asking about gearbox

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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nic08
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Joined: 21 Sep 2015, 11:11

asking about gearbox

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hi

I'm new in f1, I'm really curious about gearboxes in f1. I know it's sequential, but I'm curious about ratio that adjusted in gearboxes. What is ratio means? what is 1:2 in first gear, 1:3 in second gear, 2:5 in third gear and etc.

Tommy Cookers
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Joined: 17 Feb 2012, 16:55

Re: asking about gearbox

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actually the 8 ratios are not adjusted, they fixed for ever - under the 2015 rules

neither the gears in the gearbox nor the gears between the gearbox and the axle shafts can be altered
only replaced with identical ones

the drivers (my guess) use only gears 1-6 at Monaco - they can't go fast enough for gear 7 and gear 8
maybe at Silverstone they use only gears 3-8 after the start (because there's no slow turns)

ratio means how many crankshaft revolutions give 1 revolution of the the rear wheels
Last edited by Tommy Cookers on 03 Oct 2015, 16:20, edited 2 times in total.

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hollus
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Joined: 29 Mar 2009, 01:21
Location: Copenhagen, Denmark

Re: asking about gearbox

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This is estimated from online videos assuming a 660mm wheel diameter:

Actual (approximate) gear ratios in F1 in 2015
Rivals, not enemies.

riff_raff
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Joined: 24 Dec 2004, 10:18

Re: asking about gearbox

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F1 gearboxes use a pair of gears for each speed that have a certain ratio of tooth numbers. While the rules don't permit changing the ratio of each gearset and require a certain minimum center distance between the gear shafts, I think the number of teeth can be changed as long as other requirements are met. For example, you can use a 20T/40T gearset instead of a 22T/44T gearset, since both provide the same ratio. Can't say if it would provide any benefit though.
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

autogyro
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Joined: 04 Oct 2009, 15:03

Re: asking about gearbox

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The lay gear that includes all the output gears of the gear sets rotates in oil.
A bit like bolting a small washing machine onto the back of the engine.

riff_raff
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Joined: 24 Dec 2004, 10:18

Re: asking about gearbox

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I believe F1 gearboxes are dry sump to minimize windage losses. Changing the number and size of teeth used in a gear set can provide a modest improvement in efficiency.
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

autogyro
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Joined: 04 Oct 2009, 15:03

Re: asking about gearbox

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riff_raff wrote:I believe F1 gearboxes are dry sump to minimize windage losses. Changing the number and size of teeth used in a gear set can provide a modest improvement in efficiency.
So are washing machines.

NL_Fer
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Joined: 15 Jun 2014, 09:48

Re: asking about gearbox

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You afe to late my friend. pre 2014, cars had a 7 gear box, with ratio's ajustable per race. They would have a whole truck, full of drawers with gearsets, just to built the perfect gearbox for just that race.

autogyro
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Joined: 04 Oct 2009, 15:03

Re: asking about gearbox

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NL_Fer wrote:You afe to late my friend. pre 2014, cars had a 7 gear box, with ratio's ajustable per race. They would have a whole truck, full of drawers with gearsets, just to built the perfect gearbox for just that race.
The Jordan 191 had a 6 speed manual gearbox supplied by Hewland.
I consulted with Garry Anderson on gearbox development at the time before visiting Ferrari.
I suggested the maximum number of ratios for the projected 'motor cycle' shift sequential that Garry had in mind was 7 gears.
This was the number of ratios used for the Jordan 192 which by then had the semi auto box I had discussed with Ferrari.
Later the FIA decided to limit the number of ratios to 7.

Much later with the introduction of KERS it was found that the rear of the cars was too unstable under braking with the auto and semi auto sequential down shifts and the FIA allowed 8 gears with more fixed ratios.
So today we have F1 cars that the drivers have little or no control over car pitch and lateral stability in braking.
IMO nearly 50 percent of car control capability has gone.
Front brake lock up is now a result of out of balance electronic control not driver skill level.
The cars might just as well be auto go karts just with more power.

Tommy Cookers
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Joined: 17 Feb 2012, 16:55

Re: asking about gearbox

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in and before 2013 we had 7 speed gearboxes and some variability of final drive ratio
so the total number of overall ratio options within a season was a lot more than the current 8 overall ratios fixed throughout the season
because currently we have no variability of the final drive ratio within the season (or as yet outside the season)

ie in and before 2013 the ratios at any circuit were closer than they are currently
so the current gear ratios are wider spread than they were in or before 2013

unlike 2013 or before the whole gearbox/final drive is now a sealed unit - this is bound up with the unit life rules and penalties etc

ie the ratios have not been made closer (eg to ease downshifts or whatever)
anyway why would KERSing be problematic with the software-implemented 'brake by wire' at the rear ?
the driver brakes exactly as if the car had no KERS capability
software divides rear braking between friction and electromagnetics as appropriate, but total rear braking is always as per driver demand

imo

btw in the 60s small GP motorcycles had lots of gears, the 50cc Kreidler had 13 iirc

NL_Fer
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Joined: 15 Jun 2014, 09:48

Re: asking about gearbox

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Wouldn't there be a different feel between pads/rotors and mgu braking? And with the ratio conventional/mgu changing every corner, i can image they didn't master is perfectly at the 2014 season start.

autogyro
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Joined: 04 Oct 2009, 15:03

Re: asking about gearbox

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TC

ie the ratios have not been made closer (eg to ease downshifts or whatever)
anyway why would KERSing be problematic with the software-implemented 'brake by wire' at the rear ?
the driver brakes exactly as if the car had no KERS capability
software divides rear braking between friction and electromagnetics as appropriate, but total rear braking is always as per driver demand

imo

btw in the 60s small GP motorcycles had lots of gears, the 50cc Kreidler had 13 iirc


The only reason that 8 ratios have not become closer is because instead of dealing with the engine /KERS braking issues as expected by the FIA, most teams decided to use less than 8 gears depending on the circuits used due to the limitations of the 19th century layshaft gearbox and its inferior shift mechanics.
Total rear braking is NOT by driver demand.
The drivers have lost almost ALL control over pitch and lateral stability under braking. (notice the spins ;-) )
Braking is dominated now by computer control.
The cars are no different than ungeared go karts other than power levels.

When I was consulting with the Honda MC team I had a prototype 25 speed bevel epicyclic gearbox under test.
It was solely regulations and the limitations of lay shaft boxes that stopped multi speed development.

mirna.bagic
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Joined: 13 Oct 2015, 11:52

Re: asking about gearbox

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Where can I find information on gearboxes used in the 80's? Were they using the clutch and if so how could they downshift so fast and with so much force?.

riff_raff
132
Joined: 24 Dec 2004, 10:18

Re: asking about gearbox

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Only used the clutch for starting or leaving the pit stall.
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

spacer
9
Joined: 01 Nov 2009, 20:51

Re: asking about gearbox

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found this interesting, in the sauber vid below you can actually see the clutch being automatically blipped at every downshift

https://www.youtube.com/watch?v=0sR5oCIfXDI

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