Let me ask 'the rest of the world on here' to provide one shred of evidence that shorter gearing actually provides faster acceleration.

Subsequent columns within the spreadsheet then tally up how far the car travels during this speed increase increment (using the forumlas you posted) and give me the full picture. I can then interrorgate the columns to bring back any metric I want (distance traveled at x speed, speed at x distance, time to reach x speed and so on).

Oh I do *love* an argument where people are so fiercely agreeing with each other!

Here's the short and nasty: if you increase the final drive ratio (i.e. more teeth on the pinion or fewer teeth on the crown wheel), without making *any other change*, your vehicle will accelerate more quickly in all gears but will have a lower top speed (limited by engine maximum revs). If you reduce it, the opposite effect will occur. This is exactly the same effect as putting smaller or larger tyres on, respectively.

The closer the gearbox ratios are, the nearer the peak power you will be when you change and the more power you will deliver to the wheels, and therefore the greater the acceleration (ignoring such delights as the absolute number of gears in the box, the time it takes to change between them, the physical momentum of the engine parts, friction losses in the box etc).

One final thought: it's quite possible to get the seemingly contradictory position that decreasing the final drive ratio will *reduce* the top speed... maximum speed when maximum power is transferred to the wheels. You'd expect this to be the engine's peak power, but consider this scenario: at any speed on the road, what is holding you back is the friction with the road surface and the aerodynamic friction (form drag). Form drag is proportional to the square of the wind-speed, so ignoring tyre friction you need four times the power to go twice the speed. It's quite possible to gear the engine such that at a given speed, the power required to accelerate is more than the engine is capable of supplying at that instant, even though the engine is capable of delivering more power. This is why some cars with a long top gear are faster in the gear below...

so confirm to calculate the time it takes to go 1-30 you are using the value you have for acceleration available at 1mph and are using that rate as the average acceleration for the speed change of 29mph to derive a time.

Of course you could just mail me the sheet and I'll answer this myself if thats easier.

looking at the whole speed range of the coupe and comparing accelerative ability of 2 identical coupe's, one with shorter gearing (15% shorter)and one standard

standard vs shorter gearing (per 1000rpm)
1st 6 vs 5.1
2nd 10 vs 8.5
3rd 15 vs 12.75
4th 20 vs 17
5th 25 vs 21.25

looking at the speeds from 1000rpm to 7000rpm in each gear
with the shortened ratios the coupe can accelerate to 35.7mph in 1st before it needs a change to second so from 0mph to 35.7mph it will accelerate faster than the standard coupe

from 35.8mph to 42mph the standard coupe will accelerate quicker as it will stay in 1st

so in first the shorter geared coupe can accelerate quicker for the first 36mph then the standard coupe is quicker for 6mph

from 42mph to 59.5 the shorter geared coupe will accelerate faster, an increment of 17.5mph

after which point it will require a change to 3rd so the standard coupe will be quicker from 59.6mph to 70mph as it can stay in 2nd, an increment of 10mph

from 70mph to 89.25mph the shorter geared coupe will be faster again over a 19mph increment

i don't know about anyone else but i spend 99% of my driving below 90mph and from 0mph to 90mph the shorter geared coupe will be faster over 72mph of that speed range hence making it usefully faster in everyday situations

if you want to continue to expand the comparison to almost max speed then from 89.26mph to 105mph the standard geared coupe will be faster by virtue of the shorter geared coupe having to change in to 4th, an increment of 16mph

the short geared coupe is then faster over the increment of 105mph to 119mph, an increment of 14mph before it has to change in to 5th allowing the standard geared coupe to be faster from 119mph to 140mph an increment of 21mph

therefore from a total of 0 to 140mph the shorted geared coupe can accelerate faster between speed ranges 0 to 36mph (36), 42 to 59mph (19), 71 to 89mph (18) and 106mph to 119mph (13) giving a total of 86mph over which it will accelerate quicker

with the standard gear coupe able to accelerate quicker from 36 to 42mph (7), 59 to 70mph (11), 89 to 105mph (16) and 120 to 140mph(20) giving a total of 54mph over which it can accelerate quicker,

20mph of that increment being over 120mph which really is of no consequence in the real world

so basically the higher the speed the less impact the shorter gearing has, in fact over 120mph due to the standard coupe's gearing it will be quicker after this speed, so if you live in Germany and regularly use the autoban then stick with the standard gearing as it will likely be quicker, if however you live in the uk and drive normally the shorter geared coupe will be quicker in everyday driving

trappy given the above is a fact, can you explain how up to 120mph given that the shorted geared coupe can accelerate faster over 86mph of increments against the longer geared coupe's 34mph of increments, how it wouldn't be quicker

so confirm to calculate the time it takes to go 1-30 you are using the value you have for acceleration available at 1mph and are using that rate as the average acceleration for the speed change of 29mph to derive a time.

Of course you could just mail me the sheet and I'll answer this myself if thats easier.

Because 'having shorter gear ratios' doesn't mean you accelerate faster. The only thing pushing your car forwards is the power at a given time.

Here's a fact;
*200wbhp at 60mph in 5th gear will give the same acceleration as 200wbhp at 60mph in 2nd gear*

of course shorter gear ratios means you accelerate faster, you accelerate faster in 2nd than you do in 5th, why, because the gear ratio is shorter, the power from the engine hasn't changed, the only thing that has changed is the gearing and as the wbhp constantly changes you have to look at it over the entire rpm range

Instead, consider this to see just how ridiculous the notion that shorter ratios improve acceleration is...

Car A has ratios that yield the following speeds;
1st: 41
2nd: 70
3rd: 103
4th: 135
5th: 171

Car B has ratios that yield the following speeds;
1st: 28
2nd: 41
3rd: 70
4th: 103
5th: 135
6th: 171

The ratios are indeed shorter on Car B... infact they're short enough that they're the same as those on Car A, albeit a gear higher. Do you really think Car B would be faster than Car A?

change to all ratios makes no difference what-so-ever to the performance.

It's on on one page for me, but I presume you are referring to the following post?


My point was that Car B has (for all intents and purposes) a closer ratio'd gearbox because every equivilent gear is shorter or has a different ratio to the same gear on Car A.