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As we all know, good 15" tires are getting hard to come by. I'm pretty set on the RWL look. I can pick up a new set of Cooper Cobra CS5s in 215/60/15, which is not quite my size but the closest I'm likely to get in a tire that is reported to be pretty good. The other option that I am considering, mostly out of frustration, is the Legendary Wheels Styled Steel 17x7" wheels (link here) with 225/50/17 tires.
I have 15x6 styled wheels with Cooper Cobra's in 215/65R-15 and highly recommend them and that size.

If you want your Mustang to ride like a nightmare on rough roads go with the 17"
 

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If Ford's "proportioning valve" in the 80s did what GMs metering valve always did, it should delay the front pressure momentarily. The reason for this is excess front disk brake wear could occur in low-speed easy driving situations because the front brakes will do almost all the braking. In high-speed aggressive braking, the metering valve probably doesn't matter. For a grandmother who never drives over 25 MPH, it will prevent premature pad wear. See the link below. 1. Proportion pressure front and rear 2. 10 psi. residual check valve 3. Metering valve to apply pressure to the rear brakes before the front brakes 4. A brake warning light to detect a loss in pressure https://www.classicperform.com/Instructions/PDF/PVK.pdf
Yes, this is true but different than how the correctly termed (my bad) combination valve I used which Mustangs used in the early 70s. The metering valve works in nominal pressures to delay teh fronts for a microsecond so the slower drums can catch up eliminating nose dive and are paired with the other valves in a combo valve.

This combo valve is like the one I used, it has a shuttle to light up a light if there is a problem in one of the brake circuits which I never hooked up, and a proportioning valve for rear circuit with a delay in the rear circuit for emergency stops. No metering valve.

Check this out, a very good article I used to design my brake system:




747735


The only thing I disagree with the guy in the video is that this guy says residual valves are only for cars that have brakes in teh floorboards like cars of the forties. Residual valves keep the fluid from running into the master from lines above the reservoir level. There is a second thought process that is common that residual valves can keep the shoes of drum brakes up against the drums eliminating lag and a spongy pedal. Many firewall master cylinders come with internal residual valves for that purpose, I added a 10 # residual valve to the rear circuit of the combination valve like this since I stuck with drums out back, some will add a 2# residual valve to teh disk circuit to eliminate a spongy pedal:

747737


But I used a combination valve that had the big nut like the 1970 above that limited the pressure in an emergency stop e.g. Autocross ;o). I learned about metering valves later and would probably have sourced a combo valve with a metering valve if I had known. But I would need more research as I think a residual valve in the rear circuit does the same thing.

The bottom line was that getting rid of the fountain put pressure to my rear brakes and adding the residual valve ended my nosedive which I really didn't notice to till it was gone. Being able to stomp the brakes at the last minute without upsetting the car and sending the rear into a spin made it so I could ride the throttle hard and left foot brake into and through the entrance of turns making trailbraking a dream really impacting my times.

One of the best winter projects I've done. Do the research and design it right...
 

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I would unbolt the master cylinder from booster and inspect for brake fluid.

If rear seal on master cylinder and front seal of booster are leaking, it will pull brake fluid and mysteriously disappear.

Had this issue on my wife’s 79 F150.

6 year old tires should be replaced.
I had some old BFG’s like that...over 10 years old.
 

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As I see it, there is no specific benefit to keeping drums on the rear, other than that I have them on there already. It bothers me that I would need to modify any off-the-shelf parts to keep these drums functional in the future - boring out / rebuilding brand new wheel cylinders, rearching brand new shoes, turning drums (FWIW, I did have my drums turned a few years ago), etc. - just to get "good enough" performance in return. I do not want to have to worry about braking on my daily driver, anymore, period. So I think that my decision has finally been made there, after many years of bitching about the brakes.

I've done some more research on the 17x7 wheels. First of all - Autoworks Restomod did an episode on the Magnum 500 version of this wheel by the same manufacturer. They compared the 17" wheel+tire to an original 15" wheel+tire and found that the 17" package is actually lighter by 4 lbs, because the wheel is aluminum alloy! So that was good to find out, considering that many of you brought up the problems that adding unsprung weight could cause. Were I to switch, I would be reducing unsprung weight by around 16 lbs.

I'm most concerned about the backspacing and fitment of these things. My 15x6" wheels, with 4.00" backspacing and 215/65/15 tires, just barely clear because they are tucked in pretty perfectly. 225/50/17 tires should be just a little shorter than the old tires and so should fill up the wheelwell perfectly, just as the old tires did, but I'm afraid that they won't tuck right and may not clear. I've tried a few offset calculators and they all seem to give me different answers so who knows. Maybe I'll start a thread to see if anyone around here has those wheels (or equivalent) on their cars right now without issue.
Not sure if you have used this calculator Custom wheels, rim tire packages

It allows you to compare two wheel sizes, and where you might run into clearance issues. I have found it to be the most useful of calculators out there.


