[bob p]

No isues what so ever but it scraped sometimes? These kits are no good and not only because the tires rub sometimes but I am so sick of seeing beautiful tri five cars with the front wheels out flush with the fenders or even out past the fenders where they don't belong! because they can't engineer these kits properly! Yes these kits have been around and in use for a long time but not because they are good, It's because that is what the supliers are selling! Unless you do your research and find other options that are much better! But there is a place for these kits for people that just want to upgrade to disc brakes for a minimal investment and don't care about sacrificing the look of their car, and don't mind their tires rubbing the fenders sometimes. NO THANK'S!!!!

i honestly think that the sellers are getting away with selling these horrible kits because there are a lot of buyers who just aren't aware of the problems that these kits will cause them ... until its too late. in all likelihood, people don't know about the wheel offset problem until after they've bought the kit and then they're saddled with something that just won't work for them. so instead of throwing the kit away and spending more money to do it right, they stick with what they've got, throw good money after bad, and end up rubbing their tires.

thanks to this site, i've been able to do A LOT of research before the sale, hoping that i'd be able to avoid many of the pitfalls that go with a disc brake conversion. as much homework as i've done, i'm still not sure that i'll get where i want to be -- keeping a stock looking 14" wheel/cap combination. we'll have to see how it goes.

my criteria for success won't be the same as some other peoples' -- i don't want ANY rubbing of the tires when i've got the wheels turned hard and i'm pulling into a driveway. a properly designed car shouldn't rub its tires. if my car ends up with rashes on the tires because they're rubbing, to me the tires will be shouting out to the world that i failed to do the conversion properly. i don't want that.

 

[BigBoyzToyz]

i honestly think that the sellers are getting away with selling these horrible kits because there are a lot of buyers who just aren't aware of the problems that these kits will cause them ... until its too late. in all likelihood, people don't know about the wheel offset problem until after they've bought the kit and then they're saddled with something that just won't work for them. so instead of throwing the kit away and spending more money to do it right, they stick with what they've got, throw good money after bad, and end up rubbing their tires.

thanks to this site, i've been able to do A LOT of research before the sale, hoping that i'd be able to avoid many of the pitfalls that go with a disc brake conversion. as much homework as i've done, i'm still not sure that i'll get where i want to be -- keeping a stock looking 14" wheel/cap combination. we'll have to see how it goes.

my criteria for success won't be the same as some other peoples' -- i don't want ANY rubbing of the tires when i've got the wheels turned hard and i'm pulling into a driveway. a properly designed car shouldn't rub its tires. if my car ends up with rashes on the tires because they're rubbing, to me the tires will be shouting out to the world that i failed to do the conversion properly. i don't want that.

Since you're such a purist, keep your original drum brakes and you will be just fine.

 

[bob p]

Since you're such a purist, keep your original drum brakes and you will be just fine.

thanks for the advice, but no -- i won't end up keeping my drum brakes. i'm going to keep researching the topic until i find a workable solution that allows me to have car that looks like an old car but stops like a newer car. that solution will not involve using inferior brake designs that make tires rub.

i have to admit, i was a bit surprised by the "mountains out of molehills" and "keep your original drum brakes" comments. i was a little disappointed by them.

 

[Rick_L]

Let's do a reality check here. ALL the kits that use the Chevelle rotor, (and that's 99% or more), will move the wheel out the same excessive amount. That is what's been used to convert to disc brakes with stock spindles for 30 years or more on 55-57s, ever since the first guy figured it out. THEY ARE ALL THE SAME if they use the Chevelle rotors and stock spindles. You may call it poor engineering - what it really is is this - taking advantage of available OEM parts to do this in a simple and inexpensive manner, even if it has shortcomings.

The only other way to do this with a stock spindle is to have a separate hub and use a rear rotor from a Transam. I do not have a clue whether an OEM hub like a 61-68 full size Chevy, or a drum brake hub from a Chevelle or early Camaro will work. Probably not, I'd guess it needs to be a custom hub.

You can also get Wilwood brakes with custom hubs.

Any separate hub kit is going to cost more than one with Chevelle rotors. Cost drives this issue. Most guys that are willing to spend that kind of money are wanting the lowering that comes from dropped spindles - so there's a small market for stock spindle setups like this.

