[bgoggans]

I found a blackwall tire source for a reasonable price per tire (ie $74) and I wonder if it will be too big. The size is 205/60r13.

I know that 195/75r13 and 185/80r13 are acceptable, but is a 205/60r13 too big for the rim and/or fender well?

 

[Bearhawke]

You may be better off locating a set of small bolt pattern 14" wheels from a 1976 or older Dart/Valiant with front drum brakes; they'll bolt right up to your car using original lug nuts but will allow you to run much easier to find 14" tiles like P195/75R14 or similar.

 

[bgoggans]

Most of the local junkyards have long ago scrapped their inventory of older cars - especially due to the high demand for steel and the current going rate of $16 per 100 lbs. I do plan on trying at some point, but it is not a high priority right now. In fact, my uncle is going around and finding junk cars in peoples yards, and immediately hauling them off to the scrapyard for quick cash! Generally these cars are not good candidates for restoring, but I bet some are.

So really, are the 205/60R13 tires too big for my rims/fender wells?

This weekend, at a new local junkyard, I found several 175/70R13 tires that appear to have some life to them. Is that an acceptable size? These would be better then the dry rotted tires/snow tires I currently have (for the short term) that do nothing but hold air so I can move the car around.

Finally the new junkyard I mentioned has 1 and only 1 1976 Plymouth Valiant 4 Dr sedan with either a 318 or 273 - automatic. I don't know for sure (I don't know how to tell visually, and I could not find the VIN plate - don't know where it is on a 1976 car). Besides the rims, is there anything I can use from that car on mine? The brake MC on that car is broken, and I have no idea if the power brake booster would be useful or not - would it fit? It does have 4 way drums, but again, no rims. Would the proportion valves be good to get since it already has the two chamber MC?

 

[Bearhawke]

That 1976 Valiant with 4 wheel drum brakes was a 225 Slant Six car; all 1973 up V8 Mopars of any size were disc brake equipped. Needless to say: the rims on that Val would fit have your 1966 Dart. Note you can used the prop valve and master cylinder although you'd be better off buying a new MC.

 

[jglen490]

Going back to the tire size issue, those 205/60-13's are way too small in diameter. You'll throw the speedo way off.

Refer to something like http://www.miata.net/garage/tirecalc.html for an easy tire size comparison tool. Going to 14'' wheels will work very well and 195/70-14 would be an almost equal replacement for a 195/75-13.

 

[bgoggans]

[at]Normal - thanks. I needed that information. I wanted to stay with original size rims/tires, but that was when I was considering keeping the car as close to factory original as possible. I have since decided that I really don't care about that anymore. I want this car to be my daily driver, so I have decided that I am going to do whatever I like to the car.

[at]Bearhawke - you are correct, the 1976 Valiant I found had front disk/rear drum brakes so I did not get anything off that car including the prop valve. It does have a 273 or 318 V8 because it is too small to be a 340. I was not going to use broken MC on the car (I already have a new 2 chamber one). I was only thinking about taking the booster off and sending it in to be refurb'd and then using it, and only if it would fit, but after the conversation I had with a gentleman about a month ago, I decided against it.

 

[Bearhawke]

[at]Normal - thanks. I needed that information. I wanted to stay with original size rims/tires, but that was when I was considering keeping the car as close to factory original as possible. I have since decided that I really don't care about that anymore. I want this car to be my daily driver, so I have decided that I am going to do whatever I like to the car.

[at]Bearhawke - you are correct, the 1976 Valiant I found had front disk/rear drum brakes so I did not get anything off that car including the prop valve. It does have a 273 or 318 V8 because it is too small to be a 340. I was not going to use broken MC on the car (I already have a new 2 chamber one). I was only thinking about taking the booster off and sending it in to be refurb'd and then using it, and only if it would fit, but after the conversation I had with a gentleman about a month ago, I decided against it.

Side note here: the last year of the 273 was 1969, 340 1973 and both of those two V8's have the same external dimensions as a 1967+ 318 or 360.

If that 1976 Valiant had the whole front brake system/rear end: you may be wise in snagging everything (spindles/upper control arms/rear end) and convert your 1966 Dart to discs complete with the much more common 5 on 4.5" bolt pattern wheels.

