How is track width measured?

[JamesMayberryIII]

wheel mounting flange to mounting flange of the axle or bearing hub..
without the drum or rotor mounted...(rear) front without rotor if slip on rotor, if rotor/hub is one, the wheel mounting flange of the rotor/hub
this is why cars like the late 80's Pontiac t/a have the same spec no matter if it has rear disc brakes or drums..

[Loren]

There's a lot a great internet information on this one... Track width on any chart I've ever seen refers to how far the tire treads that touch the road surface are apart on a given axle, measured center-to-center. It's just a basic car spec for comparison and doesn't "care" anything about wheel offsets, axle width (what you get when you measure flange-to-flange) or whatever else, thus is generally useless for anything other than guessing when it comes to swapping axles around because of the variety of wheel offsets and widths that might be used. If you were intending on using some axle with it's original wheels and tires on it to replace some other original set also with it's original rolling stock, you could use published track widths and add (or subtract) the original tire widths to each, to compare resultant overall widths to judge if the whole bit would fit between outside fender lips or, clear inner fenders etc. Or for another example, if the published rear track width on the 'Vette was 60.4" and you knew the tire width at the sidewalls was 10" you could imagine prior to doing any other actual measuring you'd not be crazy by thinking the whole set might work on an old pickup with a 49" box width 'cause theoretically you'd have 50.4" inside.

Be aware that if you're using '84-up Corvette suspension on anything else, you gotta stay near the original negative offsets wheel-wise, for example you could not use positive-offset wheels for an '82-down or the suspension is going to be all out of whack.

(BTW The unrelated next-most common mistake people make in swapping C4 suspensions into things is on the other end, not realizing that they are made for a car with lots of engine setback and the steering rack goes right thru where the front of the motor would be on most other chassis. Remember the ultra-cool engine setback into the firewall on Lil' Johns C4-into-early Nova in the '80s, with the resultant big awkward box under the dash that your feet had to go around, it was not so much from trying to get trick with weight balance, rather 'cause of that steering rack being where it was. I have seen a couple of well-intentioned C4-front swaps go dead when the builder hit that point and figured that out.)

All that said, C4 suspensions were really great, and are still used in favor of newer ones because of being relatively narrow. The rear set can be narrowed even further, aluminum axles cut-and-shorten just like driveshafts. Late-C3 Dana 44 centers can be worked in there too if you're willing to do some fab.

[Dan Barlow]

One of the iseas it have that theoretically would work is stuffing it all in a mini cooper . First point being that there isn't any suspension bits that are behind the rear tires. Its a wide small car but , that engine set back is going to have the back of the heads coming to about the mirrors. I guess i could drive it from the back seat ........ . Good point on the negative offset wheels . I was figuring it would throw off the scrub radius. At this point the car I'd most like to do is a 66 impala . My brother in law has a 66 caprice with a 327 powerglide that he is keeping absolutely stock except for wheels and tires I'd like to do the opposite. But , what once would have been a 1000 dollar body is now 5000 . I love vettes but the problem is another couple can't ride with you to go on a day of driving and chatting and hitting a restaurant. He also is heavy into the 67-72 Chevy Truck and would really like to get me into one All I really need beyond stuff he has lots of duplicates of is a glove box and title . Yeah the only place the vin was is a sticker on the glove box . But again , no back seat . I'll keep mybtape measure out as I keep looking at alternative bodies.