 

[BigBoyzToyz]

Let's do a reality check here. ALL the kits that use the Chevelle rotor, (and that's 99% or more), will move the wheel out the same excessive amount. That is what's been used to convert to disc brakes with stock spindles for 30 years or more on 55-57s, ever since the first guy figured it out. THEY ARE ALL THE SAME if they use the Chevelle rotors and stock spindles. You may call it poor engineering - what it really is is this - taking advantage of available OEM parts to do this in a simple and inexpensive manner, even if it has shortcomings.

The only other way to do this with a stock spindle is to have a separate hub and use a rear rotor from a Transam. I do not have a clue whether an OEM hub like a 61-68 full size Chevy, or a drum brake hub from a Chevelle or early Camaro will work. Probably not, I'd guess it needs to be a custom hub.

You can also get Wilwood brakes with custom hubs.

Any separate hub kit is going to cost more than one with Chevelle rotors. Cost drives this issue. Most guys that are willing to spend that kind of money are wanting the lowering that comes from dropped spindles - so there's a small market for stock spindle setups like this.

Exactly, except I don't really consider the "Chevelle rotor kit" to be excessive since adjusting wheel back space is the key. But if you require OEM wheels and such then it may not be an option. I think it's absolutely wonderful that you can buy a GM rotor that fits the 55-57 spindles, bearings work, seals work, try that with a Fxrd product:confused0006: Who ever figured this out in the early 70's was quite crafty. Bottom line is it's still a very good, inexpensive option for installing disc brakes that work very well. For an OEM system the 11" rotor and large piston GM caliper is one of the best ever, kind of like the small block Chevy engine:happy0030:
Bob good luck in your quest for what you need, I just get tired of hearing the boo hoo'ing of stuff because it doesn't fit your personal agenda. For what it's worth there are more fellows installing non OEM wheels(like 17-20's) than orig.
:beer:

 

[57viper R.I.P Member Number 12]

I am looking for the cheapest and best way to put disc brakes on my '57. I know that I can order from the vendors, but was wondering if there might be a bolt on situation from a donor car.

Check your mailbox I sent a few articles your way.
Bob:anim_44:

 

[bob p]

Exactly, except I don't really consider the "Chevelle rotor kit" to be excessive since adjusting wheel back space is the key. But if you require OEM wheels and such then it may not be an option. I think it's absolutely wonderful that you can buy a GM rotor that fits the 55-57 spindles, bearings work, seals work, try that with a Fxrd product:confused0006: Who ever figured this out in the early 70's was quite crafty.
...
for what its worth there are more fellows installing non OEM wheels(like 17-20's) than orig.

There will always be more people who are willing to modify than there will be who want to keep things original. That shouldn't surprise anyone. Its the easy way out and its often the cheaper way out too.

I agree, the guy who figured this stuff out in the early 70s was a sharp cookie. And I also agree with you that wheel backspace is the key to the solution.

what surprises me is that with all of the Trifives that are out there, NOBODY seems to know how much backspace you can put on a 14" rim and have it fit over those brakes. Honestly, I find it hard to believe that CJS57 and I are the first two people in the world who have ever asked the question of how much backspace you can add to a 14" disc wheel and have it fit over the brakes.

 

[Rick_L]

There is no reason to think that a 14" x 6" wheel won't clear the caliper - it will. What might not clear is the upper ball joint. But I think it would clear that too, if you use the "short" upper ball joints.

You would be welcome to come over and demo the caliper clearance on my 67 Nova. But it's too darn hot for me to do it today. You'd probably just argue with that too.

 

[bob p]

There is no reason to think that a 14" x 6" wheel won't clear the caliper - it will. What might not clear is the upper ball joint.

