Does a drum to disc conversion increase or decrease wheel offset?

[Josh69]

Based on my current info, the Touring Classics kit rotor is .300" thick. I'm not sure which one I need, so I would verify if you need the hybrid or C5 kit for your app and get that measurement directly from them.

Considering that it uses the stock drum brake spindle and drum hub, which is machined down to fit inside the rotor hat, the only affect to your track width will be the difference between that measurement, and the thickness of your drum.

I think that theoretically, if you take that difference into consideration, and make sure that the wheel spokes clear the caliper (using the template on their site), you should be fine.

We should be able to either make a spacer if the discs increase the track width to take up the difference until we get discs on, or if it's nominal, just live with it. If the discs actually decrease track width, then you will have to determine how much room you will have to move the wheel inboard. You can start with a slight bias towards the fender lip with adequate clearace and know that it will move inboard once the discs are on if that is the case.

I am planning on using 18x8" wheels up front, with a 255 width tire at the maximum, so I should have plenty of room.

[nowukno]

I'm in somewhat of the same pickle, since I want to do a front and rear C5 brake conversion but I'm doubting those brakes will fit inside my current 15" Torq Thrust D's... Now I plan on getting the 18" Torq Thrust Classic II which is the exact same model & size wheel that StreetKing has (https://www.pro-touring.com/forum/sh...?t=7958&page=4) +/- .25" in backspacing.

So.... Since I can't afford to do both the wheels and brakes at the same time, I guess I'm asking if it would be a decent plan to just figure out what width the C5 brakes & rotors would be, and then buy my American Racing wheels off of those measurements and then simply modify or spacer the rear drums and correct the front if necesary until the new disc brakes are in place???

Sent Ya' a PM

[1FstChevy]

Alright, now this might be going more off-topic but its somewhat inter related, Would it be a safe bet to say that those same 18x8s and 18x10s I'm looking at would clear the C5 Z51 rotor/caliper setup listed here
( http://www.nastyz28.com/forum/showthread.php?t=74546 )
After reading around a bit they say that they won't clear some 17" wheels so I'm assuming that an 18" would be more than enough clearance???
Thanks!

[Josh69]

That's a question that I have too, but can't answer. Maybe give Touring Classics a call, and let us know what they say.

I'm considering the same wheels as you in 18", so I'm very curious also. If they don't know, I'd call American Racing and see if the 17" and 18" wheel centers are the same or if they are different...I know some wheel mfgr's use the same centers, and just a larger rim hoop with a bigger step up in it.

[1FstChevy]

Who are Touring classics anyway??? I guess they can supply the rotors for the Z51 setup? Since I'm doing the modification with the Kore3 components, then a 3rd gen hub and the C5 Z06 calipers with the larger abutments to accomodate the slightly larger rotors (hence Z51).

Perhaps I'm a little confused since I'm working back and forth between 2 Camaro forums here, but have you looked into simply the C5 modification? or were you looking to do the Z51, since I'm still trying to locate someone who sells the rotors and abutments for all 4 wheels at a decent price. Also... if you check out the link ( http://www.nastyz28.com/forum/showthread.php?t=74546 ) it would be nice to find those black coated abutments shown in the photo, unless you think that guy may have justed painted the zinc coated metal himself??

--------

Okay well I just checked out Touring Classics so I know what your talking about but thats a little too much for my pocket book, besides their caliper design sucks compared to the look of the black or red claipers with Corvette stamped in them, but I guess thats of course if you want that on your Camaro.

My goal is to do all 4 wheels with the Z51 for about $1,000 and I'm pretty sure it can be done, mostly just looks like I'd have to shop around a little.

Although I'm still confused with the whole +/- offset thing, it deffinitly helps if your looking at the same wheels I am, but I'd think going from an intergal Hub/Rotor thats on there from the factory to a machined down Hub from a 3rd Gen plus a new rotor it would be thicker and therefore increase wheel offset! but then again I haven't taken any measurements so perhaps I'm speaking too soon.