 

[bgoggans]

Side note here: the last year of the 273 was 1969, 340 1973 and both of those two V8's have the same external dimensions as a 1967+ 318 or 360.

If that 1976 Valiant had the whole front brake system/rear end: you may be wise in snagging everything (spindles/upper control arms/rear end) and convert your 1966 Dart to discs complete with the much more common 5 on 4.5" bolt pattern wheels.

You and I are on the same page here. I was thinking the same thing myself. I know the rear end is there (would it be the 8.75"? my guess is yes since you say the motor is probably the 360). I know the driver side disk brake setup is there. The drive shaft is gone, (would I need that anyway?). So if I got basically the front end and rear end parts, they bolt right on?

 

[valiant67]

1976 Valiant would not have an 8.75" axle. By then the 8.25" axle was the top one for the A body, the 7.25" still around as well. The 8.25" isn't as tough as the 8.75" but pretty good. But even a V8 might have a 7.25" axle, especially if it's a 318 (more likely than a 360).

If it were mine I'd do the following:
Grab all the brake parts suggested, only grab the rear stuff if it's larger than what you have. If it's the same size, just grab the drums. Then get some C body axles cut down for your 8.75" axle. I believe there were no A body large bolt 8.75" axles unless they used them in the Hemi cars. The new axles wouldn't be cheap but it would be nice. Or you could probably buy all the junkyard parts and made decent money selling of the small bolt 8.75" axle.

 

[bgoggans]

1976 Valiant would not have an 8.75" axle. By then the 8.25" axle was the top one for the A body, the 7.25" still around as well. The 8.25" isn't as tough as the 8.75" but pretty good. But even a V8 might have a 7.25" axle, especially if it's a 318 (more likely than a 360). If it were mine I'd do the following: Grab all the brake parts suggested, only grab the rear stuff if it's larger than what you have. If it's the same size, just grab the drums. Then get some C body axles cut down for your 8.75" axle. I believe there were no A body large bolt 8.75" axles unless they used them in the Hemi cars. The new axles wouldn't be cheap but it would be nice. Or you could probably buy all the junkyard parts and made decent money selling of the small bolt 8.75" axle.

My 1966 Valiant has the 7.25 and if this one has the 8.25, it would be way better (from what I read). I think I will swing by the JY tomorrow and see what is there and what it really is.

 

[dana44]

According to the calculations, the 175mm tire is 6.9 inches wide, the 205 is 8.0 inches wide. the next cool calculation is the sidewall height of the tires, being a 60 series tire and a 70 series tire, sidewall height is one millimeter difference, 122mm(60 series) to 123mm (70 series). You have to have some kind of deal if you are looking at changing the profile and all that, but at one inch on a 13 inch tire, I don't think that would be a good idea. Half inch, OK, a little over one inch, probably not a good idea for safety sake. If you were doing straight line stuff, OK, not cornering, too much roll, so not safe, sorry.

 

[valiant67]

My 1966 Valiant has the 7.25 and if this one has the 8.25, it would be way better (from what I read). I think I will swing by the JY tomorrow and see what is there and what it really is.

Definitely an improvement. I assumed yours would have had the 8.75" since it was a 273 car I thought. But yeah, many V8 cars were stuck with the 7.25".

 

[bgoggans]

According to the calculations, the 175mm tire is 6.9 inches wide, the 205 is 8.0 inches wide. the next cool calculation is the sidewall height of the tires, being a 60 series tire and a 70 series tire, sidewall height is one millimeter difference, 122mm(60 series) to 123mm (70 series). You have to have some kind of deal if you are looking at changing the profile and all that, but at one inch on a 13 inch tire, I don't think that would be a good idea. Half inch, OK, a little over one inch, probably not a good idea for safety sake. If you were doing straight line stuff, OK, not cornering, too much roll, so not safe, sorry.

OK, I am thoroughly confused now. I thought the real problem was with the tire height throwing off the speedo, but if you say the difference is only 1mm, then that is not enough to worry about. However, your statement is that the tire being 1 inch too wide is the real problem due to cornering/manuvering. Why? I thought that having more tread on the pavement is better then less. I mean, look at tires from early cars vs. today. Even 10 years ago, you would not put a tire on a car the size of my Neon or my Suzuki that is on it now. Both come in at 65 and 55 respectively. Both corner like they are on rails.

