Close Ratio Gearbox

[Hugh Barnes]

Thanks for those who have taken the time to respond.

I have owned a car in the past with a 'close ratio' box that was truly a delight to drive. However, that was an Ulsteroid, so very different from the Cabriolet. Equally, I didn't know the details of the ratios, I just had it built as a 'close ratio' box. I have also driven a Cabriolet with a close ratio box, which performed very well and seemed very 'tractable', though again, that was just known to be a (genuine Austin) Sports Box, though the origins (Nippy, Speedy, whatever) was not known.

I am intruiged by Dave Mann's comments about a set of ratios for 'heavy saloons' As I understand it, there are only the three styles available as I mentioned in my original post. Of these, Super Accessories seem better suited to track cars, the Nippy set would appear to be the most 'benign' an then the 'intermediate' set somewhere between the two. Dave can you say which of those three varieties you might be referring to, though it sounds like it might be a further version I haven't seen if the Nippy ratios you found too high?

[Robert Leigh]

As I understand it, the Nippy ratios give higher 1st, 2nd and 3rd though I'm not sure how they compare with the Andes config. Is an Andes box *just* a different second gear ratio or do others change as well?

I thought the 'Andes' gears amount to a higher second in a 3-speed box, which may be fine, but it is not to be considered for a 4-speed car.

[Oxford Jack]

Hello Hugh,
A slight correction to Charles reply, I have an AB intermediate gear set, not an 'Andes' which as I understand it refers only to the three speed box others have mentioned in this thread.
My RP has a standard back axle and runs on 17" wheels, so relatively close to your Opal configuration. The intermediate gear set raises 1, 2, and 3rd gear leaving top as it was. I find that 1st is absolutely fine for hill starts, unless very fully loaded, when a bit more welly will be required. On the flat, two up, I can easily pull away in 2nd. Where it excels is accelerating in 3rd to an easy 35+, when changing into top the engine does not bog down. The change down from top to 3rd is at a better speed for maintaining momentum and momentum is what driving the 7 is all about.
I should add that on tour with a full set of spares, luggage and 2 up my RP has been weighed at around 950kgs, no lightweight then. Those long uphill slogs in third because a change into top would result in a loss of speed are no longer an issue, unless the hill is v.steep when 3rd is now a higher option. I think you would not regret the change.

[Bob Culver]

Hi Oxford Jack
When I was running my slightly modified RP as everyday transport I often joked that a higher 3rd was desirable. !st is very low and the car would climb and start where firms CA Bedfords and others struggled.
But, at least in a hilly city, the standard car would have been insufferable with a higher 3rd as often could not reach 30 mph on modest grades with just the original 13 bhp..

[Oxford Jack]

Hi Oxford Jack
When I was running my slightly modified RP as everyday transport I often joked that a higher 3rd was desirable. !st is very low and the car would climb and start where firms CA Bedfords and others struggled.
But, at least in a  hilly city, the standard  car would have been insufferable with a higher 3rd as often could not reach 30 mph on modest grades with just the original 13 bhp..

Bob,
I should add for clarity then, high compression head, 1" SU, slightly modified cam followers, otherwise standard engine, will happily cruise at 45 to 50 as shown on sat nav, achieves 40 mpg all this over about 25,000 miles, however the top end has been rebuilt twice, the bottom end Phoenix crank and rods, Accuspark dizzy, Dynamo Conversions rewound Dynamo and solid state regulator. 
Jack

[Ruairidh Dunford]

It’ll never last...

[Bob Culver]

Hi O J and others
 
The engine state of my car similar. After 3000 miles of 60mph when the notorious Wellington southerlies obliged and sustained 35 in 3rd the crank went, taking the hand polished crankcase and home reground camshaft with it. Thereafter 30 and 50! The situation is much altered with Phoenix cranks.
 
The Seven 3rd gear ratio is unusually low; comparable 2nd gear of more powerful 3 gear cars such as Ford V8 and Zephyr etc. Low powered 3 speed cars require wide ratios; the Ford 10 near 2:1.
Many modest power cars had 3rd about 1.5:1 in the 1950s, 1.4 or less was common for medium cars later. On the roads of yesteryear many climbs were winding and slow anyway.
If the Seven seems to buzz many cars were geared similar or maintained similar rev at their typical cruise speeds, but were not all notably noisy. Isolated exhaust sysem, soft engine mounts, plain bearings, felt makes a difference!
The list may interest some with memories.
Javelin 15.5 mph per 1000 rpm
Oxford sv 1500, Minor sv 920; 15
Consul 1500, Mini 14.8
A40 Devon 1200, Ford 100E sv  1170 14.6 (The 100e revved remarkably in 2nd)
Victor 1500 14.5
MGTD and saloon 1250 14.4
A35 950 14.3
Minx sv 1260 14.2
Ford 10 sv 1170 13.7
A30 800 12.7 (leaving a trail of failed wm big ends, and a few cranks)
Fordson  commercial 1170 11.4 (with the engine inside the cab these are truly dismal. And 2nd gear of the 3, at 2:1 is similarly tedious.)
Compared with todays cars, including of small capacity, the rpm are formidable. Whereas my 1950s, 60s 1500/1600 cars maintain 4,000 rpm at our 100 kph limit, my wifes modern 1200 maintained 2200 rpm including moderate gradients!
 

[Hugh Barnes]

Thanks Bob but can we avoid the thread drift please... I'm just looking for advice on the gear ratio selection for my Cabriolet...

chheers...

[Zetomagneto]

Thanks Bob but can we avoid the thread drift please... I'm just looking for advice on the gear ratio selection for my Cabriolet...

chheers...

Someone likes Bob’s post, look at his reputation! 72

[Charles P]

Thanks Bob but can we avoid the thread drift please... I'm just looking for advice on the gear ratio selection for my Cabriolet...

chheers...

Someone likes Bob’s post, look at his reputation! 72

Yes, it's all the same person liking everything that Bob says. 

Nothing against Bob's wisdom but it does make the "reputation" score utterly meaningless 

Charles