rear disc question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68c10owner · 12-15-2019, 12:46 PM

My 78 C10 I picked up has a rear disc kit and Im wondering if it will effect the backspacing needed for custom wheels. Right now it has stock steelies so its not a issue but Ive heard it can change the backspacing required and plan to order custom wheels soon. Im not sure of the brand of the kit but it does have a CPP master. They actually dont seem to stop too well but I havent had a chance to do anything to it since its stored at a friends house.

68c10owner · 12-20-2019, 01:50 AM

Nobody knows huh?

**Palf70Step** · 12-20-2019, 08:31 AM

It is hard to say not knowing what brake setup was installed. Depending on what rim size you are planning to go with is the biggest factor. I'd say a 17" or larger rim it will be minimal, but a 15" rim clearing the caliper will most likely be an issue.

68c10owner · 12-20-2019, 08:37 AM

Quote:

Originally Posted by Palf70Step

It is hard to say not knowing what brake setup was installed. Depending on what rim size you are planning to go with is the biggest factor. I'd say a 17" or larger rim it will be minimal, but a 15" rim clearing the caliper will most likely be an issue.

Thanks. That's another issue I was conserned about. I was planning to go with 15" wheels but the wheels I want already rub in the front because of the thicker casting. I'm worried the rears may be a issue too. Might be just the excuse I need to go with bigger wheels

twinturboc10 · 12-23-2019, 09:22 PM

You could make a couple measurements to compare front to rear using a straight edge and tape measure. Does it have OEM style calipers or aftermarket?

sambrutay · 01-02-2020, 08:56 AM

The thickness of the rotor vs the thickness of a drum is what you have to take into account.

68c10owner · 01-02-2020, 09:12 AM

The type of caliper shouldn't matter but it is a aftermarket kit.

I realize the thickness of the rotor vs the drum will determine any change but the truck came with the kit installed so I can't measure the stock set up.

It's not important at this point b uh t thanks for the input

sambrutay · 01-02-2020, 04:25 PM

These are the drums off my 74 GMC
looks to be almost an 1/8" thick (the increments are 16 and 32nds)

12-15-2019, 12:46 PM	#1
68c10owner Registered User Join Date: Oct 2003 Location: Carmichael, California Posts: 3,005	rear disc question My 78 C10 I picked up has a rear disc kit and Im wondering if it will effect the backspacing needed for custom wheels. Right now it has stock steelies so its not a issue but Ive heard it can change the backspacing required and plan to order custom wheels soon. Im not sure of the brand of the kit but it does have a CPP master. They actually dont seem to stop too well but I havent had a chance to do anything to it since its stored at a friends house. __________________ Anthony

12-20-2019, 01:50 AM	#2
68c10owner Registered User Join Date: Oct 2003 Location: Carmichael, California Posts: 3,005	Re: rear disc question Nobody knows huh? __________________ Anthony

12-20-2019, 08:31 AM	#3
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,216	Re: rear disc question It is hard to say not knowing what brake setup was installed. Depending on what rim size you are planning to go with is the biggest factor. I'd say a 17" or larger rim it will be minimal, but a 15" rim clearing the caliper will most likely be an issue. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

12-23-2019, 09:22 PM	#5
twinturboc10 Registered User Join Date: Feb 2010 Location: Gretna, NE Posts: 33	Re: rear disc question You could make a couple measurements to compare front to rear using a straight edge and tape measure. Does it have OEM style calipers or aftermarket?

01-02-2020, 08:56 AM	#6
sambrutay Registered User Join Date: Dec 2010 Location: Louisville KY Posts: 622	Re: rear disc question The thickness of the rotor vs the thickness of a drum is what you have to take into account. __________________ Bruce 1964 C10 SWB #Junk 1979 C10 utility #cargopants (sold) 1971 GMC Sprint (sold) 1974 GMC Grande Sierra (sold)

01-02-2020, 09:12 AM	#7
68c10owner Registered User Join Date: Oct 2003 Location: Carmichael, California Posts: 3,005	Re: rear disc question The type of caliper shouldn't matter but it is a aftermarket kit. I realize the thickness of the rotor vs the drum will determine any change but the truck came with the kit installed so I can't measure the stock set up. It's not important at this point b uh t thanks for the input __________________ Anthony

01-02-2020, 04:25 PM	#8
sambrutay Registered User Join Date: Dec 2010 Location: Louisville KY Posts: 622	Re: rear disc question These are the drums off my 74 GMC looks to be almost an 1/8" thick (the increments are 16 and 32nds) Attached Images __________________ Bruce 1964 C10 SWB #Junk 1979 C10 utility #cargopants (sold) 1971 GMC Sprint (sold) 1974 GMC Grande Sierra (sold)



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