Peter,
The final drive retains the same ratio, the overdrive steps down the
gearbox output by around 20% (depending on the spec of the overdrive
fitted), so 1:1 non o/d becomes 0.8:1 in overdrive.
Cheers,
Bill.
Peter S. wrote:
>
> What?!
> Surely there is a difference or nobody would bother the conversion. I'm
> looking for something like 4th gear is 1:1 and with OD on its 1:.85
> Otherwise its not an OD at all - meaning the engine is turning slower than
> the prop shaft speed.
> Peter S
>
> ----- Original Message -----
> From: Andrew Mace <amace@unix2.nysed.gov>
> To: Peter S. <alfapete@pacbell.net>
> Cc: <spitfires@autox.team.net>
> Sent: Tuesday, June 29, 1999 8:15 AM
> Subject: Re: Gearbox OD or not OD, that is the question
>
> > On Tue, 29 Jun 1999, Peter S. wrote:
> >
> > > How do the ratio's and final drive compare with and without OD? I seem
> to
> > > be a fortunate ones whose got OD but I was just curious how it differs.
> > > Peter S
> >
> > Normally there was no difference at all between OD and non-OD gearsets or
> > OD v. non-OD final drive ratios, at least not on Spitfires.
> >
> > --Andy
> >
> > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> > * Andrew Mace e-mail: amace@unix2.nysed.gov *
> > * *
> > * Mrs Irrelevant: Oh, is it a jet? *
> > * Man: Well, no ... It's not so much of a jet, it's more your, er, *
> > * Triumph Herald engine with wings. *
> > * -- Cut-price Airlines Sketch, Monty Python's Flying Circus (22) *
> > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> >
> >
--
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^================^
/ \ William Davies
/ \ Total Triumph Enthusiast
__ __________________ __
/ \ ______ ______ / \ 1959 Herald 948 Coupé Y128
\__/ \ || / \__/ 1959 Herald 948 Coupé
| A \____||____/ A | 1959 Herald 948 Saloon
| = H H = | 1960 Herald 948 Saloon Export
=====U==============U===== 1961 Herald 'S'
\________________________/ 1964 Herald 1200 Saloon
| | | | 1973 Spitfire MkIV
|_| |_| 1959 Standard Atlas Pickup
|