73 Dart front Hub to Hub measurements ??

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moperformance

moperformance

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I have decided to install a Speedway straight axle kit to my 73 Dart.
The Darts front end was/is completely disassembled when I bought it and I don't have an easy way to determine the front hub to hub measurements.
Does anyone have these measurements? I need to know before I order the kit what the stock measurements are.
Thx in advance, I appreciate the help,
Bill
 
From the factory, standard track width
02-04-73d-20p2_zpsfn5ocjuz-jpg.jpg


Track width includes the wheel offset though, so, actual hub to hub is probably more like 60".
 
moperformance said:
I have decided to install a Speedway straight axle kit to my 73 Dart.
The Darts front end was/is completely disassembled when I bought it and I don't have an easy way to determine the front hub to hub measurements.
Does anyone have these measurements? I need to know before I order the kit what the stock measurements are.
Thx in advance, I appreciate the help,
Bill
Click to expand...
on mine, hub to hub factory disc on a 74 dart was 57.5 inches.
 
dukeboy_318 said:
Yes but keep in mind, that is hub face to hub face
Click to expand...

Right. But the track width shouldn't be very different? The offset on the stock rims is only +6mm, tires are centered on the rims, so, the track width should only be about 12mm = .47" different from the hub face to hub face distance. Alignment plays a small role, but given the factory alignment specs it should be negligible. Unless I'm forgetting something that's all that would change from the track width to the hub width, wheel offset (from the centerline of the wheel), the camber angle, and if they did the track width incorrectly the toe. But again, those should all be small differences on a factory car. Call it a 1/2" for the offset, 1/8" for the toe, pretty much nil for the camber on a stock car, so like 60"-ish.

The ride height is probably a bigger difference than any of those, the closer the LCA gets to parallel with the ground the wider the track will be. But that changes the hub to hub too, which is why I asked about the suspension being loaded or not. Lowered cars will have a wider track than a car at factory ride height. I haven't physically measured the hub to hub on my car, but it calculates to about 61", correcting back from the toe plate measurement.

All I'm saying is, I would expect a 73+ disk car to be a lot more like 59" to 60". A hub to hub of 57.5" is less than a SBP brake set up.
 
72bluNblu said:
Right. But the track width shouldn't be very different? The offset on the stock rims is only +6mm, tires are centered on the rims, so, the track width should only be about 12mm = .47" different from the hub face to hub face distance. Alignment plays a small role, but given the factory alignment specs it should be negligible. Unless I'm forgetting something that's all that would change from the track width to the hub width, wheel offset (from the centerline of the wheel), the camber angle, and if they did the track width incorrectly the toe. But again, those should all be small differences on a factory car. Call it a 1/2" for the offset, 1/8" for the toe, pretty much nil for the camber on a stock car, so like 60"-ish.

The ride height is probably a bigger difference than any of those, the closer the LCA gets to parallel with the ground the wider the track will be. But that changes the hub to hub too, which is why I asked about the suspension being loaded or not. Lowered cars will have a wider track than a car at factory ride height. I haven't physically measured the hub to hub on my car, but it calculates to about 61", correcting back from the toe plate measurement.

All I'm saying is, I would expect a 73+ disk car to be a lot more like 59" to 60". A hub to hub of 57.5" is less than a SBP brake set up.
Click to expand...
When I say hub face to hub face, I am NOT including the rotors. Those add about 3/8 of an inch per side. The reason I did not measure with the rotors on is because some rotors are thicker than others so to eliminate that variable, I simply took those out of play.

The 57.5 inch measurement I got was at factory ride height with a slant 6 auto drive train on factory 14inch street rims. I took a measurement from the ground to the lower control arm. Jacked the car up, Remove the rims and tires, took the brakes off and set the lower control arms on stands adjusting until I had the height above ground to that as if the rims were on and took a measurement
 
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dukeboy_318 said:
When I say hub face to hub face, I am NOT including the rotors. Those add about 3/8 of an inch per side. The reason I did not measure with the rotors on is because some rotors are thicker than others so to eliminate that variable, I simply took those out of play.

The 57.5 inch measurement I got was at factory ride height with a slant 6 auto drive train on factory 14inch street rims. I took a measurement from the ground to the lower control arm. Jacked the car up, Remove the rims and tires, took the brakes off and set the lower control arms on stands adjusting until I had the height above ground to that as if the rims were on and took a measurement
Click to expand...

I was almost with you there for a second, but 73+ disks are one piece. No separating the hubs from the rotors. What hubs did you use?
 
72bluNblu said:
I was almost with you there for a second, but 73+ disks are one piece. No separating the hubs from the rotors. What hubs did you use?
Click to expand...

Crap you're right, I was thinking of the mustang 2 spindles and brakes on my Gerst kit. :BangHead:

That said, I'm gonna go back thru my notes and confirm them. My bad
 
dukeboy_318 said:
Crap you're right, I was thinking of the mustang 2 spindles and brakes on my Gerst kit. :BangHead:

That said, I'm gonna go back thru my notes and confirm them. My bad
Click to expand...

Now it makes sense! I was getting confused there for a minute. Like, wait, how did he...?

But for the OP, I think it's safe to say as long as you're between about 57.5" and 61" you'll be fine. :D Close enough to sort it out with the backspace at any rate.
 
For your straight axle install, if you stick with around 58", IMO, most off the shelf wheels will not only work well, but look great. I would imagine, with a straight axle, you have zero concern regarding catching the upper fender lip with the tire.

From memory, at ride height, the pre 72, 9" drum cars are around 59" and the later 73 and up are around 61".

Good luck with the staight axle install. You certainly don't see too many mid-70's cars with them.........maybe that is why you want to do it.
 
I was calculating a similar project for my 72. Speedway's 48" axle with the "Chevy Brake kit" should be 56 1/2" wide hub face to hub face.
 
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