BG writes:
Hi Sajeev! I am a big fan of TTAC and visit it almost every day. I have a question for you, so here it is:
We’ve heard so much about the goodness of wide wheel tracks, where the wheels are pushed to its corner. And the benefit of this seem natural and easy to comprehend for me, better handling, better looks, perhaps even better interior room if the wheel wells can be made less deep. It’s the other end of the spectrum, the narrow wheel tracks, that I can’t understand. What could possibly be the benefit of having a narrow wheel tracks? For some reason it used to be so popular, nearly all cars featured them. Even after the wide tracks was popularized by Pontiac in the 1960s, most cars still came with wheels that are placed well inside its openings. The only reason for them I can think of to justify that is if you want to use wheel skirts or low, “barely there” wheel openings, the Bathtub Nash being a good example. But most of these cars with narrow tracks have full wheel openings, at least in front. Why the narrow tracks then, I wonder?
Sajeev Answers:
My answer for this theoretical “Narrow versus Wide Track” debate takes the path not taken: offroading on difficult trails. The newer Jeep guys (and gals) normally have wider track axles, but they tend to fare less well in certain competitions compared to older Jeeps with narrow axles. After all, what’s so great about a wide track if you have to make a three point turn to stay on the trail? Or have to slow down and lose a ton of momentum in the process?
Check out some (non-Arabian Peninsula) wartime footage and you’ll see vehicles with narrow tracks. I’m not saying that wide track vehicles let the bad guys win, but think about it: they have inherent benefits on American highways, but what if you need to scoot around in smaller situations without stopping? I wouldn’t mind a narrow track in Boston, much less Rome or Bombay.
Narrow tracks are one reason why the current Ford Ranger is such a hoot to drive compared to its superior competition from Toyota, Nissan and especially the full sizers. It turns on a dime, changes direction with ease, and it’s pretty hard to get stuck anywhere. So if you want a runabout, you want a narrow track. If you want more, get more elsewhere. And if you’re a safety freak who can’t stand the thought of someone rolling over in a narrow track vehicle, make active roll control standard and easily defeatable for those who know how to drive.
Send your queries to mehta@ttac.com. Spare no details and ask for a speedy resolution if you’re in a hurry.
I never thought that the narrow tracks on old American cars were anything except a side effect of the triumph of the body designers over the engineers. That is, the basical mechanical chassis of cars through 1975 or so (for most American cars) went back to 1949 and in some cases the 30’s. Differentials and rear axles were essentially the same units from year to year and model to model…. while the bodies of the cars got “longer, lower, and wider” every year from 1949 on.
Recall that these cars were body-on-frame designs and it’s easier to see how more and more elaborate bodies were dropped onto those same old frames and components.
In short – engineering had nothing to do with it.
Feels like you’re implying that all body on frame designs are essentially the same. That’s pretty unfair, just look at the X frame design of certain Chevy Impalas compared to the traditional ladder frame.
I am by no means an expert on this, but I hope to spur further ranting on the matter after this.
Buick spent a TON of money in the 50s developing that X-frame shape… I read somewhere recently that it was on the order of $1.5 million, which was seriously big R&D money back then.
But I still suspect Lokki is probably right.
@Lokki: I can’t speak for GM and F, but Chrysler adopted torsion bar front suspension in 1956, and went unibody across the board except for Imperial in 1960. I doubt that chassis designs from the 1940s had any bearing on chassis from the 60’s.
Also, rear axle widths varied from model to model and sometimes year-to-year even though the mechanicals in the differential itself stayed the same, so that aspect of your argument doesn’t hold water either. In fact, the Chrysler 8 3/4″ diff was used from 1957 to about 1974, so it wasn’t even around in the 40’s.
The best answer I can come up with was that that was the styling of the time.
Remember that Pontiacs did have wide track at the rear! And by the mid sixties, most full size GM cars got larger tracks (front and rear) but Pontiacs stll had a 1″ larger track at the rear (I think that the Pontiac front track was narrower of about 1/2″ at the front than it it is on my 1965 Buick). In 1971, full size GM cars (or Buicks at least?) got larger differentials and the distance between both front rotors was also larger but their track was marginally increased because their wheel offset was reduced (backspacing was reduced of 1/2″)…
I think one of the main reasons for having narrow tracks (compared with the body width) back then was the body and wheelwell design. In the early seventies, GM cars got rounded bodies that got narrower at the bottom, this resulted in the lower part of the body being narrower than the tires and exposed to projections from the tires. Some cars were even splashing water from their front wheels through their windehields. I had this problem on my ’74 LeSabre. GM had noticed this problem in 1971 and fixed this by using large rubber bands fastened by the wheelwell mouldings on 1972 models but since the base LeSabre model didn’t have wheelwell mouldings, they didn’t get those rubber bands, not even years later!
