Need An Answer - 1970 Challenger Tire Size Original Specs

[doubleyellow]

My Challenger Convertible came stock with 14" Road Wheels. I was thinking of possibly putting 15" Ralleys on the car when I finally finish it. For some strange reason the original Challenger specs do not allow ordering 15" tires on a Convertible with 440. Do you know why? Thanks

See official spec statement from 1970 below:

1970 Challenger R/T Tyres
Engine Standard Optional Recommended Brand
383/440 F70 X 14 E60 X 15** Goodyear Polyglas GT
426 Hemi E60 X 15 NONE Goodyear Polyglas GT
** N/A convertible w/440 engine. N/A w/trailer towing package

 

[DetMatt1]

Good question.

 

[340challconvert]

Just some thoughts on 15 in tires on convertibles.
My 70 A66 - 340 convertible came from the factory with E-60- 15 in tires on rallye wheels.
In / around December 1969 the factory switched the standard A66 tire to an F-70-14 (standard RT size)
There were issues with even the E-60's rubbing the fenders under oversteer conditions.
The BB 440 is an obviously much heavier weight over the front wheels.
Not sure at what point this occurred, but the factory starting having the front fenders altered for the hemi cars to solve this problem with the 15 in tires.
I don't think they modified fenders on the 440 cars.
Later in the 70 model year, the factory made modified TA fenders for the trans am Challenger and later sold a modified fender used on 1971 models (3579380-81)
The change was basically bending up the lip at the center of the wheel well to increase space from the fender to the tire.
The 440 was not available on 1971 Challenger convertibles.
You may need to modify your fender in using 15" wheels on your Challenger.
There were three different fenders that went on to 70-71 Challengers.

 

[moparleo]

These specs were for the tires available at the time. It said no E60-15 not no 15" If this is for display. No worry, the car is not moving. If you want to drive the car, go with radials, no fit problem and much safer tires. I worked for a major tire dealer in the early-mid seventies. All tires were junk. The tires with the least problems were actually the cheapest, lowest tech tires available. Basic bias ply tires. They just wore out quickly and handled terribly. Belted tires, both fiberglass and steel were just being tried and all brands suffered from belt seperations,. Radials were the worst. Only Michelin, which pioneered radials in the 40's had any success with radials. An E60-15 tire was the smallest 15" 60 series made. and had the lowest load capacity. The same as a small 14" tire.

 

[doubleyellow]

You guys are awesome. Thanks very much for the information.......the fenders on my car are factory replacements due to an accident in the late 70's.....need to figure out p/n my replacements are.....where are the part numbers located (if they even are)? Thanks very much

 

[340challconvert]

You guys are awesome. Thanks very much for the information.......the fenders on my car are factory replacements due to an accident in the late 70's.....need to figure out p/n my replacements are.....where are the part numbers located (if they even are)? Thanks very much

The part numbers would have been stenciled inside the fender, usually above the wheel opening.

 

[doubleyellow]

OK, so no stamped numbers......only ink stenciled (long gone)

Question - it's confusing - is the wheel "opening" the same on the standard and hemi/TA fenders? In other words is there only 1 part number for the wheel lip chrome molding? is just the inner fender opening lip turned up to make the hemi/TA fender (to prevent the tire from hitting the inner fender lip)?

 

[340challconvert]

OK, so no stamped numbers......only ink stenciled (long gone)

Question - it's confusing - is the wheel "opening" the same on the standard and hemi/TA fenders? In other words is there only 1 part number for the wheel lip chrome molding? is just the inner fender opening lip turned up to make the hemi/TA fender (to prevent the tire from hitting the inner fender lip)?

My understanding is that the lip was turned up, and the wheel molding width then needed to be trimmed in that area in order to fit. I think all Challenger wheel molding was the same.
Interesting point: 70 A66 340 Challengers had the molding deleted as part of the package (early A66 cars came standard with the 15x7 wheels) Molding was also deleted on the Trans Am cars.

 

[340challconvert]

I am fortunate to have put away a pair of NOS fenders I bought around 1980.(624 & 625)
The right side fender had a little handling damage on the top/ front but who would argue on grabbing them at the time they went NS1
If I get a chance, I will take a photo of the wheel well lip at the apex of the NOS fender and the original that is on the car.
Here's a pic of the stenciled part number and the part number sticker.

 

[doubleyellow]

Very cool.

 

[moparlee]

I am fortunate to have put away a pair of NOS fenders I bought around 1980.(624 & 625)
The right side fender had a little handling damage on the top/ front but who would argue on grabbing them at the time they went NS1
If I get a chance, I will take a photo of the wheel well lip at the apex of the NOS fender and the original that is on the car.
Here's a pic of the stenciled part number and the part number sticker.

Good thinking on your part back in 1980. I am sure that most of us wished we had done the same thing back in the day.

 

[340challconvert]

Interesting pictures of the 625 fender compared to a regular 71 Challenger fender.
Shows an external bulge over the wheel well on the "TA" 625 fender vs a regular RT fender.
Interesting visual comparison.

Notes from the original author:
Left pic fender w bulge above wheel
Rt pic no bulge above wheel
My friend already had his T/A in 1980 when I bought my R/T. Parked side by side, looking down the line from the rear bumper, I could see the bulge on the front fenders on both driver and passenger side. You have to have a regular fendered car next to a T/A to see it. On my replacement fender, I see the same bulge that I saw 28 years ago. My original passenger fender doesn't have it. If you have original fenders on your T/A, you should see the difference when parked next to a standard one. My part number is 3579625

This picture shows the bulge on the gunmetal challenger's side by side next to my original R/T non-bulge fender. His fender was a replacement T/A fender, with the cutout. His driver's side is original and doesn't have the bulge or the cutout.

Author's Notes continued:
My 71 challenger convertible was wrecked on the driver's side left front, a long time ago, before I got it. Someone replaced the driver's fender, then is sat never to be finished, changing hands several times. The fender still has the part number on the inside. 3579625

It was put on the car and sprayed behind the headlight buckets. It was never painted besides a light coat of primer, so it has very light surface rust and a little rust on the inside by the buckets. It is a T-A replacement fender that has the special outward curve on the body line for the bigger tires. You can only see it if you eyeball down a T-A fender and eyeball a regular fender. T/A owners know of this bulge. I'm not talking about a rolled fender lip. It has the cutout in front, shown in the picture below.
__________________________________________________________________
I never made the actual comparison of the 624-625 fenders that I have with the original A 66 fenders that came w factory 15" wheels on the car.
If there is a bulge, it certainly would provide additional tire clearance!