Gearing - how it has changed over time

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Sun 2 Sep 2018 14:33
Gearing - how it has changed over time - smallcar
Being a devotee of that Flickr blog that shows lots of old car tests from the 60s onwards I’m amazed by how short the gearing was on many cars prior to the mid 1980s. Modest sized hatchbacks had top gear at around 15/16mph per 1000rpm in top and even 2 litre cars and above from various makes including Mercedes and BMW were geared around 19-20 tops. Must have made so many cars very noisey at motorway speeds. The report on the Audi 100 in 1982 had what’s was seen as insanely high gearing at 27.9 per 1000rpm.

Last night for comparison I tried cruising along at 60 in 4th then 5th and then 6th in my Honda CRZ and looked at the Rev counter to realise that the original CRX in the 80s would have had a top gear ratio equivalent to less than 4th in my current car.

Why did it take manufactures so long to cotton on to higher gearing and reduced racket at motorway speeds? I know some cars had overdrives but it seems like most cars in the 1960s and 1970s must have been impossibly noisy and stressed at 70mph or more.
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Sun 2 Sep 2018 15:03
Gearing - how it has changed over time - badbusdriver

Well at least one reason i can think of if we are going back to pre-80's is aerodynamics, and the lack of. Maybe not such a factor in more powerful machinery, but bread and butter stuff like Cortina's would require a fair amount of the 100bhp (for a 2.0 model) to push it's big square front end through the air at 70mph. Presumably the engine did not have enough power or torque to achieve this at less than 3000rpm.

Also, the lack of power itself. Going back to the Cortina again, the most powerful version of the MK4 and 5 was the 2.3 which had, if memory serves, about 110bhp in the MK4 and slightly more in the MK5. Compare the equivalent Ford today, the Mondeo, the LEAST powerful version has 125bhp, whereas the most powerful one has 240bhp. Bear in mind that Ford seem (sensibly) to have opted out of chasing the big power outputs, at least for the Mondeo, some of it's rivals can be had with quite a bit more power than that, and also the much superior aerodynamics mean that less power is required to maintain that 70mph cruise, so the gearing can be longer to reduce the rpm.

We have a Honda Jazz CVT and the topmost of its 7 electronically stepped ratio's results in about 2100rpm at 70mph!. Doesn't need much of an incline for that to change, but even in '6th' it is still only pulling about 2500rpm.

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Sun 2 Sep 2018 15:11
Gearing - how it has changed over time - badbusdriver

Just noticed that the least powerful Mondeo is the 120bhp 1.5 diesel and not the 125bhp ecoboost.

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Sun 2 Sep 2018 15:20
Gearing - how it has changed over time - smallcar
I suppose an issue with only having 4 gears was if 4th was higher the gaps in between might have been too much?

The thing is cars now are much heavier so that cortina whole being not v unaerrodymanic did weight not more than 2/3 of Mondeo now.

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Sun 2 Sep 2018 15:26
Gearing - how it has changed over time - badbusdriver

Weight will certainly affect the acceleration but, within reason, does not affect top speed and therefore gearing can be much longer despite being much heavier.

Edited by badbusdriver on 02/09/2018 at 15:28

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Sun 2 Sep 2018 19:20
Gearing - how it has changed over time - Engineer Andy

My Mazda3 gen-1 1.6 petrol (standard injection) built in 2005 is quite short in the gear - at 70mph in 5th its at about 3400 rpm. God knows what it is in 1st gear, as it wants to rocket away and low speed manouvring can be quite tough - they needed to lengthen that gear a bit.

