1974 corvette tire sizes
Racer
Joined: Feb 2010
Posts: 362
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From: nashville tn
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Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
you can go up to 245/60/15 this will fit most C3 applications, without fitment issues front and rear,
sizes larger than this, many variables come into play. all this assumes original offset wheels.
sizes larger than this, many variables come into play. all this assumes original offset wheels.
Last edited by 69Vett; May 29, 2016 at 10:25 PM.
Le Mans Master
Joined: May 2007
Posts: 5,007
Likes: 1,114
From: North tonawanda NY
same here on my 74 but changing to 255/45/18 soon
keep in mind bigger tires can have a noticable sluggish effect on the gear ratios... These cars already suffer in this department and larger diameter tires make it worse.
When I increased the tire size in my jeep and truck it was quite a dramatic effect as far as power loss. going from 28.x sized tires to 35" for example required going from 3.38 to 4.56 gears in the rear end just to bring the final gear ratio back to stock and be able to use the overdrive and have the speedo work correctly with the stock gear..... on my jeep I had to switch to 4.56 gears to have the correct ratio with 32" tires and use 5th gear and original speedo gear.
just a couple inches diameter difference is like putting the next size numerical gears in the rear end. A lot of people dont understand this... Truck forum is full of kids with big wheels on thier trucks complaining they drive like dogs and cant get out of their own way.
keep in mind bigger tires can have a noticable sluggish effect on the gear ratios... These cars already suffer in this department and larger diameter tires make it worse.
When I increased the tire size in my jeep and truck it was quite a dramatic effect as far as power loss. going from 28.x sized tires to 35" for example required going from 3.38 to 4.56 gears in the rear end just to bring the final gear ratio back to stock and be able to use the overdrive and have the speedo work correctly with the stock gear..... on my jeep I had to switch to 4.56 gears to have the correct ratio with 32" tires and use 5th gear and original speedo gear.
just a couple inches diameter difference is like putting the next size numerical gears in the rear end. A lot of people dont understand this... Truck forum is full of kids with big wheels on thier trucks complaining they drive like dogs and cant get out of their own way.
Last edited by augiedoggy; May 31, 2016 at 02:07 PM.
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,028
From: eastern NC
255/60R15 was the optional size starting in 1978 and is the same diameter as the standard tire, 225/70R15.
Good luck... GUSTO
