Hi all,
Yes the competition manual does reference a ratio used in the works
cars, but that was a 4.55:1 ratio! It is recommended to be used with
O/D, for racing purposes the 4.1:1 was recommended. I would bet there
were a wide variety of ratios (aftermarket) around with all the track
time these cars saw.
Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
Alan Crane wrote:
>
> According to my original sales brochure for the 67 TR4A, the standard
> rear end was 3.7, but 4.1 was an option with OD. So your 4.28 probably
> is not factory original. However, I recollect that alternative gearing
> was available from the aftermarket and was relatively easy to install in
> the standard differential. The Triumph Competition Manual may talk
> about that.
>
> Alan
>
> > Date: Thu, 04 Mar 1999 00:49:18 -0800
> > From: John Cowan
> > Subject: TR-4A - 4.28 rear end; what gives?
> >
> >
> > I measured the ratio of the differential on my '66 solid axle TR-4A
> > several times and it fell between 4.26 and 4.28 to 1. This result was
> > unexptected, but is borne out by the fact that the car revs up and tops out
> > especially quickly. I've heard rumor of a special 4.3 to 1 rear end, which
> > if accurate could explain what I have (the disrepancy being experimental
> > error, although I was pretty careful).
> > Is there a 4.27 or 4.3 to 1 differential available? If so, it would
> > seem suitable for Autocross. Would it also be suitable for road racing?
> > Thanks.
> > John Cowan
> >
> >
> --
> Alan T. Crane
> 2312 Warren Court
> Silver Spring, MD 20910
> tel: (301) 589-3502
> fax: (301-589-3503
> acrane@crosslink.net
--
MZ
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