can I use my 3/4 calipers and spindles with a 1/2 ton rotor? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

G-NUT · 05-23-2014, 01:35 PM

I have a 1985 GMC Sierra Classic 2500 with the towing package brakes and 8 lug bolt pattern. I'm not sure of what size rotors and calipers an all that I have but my question is there a way to use what I have existing and go to a 5 lug bolt pattern?

I ask because I like my braking but I want the 5 lug bolt pattern for greater wheel selection.

Also, I don't know what rear-end I have but it's huge and it has 14 bolts.

My end goal is to install a Porterbuilt front DropMember and KP Components 4-link cantilever rear.

Keith Seymore · 05-23-2014, 01:42 PM

Quote:

Originally Posted by G-NUT

I have a 1985 GMC Sierra Classic 2500 with the towing package brakes and 8 lug bolt pattern. I'm not sure of what size rotors and calipers an all that I have but my question is there a way to use what I have existing and go to a 5 lug bolt pattern?

I ask because I like my braking but I want the 5 lug bolt pattern for greater wheel selection.

Nope.

Different animal.

Here are the brake system release charts (for '74 and for '87) in case you want more detail.

http://67-72chevytrucks.com/vboard/s...d.php?t=510519

K

**lolife99** · 05-23-2014, 02:01 PM

Actually there is a way.
Www.earlyclassic.com sells a c20 to c10 spindle.
(C30 has the same ball joint and tie rods as the c20)
These conversion spindles allow you to use your existing a-arms and tie rods.
Install them with HD1.25" wide 1/2-ton rotors calipers and bearings.
It's a super easy way to get 5-lug wheels on the c20 and c30 trucks.

Keith Seymore · 05-23-2014, 03:02 PM

Quote:

Originally Posted by lolife99

Actually there is a way.
Www.earlyclassic.com sells a c20 to c10 spindle.
(C30 has the same ball joint and tie rods as the c20)
These conversion spindles allow you to use your existing a-arms and tie rods.
Install them with HD1.25" wide 1/2-ton rotors calipers and bearings.
It's a super easy way to get 5-lug wheels on the c20 and c30 trucks.

Nicely done.

You would lose some braking, though, by going to a smaller 1/2 ton rotor and caliper.

K

Jonboy · 05-23-2014, 03:22 PM

My '74 had D52 calipers on the front, FWIW. I was doing a 1/2 ton suspension swap anyhow, so I just used them, since they had fresh pads and hoses.

G-NUT · 05-23-2014, 04:04 PM

Thing is I will be going with a Porterbuilt front Dropmember system which will come with new upper/lower control arms and lowered spindles. I can get this setup for a C20, but I want to run the 5-lug setup for wheel options.

at EarlyClassics, I see the C20 3/4 ton to 1/2 ton spindles. I might get the Porterbuilt kit without spindles and use these spindles.

Jonboy · 05-23-2014, 04:27 PM

As long as the frame dimensions are correct for your C20, I would go ahead and run the C10 parts on the front. I am guessing towing is not your goal.

05-23-2014, 01:35 PM	#1
G-NUT Registered User Join Date: Apr 2014 Location: Baldwin County, Alabama Posts: 163	can I use my 3/4 calipers and spindles with a 1/2 ton rotor? I have a 1985 GMC Sierra Classic 2500 with the towing package brakes and 8 lug bolt pattern. I'm not sure of what size rotors and calipers an all that I have but my question is there a way to use what I have existing and go to a 5 lug bolt pattern? I ask because I like my braking but I want the 5 lug bolt pattern for greater wheel selection. Also, I don't know what rear-end I have but it's huge and it has 14 bolts. My end goal is to install a Porterbuilt front DropMember and KP Components 4-link cantilever rear.

05-23-2014, 02:01 PM	#3
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,703	Re: can I use my 3/4 calipers and spindles with a 1/2 ton rotor? Actually there is a way. Www.earlyclassic.com sells a c20 to c10 spindle. (C30 has the same ball joint and tie rods as the c20) These conversion spindles allow you to use your existing a-arms and tie rods. Install them with HD1.25" wide 1/2-ton rotors calipers and bearings. It's a super easy way to get 5-lug wheels on the c20 and c30 trucks. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

05-23-2014, 03:22 PM	#5
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: can I use my 3/4 calipers and spindles with a 1/2 ton rotor? My '74 had D52 calipers on the front, FWIW. I was doing a 1/2 ton suspension swap anyhow, so I just used them, since they had fresh pads and hoses. __________________ 1974 Jimmy- 5.3/4L80e/NP241

05-23-2014, 04:04 PM	#6
G-NUT Registered User Join Date: Apr 2014 Location: Baldwin County, Alabama Posts: 163	Re: can I use my 3/4 calipers and spindles with a 1/2 ton rotor? Thing is I will be going with a Porterbuilt front Dropmember system which will come with new upper/lower control arms and lowered spindles. I can get this setup for a C20, but I want to run the 5-lug setup for wheel options. at EarlyClassics, I see the C20 3/4 ton to 1/2 ton spindles. I might get the Porterbuilt kit without spindles and use these spindles. __________________ '84 Suburban C10 Silverado - laying pinchweld to the ground on 22/24. /Porterbuilt / Accuair / Bonspeed / Landsail / Auburn Gear / Richmond Gear / Moser / Raybestos / ProMaxx / Edlebrock / Street Demon / Taylor Wire / K&N / MSD / KillMat / SOLD: 1985 GMC Sierra Classic 2500 3+3 Crew Cab Long Bed

05-23-2014, 04:27 PM	#7
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: can I use my 3/4 calipers and spindles with a 1/2 ton rotor? As long as the frame dimensions are correct for your C20, I would go ahead and run the C10 parts on the front. I am guessing towing is not your goal. __________________ 1974 Jimmy- 5.3/4L80e/NP241



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