Front Wheel Size
Thread Starter
Race Director
Joined: Jun 2002
Posts: 12,198
Likes: 15
From: Columbia MD
Front Wheel Size
Hey guys, is there any benefit to upgrading from stock C5 size in the front (17x8.5) to 18s (18x9.5) for street use? If so, why not 18s all around from the factory? I read in "All Corvettes Are Red" that, since the suits at GM wanted the C5 to be the "most slippery production car made" in terms of drag coefficient, that the narrower 17x8.5 had to be used to attain this goal. Thanks.
Le Mans Master
Joined: Aug 2000
Posts: 8,762
Likes: 2
From: Murphy TX
The only performance benefit I can think of by an increase in diameter and no width increase is you MIGHT be able to put a bigger rotor in there. I say might because with the same width the caliper clearance may be an issue.
Other than that, a simple increase in diameter may gain you some steering response because you'll need to run a lower profile tire (hence stiffer sidewall). At the same time that action may harshen your ride a bit.
You may loose a small fraction of braking power due to moving the rotating mass further away from the wheel centerline, but I can't say whether you'd notice or not.
I'd say just going to an 18" in the same width would be primarily for looks.
Just my thoughts.
Other than that, a simple increase in diameter may gain you some steering response because you'll need to run a lower profile tire (hence stiffer sidewall). At the same time that action may harshen your ride a bit.
You may loose a small fraction of braking power due to moving the rotating mass further away from the wheel centerline, but I can't say whether you'd notice or not.
I'd say just going to an 18" in the same width would be primarily for looks.
Just my thoughts.
Melting Slicks
Joined: Nov 2004
Posts: 2,275
Likes: 6
From: Lake Oswego, Near Portland Oregon
Wider 18s up front make sense, actually where I want to get to in due time.....along with wider 18s in the rear. The 18 x 9.5 up front will allow a slightly wider tire in a 35 series, and won't 'upset' the cornering balance. You don't want to run same width front tire as back unless you are also adjusting spring and sway bar rates to match, something any serious racer will do at the drop of a hat, but is beyond the usual mechanical skills and financial needs of the needs of the average C5 driver. In the last half year I ve been here, I have seen postings by several C5 owners that are running 18s F and R. Seems a good mod.
Last edited by FiberglassFan; Apr 16, 2005 at 03:43 AM.
Melting Slicks
Joined: Nov 2004
Posts: 2,275
Likes: 6
From: Lake Oswego, Near Portland Oregon
Wider 18s up front make sense, actually where I want to get to in due time.....but same width, why bother??? They will weigh more and have higher rotating mass, both negatives.
Burning Brakes
Joined: Mar 2000
Posts: 962
Likes: 6
From: Jackson MI
Using 265/35/18 up front and 295/35/18 on the rear keeps the revolutions per mile almost exactly like stock and provide better cornering and traction. This combo is used by many C5 folks and works very well. use 9.5 HRE's up fromty and 10.5 wheels in the back.
