18's & 20's: What to do?

[ScotI]

Ok guys.... most of us have seen the staggered wheel set-up on cars. I've seen some 20" rear wheels w/puny 11" discs & it just doesn't look right. So what are your opinions . . .....?

I have 18x8" front wheels on my 74 Chevy pick-up w/the stock 12" x 1.25" rotors & the fit looks 'right'; meaning not too small.... not too big. I have 20x10's on the back w/the stock HD drums (11" brakes but the O.D. of the drums is 13"). Despite what they are, they look right. IMO, even though they're only drum brakes, they look better proportionally than the cars I've seen using large diameter wheels w/small rear disc set-ups.

I will be using these wheels on a 79 Malibu. The plan is to upgrade the stock front discs from 10.5" to 12" LS1 brakes & I was thinking about the Master Power rear drum brake upgrade kit to get the same 11"/13" O.D visual (but w/a car pattern). My buddy thinks we should stick w/rear discs. But, to 'look' proportionally right, I would need a larger diameter rear disc than what is 'typically' offered.

I asked about 'staggered' disc set-ups in another thread but didn't get much feedback. Although this might not be the ideal way to get optimum braking, we aren't planning any track events in our future..... we merely want to improve the braking vs. what was originally offered. The compromise would be 4whl disc brakes using 12"/dual-piston caliper LS1 stuff up front & 13"/single piston brakes out back. I think this could be tuned to work well (using an adj prop valve which I would need/want for the F/R tire height difference anyway) . . ..... but, can it work better than the stock 10.5" disc/9" drum brakes?
The rest of the car is:

Big small block
Richmond 6spd
SC&C Stage 2 arms/Tall upper/lower BJ's; 2" Dropped spindles
LS1 front brakes
GN 8.5" 3.42 rear end

Am I 'nucking futs' or is this something that can be accomplished? I figure if it's possible, one of you guys will be able to help us figure it out! Obviously we're not trying to set the performance bar for braking..... just an improvement over stock that maintains visual symmetry.

[68Camaro]

I'm no expert, but I don't see a problem. If you have the space why not. There was a nice silver Chevelle (68 or 69') that competed in the CarCraft Challenge I believe that had larger rear discs.

[ScotI]

....If you have the space why not. There was a nice silver Chevelle (68 or 69') that competed in the CarCraft Challenge I believe that had larger rear discs.
Having the space & making the space is the same thing isn't it?:rotfl:

[oorange67]

bear makes a plus 1 rear rotor for c5 vettes that if you don't go with 14' fronts makes the rear brakes bigger I've heard no problems from this setup...

[gearbanger]

I am no professional, but I wouldn't size my brakes based on how big the area is inside my wheels. I have 12" discs on the front of my GTO with 17" wheels and drums on the back with 18" wheels. It stops really well the way it is for street use. Just so I don't have to worry about brake fade, I will probably put on an 11" or 12" discs in the rear in the future but I am not worried about filling my wheel with rotor.

Corvettes have bigger brakes in the rear because they have a 50-50 weight distribution and they have bigger tires in the back, so the rear can do more work. If I put bigger brakes in the back of my car, I wouldn't be able to take full advantage, because it is light in the rear, like most muscle cars. I would have to put a prop valve on it and dial back the rears so they wouldn't lock up all the time under hard breaking. Just put a nice looking set of discs all the way around and it'll look right.

[gearbanger]

By the way, that is a b@d@ss looking Malibu.

[ScotI]

The C6 Vette I took my measurements from had smaller rear brakes vs. the fronts: (almost 13" fronts;12" rears).
These measurements were taken from a car w/the wheels/rotors still mounted so they're not exact. I did notice on Baers website they had pics of a C5 Z06 w/larger rears vs the fronts.

This weekend I got a chance to test the wheels on a C6. The rears cleared w/no problems but that 12" diameter rotor looks dwarfed by the 20" wheel. I don't know why, but the drum on my truck looks much larger than its 13" O.D. Maybe it's because I have them painted black so they stand out more?

