C-1 large rear tires
02-24-2011, 10:20 PM
#1
Burning Brakes
Thread Starter
C-1 large rear tires
I recently installed large 235R60x15 tires on the rear of my 61. This seems to be a routine question. Although there are several posts, they are not complete in one place. So to thank all that have posted in past and help all in future, I have attempted to have pics and maximum example.
I got the help of Bill (wmf62), the master all things C-1, to have a starting reference.
I used 235 Goodrich T/A tires because my GTO buddy had a pair that would not fit his GTO front end, I would have tried 225 otherwise.
1.Bought Summit rally wheels 15x7 5-4.75 with 4 inch backspace (5-4.75 is the bolt pattern spacing). Must be 4 inch backspacing, not 4.25
2.I did weld 4 small nubs on the wheels to hold my original full face hubcaps. Made a small wooden gauge pattern (from the old wheels) to position the nub welds the correct depth.
RESULTS:
1.The 235R60x15 with the 15x7 wheels with 4 inch backspace do fit with just adequate inside clearance 3/8" from rear leaf spring and 1/2"+ on wheel well face.
2.The rally wheels will accept the original hubcaps but are tight. Must have the numbs to hold the hubcaps on.
3.A 245 tire would be too wide
4.A R70 or 75 tire would be too tall/profile and be more likely to rub the outer fender.
Joe
I got the help of Bill (wmf62), the master all things C-1, to have a starting reference.
I used 235 Goodrich T/A tires because my GTO buddy had a pair that would not fit his GTO front end, I would have tried 225 otherwise.
1.Bought Summit rally wheels 15x7 5-4.75 with 4 inch backspace (5-4.75 is the bolt pattern spacing). Must be 4 inch backspacing, not 4.25
2.I did weld 4 small nubs on the wheels to hold my original full face hubcaps. Made a small wooden gauge pattern (from the old wheels) to position the nub welds the correct depth.
RESULTS:
1.The 235R60x15 with the 15x7 wheels with 4 inch backspace do fit with just adequate inside clearance 3/8" from rear leaf spring and 1/2"+ on wheel well face.
2.The rally wheels will accept the original hubcaps but are tight. Must have the numbs to hold the hubcaps on.
3.A 245 tire would be too wide
4.A R70 or 75 tire would be too tall/profile and be more likely to rub the outer fender.
Joe
Last edited by devildog; 02-25-2011 at 06:02 PM.
02-25-2011, 12:16 PM
#2
Le Mans Master
Joe, would you happen to have a pic looking down the side of the car that might show how 'snug' those 235's are to the wheelwell lips?
On some of those previous threads, I posted that my '61 is in need of some narrower tires because I'm tired of the super stiff ride with the air shocks (to keep the tires from contacting the wheelwell lips) along with 5 leaf springs and Traction Masters and want to yank out the air shocks. Here's that pic of my '61 showing too much tire pooching out under the lip.
My problem is caused by two things, 7-inch wheels with a shallow 3 5/16 backspacing and 255-60x15's. It looks like your new combination of 235's which has about 1/4-inch less section width (per side) and almost 3/4 inch more backspacing over my Centerlines, has worked for you. Does that 3/8-inch clearance you mention to the fender face seem like it will clear or is it one of those 'cross your fingers' things when you hit a bump?
Mike T.
On some of those previous threads, I posted that my '61 is in need of some narrower tires because I'm tired of the super stiff ride with the air shocks (to keep the tires from contacting the wheelwell lips) along with 5 leaf springs and Traction Masters and want to yank out the air shocks. Here's that pic of my '61 showing too much tire pooching out under the lip.
My problem is caused by two things, 7-inch wheels with a shallow 3 5/16 backspacing and 255-60x15's. It looks like your new combination of 235's which has about 1/4-inch less section width (per side) and almost 3/4 inch more backspacing over my Centerlines, has worked for you. Does that 3/8-inch clearance you mention to the fender face seem like it will clear or is it one of those 'cross your fingers' things when you hit a bump?
Mike T.
02-25-2011, 04:57 PM
#3
Burning Brakes
Thread Starter
Mike, I have more than 3/8 clearance on the wheel well face. The 3/8 was space at the springs.
