Lancia Stratos reverse gear speed

[GVK]

Saw a comment that the Lancia Stratos could do 100 mph in reverse, I think that's absolute bks as for it to that it would need to be able to do 100mph in FIRST gear too! As fundamentally the manual gearbox reverse gear uses the same ratio as first.

Am I correct in my assumption?

[CraigyMc]

GVK said:

Saw a comment that the Lancia Stratos could do 100 mph in reverse, I think that's absolute bks as for it to that it would need to be able to do 100mph in FIRST gear too! As fundamentally the manual gearbox reverse gear uses the same ratio as first.

Am I correct in my assumption?

37.4mph at 8000 in reverse gear per https://rallycars.com/cars/lancia-stratos-2/lancia...

Gear ratios - speed at 8000 RPM:
1:3.554 - 64.83 Km/h
2:2.459 - 93.69 Km/h
3:1.781 - 129.36 Km/h
4:1.32 - 174.54 Km/h
5:0.986 - 233.67 Km/h
R:3.3

[TA14]

I don't recall rear vision being too good out of the Strato's.

[GVK]

TA14 said:

I don't recall rear vision being too good out of the Strato's.

Very true!

[brillomaster]

Someone got confused and thought 67kph was 67mph.

Then someone else converted 67mph to 105kph.

Then someone else thought 105kph was 105mph.

Or someone just thought 60kph is 100mph. Units of measurement are hard. For example ask me what my weight is in metric I wouldn't have a clue.

[Timer]

GVK said:

Saw a comment that the Lancia Stratos could do 100 mph in reverse, I think that's absolute bks as for it to that it would need to be able to do 100mph in FIRST gear too! As fundamentally the manual gearbox reverse gear uses the same ratio as first.

Am I correct in my assumption?

Right speed wrong car? The LCC Rocket clocked 104mph in reverse.

[samoht]

GVK said:

As fundamentally the manual gearbox reverse gear uses the same ratio as first.

I'm pretty sure that reverse gear, in almost all cars, uses a separate unique set of gears unrelated to any of the forward gears. Thus the reverse gear ratio could be whatever the manufacturer chooses. They're also often straight-cut rather than helical gearwheels, hence the whining sound in reverse gear.

With some old cars if they couldn't get up a hill in first it was worth trying to get up backwards, as it was a lower ratio than first.

Timer said:

Right speed wrong car? The LCC Rocket clocked 104mph in reverse.

Bike gearboxes don't have reverse gears. Thus if using a bike gearbox in a car, some other method to reverse is needed. Adding a separate 'reverse' gearbox then means that all the normal ratios are available in both directions, hence the car could go as fast backwards if not for the stability issues with high-speed reversing.

[Blib]

TA14 said:

I don't recall rear vision being too good out of the Strato's.

[thegreenhell]

samoht said:

GVK said:

As fundamentally the manual gearbox reverse gear uses the same ratio as first.

I'm pretty sure that reverse gear, in almost all cars, uses a separate unique set of gears unrelated to any of the forward gears. Thus the reverse gear ratio could be whatever the manufacturer chooses. They're also often straight-cut rather than helical gearwheels, hence the whining sound in reverse gear.

With some old cars if they couldn't get up a hill in first it was worth trying to get up backwards, as it was a lower ratio than first.

Also, usually a crash gear, rather than a synchronised constant mesh like all the forward gears.

[Hustle_]

samoht said:

GVK said:

As fundamentally the manual gearbox reverse gear uses the same ratio as first.

I'm pretty sure that reverse gear, in almost all cars, uses a separate unique set of gears unrelated to any of the forward gears. Thus the reverse gear ratio could be whatever the manufacturer chooses. They're also often straight-cut rather than helical gearwheels, hence the whining sound in reverse gear.

With some old cars if they couldn't get up a hill in first it was worth trying to get up backwards, as it was a lower ratio than first.

Timer said:

Right speed wrong car? The LCC Rocket clocked 104mph in reverse.

Bike gearboxes don't have reverse gears. Thus if using a bike gearbox in a car, some other method to reverse is needed. Adding a separate 'reverse' gearbox then means that all the normal ratios are available in both directions, hence the car could go as fast backwards if not for the stability issues with high-speed reversing.

[/thread]

All the facts

[Fessia fancier]

I think the confusion arises because it looks like it is doing 100MPH even when standing still….

[hidetheelephants]

samoht said:

GVK said:

As fundamentally the manual gearbox reverse gear uses the same ratio as first.

I'm pretty sure that reverse gear, in almost all cars, uses a separate unique set of gears unrelated to any of the forward gears. Thus the reverse gear ratio could be whatever the manufacturer chooses. They're also often straight-cut rather than helical gearwheels, hence the whining sound in reverse gear.

With some old cars if they couldn't get up a hill in first it was worth trying to get up backwards, as it was a lower ratio than first.

Due to the layout of conventional gearsets there are limits on how much variation there can be(it would be impractical for reverse to be a significantly larger or smaller ratio than the largest or smallest indirect forward gear ratio, although not impossible a large difference would result in a very oddly shaped gearbox casing to accommodate the necessarily oversize pinions) and generally manufacturers will want reverse to be about the same ratio as 1st, given the difficulties of observation the slower reverse is the better.

[Dapster]

Transpires that an image of cars racing in reverse looks very much like an image of cars racing normally, but the Dutch ran a race of Daf 66s in reverse - absolute bloody chaos ensued. This is what you can do with an old school Variomatic CVT transmission

https://www.youtube.com/watch?v=lLgPTJWAysY

[richhead]

samoht said:

GVK said:

As fundamentally the manual gearbox reverse gear uses the same ratio as first.

I'm pretty sure that reverse gear, in almost all cars, uses a separate unique set of gears unrelated to any of the forward gears. Thus the reverse gear ratio could be whatever the manufacturer chooses. They're also often straight-cut rather than helical gearwheels, hence the whining sound in reverse gear.

With some old cars if they couldn't get up a hill in first it was worth trying to get up backwards, as it was a lower ratio than first.

Timer said:

Right speed wrong car? The LCC Rocket clocked 104mph in reverse.

Bike gearboxes don't have reverse gears. Thus if using a bike gearbox in a car, some other method to reverse is needed. Adding a separate 'reverse' gearbox then means that all the normal ratios are available in both directions, hence the car could go as fast backwards if not for the stability issues with high-speed reversing.

Most manual gear boxes use an idler gear on 1st for reverse, this is often 1:1 , so can be the same as first, but not always. Some auto boxes use reverse on the output shaft, so theoretically top speed can be the same in reverse as forward, some would even change gear in reverse.

Edited by richhead on Wednesday 12th November 00:39