Sent from the interwebs... where else?
 

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Please feel free to give me a call Kelly. I'll explain anything you need to know to get your car to stop like a modern car (although I can't offer you ABS right now). Happy to discuss various options based on budget and answer any questions you may have.

Nobody has ever told me I've sold them brakes that were just to darn good! :)
 

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I felt the need to chime in again, so I did. Running 17" tires in my case made for a harsher ride pre and post SoT coilover front suspension. That may not be what you are looking for given the miles you like to drive. When I added 2008 GT front disks I also added a Ford style combination valve purchased of eBay, along with a 10# Wilwood residual valve for the rear drums. The actual rear drums on my car are the originals. Not sure if it's some kind of cosmic weirdness but while autocrossing I have near perfect brake balance with as much brake as I need with no lockup unless I get stupid. I get a lot of "your still running those rear drum brakes" at every event I participate in. Unless you're doing 100 mph track days the drums will be fine. If you must do rear disks do the mini drum e-brake inside the hat of the disk and not the crappy wind back Lucas style crap that can barely even handle parking brake duties on a new car.
I'll keep my original drums that can still stop my car in a reasonable distance with only the e-brake or adapt a disk with mini drum e-brake setup.
748204
 

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I felt the need to chime in again, so I did. Running 17" tires in my case made for a harsher ride pre and post SoT coilover front suspension. That may not be what you are looking for given the miles you like to drive. When I added 2008 GT front disks I also added a Ford style combination valve purchased of eBay, along with a 10# Wilwood residual valve for the rear drums. The actual rear drums on my car are the originals. Not sure if it's some kind of cosmic weirdness but while autocrossing I have near perfect brake balance with as much brake as I need with no lockup unless I get stupid. I get a lot of "your still running those rear drum brakes" at every event I participate in. Unless you're doing 100 mph track days the drums will be fine. If you must do rear disks do the mini drum e-brake inside the hat of the disk and not the crappy wind back Lucas style crap that can barely even handle parking brake duties on a new car.
from the posts I’m reading, it sounds like Kelly_h decided some time ago that 17” wheels and big discs all around were the only way to achieve the braking satisfaction desired.
I don’t agree, but each much follow their own path. My way, I.e. “less is more “, is not for everyone. I suppose complicating a simple car has its own allure.

Z
 

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My way, I.e. “less is more “, is not for everyone. I suppose complicating a simple car has its own allure.
Z
Wait!! This comment from a guy who posts a picture of 4x2 Webers on his small block?
 

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Wait!! This comment from a guy who posts a picture of 4x2 Webers on his small block?
ha ha . I k ew that was coming Just a matter of how long.

yes, life is full of contradictions, (aka BS) and I’m no exception. I’ve a weakness for period correct induction modifications, as evidenced by my affairs with the IDA Weber 48’s and all those vintage Paxton’s along the way.

Everyone draws the line in a different place. My do not cross line is 17” wheels and rear discs. Those make perfect sense to many, just not to me.

Z

PS I did have a secret interlude with 16” wheels for a year, but the look never grew on me, so I settled on the 15”. And I got tired of only driving the car at night so no one could see what I’d done... ;)
 

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ha ha . I k ew that was coming Just a matter of how long.

yes, life is full of contradictions, (aka BS) and I’m no exception. I’ve a weakness for period correct induction modifications, as evidenced by my affairs with the IDA Weber 48’s and all those vintage Paxton’s along the way.

Everyone draws the line in a different place. My do not cross line is 17” wheels and rear discs. Those make perfect sense to many, just not to me.

Z

PS I did have a secret interlude with 16” wheels for a year, but the look never grew on me, so I settled on the 15”. And I got tired of only driving the car at night so no one could see what I’d done... ;)
That's funny !
 

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I'm running Vredestine Sportrac 5s. 205/60/15 front, 225/60/15 rear. These are probably the best reasonably priced 15" tires still available in sizes that don't look like garbage on these cars.

Personally, I think that if you are not actually competing, you don't need more tire than the above and the KH front discs with rear drums. And even if you did want more, I recommend two sets of wheels and tires. If you have under 300 UTQG like the Sportracs, you will EAT tires- expensive ones- doing lots of street driving. You'll be replacing $800-1000 worth of tires on average every 10k miles. You hardly ever see anyone mention that. If you get 17s and go with a 600 UTQG tire, what's the point?
 

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