Wait Sajeev. Weren’t you arguing for lower wider a few days ago when the “bench seat/column shift question” came up? I’d rather have lower and wider (including the track) for highway use. Trucks/off-roaders can be tall and tippy because of the specialty jobs they can be asked to do. (Plus I have a problem with people using SUVs and trucks as daily drivers unless they’re working the right job.)
Give me low and wide with easy three across seating.
Honestly, I am trying to take my *personal* tastes out of the equation, just giving reasons why items like a narrow track and bench seats have purpose in our design lexicon.
Plus, I do enjoy playing Devil’s Advocate. It’s kinda my thing.
Carry on, Sir. I’m going to keep wasting my day off by looking at V8 powered, BOF, RWD sedans, coupes, and wagons trying to figure out which one I’ll lay my money down on when I’m ready.
“E Aho Laula.” Wider is better. http://www.youtube.com/watch?v=tevP8NOsBQs
I understand that in Canada, the Wide-Track Pontiac of the 1960’s had Chevrolet underpinnings (among other things) which made the small wheels look even smaller than their American cousins.
As far as off-roading, the ability to maneuver on trails is a function of overall width and turning radius. Track width only affects this ability in Jeeps because the overall width of modern Wranglers is set by the Track width. If you look closely at rectangle-light Wranglers and earlier Jeeps you’ll notice that the stock axle/tire combo let the body tub set maximum width at the rear so the track was narrower than the overall (by more than just a single tire width). Newer Jeeps are truly disgustingly wide.
Turning radius has essentially nothing to do with track width, but far more to do with wheelbase. The only possible steering effect track width can have is if the steering is poorly engineered (or forced to use sub-optimal off-the-shelf parts) and excessive Ackermann error causes the tire scrub to fight the turn.
Wider tracks are more stable using the static stability formula that compares Cg height to track width. This ratio has only minimal correlation with dynamic stability, where other factors such as instant roll center height compared to Cg height and roll axis inclination combined with roll stiffness of the front vs. rear axles has more to do with dynamic stability in the absence of a sliding curb strike.
The only possible steering effect track width can have is if the steering is poorly engineered (or forced to use sub-optimal off-the-shelf parts) and excessive Ackermann error causes the tire scrub to fight the turn.
I’ve seen that a fair bit, but I guess that comes from my time with aftermarket add-ons, not always OEM applications. Very good point.
Your point on the newest Wrangler is well taken. It’s gotten entirely too big. Hopefully Fiat will at some point downsize the beast.
Sajeev:
You got me on your take of the Ford Ranger. I had a 1996 short bed, standard cab, 4 cyl 5 speed and did get a kick out of driving it. I tried getting rid of it many times ’cause my back could eventually only stand 20 minutes or so in it, as the driver’s seat became butt-sprung (I’m not heavy) and felt like you were sitting in a hole! Had to keep it for years until I bought my Impala – instant relief!
As far as the old iron goes – all of them, no matter if full-size, compact or mid-size, looked much too large for the wheels and tires then current. Plus, the front and rear overhang was out of this world. Car mags back then had a field day ranting about the overhangs on American cars! Pontiac used the wide-track as a great marketing tool to differentiate their products as being performance-oriented. Whether that was entirely true or not, who knows? An old mechanic my family used back then used to complain that wheels and tires were much too small on almost everything the domestics produced. Aside from all that, my old ’64 was sure a beaut!
Dan:
I’ll take wide and three across, but not too low, as there are too many obstructions like curbs, speedbumps and stuff that the front air dams already take a beating on.
Just like the oversized wheels that are popular today the undersized wheels were popular in the 1960’s. I can remember my German cousins marveling at our old Mercury Monterey which was close to 20 feet long, but had 14″ wheels. They thought it looked like a clown car, and they were right. Of course popular (?) tastes have gone the other way, 19″ and 20″ wheels are sold as a performance upgrade on many cars… WTF? Do the people buying these things realize how much weight and space is wasted on making those huge hoops work with the rest of the car? What a joke!