My suspension is stock, because I too like to have a normal ride for the highway and anound town.
It is not overly obvious that I have 235R60 rear vs 205R75 on front
I have a full tool box, extra parts, gallon of water, hydraulic jack, helmet, and more junk weighting down the rear, but adequate top and side clearance to tire.
Joe
My suspension is stock, because I too like to have a normal ride for the highway and anound town.
It is not overly obvious that I have 235R60 rear vs 205R75 on front
I have a full tool box, extra parts, gallon of water, hydraulic jack, helmet, and more junk weighting down the rear, but adequate top and side clearance to tire.
Joe
Joe, would you happen to have a pic looking down the side of the car that might show how 'snug' those 235's are to the wheelwell lips?
On some of those previous threads, I posted that my '61 is in need of some narrower tires because I'm tired of the super stiff ride with the air shocks (to keep the tires from contacting the wheelwell lips) along with 5 leaf springs and Traction Masters and want to yank out the air shocks. Here's that pic of my '61 showing too much tire pooching out under the lip.
My problem is caused by two things, 7-inch wheels with a shallow 3 5/16 backspacing and 255-60x15's. It looks like your new combination of 235's which has about 1/4-inch less section width (per side) and almost 3/4 inch more backspacing over my Centerlines, has worked for you. Does that 3/8-inch clearance you mention to the fender face seem like it will clear or is it one of those 'cross your fingers' things when you hit a bump?
Mike T.
On some of those previous threads, I posted that my '61 is in need of some narrower tires because I'm tired of the super stiff ride with the air shocks (to keep the tires from contacting the wheelwell lips) along with 5 leaf springs and Traction Masters and want to yank out the air shocks. Here's that pic of my '61 showing too much tire pooching out under the lip.
My problem is caused by two things, 7-inch wheels with a shallow 3 5/16 backspacing and 255-60x15's. It looks like your new combination of 235's which has about 1/4-inch less section width (per side) and almost 3/4 inch more backspacing over my Centerlines, has worked for you. Does that 3/8-inch clearance you mention to the fender face seem like it will clear or is it one of those 'cross your fingers' things when you hit a bump?
Mike T.
Last edited by devildog; 02-25-2011 at 06:06 PM.
02-26-2011, 07:07 PM
#6
12.14 w/ the original 327
Good job Joe. The new wheels and tires look great.
I've been kickin around the idea of a cam swap, and possibly a ported factory intake prior to our next meeting. Now, I'm starting to think I may need to do a wheel swap as well...
I've been kickin around the idea of a cam swap, and possibly a ported factory intake prior to our next meeting. Now, I'm starting to think I may need to do a wheel swap as well...
02-26-2011, 11:20 PM
#7
Race Director
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Looks great Joe. We're going to need to add some spring clamps etc to keep the wheelhop down with 500+HP hammering those new hides!
BTW everyone...does that LOOK like it has a 500 hp motor in it???? Gotta be fun to watch the C5-C6 guys' faces at a 50 mph stomp!
JIM
BTW everyone...does that LOOK like it has a 500 hp motor in it???? Gotta be fun to watch the C5-C6 guys' faces at a 50 mph stomp!
JIM
02-26-2011, 11:55 PM
#8
Burning Brakes
Thread Starter
No wheel hop with these tires. I can still easily 'chirp' them when shifting gears, but seems to be more of a smoother grip.
The smaller diameter of the R60 also gives me 100-200 rpms which helps to keep the cam in range during the 35-45 mph street driving and less surging when at 65-70 in 5th gear.
The smaller diameter of the R60 also gives me 100-200 rpms which helps to keep the cam in range during the 35-45 mph street driving and less surging when at 65-70 in 5th gear.
02-27-2011, 12:24 PM
#9
Race Director
You will find that 3/8" spring to tires wills may cause sidewall rubbing of the tires on the springs going around corners. it doesn't seem to be a problem, but I always noticed the side wall was rubbed a bit when I had wider tires on my car.
Doug
Doug
02-27-2011, 07:13 PM
#10
Burning Brakes
Thread Starter
Joe