As far as sizing the brakes vs. wheel diameter, I've seen late model Tahoes/Explorers all over town w/20's. If they still had the stock rear discs, it just doesn't look right; & it didn't look right when I mounted the wheel on the test vette.

I'll stick w/HD drums if I cant get something in a 13" diameter rear disc. The main reason for wanting to know the info was to identify a source for plain, un-slotted, un-drilled rotors vs. using Baers stuff.

[ScotI]

By the way, that is a b@d@ss looking Malibu.
Thanks . . ....

[USAZR1]

Your 74 truck wheels are a 5x5 bolt circle. Your Malibu is 5x4.75. You plan on using adapters?
How many cars have larger brakes in the rear? Not many. Having the rears lock up first isn't a lot of fun.
Nice car.

[ScotI]

The truck has redrilled front rotors that are 5x4.75 & uses adapters in the rear (they center the wheel in the well as well as change the bolt pattern).

I understand that typical installations utilize larger fronts. But, staggered wheel sizing isn't typical. I figured a larger diameter out back w/a single piston caliper would be about the same as a small diameter rotor w/a better dual piston caliper.

My friends are street-rodders that aren't necessarily worried about braking compromises. I like looks & better performance.

I do appreciate all the input towards a possible solution.

[BLWN1]

What are your wheel specs and tire sizes.. that does not look like a 10in wheel and I love it...

[email protected]

[ScotI]

What are your wheel specs and tire sizes.. that does not look like a 10in wheel and I love it...

[email protected]
Fronts: 18x8" 5.25"BS 245/40-18
Rears: 20x10" 6.0"BS 295/40-20

[BLWN1]

Wow, sorry to bring it back, did you clearance any for the 10s?

[ScotI]

Notched frame & mini-tubs.

[796spdbu]

Scoti,
Those 18''s look lost compared to the 20''s,still looks killer.I have a bu but cant decide on wheel size.I had always thought 20''s would look too big,damn i was wrong....narrow mind,I guess.Got any pics of the mini tub and frame notch?

[ScotI]

Scoti,
Those 18''s look lost compared to the 20''s,still looks killer.I have a bu but cant decide on wheel size.I had always thought 20''s would look too big,damn i was wrong....narrow mind,I guess.Got any pics of the mini tub and frame notch?
I haven't been out to the shop lately. This time of year I'm extra busy (food manufacturing facility) & personally preparing for the holidays consumes more hours than I have.

Currently the frame rails are notched to the factory seam & the tubs are cut but that's about it. After the new year (& after my work truck gets the current drivetrain swap completed) I'll get back out there & get some more pics. Until then, this is the only other pic I have....

[796spdbu]

Thanks for the pic and good luck with the drive train swap.

[robbie9999]

[quote=gearbanger]I am no professional, but I wouldn't size my brakes based on how big the area is inside my wheels. I have 12" discs on the front of my GTO with 17" wheels and drums on the back with 18" wheels. It stops really well the way it is for street use. Just so I don't have to worry about brake fade, I will probably put on an 11" or 12" discs in the rear in the future but I am not worried about filling my wheel with rotor.

[robbie9999]

can I see some pics of the cars with 18 inch

[email protected]

[fast Ed]

I don't know about GM (I'm a Ford dealer parts guy), but the 97 and newer F-150 trucks use thin solid rear rotors that are larger diameter than the fronts, with single piston calipers, fronts are dual. I believe the main reason for this is to accommodate a large enough hat for the internal shoe-type parking brake.

But it does illustrate that with properly sized calipers, the rear rotors can be larger than the fronts. Again, these are solid, non-vented rotors on the rear, around .650" thick, IIRC.

cheers
Ed N.

[ScotI]

Good to know about the F150's. I'm still undecided on a direction so thanks for the info.