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Sun 2 Sep 2018 16:01
Gearing - how it has changed over time - BMW Enthusiast

I think that the 8 speed torque converter auto gearboxes are the future of motoring in the world of automatics and will be the norm soon. Manufacturers such as Ford, Vauxhall, PSA, Alfa Romeo, Other Fiat Chrysler models and Volvo are now using them. Even Kia and Hyundai too. They are extremely efficient, reliable and make the car very relaxing to drive. My 2.0 diesel 5 Series runs at 1750rpm in 8th gear at 72mph. It's running in 5 gear at 28mph which would be totally impossible in a diesel manual and it shifts up into 8th gear at 62mph. All car engines are different though and it will be interesting to see how these gearboxes perform in the new Ford Focus especially in the 1.5 diesel and the 1.0 petrol ecoboost. Not everyone likes auto gearboxes but I choose them due to an injury sustained on my left leg some years ago which makes driving a manual uncomfortable.

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Sun 2 Sep 2018 17:54
Gearing - how it has changed over time - skidpan

When I first started driving most cars were 4 speed and N/A petrol. The ones I could afford to insure were 1600cc max. They cruised at about 4000 rpm at 70mph.

Then they introduced 5 speed boxes. The engines changed sod all. Adding a 5th gear brought the revs down to about 3500 at 70 mph but seemed to make no difference to the mpg, stayed at about 33 at best. Lets call it progress but nothing to get too excited about.

Then we got fuel injection. Still 5 speed but more power but the revs at 70mph stayed the same as did economy. There was an upside though, the cars being more powerful and faster. Progress was finally reaching mass market cars.

Then everything started to get heavier and slower.

So we went to diesel, Golf TDi 90 PS. 2400 rpm at 70 mph in 5th, decent performance and high 40's mpg overall.

Move on 12 years and we buy a BMW 118D. 142PS, 1800 rpm at 70 in 6th. performance was excellent and mpg about the same as the Golf, that was progess especially when there was no smoke thanks to the DPF.

Now of course we drive a Skoda Superb TSI 1.4 150 PS and a Fabia TSi 1.0 110 PS. The Fabia is doing 2200 rpm at 70 mph in 6th and the Superb 2300 rpm at 70 in 6th. Both have excellent performance, 10 years ago I would not have dreamed of driving 1.4 and 1.0 petrols even with a turbo.

My first car was a 1 litre Anglia. It had about 40 bhp, did about 4400 rpm at 70 mph (based on gearing and tyres size - no rev counter) and did about 30 mpg. Compare that to the 1.0 TSi Fabia above. But its taken from 1964 to 2018 to achieve that. Where will we be in 54 years time?

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Sun 2 Sep 2018 18:10
Gearing - how it has changed over time - gordonbennet

The highest geared car i've ever been in was a Jag XJ6 4.2 manual with overdrive, which was turning over at something ridiculous like 2200rpm @ 120mph, for years i thought it was revving slower but i know it was something like that because i remember working out that in theory 200mph would have been 5000rpm.

Highest geared lorry i drove was a 1984 Seddon Atkinson artic which cruised at 70mph @ 1100 rpm, near enough peak torque figure and only an 8 speed box the bottom 2 of which were seldom if ever used, max revs on the Cummins engine in that was about 1850 IIRC, you can work out its max speed potential yourselves.

Having only 4 gears left most cars of the time with high revs at 70mph, it was only cars with overdrive that had sensible cruising revs, and unless the engine was big enough if too tall gearing the car would need to drop at least one gear for hills, and the motoring magazines would slate it.

Edited by gordonbennet on 02/09/2018 at 18:11

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Sun 2 Sep 2018 18:53
Gearing - how it has changed over time - smallcar
To me fitting a car wth more gears seems pretty straightforward. It seems odd to me how long it took manufacturers to go to 5 gears and perhaps 6 is the sensible limit. I read soemwhrre that the Germans favoured Not overlong gearing even on their big engine models to give instant pick up on autobahns which in the 60s and 70s were mainly two lane so often the speed changes were quite significant after a vehicle pulled in our out of the slow lane.
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Sun 2 Sep 2018 18:49
Gearing - how it has changed over time - SLO76
All down to available power. An average family car from the 80’s, say a Sierra 1.6 for example which had only 75bhp and 91lb/ft of torque. Although it was much lighter than a current Mondeo it had far less power with around half the torque of todays 1.5 turbo diesel equivalent which can therefore pull a much taller ratio. Economy was also less of an issue too.

