Disc Brakes, 14" Drum Wheels, and OPGI's Kit - Chevelle Tech
Brakes, Suspension & Steering Conversion questions & more.

 1Likes
  • 1 Post By Tom Mobley
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 10 (permalink) Old Feb 17th, 16, 8:34 PM Thread Starter
Tech Team
Matt
 
Join Date: Apr 2012
Location: NE Ohio
Posts: 278
Disc Brakes, 14" Drum Wheels, and OPGI's Kit

This topic seems to get beaten to death but I haven't come across a conclusive answer - especially with this specific question.

My '71 currently has the factory manual drums and 14" steel (not-rally) wheels. I'm going to convert to a power disc/drum setup, and if at all possible I want to keep my current wheels (and tires). It's a daily driver with a 307, so I don't need crazy-big brakes, OEM-style are fine for now.

Every disc swap kit I've come across - except one - has specified that it will require 15" wheels, even when they use OEM calipers and rotors. The one that claims it will fit the 14" 'drum' wheels is this one from OPGI:

https://www.opgi.com/chevelle/1971/b...rakes/CH28690/

Like a lot of stuff on their website, this kit seems a bit pricey, but it's the only one I've seen that claims it will fit with the original 14" wheels - and this fitment is confirmed in the reviews.

Here's the big question though - the kit says it uses OEM calipers and 11" rotors (which is the OEM size, yes?). What makes this particular kit fit with the 14" wheels when the other kits claim they don't?

What's going on here?

I'd contact OPGI directly but they still haven't even gotten back to me from an e-mail on Saturday about the MC in that kit (which looks like it's disc/disc) so I don't have high hopes of help from them.

Thanks!

Industrial controls engineer by day, mechanic by night, a few screws loose 24/7

'71 4-Door Malibu
My old daily, a project to be a driver again
Previously: 307 / Powerglide
Current: 307 / Muncie M20
Soon: 383 / Muncie M20
MM54 is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old Feb 18th, 16, 1:52 PM
Tech Team
Bryan
 
Join Date: Apr 2015
Location: SE Michigan
Posts: 762
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

I have been eyeballing conversion kits and it seems like SSBC is about the only company out there that makes a kit that will fit 14" wheels. I will be buying it and installing as soon as the weather allows up here. It is around the same price range as the OPGI kit.
This is for a '66 so the same may or may not be the case for your '71.

'66 SS Clone
Fast Burn 385hp Crate 350 (for now)
Muncie M20 & 3.42 Posi
UMI Stage 2 Suspension all around
bry66 is offline  
post #3 of 10 (permalink) Old Feb 18th, 16, 2:59 PM
Boldly procrastrinating
Tom Terrific II
 
Join Date: Oct 1998
Location: Glendale, Az
Posts: 28,714
Garage
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

You 71 might have disc brake wheels on already. Disc brakes were increasingly common by then, I think switched over to using all disc brake wheels to avoid assembly line problems. It may be that the only way you'll really know is to try it. Wheels are much cheaper than brakes, I'd get the brakes on and find wheels. If your wheels won't work someone will have ones that do.

Why stay with 14s anyway? tire selection is getting really limited, worse than 15.

Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife.
Tom Mobley is offline  
 
post #4 of 10 (permalink) Old Feb 18th, 16, 6:11 PM Thread Starter
Tech Team
Matt
 
Join Date: Apr 2012
Location: NE Ohio
Posts: 278
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

Quote:
Originally Posted by Tom Mobley View Post
You 71 might have disc brake wheels on already. Disc brakes were increasingly common by then, I think switched over to using all disc brake wheels to avoid assembly line problems. It may be that the only way you'll really know is to try it. Wheels are much cheaper than brakes, I'd get the brakes on and find wheels. If your wheels won't work someone will have ones that do.

Why stay with 14s anyway? tire selection is getting really limited, worse than 15.
I was thinking about the just-try-it approach - the car's basically in a shed right now, sharing space with some ladders, wood, and the occasional chicken/turkey/peacock (it's under a cover) so I can't really leave it in much of a taken-apart state for very long, though I suppose I could assemble a spindle/hub and try it on one of the wheels (or the spare).

