20” wheels to 15” wheels - The 1947 - Present Chevrolet & GMC Truck Message Board Network

epfatboy · 03-24-2025, 03:16 PM

Yep, 20” to 15” is the direction I’d like to go.
Want to do this on a 1974 C10 short bed step side. Truck has a 4” drop.
Current sneakers are 275/40R20 front and 315/30R20 rear, no rubbing. Mounted on 5x5 Riddler rims..

WITH UNKNOWN Backspace.

Anyone have some experience with what fits my combo in terms of a 15 (ish) rim, I assume a 15/10 5x5, really looking for BS (or offset) and what rubber your running on a step side.

I’m buying new so I have some option, like I might not hate the idea of a 16 or 17” rim but I do like a meaty sidewall.

I can measure, and will, just being lazy and want to window shop.

**raggedjim** · 03-24-2025, 08:15 PM

Lots of choices from this thread...

https://67-72chevytrucks.com/vboard/...d.php?t=703601

Loco83 · 03-28-2025, 01:32 PM

15x8 and 4" BS and 15x10 with 5" BS, 245/60/15"s and 295 /50/15's.

epfatboy · 03-28-2025, 05:38 PM

Loco,

You’re the man, that’s what I needed. Those look nice in there.

Should mention (and research) I’m running rear disc with eldo calipers pretty sure they fit 15” rims….

72c20customcamper · 03-28-2025, 06:02 PM

Quote:

Originally Posted by epfatboy

Loco,

You’re the man, that’s what I needed. Those look nice in there.

Should mention (and research) I’m running rear disc with eldo calipers pretty sure they fit 15” rims….

I have the same setup on my Chevelle on the rear no problems with 15” inch rims .

epfatboy · 03-28-2025, 06:13 PM

Research disc caliper to 15" rim fitment... CHECK. Thanks for that.

Richard D · 04-05-2025, 12:33 PM

Quote:

Originally Posted by Loco83

15x8 and 4" BS and 15x10 with 5" BS, 245/60/15"s and 295 /50/15's.

Perfect, the front is just a tiny bit shorter than the rear. I had custom truck rallys 15x10 with 5" backspace years ago, does anyone make them off the shelf?

v30crewcab · 04-05-2025, 06:40 PM

what spindles do you have? 15" don't like 3" drop spindles.

epfatboy · 04-05-2025, 09:17 PM

Not a great pic (as of today, I’m behind nothing new) but it shows the 20” wheels I’m looking to replace. Tires are 315/30R20 (27.4” tall) and 275/40R20 (28.6”).

I like the idea of 15” with:
295/60R15 ( 28.9) and 245/70R15 ( 28.4)

Little more height tire won’t hurt (4L80e/3.73) and I’ll like the extra sidewall.

I have a 2” spindle/2” spring drop front and an axle over rear.

SCOTI · 04-08-2025, 10:38 AM

Standard truck ralleys are always a good choice for Squarebody trucks....

Front: 15x6.5" Van ralley; 215/75-15 tire @ 27.7"
Rear: 15x8.0" Truck ralley; 255/70-15 tire @ 29"
88-98 15" OE trim rings

03-24-2025, 03:16 PM	#1
epfatboy Registered User Join Date: Mar 2018 Location: Barrington nh Posts: 137	20” wheels to 15” wheels Yep, 20” to 15” is the direction I’d like to go. Want to do this on a 1974 C10 short bed step side. Truck has a 4” drop. Current sneakers are 275/40R20 front and 315/30R20 rear, no rubbing. Mounted on 5x5 Riddler rims.. WITH UNKNOWN Backspace. Anyone have some experience with what fits my combo in terms of a 15 (ish) rim, I assume a 15/10 5x5, really looking for BS (or offset) and what rubber your running on a step side. I’m buying new so I have some option, like I might not hate the idea of a 16 or 17” rim but I do like a meaty sidewall. I can measure, and will, just being lazy and want to window shop.

03-24-2025, 08:15 PM	#2
raggedjim Senior Member Join Date: Jun 2002 Location: Murray, Kentucky Posts: 4,102	Re: 20” wheels to 15” wheels Lots of choices from this thread... https://67-72chevytrucks.com/vboard/...d.php?t=703601 __________________ Roger '68 Short step - https://67-72chevytrucks.com/vboard/...d.php?t=849675 '69 ('70?) 2wd Blazer - https://67-72chevytrucks.com/vboard/...d.php?t=856475 '70 GMC Jimmy 2wd '73 Firebird - https://67-72chevytrucks.com/vboard/...d.php?t=853203 Ideas - https://67-72chevytrucks.com/vboard/...d.php?t=851743

03-28-2025, 01:32 PM	#3
Loco83 Registered User Join Date: Nov 2018 Location: Cali Posts: 408	Re: 20” wheels to 15” wheels 15x8 and 4" BS and 15x10 with 5" BS, 245/60/15"s and 295 /50/15's. Attached Images

03-28-2025, 05:38 PM	#4
epfatboy Registered User Join Date: Mar 2018 Location: Barrington nh Posts: 137	Re: 20” wheels to 15” wheels Loco, You’re the man, that’s what I needed. Those look nice in there. Should mention (and research) I’m running rear disc with eldo calipers pretty sure they fit 15” rims….

03-28-2025, 06:13 PM	#6
epfatboy Registered User Join Date: Mar 2018 Location: Barrington nh Posts: 137	Re: 20” wheels to 15” wheels Research disc caliper to 15" rim fitment... CHECK. Thanks for that.

04-05-2025, 06:40 PM	#8
v30crewcab Registered User Join Date: Apr 2012 Location: Chatt Tn Posts: 1,022	Re: 20” wheels to 15” wheels what spindles do you have? 15" don't like 3" drop spindles. __________________ 88 military v30 crewcab shortbed 5.9 cummins, nv4500, 205 86 k30, 89 diesel burb, 76 gmc pathfinder 71 longbed 5.3 4l80 http://67-72chevytrucks.com/vboard/s...d.php?t=522535

04-05-2025, 09:17 PM	#9
epfatboy Registered User Join Date: Mar 2018 Location: Barrington nh Posts: 137	Re: 20” wheels to 15” wheels Not a great pic (as of today, I’m behind nothing new) but it shows the 20” wheels I’m looking to replace. Tires are 315/30R20 (27.4” tall) and 275/40R20 (28.6”). I like the idea of 15” with: 295/60R15 ( 28.9) and 245/70R15 ( 28.4) Little more height tire won’t hurt (4L80e/3.73) and I’ll like the extra sidewall. I have a 2” spindle/2” spring drop front and an axle over rear. Attached Images

04-08-2025, 10:38 AM	#10
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,569	Re: 20” wheels to 15” wheels Standard truck ralleys are always a good choice for Squarebody trucks.... Front: 15x6.5" Van ralley; 215/75-15 tire @ 27.7" Rear: 15x8.0" Truck ralley; 255/70-15 tire @ 29" 88-98 15" OE trim rings Attached Images __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.* Last edited by SCOTI; 04-08-2025 at 05:21 PM.



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