Top speed / gear ratios / calculations

[jp_lcr]

Apoligies if asked before but does anyone know the standard gear ratios for a 172 Cup gearbox, tried searching but not found it?

I'm wanting to confirm max speed in each gear, think there are calculators online from gearing and tyre dimensions to work out theoretical max speed, also any easy way to factor transmission losses?

I work in data / analytics like playing with numbers and wondered whether can model the odd corner / section which is borderline for which gear, appreciate there are a thousand other factors but all other thing being equal there must be an optimum.

If I'm thinking about it in the wrong way happy to be corrected, just an idea

 

[Eddie555]

Overthinking it. I just drive it like I stole it. ?

 

[imprezaworks]

bet your fun at parties lol

x

 

[mantis946]

Something I put together a while ago for my PH1, may be of help.

Car

Power

Weight

P/W

drag coe

Rev limit

ratio 1

ratio 2

ratio 3

ratio 4

ratio 5

ratio 6

ratio 7

FD

Wheel diam (M)

Clio

165​

1.035​

159.42​

0.358​

7250​

3.09​

1.86​

1.32​

1.02​

0.79​

4.07​

0.576​

MPH

38.90​

64.63​

91.06​

117.85​

152.16​

 

[Hollidog]

This is from the PMS website, seems to be accurate to me, ignore the last red line as this relates to installing the 5th gear from a Megane box.

You can find it here

 

[Usr117063]

JC5, JB3, JB5, JB1 and JB0 Renault Gearbox Ratios

All JC5, JB3, JB1 and JB0 Renault gearbox Gear ratios - 1st Gear: 3.091 2nd Gear: 1.864 3rd Gear: 1.321 4th Gear: 1.029 5th Gear: 0.794 Final Drive: 4.067

www.volvohowto.com

 

[jp_lcr]

thank you Cliosport for the piss taking I was expecting and the info

 

[jp_lcr]

sits in corner at party with calculator

 

[massiveCoRbyn]

I've got a spreadsheet with them on somewhere (and one for 197/200). Allows you to input tyre sizes, engine speed etc. If you'd like it, send me your email address and can send it over.

 

[RIC172]

 

[Nafoff]

I've got a spreadsheet with them on somewhere (and one for 197/200). Allows you to input tyre sizes, engine speed etc. If you'd like it, send me your email address and can send it over.

Morning chap, is it possible to get this file off of you please? would be very useful as I am setting up my RT dash

 

[Nafoff]

Something I put together a while ago for my PH1, may be of help.

Car

Power

Weight

P/W

drag coe

Rev limit

ratio 1

ratio 2

ratio 3

ratio 4

ratio 5

ratio 6

ratio 7

FD

Wheel diam (M)

Clio

165​

1.035​

159.42​

0.358​

7250​

3.09​

1.86​

1.32​

1.02​

0.79​

4.07​

0.576​

MPH

38.90​

64.63​

91.06​

117.85​

152.16​

Was this for a 15" wheel?

 

[bozothenutter]

If you add air resistance you can approx actual speed...😉

 

[mantis946]

Was this for a 15" wheel?

15" with a 195 tyre, changes to 0.586 if it's a 205.

 

[mantis946]

If you add air resistance you can approx actual speed...😉

I calculated that too haha need power (In watt's I think it was) area of the car, drag and air density. Done the below based on sea level if I recall.

Power (BHP*746)	123090​
Width	1.639​
Height	1.417​
Area (Width*Height)	2.322463​
Drag Co	0.358​
Air Den	1.25​
Max speed	132.81​

Surprising how much reducing drag buys you in performance, if the 172 had similar slippy-ness to a GTR you'd get:

Power	123090​
Width	1.639​
Height	1.417​
Area	2.322463​
Drag Co	0.27​
Air Den	1.25​
Max speed	145.77​

 

[bozothenutter]

I calculated that too haha need power (In watt's I think it was) area of the car, drag and air density. Done the below based on sea level if I recall.

Power (BHP*746)	123090​
Width	1.639​
Height	1.417​
Area (Width*Height)	2.322463​
Drag Co	0.358​
Air Den	1.25​
Max speed	132.81​

Surprising how much reducing drag buys you in performance, if the 172 had similar slippy-ness to a GTR you'd get:

Power	123090​
Width	1.639​
Height	1.417​
Area	2.322463​
Drag Co	0.27​
Air Den	1.25​
Max speed	145.77​

This I like!