I do like the 15" rally wheels but I was hoping to avoid having to buy a set of wheels and tires, since that's a non-negligible cost to add on to all the other parts I will be buying to get this thing back on the road.

The wheels on there now are the stamped/welded steel wheels (with neat brushed metal hubcaps), the cheapest of the cheap. It would be nice (and make sense) if they cleared discs but I imagine it's also possible that disc cars got bumped to rally wheels by default.

I suppose my tentative plan can be to get the "Right Stuff" kit from Summit (Summit is nice because I don't have to pay shipping, just a 30 minute drive) and try it - if it clears, great! If it just touches the edge of a bracket... I can clearance it. If there's no hope of fitment, I guess I'll be in the market for new wheels/tires - the $200 saved on the kit can go towards that.

Industrial controls engineer by day, mechanic by night, a few screws loose 24/7

'71 4-Door Malibu
My old daily, a project to be a driver again
Previously: 307 / Powerglide
Current: 307 / Muncie M20
Soon: 383 / Muncie M20
MM54 is offline  
post #5 of 10 (permalink) Old Feb 19th, 16, 2:48 AM
Boldly procrastrinating
Tom Terrific II
 
Join Date: Oct 1998
Location: Glendale, Az
Posts: 28,714
Garage
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

sounds good. flexible, keeping an eye out for possible options.

My 70 is a plain Malibu, had 4 wheel drums with power. Also had 15" Rallys. I bought it from the original owner, I asked her why she had those wheels put on it, she said it came like that. Never found a build sheet, so her word rules the day, I guess. They are disc brake Rallys. The car had one Vette trim ring for an 8" wheel. Who knows?

Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife.
Tom Mobley is offline  
post #6 of 10 (permalink) Old Feb 19th, 16, 9:56 PM Thread Starter
Tech Team
Matt
 
Join Date: Apr 2012
Location: NE Ohio
Posts: 278
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

Just for future reference - I went through my pictures from rebuilding the front end a few years ago and found these two, showing the wheels that are on it. The second picture is the best view of the inside I could find - per another thread, if the wheel is 'flat' the whole way across the inside then it may fit (this post also mentioned pre-69 wheels, these are '71).

It may be a while before I get the brakes and find out ho this will go, but eventually I will update this thread with pictures/results of this attempted fitment for anyone's future reference.





Edit: Found a picture of my spare which I'm pretty sure is the same wheel (and original tire - which I would never drive on)


Industrial controls engineer by day, mechanic by night, a few screws loose 24/7

'71 4-Door Malibu
My old daily, a project to be a driver again
Previously: 307 / Powerglide
Current: 307 / Muncie M20
Soon: 383 / Muncie M20

Last edited by MM54; Feb 19th, 16 at 10:12 PM.
MM54 is offline  
post #7 of 10 (permalink) Old Feb 21st, 16, 3:42 PM
Boldly procrastrinating
Tom Terrific II
 
Join Date: Oct 1998
Location: Glendale, Az
Posts: 28,714
Garage
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

wow, original spare? I'll bet it has the holy grail of restorers, original air in the tire. J/K, I guess I've seen too many of the Vette guys and their originality fetish.

measuring tape, compare the width of the larger diameter section with the same section on the spare. should be able to do it without taking a wheel off. The wheel in the second pic looks like a DB wheel to me, but I'm the farthest thing from an expert on 14" wheels.
MM54 likes this.

Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife.
Tom Mobley is offline  
post #8 of 10 (permalink) Old Feb 22nd, 16, 12:19 AM
Gold Founding Member
 
Join Date: Aug 1998
Location: the Seasonally Frozen Wastelands
Posts: 10,935
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

Quote:
Originally Posted by MM54 View Post

Every disc swap kit I've come across - except one - has specified that it will require 15" wheels, even when they use OEM calipers and rotors. The one that claims it will fit the 14" 'drum' wheels is this one from OPGI:

https://www.opgi.com/chevelle/1971/b...rakes/CH28690/

Like a lot of stuff on their website, this kit seems a bit pricey, but it's the only one I've seen that claims it will fit with the original 14" wheels - and this fitment is confirmed in the reviews.

