How do I measure for Straight Axle track width?

TRT,

Speedway's kits measure as follows"

44", 52 1/2" hub to hub
46", 54 1/2" hub to hub
48", 56 1/2" hub to hub
50", 58 1/2" hub to hub

See a theme here? Add 8 1/2" to the king pin measurement and you're golden. Hub is the wheel mounting surface.

What I would do is pull the front tires with the lower arms resting on jacks and use a couple yard sticks or levels on the drum face and measure the distance, mounting surface to mounting surface. Find the axle that is the closest match based on what wheels/offset you want to run on the front. I don't think your car is narrower than my '55 Chevy and the 46" was too narrow for mine.

The backing plate is the wrong place to measure. Just like working with wood, measure twice (or more), cut once.

I like the tires to track fairly even with the fronts. It looks better and the tires fit better in the wheel well. Also, the wide-track worked for Pontiac.

Mike

Well I wont make any apologies for buying the Speedway kit. I hear people complaining about Speedway, and I've had nothing but good experiences with them. Many companies build very fine straight axles, and competitively priced too, but the Speedway axle and kit is a fine product, and complete down to the smallest part.
For those of us who don't have the experience or knowledge to put together all the parts needed to complete a straight axle, it's a viable option. I've done 3 other axle cars using 55-59 Chevy truck axles, and they also work excellent, but none of them worked out as well as the Speedway axle in my Austin did. The Speedway axle I bought was surprisingly heavy, and once I cut and narrowed it to fit I found out why. It's 3/8" wall tubing, which is a bit heavier than most, but I'm sure it will hold up for as long as I'm alive and own my car.
Coupebuilder, I'd be interested in what your company provides in the way of complete kits also, as I like options. If you have something similar to the Speedway gasser axle kit, with disc brakes and all the hardware for the $800 price that Speedway sells their's, then please let us know.

Gentlemen, don't get me wrong. I'm not putting down the Speedway kit at all. Its just that almost every car that being built, and every car you see is running a Speedway axle kit. To me it's like going to a all Corvette show, after seeing a few they all look the same. Looking under a car and seeing what axle they chose, how they set up their steering, what they used to mount the axle, basically how they engineered it is what interests me.
But, I realize the bottom line is fittment, drivability, owner/installer skill level, safety, and wallet size are the things that should determine your choice of axle. The Speedway axle is a fine kit, I just feel that people in general don't realize that there are other options or take the time to think a little outside the box.
Sorry for the rant, this is just my .02cents....

I did look at other axles prior to doing the Speedway. None of the donor axles were even remotely close to the width I needed, which was 52" to the outside edge of my tires. My car is so small that I quickly realised I needed to go to an axle that was either custom, or a tube axle that could be safely narrowed.
I then began looking at what could be purchased and would be the exact width I needed without cutting it down. All the makers I spoke to were in the $350-$500 range for a custom width. I then talked with them about the various steering brackets, tie rods, joints, etc. and found that they usually either sent me towards a used source, or a second vendor to buy the rest the spindles, brackets, etc. Often the vendor they sent me towards was Speedway for the rest.
After going through the options, I decided it was easier, cheaper, and less hassle to so to Speedway and get all of the parts as a kit and narrow the axle. I welded two pieces of angle iron on the main tube to retain the kingpin alignment, then cut 6" out of the middle of the tube. After that I got a 12" piece of shaft from a conveyor assembly and pressed it half into each side of the main tube. I left it about .5" apart in the middle and that was welded up to surface and turned down. It added some unsprung weight to the axle, but kept it strong.
Once it was welded up I cut the angle iron off the tube, ground it smooth and installed it under the car with 7 degrees on the king pins. It tracks straight at freeway speeds, and corners well too.

Hey guys, first of all by no means am I putting down the Speedway kit. Some of their parts are very good and some are so-so. I buy a few things from them here and there and the service is good and prices not bad. However, when it comes to the axles I have seen piss poor welding on several and when it comes time to get install help there is no one to guide you. I am no expert in every possible vehicle scenario and I will be the first to tell you that if asked. However I have built hundreds of axles and installed dozens of them in various cars from narrow 33 Willys, to Henry J's to T-birds etc. My axle alone is less expensive than the custom Speedway axles and complete kits priced competitively. I am slightly more on complete kits because I only use top quality parts....USA made forged spindles, USA made caliper brackets, USA made springs (not trailer springs) brand new calipers instead of re-man and a killer forged steering arm setup for top steer that I was one of the very first to develop ten years ago. It all but eliminates bumpsteer in most cases and makes a much better look than a drag link angled down at 30 degrees. I can also design any type of bracket you need and weld it on the axle before the king pin bosses, that way it is a 360 degree weld and won't warp the axle. I am not trying to bash anyones setup, just offer a different option than the big-box type stores that have taken over the country. We all look to save a few bucks when possible, me included. But I pride myself on making parts and cars safe and top quality and when your doing 100mph do you really want to worry about whats under the front end? Take a look at our website and you can see some of the cars and parts we build. www.fasttimesrods.com

Nice website and nice cars you are building there... That T-Bird Gasser is Awesome! You got my attention now, so how much for complete kit minus the calipers & rotors, my dad is in the parts buisness and I can get these parts for cost.... but would need to know for what year, make & model ( rotors & calipers ) bolt to your brackets & spindles and can you give me a parts list what comes in the kit. I am working on a budget so maybe we can work something out. You can PM me or email me at [email protected]
I understand what you are saying about the big box stores cause my dad works for a small parts warehouse selling to mom & pop owned parts stores that actually still use books to look up parts and are more knowledgeable unlike the 16yr. old working at "O'ReillyZone". I rather spend my money in the Mom & Pop type parts stores where the owners use to be involved or still are involved in some sort of car racing or car building, yeah they're a little more expensive but you don't have to put up with idiots. Hope I didn't offend anyone it wasn't my intentions just been burned too many times.