JeremyNYR

iTrader: (2)

I hate to ask this because it's probably been covered, but I've searched extensively and haven't found a complete answer.

I have 16" crosslace rims that I am thinking about keeping when I do my Front and Rear LS1 brake install. I found information that suggested they would fit, but require a small spacer due to the taper on the rim's inside diameter. Somewhere I saw that the .030" spacer used on cars that came with these rims and drum brakes would be sufficient.

Questions:
1- is the spacer required for the front rims, rear rims, or both?
2- is the thickness of .030" correct?

arrowcamaro

iTrader: (2)

I dont know what thickness they are but I used the rear spacers off of a drum car on my fronts. Its a tight fit. The front wheels stick out noticeably with this set up.

I have a hunch that i can now rotate the backs to the fronts and the fronts to the back. I think the back wheels will now fit on the front with one of those spacers (plus the thickness of the rotors) and your wheels will no longer stick out and will be more in line and track close to identical(as opposed to the rears being in further then the fronts)

JeremyNYR

iTrader: (2)

very interesting... I think the difference in the front and rear offsets is 16mm, which is approximately .63". Maybe those spacers are a lot bigger than stated... although the front LS1 rotors sitting over the 3rd gen hub move your front rims out also. Do you have LS1 brakes in the rear? If so, did the rear rims bolt right over the rear LS1 brakes?

ebmiller88

iTrader: (7)

The "rear drum" spacers are more like .185" or so, I have posted the correct amount on here before but can check again. The 16" wheels should clear LS1 rear discs without issue.

Ed

JeremyNYR

iTrader: (2)

And is the size of that spacer pretty much exactly what you need for clearance in the front, or can you get away with a smaller spacer? I should have the ability to machine my own steel spacers at work if needed. I'm now mostly interested in figuring out if the wheel will have to be pushed out enough for me to want to swap my front rims for another 2 rear rims.

arrowcamaro

iTrader: (2)

I can snap a pic tomorrow if you'd like.

ebmiller88

iTrader: (7)

The "drum" spacer is .145" thick, I doubt you'll find anything smaller/thinner than that. Let's think about this a minute, why would you "need" to go thinner than that? .145" is roughly the thickness of a matchstick. This will get you the room you need and that's all you need.

Ed

JeremyNYR

iTrader: (2)

yeah, i realize that somewhere around 1/8" is pretty small! But I have not yet measured how much the LS1 rotors will push out the wheel, so it starts to add up. I also don't know how available those spacers are to purchase, so if I were to machine my own, I might as well go as small as I can and possibly retain the existing wheel studs while I'm at it.

I'll give a rundown of my plans/ situation. I have all the parts from an LS1 car to do the brake swap on my 84 T/A that has a 9-bolt rear axle (currently with non-pbr disk brakes). I will be opening up the rear axle soon to rebuild the posi unit, and was thinking that I might as well swap the rear LS1 brakes on at the same time while the axles are out. I'm also sending my car in for a repaint in the next couple weeks. I have been planning on buying new aftermarket rims, but I'm starting to think about saving some money and just refinishing the crosslace rims that I have instead.

So if I stay with the crosslace rims, I want to see what complications it may create when upgrading to LS1 disk brakes. It sounds like the rear is no problem. If converting the front to LS1 brakes pushes out the front rims as much as arrowcamaro says, then I might not be happy with the appearance of the crosslace rims afterwards... or might want to swap my fronts for 2 rears to make up the difference if the math points to that solution.

arrowcamaro

iTrader: (2)

I can tell ya right now, you wont be able to run the stock length studs up front-not safely atleast.

JeremyNYR

iTrader: (2)

can yoy send me the picture you were referring to earlier? thanks

arrowcamaro

iTrader: (2)

Here ya go...

Note: the steering wheel is perfectly straight.

JeremyNYR

iTrader: (2)

thank you very much for the pictures. Taking a stab at it, i'd say they look to stick out about 3/4 of an inch further than mine do right now. the outer edge of mine seem to line up with the center body line in the fender and yours look close to the outer edge of the wheel well lip on top.

ebmiller88

iTrader: (7)

Let's slow you down a bit, there's some info you don't have. The LS1 brakes will push you out .300" per side, plus the .145" spacer height to clear the wheel so ~ .500" per side on the front.

Next, the LS1 brakes are not a direct bolt on to a 9 bolt like they are a 10 bolt, the 9 bolt has a different axle flange bolt pattern. If you want to install them, you will need to do some measuring and see where you want to put the new holes in your flanges.

Third, you will NEED overlength studs to compensate for the rotor hat height of .300"

Ed

JeremyNYR

iTrader: (2)

I was aware of the complications with the 9-bolt, I just figured my last post was long enough without getting into that and wanted to focus on the front because that's where I feared some rim offset issues. I should've also just measured my rotor hat height before making this post. Thank you for the information! It sounds like the best way to go with the crosslace rims would be to trade my 2 fronts for rears, which would make the wheel sit in ~.2" further rather than have the original front rims stick out ~.450" further. Actually, if I make my own spacers ~.345" thick, it'd be no change in track.

Overall, I'm thinking that I'm going to wait until next year to install my brakes and either refinish my crosslace rims (trading my fronts for rears of course) or buy aftermarket rims. I'll also do a nice rebuild on my slipping posi unit and a gear swap while I'm in there. Good paint jobs are very expensive and it's just getting very difficult to justify any additional spending for this year. But now I have more of the facts at hand and can make a more educated decision. Thanks guys

Dans87GTA

iTrader: (1)

Just to make sure I read this right you do have to use a spacer on LS1 brakes with the 16" GTA wheels, im really not looking to run a spacer so i was thinking running the C4 brakes instead, which of the 2 are the better way to go, I think I remember reading that the C4 are lighter but the LS1 have bigger pistons? thanks for any help, and if im wrong about worrying about a spacer be sure to tell me. Oh and ed either way you be getting a order from me really soon!

Daniel

fly89gta

iTrader: (1)

Ed, you PM'ed me a few days ago with options on my GTA since I'm gonna keep the GTA wheels. I'm just going to stick with the C4 upgrade since I don't want to run spacers...will there be anything that I need to modify since I have a 9-bolt rear?