BTW, I love the Van and Fitz Pontiac ads. I can remember those from my childhood. I still want to be the man in those ads, driving those cars…
So narrow tracks might have some advantage for an off-road vehicle? Sound reasonable enough, though wouldn’t the wider body gets them stuck in narrow trails anyway? If the body’s roughly the same width as the track, then it’s not really narrow tracks, it’s just a narrow vehicle. Also, this doesn’t answer the primary question: many narrow-tracked vehicles from yesteryear are hardly off-road capable. The likes of Big Three sedans, coupes and station wagons from the 1960s and 1970s often have wheels placed well inside of its body. These long, low cars with very low ground clearance and long overhangs (especially in the rear!) are hardly off-road vehicles, they’re barely able to get over driveway inclines without scrapping their bottom! Why the narrow tracks then?
Lokki’s answer makes more sense. Though given how long so many Detroit cars came with narrow tracks, surely at some point some of them got new chassis, yet they don’t suddenly become “wide track” with them. GM’s B-body of the 1990s still have a rather narrow track.
Track width is mostly a consequence of the rest of the car. The Model T and old Jeeps had narrow tracks because they had inline engines and leaf spring suspensions, while modern cars have V-engines and A-arm suspensions that require more width to package. There can be some tweaking done in the name of vehicle dynamics, but that’s usually on the order of millimeters. Pontiac’s “wide track” was just a design language, one that appealed to everyone’s basic understanding of physics and happened to look pretty cool. But you can’t say unequivocally wide is better than narrow – you design based on other requirements and let the track fall where it may.
I think Model Ts and Jeeps had narrow tracks because of existing ruts on dirt roads going back to wagon days.
I think Jimmy7 may have something. There is some link back to roman chariots, if you look hard enough.
No really. Look at railroad widths. It goes way back.
I would approve 19″ wheels if they took 60 series tires. I like huge diameter OD.
My favorite bikes are 29ers. Just roll over stuff and the compliance is better.
IMHO, the overhang phenomenon became excessive in the late ’60’s and early ’70’s by virtue of consumer and Uncle Sam pressure for safer cars. The design response was to accentuate the body on the outside to provide perception of better protection from impacts. Probably Ford was the worst offender – those Torinos were hideous. Fortunately OPEC came along to end the madness.
I have read that the Pontiac Wide Track of the late 50s-60s was more marketing hype than engineering. The track was increased something like an inch and was mainly for style because it made the car look lower and wider.
I think that the only real advantage of a wider track is resistance to rollover. More width and less height will make a car less likely to roll.
track width is the most expensive design change outside of door openings
not only the vehicle – rear axle / front suspension have to be reengineered, but
the assembly fixtures and component manufacturing tooling need to be expensively modified to accomodate the the change. that is why you see a lot of variations stretching ahead and behind the cabin but little change in track from year to year
93 / 94 Mustang model change would have been prohibitively expensive if new model had
changed the track as originally designed, see “Comeback” published in mid 90’s for details
– transporters also have to be retrofitted when these kind of changes come out
You’re correct on the cost of design changes as it relates to track width. I shudder (always have) when kids and not-so-young-kids put wide wheels, especially the old “chrome-reverse” style on their rides. Doing that to a standard axle set-up changes the geometry and adds stress on bearings – forcing the machinery to do things it wasn’t designed to do.
Especially of the designs from the 1960’s, the front and rear clips differed so much, but the greenhouses (on the full-size GM cars, for example) were identical in nearly all cases.
The most glaring example that comes to my mind of the body changing but not the doors or windows is the Ford Escape. They should have altered that by now to bring it up-to-date.
I’m a fan of a narrow track for the city – and the suburbs. There are so many times when you can squeeze by in traffic where otherwise you’d be stuck. In fact, I wouldn’t mind having a city car with longitudinal seating seating for two.
Even the narrow country roads where I live can be challenging for some vehicles. I was following an 18 wheel dump truck this afternoon near my house and noticed that he had to center the yellow line between the left set of dual tires and still had barely a foot to his right.
These roads are curvy and you often encounter someone taking up part of your lane with little or notice. Come to think of it, I had a scary encounter on my bike when an oncoming Accord was taking up half of my lane on a curve – if I had been in my car we might have collided. And you usually don’t have an option of swerving off the road since there are stone walls, trees, and rock faces occupying the shoulders. On the plus side, the scenery is fantastic.
Don’t know about narrow track, but narrow tires are better in off-road mostly because of better contact/friction with road caused by more weight per area. Wide tires are more prone to aquaplane for example. Same on snowy roads. Recall seeing one video about some developed 4×4 offroader where common land rover with wide tires almost floated in liquid mud with near to no friction at all, while car with narrow tires easily reached bottom of puddle and easily rode ahead. Probably same with snow/ice. Someone ever noticed uber-narrow tires on WRC/autocross cars for winter stages?
The sides of the car would probably stay cleaner with the wheels tucked further in.