You would be welcome to come over and demo the caliper clearance on my 67 Nova. But it's too darn hot for me to do it today. You'd probably just argue with that too.

if its a meaningful comparison there would be no argument whatsoever and the search for information would finally be over. but if it turns out to be a meaningless comparison of apples to oranges, then the search for knowledge will have to continue. continuing the search for the right answer is not arguing.

its not that i want to argue with you, rick. its just that nobody who actually has that setup is willing to go on the record with firm numbers, so i'm left trying to figure this all out using math, the calculator, clearance sketches and asking a lot of questions.

i have been told by CJS57 that a 14x6 with 4"BS or a 14x7 with 4.5" BS probably WILL NOT clear the caliper, but that they it definitely WILL clear the upper ball joint. you're now arguing the exact opposite. that raises more questions.

when you say that a 14x6 will clear the caliper, i would like to ask what backspace you have in mind when you say that, and how much clearance you have at that backspace.

i've been told that i should expect a lower likelihood of clearance as the amount of backspace increases, because the profile of the rim "falls toward the hub" as you move from the inner edge of the rim toward the mounting surface. more backspace means gradual drop. with the big 69 chevelle caliper, its a question of clearance, and the amount of clearance changes as backspace changes. what i need to know is whether it will clear 14x6 at 4" backspace, not the stock value.

so far i haven't been able to get a firm answer out of anybody who actually has the early chevelle caliper setup, so the question remains unanswered and my only options are to pursue trying to find the information whatever way i can. i'm sorry f you're growing tired of this, but imagine how tired of this i must be. i can guarantee that i've wasted more time researching this problem than you have spent reading my posts.

 

[BigBoyzToyz]

I have a 14x7 Chevy rally wheel set which have 4.5" BS and I have a car with the Heidt's 10.5" rotor/big GM caliper combo, I will go out, in this heat, jack it up, and try one for you.

 

[Rick_L]

What I was thinking would clear would be a standard 14" x 6" Chevy Rally wheel, which is what I run on the rear of my 67 Nova. I have 14" x 5" on the front for clearance purposes - the negative offset is a little more than the 6". I think the 14" x 5" has a 3-1/2" backspace and the 14" x 6" has a 3-3/4" backspace, maybe 4". I'd have to pull wheels off both ends of the car to check as I don't have any other 14" x 6" Rallies on hand. The Nova has Chevelle rotors and calipers with OEM caliper brackets, should be apples to apples.

BBT's 14" x 7" wheels should tell what's needed. I don't think any of them will have a clearance problem. Rally wheels are built to clear discs.

 

[BigBoyzToyz]

OK. 4.5" BS on a 14" wheel is a no go. Diameter is fine, no problem with ball joints, the front edge of the caliper sits against the wheel. I placed a 1/4" spacer, better but still rubs. At 4" BS the caliper just barely rubs at the end of the mounting pins. They could be ground, slightly-probably 1/16" to clear. I would say 3 7/8" BS is max for 14" rally wheel(I would play it safe with 3.75" BS). This is Heidt's 2" drop, 10.5" rotor with big GM caliper.
Im my opinion, a 14X6 disc brake wheel with 3 3/4-3 1/2" BS would work both on inside and not hit the fender on the outside, as long as no more than a 215 tire is used.

Are orig 14" wheels 5" wide or 6"? If 5" then 3.5" BS would be great.

 

[bob p]

Wow. Thanks for going to all of that effort. That's some very useful information that will change what I was thinking about using.

Let me summarize what I understand from your tests:

OK. 4.5" BS on a 14" wheel is a no go. Diameter is fine, no problem with ball joints, the front edge of the caliper sits against the wheel.

14x7 @ 4.5" BS
Even though the TriFive Front Tire Calc said that the 4.5" backspace was just right for a 14x7 wheel, I had my doubts about clearing the caliper, and you've established that there just isn't enough clearance for the caliper. Thanks for going to all the effort to test the actual fitment for me -- now I can cross that option off of the list.

14x6 @ 4.0" BS
This is the other option that I had been thinking about. The TriFive Calc says that it would provide the exact same tire location. I was thinking that it might be easier to fit a 6" wheel over the caliper than the 7" wheel because the rate of taper of the rim profile is different. Let's see what your other tests infer about that option:

I placed a 1/4" spacer, better but still rubs. At 4" BS the caliper just barely rubs at the end of the mounting pins. They could be ground, slightly-probably 1/16" to clear.

14x7 @ 4.25" BS
If I understand correctly, you took took a 1/4" spacer and placed it behind the 14x7 wheel with 4.5" BS and it still didn't clear the caliper. Am I correct in interpreting that when you take a 14x7 wheel with 4.5" BS and add 1/4" spacer, then that pushes the wheel out to a point that its equivalent to a 14x7 wheel with 4.25" backspace? Since there was still rubbing with a single 1/4" spacer, that eliminated 4.25" BS as a viable option?