I had a shot of an 83 A plate Vauxhall Chevette a while ago and it surprised me how comfortable the ride was but the low gearing meant eardrum splitting noise at anything over 70mph. I don’t miss the low power and low gearing but I do miss the softer (but bouncier) ride most cars offered in the 80’s and 90’s. Old French metal in particular were hugely comfortable but also big Ford’s and Vauxhall’s were very sofa-like in ride comfort.

Manufacturers are too busy chasing good reviews from today’s handling obsessed motoring press. I don’t care how quickly my car can lap the Nurburgring but I do care if it rattles my teeth on every bump on the road.

Edited by SLO76 on 02/09/2018 at 18:55

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Sun 2 Sep 2018 18:58
Gearing - how it has changed over time - smallcar
Slightly off topic - I wonder if anyone will produce a car with the ride comfort of say a Peugeot 305 or 604 or a Renault 20/30 or a Jaguar XJ. They really were the definition of comfy. There’s very little choice now on the ride front whereas there was in the 70s and 80s.

Edited by innerlondon on 02/09/2018 at 19:05

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Sun 2 Sep 2018 19:46
Gearing - how it has changed over time - Terry W

Road condition and technology has changed massively in 50-60 years and gearing is but one of a huge numbers of other factors which have evolved. my first car was a 1200cc Ford Anglia. Current car is a 1.4TSI Octavia which is shortly to be replaced.

My current car is heavier, bigger, much faster, better equipped (electric windows, C/L, heater, AC, etc etc) than the 1961 Anglia with less than 50 horses trying to escape. It also averages 50mpg vs Anglias 25-30mpg. Manufacturing and lubrication technologies have allowed greater precision and lower production costs.

Road conditions have also changed - motorways were the M1 Preston bypass. Dual carriage ways an exception even on the main arterial roads. Talk was of ring roads around then major congested urban centres. The opportunity for 70mph motoring was generally very limited.

There was no real expectation of driving a return trip of 300 miles in a day for a one hour meeting or a 3 hour luch with friends.

It is no point in looking back somewhat nostalgicly to a world that will never exist again, only the largely academic and possibly interesting way we got from there to here.

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Sun 2 Sep 2018 19:54
Gearing - how it has changed over time - oldroverboy.

Gearing and gearboxes became better with cnc machining and cash. It cost money to build a 5 speed againsta 4 speed, (i remember a 3 speed ford pop my dad had....

Once cars all became more durable, then manufacturers invested to produce more power, contactless ignition, fuel injection etc etc.

Does anyone know the cost of a mercedes bosch mechanical injection on a 60's car.. horrendous. still horrendous, but replace rather than repair.

What frightens me is the cost of LED headlights and rear lights, mirirs with led indicators...

2 headlights on a jag xf will see not much change out of £2500.

Ouch.

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Sun 2 Sep 2018 19:58
Gearing - how it has changed over time - SteveLee
Slightly off topic - I wonder if anyone will produce a car with the ride comfort of say a Peugeot 305 or 604 or a Renault 20/30 or a Jaguar XJ. They really were the definition of comfy. There’s very little choice now on the ride front whereas there was in the 70s and 80s.

Apparently Citroën are heading back in that direction, ride quality will be optimised over out-right handling - about time too, the DS brand will be tuned more like the German back-breakers. I remember when speed humps first appeared in the late 80s - I didn't know what all the fuss was about - I could hardly feel them, but then I was driving a Citroën CX at the time - my god I got a riude awakening as soon as I drove someone else's car...

More on topic, my 1995 Jag XJR (supercharged) had 40mph per thousand gearing, it was mad bombing along at 120mph in silence with the engine barely breaking a sweat. My 82 Rover SD1 Vitesse had pretty tall gearing too - can't quite remember what it was now. My Dolly Sprint (with overdrive) was a great cruiser too.

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