Wheel fitment - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mmorgan32 · 05-13-2015, 01:40 AM

Does anyone know if a 17 inch wheel will fit over disc brakes when switching to disc brakes from drums? I have a 70 c20 by the way

lowrollin70gmc · 05-13-2015, 02:22 AM

A 17 should fit fine, the smaller 16s are stock on 3/4 tons so I wouldn't worry about it.

If you are concerned you can mock up the rotor and caliper inside the wheel to double check while the parts are still returnable.

Mmorgan32 · 05-13-2015, 11:59 PM

Quote:

Originally Posted by lowrollin70gmc

A 17 should fit fine, the smaller 16s are stock on 3/4 tons so I wouldn't worry about it.

If you are concerned you can mock up the rotor and caliper inside the wheel to double check while the parts are still returnable.

I've looked at a few kits to switch it to discs and they all say stock wheels won't fit. I had a 72 gmc with stock discs and 18s fit fine. I'd just rather go with a 17 and bigger tires on my current truck

leftybass209 · 05-14-2015, 12:11 AM

Stock 1970 and earlier drum brake wheels (3 nub steelies) won't fit. Modern 17's didn't come around until well into the disc brake era and should fit fine as long as they don't have a goofy backspace.

Mmorgan32 · 05-14-2015, 12:13 AM

Quote:

Originally Posted by leftybass209

Stock 1970 and earlier drum brake wheels (3 nub steelies) won't fit. Modern 17's didn't come around until well into the disc brake era and should fit fine as long as they don't have a goofy backspace.

What's a good backspace to get I don't want it to stic out just be even with the fender. I love my steelies they just sit in so far

Mike C · 05-14-2015, 08:02 AM

Disc brakes move the wheels out some. The reason the stock wheels don't fit disc brakes isn't the diameter but the shape of the center. It is not shaped to clear the caliper. 17's have the most tire sizes available and probably wheel choice as well.
Posted via Mobile Device

Mmorgan32 · 05-14-2015, 10:07 AM

Quote:

Originally Posted by Mike C

Disc brakes move the wheels out some. The reason the stock wheels don't fit disc brakes isn't the diameter but the shape of the center. It is not shaped to clear the caliper. 17's have the most tire sizes available and probably wheel choice as well.
Posted via Mobile Device

That's what I wanted to know. Thanks

Lees68GMC · 05-14-2015, 10:19 AM

Mike's right the "Center section" and the "Hoop" are too close to clear disc brake calipers, sometimes even grinding on the calipers won't help. Also the back spacing is critical as the improper offset can cause the inner rim edge to hit steering knuckles, tie rods, sway bar, etc.

Mmorgan32 · 05-14-2015, 10:40 AM

Quote:

Originally Posted by Lees68GMC

Mike's right the "Center section" and the "Hoop" are too close to clear disc brake calipers, sometimes even grinding on the calipers won't help. Also the back spacing is critical as the improper offset can cause the inner rim edge to hit steering knuckles, tie rods, sway bar, etc.

Damn is that hitting the tie rod? Is that a 17 with a negative offset?

**derotoreut** · 05-14-2015, 10:20 PM

17" Hummer wheels fit on my 69 C20 with front disc brake conversion.

Mmorgan32 · 05-14-2015, 11:58 PM

Quote:

Originally Posted by derotoreut

17" Hummer wheels fit on my 69 C20 with front disc brake conversion.

That looks sick! Makes me not want to lower mine

05-13-2015, 01:40 AM	#1
Mmorgan32 Registered User Join Date: Jul 2013 Location: Fresno, ca Posts: 303	Wheel fitment Does anyone know if a 17 inch wheel will fit over disc brakes when switching to disc brakes from drums? I have a 70 c20 by the way __________________ 1972 gmc c15 short bed... Sold 1970 chevy custom camper patina daily driver

05-13-2015, 02:22 AM	#2
lowrollin70gmc Too many projects Join Date: Mar 2004 Location: Fargo, ND land of the flat hills Posts: 1,147	Re: Wheel fitment A 17 should fit fine, the smaller 16s are stock on 3/4 tons so I wouldn't worry about it. If you are concerned you can mock up the rotor and caliper inside the wheel to double check while the parts are still returnable. __________________ Andrew 84 GMC C1500 SWB 6.2 Diesel/700R4/3.42 "Grandpa's odd duck" 70 GMC C1500 LWB My first truck: shaved, bagged, and more: the lowrollin70gmc 68 K20 Suburban 12V Cummins/NV5600/NP205/D60/11.5AAM 3.73s "Dakota Cadillac" 63 Chevy II Nova Coupe 250 I6/T56/4.56s "Economy car" 53 Willys Wagon 350/NV4500/BW4401/HP D44/9inch “Winter Wagon” 30 Model A 16 Focus ST

05-14-2015, 12:11 AM	#4
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,189	Re: Wheel fitment Stock 1970 and earlier drum brake wheels (3 nub steelies) won't fit. Modern 17's didn't come around until well into the disc brake era and should fit fine as long as they don't have a goofy backspace.

05-14-2015, 08:02 AM	#6
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,738	Re: Wheel fitment Disc brakes move the wheels out some. The reason the stock wheels don't fit disc brakes isn't the diameter but the shape of the center. It is not shaped to clear the caliper. 17's have the most tire sizes available and probably wheel choice as well. Posted via Mobile Device

05-14-2015, 10:19 AM	#8
Lees68GMC Registered User Join Date: Jul 2013 Location: Prescott Arizona Posts: 343	Re: Wheel fitment Mike's right the "Center section" and the "Hoop" are too close to clear disc brake calipers, sometimes even grinding on the calipers won't help. Also the back spacing is critical as the improper offset can cause the inner rim edge to hit steering knuckles, tie rods, sway bar, etc. Attached Images __________________ 68 GMC SWB Vortec 5.3 98 Chevy Blazer ZR2 94 Mazda Miata, LS2 6 speed, sold "No matter what happens, nobody gets out alive" Last edited by Lees68GMC; 05-14-2015 at 10:29 AM.

05-14-2015, 10:20 PM	#10
derotoreut Roto Reuter thats the name... Join Date: Feb 2010 Location: Darien, NY Posts: 1,853	Re: Wheel fitment 17" Hummer wheels fit on my 69 C20 with front disc brake conversion. Attached Images __________________ ~ Dan My 70 K10 SWB build:http://67-72chevytrucks.com/vboard/s...d.php?t=782232 My 71 SWB build:http://67-72chevytrucks.com/vboard/s...d.php?t=651394 1970 SWB Fleet K10 4X4, 5.3L LM7, 4L60E, Dakota Digital RTX, Vintage Air, Ididit tilt 1971 SWB Fleet C10 - Original SWB Arizona truck, new custom restoration project "Kick out your motor and drive while you're still alive - kick it out!" - Heart 1977



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