Here's the big question though - the kit says it uses OEM calipers and 11" rotors (which is the OEM size, yes?). What makes this particular kit fit with the 14" wheels when the other kits claim they don't
Those may be OEM calipers, but they're not the original-style calipers as would be used in '69--'72. Those calipers are MUCH newer.

The caliper mounting bracket is nothing like the '69--'72 caliper mounting, either. I bet you'd find that it's COMPLETELY and IMPROPERLY lacking support for the middle of the caliper, unlike the GM design.

Typical OPGI.

.
.
For the good of the Free World, DEMAND COMPENSATION FROM CHINA for their release of an engineered virus from their Wuhan laboratory. Two trillion to start with, increasing as needed from there.
Schurkey is offline  
post #9 of 10 (permalink) Old Feb 26th, 16, 7:25 PM Thread Starter
Tech Team
Matt
 
Join Date: Apr 2012
Location: NE Ohio
Posts: 278
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

Quote:
Originally Posted by Tom Mobley View Post
wow, original spare? I'll bet it has the holy grail of restorers, original air in the tire. J/K, I guess I've seen too many of the Vette guys and their originality fetish.

measuring tape, compare the width of the larger diameter section with the same section on the spare. should be able to do it without taking a wheel off. The wheel in the second pic looks like a DB wheel to me, but I'm the farthest thing from an expert on 14" wheels.
Ha! I've seen that sort of thing as well.

I'll definitely take a look, I've been thinking about it (I've been traveling for work the past week) and I think I'm going to go for the 'normal' kit, and if it won't work with my wheels, I'll get 15" rallys. Like I said, I'll be sure to keep this thread up to date for future reference (I can't be the only one puzzled by all this).

Quote:
Originally Posted by Schurkey View Post
Those may be OEM calipers, but they're not the original-style calipers as would be used in '69--'72. Those calipers are MUCH newer.

The caliper mounting bracket is nothing like the '69--'72 caliper mounting, either. I bet you'd find that it's COMPLETELY and IMPROPERLY lacking support for the middle of the caliper, unlike the GM design.

Typical OPGI.
I did notice the bracket doesn't look like any of the other brackets I've seen (it's machined from a plate as opposed to stamped like the others) - I was wondering about the flex in the bracket, but now that you mention it, if I'm looking at this right, the caliper is not very well supported, especially in terms of the torsional load from, oh I don't know, something like using the brakes. Seems like more reason to avoid this kit (especially for a daily driver).

Industrial controls engineer by day, mechanic by night, a few screws loose 24/7

'71 4-Door Malibu
My old daily, a project to be a driver again
Previously: 307 / Powerglide
Current: 307 / Muncie M20
Soon: 383 / Muncie M20
MM54 is offline  
post #10 of 10 (permalink) Old Jul 31st, 16, 5:48 PM Thread Starter
Tech Team
Matt
 
Join Date: Apr 2012
Location: NE Ohio
Posts: 278
Re: Disc Brakes, 14" Drum Wheels, and OPGI's Kit

Right, so, it's been a while but I finally have an answer. I picked up a set of 15x7 rally wheels at a swap meet a while ago and yesterday installed "The Right Stuff" power disc conversion on the front of the car.

Much to my surprise, my 14" drum wheels (pictured and described in previous posts) fit! I didn't check clearances, so they may be very tight, but they go on and spin freely with these disc brakes, so there's some sort of answer.

That said, I'm sticking with these rally wheels


Industrial controls engineer by day, mechanic by night, a few screws loose 24/7

'71 4-Door Malibu
My old daily, a project to be a driver again
Previously: 307 / Powerglide
Current: 307 / Muncie M20
Soon: 383 / Muncie M20
MM54 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 1403 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome