Wheels / Tires: How big?

[Hawklover]

Question for Avanti owners:

The size 205X75X15 is usually utilized for Avantis................but, can a 215X70X15 be subbed?.............and not break the front fender on sharp turns?

[RadioRoy]

The 70 and the 75 part is the aspect ratio, or the ratio of the height to the width (or vice versa) of the tire. The second size you mention is wider than the first size because of two factors - a wider aspect ratio (70 vs 75) plus a larger tire size (215 vs 205).

Sticking with the first size would be my choice, but if you want to go bigger, then a 215X75X 15 is what I would go for. Not a 70.

Disclamer. I do not have an Avanti, so I have no direct experience with these sizes on that car. I do use 215 and 205 on Larks and 54-56-51 cars, but all with 75 aspect ratios.

[Skybolt]

If you take a look at this web page http://www.1010tires.com/tiresizecal...?action=submit and scroll down and enter the security code you can see that the 215 tire is slightly smaller in diameter to the 205. This might make up for the extra width and bring the tire closer or the same distance from the fender. Only an Avanti owner who has the same wheels and the make and size of tires you want to use can tell you the results. I have used different brands of tires with the same dimensions and had different results. Len.

[Dick Steinkamp]

The 70 and the 75 part is the aspect ratio, or the ratio of the height to the width (or vice versa) of the tire. The second size you mention is wider than the first size because of two factors - a wider aspect ratio (70 vs 75) plus a larger tire size (215 vs 205).

Sticking with the first size would be my choice, but if you want to go bigger, then a 215X75X 15 is what I would go for. Not a 70.

Disclamer. I do not have an Avanti, so I have no direct experience with these sizes on that car. I do use 215 and 205 on Larks and 54-56-51 cars, but all with 75 aspect ratios.

Not exactly...

The number (215 or 205) is the width of the tire in millimeters. A 215 is a wider tire than a 205 regardless of the aspect ratio.

The aspect ratio (70 or 75) is the height of the sidewall as a percent of the width. The sidewall height on a 215 70 15 is 215 X .70 or 150.5 mm. The sidewall height on a 205 75 15 is 205 X .75 or 153.75 mm.

Since a 215 70 15 is a shorter tire than a 205 75 15, I would think it would not hit the fender. It is a poor choice, however, for a stock 5" wheel. A 205 75 15 is marginal on a 5' wheel. A 215 70 15 is REALLY pushing it on this narrow of a wheel.

To use a 215 70 15 you should go to a 6" wide wheel, but then you have to closely dial in the offset (backspacing) in order for the tire to clear the fender AND the tie rod ends.

[Skybolt]

Dick? Is that last post for me? Or are you wanting me to jump in?

[Hawklover]

Forgot to mention, the car is using MoPar Cordoba wheels from 1977.

Not exactly...

The number (215 or 205) is the width of the tire in millimeters. A 215 is a wider tire than a 205 regardless of the aspect ratio.

The aspect ratio (70 or 75) is the height of the sidewall as a percent of the width. The sidewall height on a 215 70 15 is 215 X .70 or 150.5 mm. The sidewall height on a 205 75 15 is 205 X .75 or 153.75 mm.

Since a 215 70 15 is a shorter tire than a 205 75 15, I would think it would not hit the fender. It is a poor choice, however, for a stock 5" wheel. A 205 75 15 is marginal on a 5' wheel. A 215 70 15 is REALLY pushing it on this narrow of a wheel.

To use a 215 70 15 you should go to a 6" wide wheel, but then you have to closely dial in the offset (backspacing) in order for the tire to clear the fender AND the tie rod ends.

Skybolt

[Dick Steinkamp]

Dick? Is that last post for me? Or are you wanting me to jump in?

Wow...I don't know how that happened. I didn't type your handle there...it just appeared. Sorry about that. I've edited it out.

[Bob Langer]

I have 215x70's on 15x6 Weld wheels and have no problems.

[Gunslinger]

I have P215/70R15's on 15"x6" Magnum 500's with no problem at all.

[plwindish]

I have P215/70R15's on 15"x6" Dayton Wires with no problems.

[53k]

Question for Avanti owners:

The size 205X75X15 is usually utilized for Avantis................but, can a 215X70X15 be subbed?.............and not break the front fender on sharp turns?

I have always maintained that a 205x75x15 is not the correct tire for any car that originally came with 6.70x15s. A 205x75 is enough lower profile that you experience quite a bit of speedometer/odometer error. Assuming use of six-inch rims, 205x75x15 is a good replacement for 6.40/6.50x15 tires. I run 215x75x15s on my Daytona Wagonaire and my '64 Avanti. I have no clearance problems on the Avanti. I just put a set of 215x70s on seven-inch rims on my '84 Avanti with no clearance problems (but that's a different animal). A few years back I ran 225x75x15s on a '64 Avanti. I could make the tires rub the fender on a tight turn when hitting a bump, but the car sat too low in front. A set of 1/2-inch spacers for the front springs solved that.
Randy Nesselrodt, owner of Big L Tire in Harrisonburg, VA and long-time Avanti owner also puts 205x70x15s on his Avantis, both Studebaker and post-Studebaker. He just prefers the look of the 70 width and likes the lower profile. Personally I think the larger tire fills the wheel opening better and looks more like it is the way the car was intended to look.
In this picture I have placed, from the left, a NOS 6.70x15 bias ply tire, a 215x75x15 radial, a 205x75x15 radial and a 195x75x15 radial. While there is no harm in using the 205, it is is not the same diameter/circumference at the 6.70. Using 215s puts my speedometer very close to right on GPS or mile marker speed and distance.

[SN-60]

I run 215X70X15 Snows on the rear of My '83 (winter driving) with no clearance issues (on 6" mopar wheels)

[mapman]

I have 215X70X15 Whitewall radials on stock avanti rims on my '63 Avanti. All arguments aside I have had no clearance or any other problems with them and they look great. My car has had limited use and I have never checked the speedometer error.
Rob

[Colgate Studebaker]

As stated above, to keep the speedometer as close to correct as possible, the tire O.D. should be kept as close to the original spec as possible. The width (75, or 70) will be marginal in its clearances. Trying to use something like a 235R60 or larger/wider is where things wouldn't fit. Like most of the guys that have posted, using 6' wheels with the 70's is not a problem for fit, but are their speedo's accurate? Just my 2 cents worth. B.V.

[WCP]

Tires from different manufacturers for a given size specification don't necessarily have the same revs/mile rating. You need to look at the vendor charts listing revs/mile for accurate comparisons. It's best to select the tire you like and then adjust your speedo drive pinion to correct speedometer readings to match a GPS at 60mph. It's simple enough to do.