View Full Version : TR2/3/3A tr3 wheelbase

09-09-2006, 03:57 PM
I was wondering is there any advantage to having a narrow wheelbase like on a tr3. Why did the engineers design the tr3 with such a narrow wheel base? They must have known that a wider wheelbase will help in a rollover. Does the narrow wheelbase have less friction in the turn? I just can not imagine it was just for the narrow roads. When I see the new BMW or new Toyotas the wheelbase looks like it would handle the turns much better.

09-09-2006, 04:03 PM
Mostly I think it boiled down to economics. They had existing drive trains and tooling from the Vanguards/Standards/2000 roadsters and they were operating within these constraints in order to build a sporting car for the least amount of investment. Considering the wheel base of previous pre-war models it wasn't all that unusual. The clam-shell fender stuff was downright tiny compared to what eventually led to the TRX/TR1/TR2.

And the rollover problems that TR2/TR3 have in my opinion is not so much a factor of narrow wheelbase but more of a problem with the finite and abrubt travel of the rear axle. Since it sits ON TOP of the frame (for chrissake) you go up to the limit and then immediately the wheel is forced to slide instead of gently flex a hair more with some warning.

Andrew Mace
09-09-2006, 04:09 PM
Not to sound flippant, but pretty much all cars were narrower in track (not wheelbase) 50 years ago. And as Jim noted, Triumph worked as much as possible with existing or easily modified existing bits (the original TR2 rear end was, I think, a NARROWED Mayflower rear end, but shortening axle tubes and axle shafts was not a major expenditure...and Triumph did widen both front and rear track for the TR4).

If you're old enough to remember such (I sure am), it was around 1959 that John Z. DeLorean's Pontiacs were advertised heavily as "wide track" Pontiacs!

09-09-2006, 04:14 PM
yeah... Mayflower... that's the one I couldn't remember without opening a book.

Graham Robson has a very good history called 'The Triumph TRs' that goes into great detail on the development process. 'Triumphs in America' by Mike Cook is another good read on the history of sales, marketing, and competition of the Triumphs but with less emphasis on the engineering. Both are worth it for the pictures alone.

Geo Hahn
09-09-2006, 04:23 PM
A curious thing about the TR3 'track' is that the front track is wider than the rear track... i.e. the footprint of a TR3 is an isosceles trapezoid but not a rectangle (if I remember it right from Mr Coy's Geomtery class).

09-09-2006, 05:12 PM
Not unique to TR. My "dart" has a 36" rear and 38" front track; both too narrow IMHO. /ubbthreads/images/graemlins/savewave.gif

09-09-2006, 07:41 PM
A curious thing about the TR3 'track' is that the front track is wider than the rear track...

[/ QUOTE ]

So is the TR4... not to mention the TR4A, TR5/250 and TR6. In fact, I think it's actually not that uncommon in sports cars, or all cars, in general. The IRS cars have about 1/2" narrower rear track, the live/solid axle are more like 1". I think the difference is largely due to the little bit of negative rear wheel camber on the IRS TRs.

For something even more radical, look up a Messerschmidt three-wheeler! Talk about a narrow rear "track"!

After all, didn't Buckminster Fuller show us that the triangle is one of the strongest structures?


Geo Hahn
09-09-2006, 07:52 PM
Then there's the Reliant Robin... a 3-wheeler with the single wheel in the front. I have no idea how slow you have to take a corner in one of these.


09-10-2006, 08:41 AM
Having the single wheel in the front on a three wheeler makes the vehicle very unstable in turns. That's why you don't see anymore three wheel ATVs. Morgan had it right by putting the single wheel in the rear on his three wheelers. (https://www.dream-car.ch/Beitraege/GPMutschellen_04/IMG_0578.JPG)