On Fri, 18 Jan 2002, Alan & Debbie Lindner wrote:
> There have been many emails every couple months about what
> size tires on what size wheels us owners have used. I am curious
> how do these different sizes effect the car. I know I could put on
> shorter tires, say 205/65-15 and have my speedometer adjusted.
> But how did the engineers go about deciding on the 185s on a 15
> inch rim back in the end of the 60s'.
All TR Triumphgs were supposed to be able to do the "magic tonne". This is
about 5000 RPM's in 4th non-overdrive in a TR6 with stock tires.
So, the engineers arrived at this number with the gearing, tire diameter
and available horsepower.
> Was is the best tire for the performance at the time?
For street use? Not sure. The original Goodyear G800's were pretty sticky.
THey didn't last very long either, I presume owing to the relatively soft
rubber compound. Ironically, people bought Michelin X's because they wear
better - the _antithesis_ to a performance tire.
Go figure.
Nowm if you were into racing, the tire to use was likely the Goodyear Blue
Streak... real "gumball tires" (for the day).
But frankly, I'm glad tire technology has changed. Tires today are apples
and oranges to tires of yesteryear. I don't give a crap about originality
and I love the modern tires for just about every reason.
> Were there power and torque calculated for the different engines
> and they then matched tires up?
Yes. But they had to make this work for the Fed. Spec. cars, so the 185's
were it. I'm not certain, but I think the home market cars used 175's.
They also had 3.45 diffs and _way more power_ in stock form.
> Do the axles and differentials have max speeds that we approach?
???
The cornering forces that you can get with lowered suspension and modern
sticky tires are way higher than what was available in 1969. So in that
sense, you need to more cognizant of the condition of your suspension
parts. By way of example, I converted my car (an F Prepared SCCA
autocrosser) to Corvair axles (which are much beefier and more betterer
that stock *).
The differential is okay to about 200 HP maybe a bit more, then you have
to start thinking about _not_ dumping the clutch every time that you
shift. :-) The axles are okay to that point too. But the differential is
not sensitive to speed, per se. If you have 4.875 gears, the input turns a
lot more than if you have 3.45 gears, but that's about it (other than
limiting top speed as a function of the engine redline.)
> Thanks in advance for all your opinions.
> =========================
> Alan Lindner
> '72 TR6 French Blue set for racing
> CC75676L
> San Diego, CA
You're welcome.
rml
* notice the use of the triple comparative! Bravo!
------------------------------------------------------------------------------
Bob Lang Room N42-140Q | This space for rent
Consultant MIT unix-vms-help |
Voice:617-253-7438 FAX: 617-258-9535 |
------------------------------------------------------------------------------
|