14x7 @ 4.00" BS
If I understand things correctly, you took a 4.5" BS wheel and you must have placed two of the 1/4" spacers on it to simulate a 4.0" backspace, right? You didn't specifically say that you did that, but if that's the case then I understand exactly what you were doing.

I would say 3 7/8" BS is max for 14" rally wheel(I would play it safe with 3.75" BS). This is Heidt's 2" drop, 10.5" rotor with big GM caliper.

Would it be a viable option to try a 3-7/8" BS wheel, and if there wasn't enough clearance, add a 1/8" spacer to produce the equivalent of a 3-3/4" BS? I was thinking that doing it that way would give me two options, while going with a 3-3/4 would only give me one option.

Im my opinion, a 14X6 disc brake wheel with 3 3/4-3 1/2" BS would work both on inside and not hit the fender on the outside, as long as no more than a 215 tire is used.

Thanks -- its looking like the proper tire will be nothing larger than a 215. That would suit me fine.

Are orig 14" wheels 5" wide or 6"? If 5" then 3.5" BS would be great.

The 57 wheel and tire specs page says that the originals are a "0.560 offset x 14x5J (modified)" wheel. I have no idea what has been "modified." I'm not sure that I would want to go with a 5" rim because the spec pages for the tires I have been looking at require a minimum rim size of 5.5" and 6".

 

[BigBoyzToyz]

Yes, I placed 1/2" of spacers and the caliper pins would just scrape, very slight, at points on the wheel. The spacers mic'd out at .516". At this BS I could grind the tips on the pins or grind some of the metal on the inner part of the wheel, either would have allowed the caliper to fully clear...however I would go with a 3 3/4" BS wheel for breathing room. Again, I could not imagine a 6" wide wheel, with 3 3/4" BS and a 215 tire ever rubbing on the fender lip. Keep in mind that with a 15" wheel none of this would have occured.

 

[bob p]

Thanks. Now I understand exactly what you did when you took those measurements. Having those spacers on hand really helped you to get a lot more information out of the experiment that you would have gotten by just hanging the wheel. Thanks again.

Yes, I understand that none of this would have happened with a 15" wheel. As you can probably imagine, as I have been beating my head against the wall over this 14" wheel stuff, I have been giving serious thought to re-styling my car around 15" or 16" custom wheels...

I think your experiment provided 95% of the information I was looking for. The only question that I have about this now is how close we are getting to a real 14x6 wheel with 4.0" BS when we simulate it with a 14x7 with 4.5" BS and 0.5" of spacers. I think that there's going to be some subtle difference in the rim profile between a 14x7 with 4.5 BS with 0.5" spacers and a real 14x6 with 4.0 BS, perhaps just enough that the 14x6 with 4.0" BS wheel's profile might have just a little more breathing room around the caliper.

I realize that at this point I am probably splitting hairs.

What do you think of the idea of using a 14x6 wheel with 3+7/8 BS and adding a 1/8" spacer if things are too tight? Would that provide the same amount of fallback to safety as playing it safe with a 3+3/4 BS?

 

[CJS57]

How in the world did this thread get into the "Website Help and Instructional How-To Videos"? Maybe a moderater should move it to Suspenion and Brakes? So people could use the info.

 

[bob p]

that's funny. i was looking for this thread to find the info that i posted above (lost my notes) and I couldn't find it! Thanks CJS!

 

[57viper R.I.P Member Number 12]

I am looking for the cheapest and best way to put disc brakes on my '57. I know that I can order from the vendors, but was wondering if there might be a bolt on situation from a donor car.

Alabama:
Check your e-mail for several articles on the no kit way of doin things.
Bob:beer:

 

[CJS57]

57 Viper, I don't know if I ever thanked you for the help on removing the residual valve on my stock MC. It worked perfect! I do have dual pot system waiting to go in now. Thanks! Chris

 

[57viper R.I.P Member Number 12]

Chris:
I don't want to be the bearer of bad news but don't be surprised if that dual system isn't as trouble free as the stock one has been but good luck with whatever you decide.
Bob