Oh, and if your looking to get the same wheels, I have connections with this guy in Oklahoma who can get you the exact same set that I'm looking at and that StreetKing has for less than $1200.00 delivered to your door.

[1FstChevy]

Okay... well I spoke to the wheel guy and he said even with the switching brakes situation he said the difference would probably be so minimal that he would still recommend the 18x8 with 4.5BS and 18x10 with 5.75BS.

Now I haven't given American Racing a call yet to determine a good to go clearance but hopefully I can get around to that before they close up shop.

I'm hoping to figure this out soon since with the way I'm doing it I've got to have the wheels first before the big brakes, and obviously it would be a bad idea to order the fancy custom offset American Racing wheels without knowing first, but if they come in incriments of .25" BS I'd think it would at least be narrowed down between either 4.5/4.75 and 5.5/5.75 for whatever brake setup, of course you have a 1st Gen though so that would probably be a little different?

[Josh69]

I have a Firebird, so mine might be altogether different due to the 'wide trac' from the 60's Pontiacs, and my rear axle is a BOP unit rather than Chevy. So I'm taking any speak of offset on this forum with a grain of salt for my application until I measure it since most have Camaros.

I've decided to get the brakes on first and buy a wheel mate so I can nail everything once it's on the car. I am rolling the heck out of my quarters before paint for clearance. I am interested in those wheels, or the AR500's....still have to decide. I'll keep you in mind if I need to utilize your contact.

I will most likely take the caliper and powder coat it the color of my choice, and stencil PONTIAC on it, or I may end up with wilwoods....it's all up in the air for now. My car should be painted within the next couple of weeks, so once I start to assemble it, I'll make a decision from there.

[ponchopwr70]

I just ordered wilwood brakes for my lemans. I have the bop rear end. I think the offset is very small 1/8 or 1/16 not sure. On the fronts there is a change in offset I think a 1/4 according to willwood. But I ordered the 13" 6 piston front and 12" 4 piston rear. My front tires need to come out a little any way. I have 17x8 with 4.75 front and 17x9.5 with 5.5 rear. I'm not expecting any problems (knock on wood).

[1FstChevy]

Hmm... well I'd consider setting the car up for a few weeks so I could do the brakes first and then go off of those measurements for the wheels, except I don't have it in a garage at the moment so it would stay outside with no wheels.... ; ( and then once I order the wheels it would be about another 3 weeks since they are custom order... so maybe a month!? and thats if i could swap over the brakes without any complications in a week?

BTW ponchopwr70... Those sound like some serious brakes, I've heard rave reviews about the Z51 C5 setup with the 2 piston fronts and 1 in the rear so I can only hope that your 6/4 piston set up stops that mother on a dime.

I'm thinking the best alternative for me would just be to measure all the brake components that are going onto the car in advance so I'll know the difference that way my car won't be inoperable forever... and I would'nt mind a 1/10th here or there but if my front wheels came out 1/4in or something like that to the degree that they almost exceeded the back wheels then I might be concerned...

Also... I know many people have done the C5 conversion on here... I'm interested to know if anyone whos done the Z51 setup knows of a place to get quality drilled rotors @ a decent price, I think they are the 13.4in rotors???

[TheMonkey]

Okay... well I spoke to the wheel guy and he said even with the switching brakes situation he said the difference would probably be so minimal that he would still recommend the 18x8 with 4.5BS and 18x10 with 5.75BS.
....

i would be very cautious about just listening to what a wheel guy says.

consider installing the brake conversion first and measuring your scrub radius, and determine your offset that way.

simply referencing back to stock scrub radius may not be ideal, as scrub radius was not as crucial with skinny tall tires from the 60's. with wide radials on 18" rims, proper scrub is waaay more important.

here's a discussion on a method of measuring scrub radius and why it's important. consensus seemed to be 1/2" to 2" SR.

https://www.pro-touring.com/forum/sh...ighlight=scrub

don't count on just getting lucky, and don't count on what other posters say will work.