C5 Brakes in front: What is your backspacing?

[67rstbkt]

I'm interested in knowing what you first gen f-body guys with C5 brakes are running for your front wheels as far as backspace? I'm looking around and found a set of 18x8 with 4.5 bs. What are your specs? Lowered? Pics would be great! If it matters, I'm using the original drum hubs. Thanks

[Paul Huryk]

I'm not a 1st gen guy, but be aware that many wheels do lot offer enough clearance for large brake systems. I'm not referring to the caliper hitting the wheel barrel, but the face of the caliper contacting the back of the spokes on the wheel.

Make sure this isn't the case before you purchase!

[67rstbkt]

I'm not a 1st gen guy, but be aware that many wheels do lot offer enough clearance for large brake systems. I'm not referring to the caliper hitting the wheel barrel, but the face of the caliper contacting the back of the spokes on the wheel.

Make sure this isn't the case before you purchase!


Good point! I'm not sure how else to measure right now other than to get the wheel. The wheels I'm looking at are fairly new on the market, so I'm not sure how else to find out that part of it. If I have some reference on bs, though, that's at least one problem solved.

My other choice is to use the 18x9 with 5.25 bs on the front as well, but I'm not sure if this would be too wide on the front and if 245/40/18 would look weird on that width.

[Rick Dorion]

I don't know the spec but pad height is the other determining factor. Perhaps someone will chime in with that. Also, Kore3 has templates that would help.

[67rstbkt]

I don't know the spec but pad height is the other determining factor. Perhaps someone will chime in with that. Also, Kore3 has templates that would help.

Right, but I would still need the wheels to check that. I just want to know what others are running for backspace for now.

[Rick Dorion]

I have C5 wheels. The front is 17x8.5 with 7" backspace that is reduced to 5" backspace using 2" adapters.

[67rstbkt]

I have C5 wheels. The front is 17x8.5 with 7" backspace that is reduced to 5" backspace using 2" adapters.

Interesting, I wonder how that extra .5" width affects everything. If you were to move the wheels out (hypothetically), would there still be enough space? Or are you pushed out to max right now? Thanks for the input

[67rstbkt]

Any other setups? I would be really interested in hearing what other's are using? I've been reading on this a bunch and so far, this is what I'm finding:
18x8 with 4.5 bs, should work on a stock drum setup.
C5 brakes will move the wheels out .25

What I do not know is:
1: are the wheels that close at 4.5 that the extra .25 will be an issue? I don't mind doing some work in the wheel well as I'm still in bodywork phase
2: are the 18x9 with 5.25 a better option? Will that be too wide on the front?

[Apogee]

Keep in mind that a stock Chevy drum hub and Pontiac drum hard are not necessarily the same thing. If you set a Chevy drum hub flat on a table with the snout pointing up, you should have about 2.40" from the table to the face of the flange. Additionally, while it's only a 1/16" difference, the C5/C6 front brake kits increase the track width by the difference in the thickness of the drum hat (.105") and the rotor hat (.295"), basically 3/16" per side.

Per Rick's post above, an 8.5" wide wheel with 5" BS puts the outer lip in the same position as an 8" wide wheel with 4.5" BS, it just extends inward by the 1/2" wheel width difference.

Tobin
KORE3

[67rstbkt]

Keep in mind that a stock Chevy drum hub and Pontiac drum hard are not necessarily the same thing. If you set a Chevy drum hub flat on a table with the snout pointing up, you should have about 2.40" from the table to the face of the flange. Additionally, while it's only a 1/16" difference, the C5/C6 front brake kits increase the track width by the difference in the thickness of the drum hat (.105") and the rotor hat (.295"), basically 3/16" per side.

Per Rick's post above, an 8.5" wide wheel with 5" BS puts the outer lip in the same position as an 8" wide wheel with 4.5" BS, it just extends inward by the 1/2" wheel width difference.

Tobin
KORE3

I just checked and 2.4 is about what I have on that hub to face on the drum hub. So, if I'm reading this correctly (and I might not be), what you're saying is that Rick's specs put the wheel in the same position, except his wheel is just a bit wider? So outside should be pretty close to the same, his just extends towards the inner fender by that 1/2"?

The other thing is I'm not sure if his C5 wheels have an offset and how that would affect things. The wheels I'm considering have zero offset

Thanks

[Jameson]

Im running 18x8's (Boss 338's) up front with 4.5in of backspacing... I also have C5 brakes up front with 98-03 Blazer spindles and FlynBye C5 brackets and have plenty of room between the caliper face and rim spoke, a little over finger width.

[67rstbkt]

Im running 18x8's (Boss 338's) up front with 4.5in of backspacing... I also have C5 brakes up front with 98-03 Blazer spindles and FlynBye C5 brackets and have plenty of room between the caliper face and rim spoke, a little over finger width.

Thanks for the response, few questions for you.
Is your car lowered?
What's the advantage of using the Blazer spindles? and how do they affect wheel placement?

[Rick Dorion]

I don't remember the offset of the front C5 wheel. I measured the stock 7" BS since I understand that. Two things, also: My current setup is on my 67 Belair which has huge wheel wells and I could go with a thicker adapter to better position the wheel/tire package. I'm deciding between 2.5" adapter and 2.75" which would make my backspace either 4.5 or 4.25".

[67rstbkt]

Thanks for all the input, I went ahead and ordered the wheels I was looking at. 18x8 4.5 backspace for the fronts. I'll let you guys know how it turns out.

[Jameson]

Thanks for the response, few questions for you.
Is your car lowered?
What's the advantage of using the Blazer spindles? and how do they affect wheel placement?

Yes its lowered 2.5-3in the front, Blazer spindles allow us Gbody guys mount C5 calipers easier and use a sealed bearing hub instead of the older style.. No effect of wheel placement

[kim]

I have honda freed n kawasaki ER6F

[67rstbkt]

I ended up getting these wheels, I'll post updates in my build thread as I get more parts on the car. The fronts look like they will clear, even with the C5 brake setup. I'll have to order some more parts to know for sure, but it does look very close. I may end up doing a little rolling on the edge before I paint just to be on the safe side. We shall see..........