Centerbore for Drum Brakes - The 1947 - Present Chevrolet & GMC Truck Message Board Network

javadoc · 03-20-2008, 06:38 PM

Quick question... I'm looking at some wheels but need to know the centerbore for the drum brakes (fronts actually) to make sure that I don't have a fitment problem caused by a centerbore incompatibility. So, anyone know the magic number off hand?

Thanks!

~Scott

*blackedoutharley* · 03-21-2008, 08:38 AM

Any wheel you get in 6 on 5.5" bolt circle that is the proper offset (standard) will have the proper centerbore to clear the brakes. This is the same bolt circle used on all 4X4's which have the big hubs (straight axle 4x4's).

Some of the wheels offered for late model trucks with the 6 lug pattern may have a smaller bore but also have a more positive offset (increased backspacing) but any 15"X8" wheel should have no problems clearing.

javadoc · 03-22-2008, 02:04 AM

Thanks for the reply! So, no reason to worry about the centerbore being too small, and the wheel not going on. Good to know. I'm used to needing to be very aware of this with my other cars/projects.

*blackedoutharley* · 03-22-2008, 11:00 AM

No, you should be just fine but remember (especially with aluminum wheels) that the studs on our trucks are on the short side. Go to your local tire shop and tell them you need new 7/16" "ET" lug nuts if using alloy wheels. They might try to tell you that they are not the correct lug nut but they are. If you cant find them let me know, I stock them (and use them on my '65)

03-20-2008, 06:38 PM	#1
javadoc Hey Watch this... Join Date: Sep 2007 Location: Parker, CO Posts: 414	Centerbore for Drum Brakes Quick question... I'm looking at some wheels but need to know the centerbore for the drum brakes (fronts actually) to make sure that I don't have a fitment problem caused by a centerbore incompatibility. So, anyone know the magic number off hand? Thanks! ~Scott __________________ What have I gotten myself into now? 1964 Chevy Stepside - 383 hydraulic roller Vortec ... a work in progress 2000 Volvo V70R - 340awhp, 22psi, meth-injected of Porsche-eating fun. The grocery-getter on steroids

03-21-2008, 08:38 AM	#2
blackedoutharley Account Suspended Join Date: Jul 2007 Location: Plumas Lake, Ca. Posts: 1,009	Re: Centerbore for Drum Brakes Any wheel you get in 6 on 5.5" bolt circle that is the proper offset (standard) will have the proper centerbore to clear the brakes. This is the same bolt circle used on all 4X4's which have the big hubs (straight axle 4x4's). Some of the wheels offered for late model trucks with the 6 lug pattern may have a smaller bore but also have a more positive offset (increased backspacing) but any 15"X8" wheel should have no problems clearing.

03-22-2008, 02:04 AM	#3
javadoc Hey Watch this... Join Date: Sep 2007 Location: Parker, CO Posts: 414	Re: Centerbore for Drum Brakes Thanks for the reply! So, no reason to worry about the centerbore being too small, and the wheel not going on. Good to know. I'm used to needing to be very aware of this with my other cars/projects. __________________ What have I gotten myself into now? 1964 Chevy Stepside - 383 hydraulic roller Vortec ... a work in progress 2000 Volvo V70R - 340awhp, 22psi, meth-injected of Porsche-eating fun. The grocery-getter on steroids

03-22-2008, 11:00 AM	#4
blackedoutharley Account Suspended Join Date: Jul 2007 Location: Plumas Lake, Ca. Posts: 1,009	Re: Centerbore for Drum Brakes No, you should be just fine but remember (especially with aluminum wheels) that the studs on our trucks are on the short side. Go to your local tire shop and tell them you need new 7/16" "ET" lug nuts if using alloy wheels. They might try to tell you that they are not the correct lug nut but they are. If you cant find them let me know, I stock them (and use them on my '65)



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