 

[dana44]

OK, I am thoroughly confused now. I thought the real problem was with the tire height throwing off the speedo, but if you say the difference is only 1mm, then that is not enough to worry about. However, your statement is that the tire being 1 inch too wide is the real problem due to cornering/manuvering. Why? I thought that having more tread on the pavement is better then less. I mean, look at tires from early cars vs. today. Even 10 years ago, you would not put a tire on a car the size of my Neon or my Suzuki that is on it now. Both come in at 65 and 55 respectively. Both corner like they are on rails.

The two tire sizes, broken down is 175/70/13, which means the surface of the tread is 6.9 inches (rounded a tad bit), and the sidewall is 70 percent of that 175 which is 122mm tall from the bead to the tread. The 205/60/13 has a tread width of 8.07inches, and the sidewall is 60 percent of the 205 which is 123mm tall, and the tread width being more than an inch wider at the bead, unless your rims are 7.0 inches wide, which I really doubt they are, the tread width to the bead width is like an over-inflated balloon and standard pressure will make the tire balloon and actually ride on the center of the tread, with a wider tread width to the bead width. Being how small the bead diameter is, being 13 inches, if the rim is (most likely) 5 inches, or even 6 inches, the tread being half an inch wider than the rim is one thing (about the limit), but you most likely are looking at the tread being more than 2 inches wider than the bead. That is too wide to safely drive around, a corner too hard could blow the bead on the rim and that would be catastrophic to say the least. Now, if you had rims that were 7.0 inches wide, then we would be safe, but guaranteed stock 13 inch rims aren't that wide.

Does this help with the geometry?

 

[valiant67]

13" rims were only 4.5" wide, they are designed for a taller sidewall and a narrower tread compared to the modern tire profiles.

 

[bgoggans]

Yes, that helps tremendously and makes it crystal clear - thanks!

So upon some in depth reading, I found out that the original tire size of 700-13 (or 7.00x13) refers to the width of the tire 7.0" (~178mm) and the aspect of tires at the time were approx 80% of width leaving us with ~ 5.6" (~142mm).

Which is roughly a 180/80R-13 tire by today's coding. Not a size I can find.....

Replacement tire sizes I have already been told are acceptable:

185/80R-13 - 185mm (7.28") width and 148mm (5.83") aspect (slightly wider and taller - speedo reads faster)
185/75R-13 - 185mm (7.28") width and 139mm (5.46") aspect (slightly wider but shorter - speedo reads slower)

What about these sizes?

175/80R-13 - 175mm (6.89") width and 140mm (5.50") aspect (slightly narrower and shorter - speedo reads slower)
195/75R-13 - 195mm (7.60") width and 146mm (5.75") aspect (wider and taller - speedo reads faster)
195/70R-13 - 195mm (7.60") width and 137mm (5.40") aspect (wider and shorter - speedo reads slower).

By my calculations, a 175/80R13 tire is very very close and while the speedo may be off a little on the slow side, I found WW tires for $50 apiece. If these tires are acceptable, I will get them for now and put off switching over until a future date.

Milestar MS75 Tires


SIZE: P175/80R13
PART: 24700001
SIDEWALL: WW
SPEEDRATING:
LOADRANGE:
UTQG: 440 A
PRICE: $49.75

 

[dana44]

175/R80-13 would be the best, even though it is a tall sidewall, it should be stiff enough to give decent handling, and based on the rim size to the footprint, a taller sidewall would be safer to keep the footprint on the ground. You won't be doing any autocross on concrete, but then again, she didn't stock, either.

 

[abgwin]

My '66 Barracuda came with 175 70 R13s on it, so they do fit the wheels and the wells without issue. Unfortunately, replacements in that size are becoming hard to find on the cheap.

 

[Dave Z]

You know, what worries me about "cheap tire" discussions is the fact that you're taking a car with already poor brakes (by today's standards) and adding in lousy tires. You might find that in the long run you're spending a lot more on a cheap tire, when you throw in the accident that leaves you in your hospital and your car in the crusher. Just sayin'. Sometimes you save more by spending more.

 

[abgwin]

For what it's worth, I just picked up 4 Nankang CX 668 175 70 R13s for $250 out the door. Tire chain called Evans Tires in southern California.

So there are still some to be had out there.