Wheel Upgrade Inquiry
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,694
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From: Beaverton Oregon
Wheel Upgrade Inquiry
So I'm wanting to upgrade to 17" Wheels. My '86 currently rides on 255/50/16. To maintain the ride height and speedometer calibration, what tire should I purchase for a 17" x 9.5" wheel? I was thinking a 245/45/17? Thanks.
Burning Brakes
Joined: Jun 2006
Posts: 1,096
Likes: 28
From: Baltimore MD
The best way to be sure of tire height would be to visit the website of the tires you presently run, verify their height, then do the same for the tire size/brand you intend to use. It's not foolproof, but will get you a closer idea for sure.
Personally, I think 245/45's are too narrow on a 9.5" wide wheel. I have 17x9.5's on the front of mine, and the 275/40's fit them perfectly.
245/45's are better suited to 8"-8.5" wheel
Personally, I think 245/45's are too narrow on a 9.5" wide wheel. I have 17x9.5's on the front of mine, and the 275/40's fit them perfectly.
245/45's are better suited to 8"-8.5" wheel
Racer
Joined: Nov 2004
Posts: 406
Likes: 62
From: Central Cal
This should help:
Go to the tire size calculator on this site to figure out the diameter of the tire that you will need to match your stock confirguration which is 26.039 diameter(anywhere between 26 & under 27 will be fine); http://www.americanracing.com/techce...§ion=tech#
Then go to this site to see what they look like compared to what you had; http://www.bigcustomwheels.com/rt_specs.jsp
Go to the tire size calculator on this site to figure out the diameter of the tire that you will need to match your stock confirguration which is 26.039 diameter(anywhere between 26 & under 27 will be fine); http://www.americanracing.com/techce...§ion=tech#
Then go to this site to see what they look like compared to what you had; http://www.bigcustomwheels.com/rt_specs.jsp
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,694
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From: Beaverton Oregon
Melting Slicks
Joined: Feb 2007
Posts: 3,266
Likes: 8
From: Indian Rocks Beach FL
St. Jude Donor '08-'09-'10
255/45 ZR17' on the front are 26" in diameter and recommended rim width is 8"-9.5". 285/40 ZR17 on rear are 26.1" in diameter and recommended rim width is 9.5"-11". This is the combination I have on 9.5inch rims all around. I'm very happy with the way the car rides and handles.
Pro
Joined: May 2002
Posts: 518
Likes: 17
285/40/17 on 9.5" wide wheels should be perfect to replace 255/50/16's.
255/45 ZR17' on the front are 26" in diameter and recommended rim width is 8"-9.5". 285/40 ZR17 on rear are 26.1" in diameter and recommended rim width is 9.5"-11". This is the combination I have on 9.5inch rims all around. I'm very happy with the way the car rides and handles.
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Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The 275/40-17 when mounted on a 17x9.5 wheel will be so close to the diameter of the 255/50-16 tire on the OEM wheel, you won't really notice a difference in indicated speed on the speedometer.
The 275/40 tire is widely available in different brands and performance levels. GM really made no changes when they went to the 275/40-17 in 1988. And in 1988, the base wheel was still a 16" with 255/50 tires; the 17" was an option.
The 275/40 tire is widely available in different brands and performance levels. GM really made no changes when they went to the 275/40-17 in 1988. And in 1988, the base wheel was still a 16" with 255/50 tires; the 17" was an option.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
At 60 mph with these tires, your speedo will read this:
255/50R16 = 60.2 mph
255/45R17 = 60.2 mph
275/40R17 = 61.1 mph
When GM switched to the 275 tire they changed the speedo gears.
255/50R16 = 60.2 mph
255/45R17 = 60.2 mph
275/40R17 = 61.1 mph
When GM switched to the 275 tire they changed the speedo gears.
Pro
Joined: May 2002
Posts: 518
Likes: 17
The 285/40/17 was paired with the 255/45/17 from the factory on later base suspensioned C4's, and both are a perfect match for the 255/50/16 at roughly 26" tall.
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,694
Likes: 0
From: Beaverton Oregon
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,694
Likes: 0
From: Beaverton Oregon
I'm going to look at some 17 x 9.5 Saw Blades in the AM from a 1990.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
I'm using 275/40-17 tires on 17x9.5 wheels that have a 38mm offset (got them from AFS). I have zero problems with tire clearance in the wheelwells or with the speedo reading.
The 285/40-17 tire was only used on the rear of 1993 and later C4's. The rear wheel was a 17x9.5 while the front wheel was an inch narrower at 8.5 and the front tire was narrower at 255/45.
Don't bother with the odd sized tires; use the 275/40 tire size and you will be OK.
The 285/40-17 tire was only used on the rear of 1993 and later C4's. The rear wheel was a 17x9.5 while the front wheel was an inch narrower at 8.5 and the front tire was narrower at 255/45.
Don't bother with the odd sized tires; use the 275/40 tire size and you will be OK.
with c4cruser...and you can run a 315 on a 11" wheel in back if you want.
