years now, and I haven't heard of anyone having an issue with them. Scott's aluminum hubs were engineered specifically for the large bearing.

Contact him and discuss it. He's great to work with. Then if you still aren't comfortable about the modified hubs, either get his aluminum hubs, or buy your own "1LE" rotors and cut them down. They're just like standard 10.5" 3rdgen front rotors, just larger in diameter and made for the large bearing.

But there's a new option "coming soon." The future of big brake upgrades for 3rdgens. It will make big brake conversions, as we've known them, obsolete.
Verse in 3D modeling ? - Third Generation F-Body Message Boards

Dyno Don

iTrader: (7)

I used the one piece Chevelle rotors with the big bearing, but I had to make different brackets to hold the calipers.

BBU.COM

I have a few thoughts I`d share , one would be if your uncomfortable with any kind of modification you should probably stay with bone stock even though it is inadequate for today's roads. Two, the set 34 bearing is more than adequate for anything you will do with the car on a normal basis, even autocross, road course. If you look up load ratings, you will see the "tiny" set 34 is just as capable as the set 3 "1LE" as far as load rating goes. What the set 3 does beyond the set 34 is spread the load over a wider area of the hub and it`s larger rollers reduce bearing speed resulting in less heat for the same amount of load/ speed- so less break down over the long haul of the grease. ( so this works great for cars with wheel adapters or cars that see extreme track conditions)
Measuring the wall thickness at it`s minor thickness after boring results in most cases just the same as the material thickness that attaches the rotor disc to the hub ! , yes only .200 of cast iron connects the disc to the hub at its thinnest point. Prior to releasing this mod, like mentioned it was tested and well tested.... What drove me to offer this was the 79-81 G body rotors, the same casting but they have the set 3 and set 6 naturally, same pin, same lug pattern, same register. The only problem with using those was the lug stud bore, it's .548 or something larger than your typical M12 knurl. I even had guys on here say why dont you use those 79 rotors? it boiled down to not everybody wants to swap to 3 inch 1/2 x 20 studs, so this is where it was born. Now since this has been offered none, I mean none have had a problem or at least brought me a problem with these, the track record speaks for itself. I...I dont like doing them, I`d rather sell the billet hub, it is a lot of work to make them fit and time. But I do it because there is a need.
As far as hubs not "wallowed" out..... I do have the best available, bar none hub for the 3rd gen, set 3 , set 6 , stock seal, stamped or bolt on billet cap, extended register, 2.5 M12 studs. I`d say if your looking to upgrade your brakes and want that billet hub you better move fast, they are going faster than than ever.