DamirGTI 342 Posted January 8, 2007 Hi ! Please , can somebody tell me how to read (understand) gearbox ratios ? for instance : 1.6/1.9 3,31 1,88 1,36 1,07 0,87 3,69 1.6/1.9 5,5 9,7 13,4 17,1 21,0 what these numbers means , rmp.?! if so how rmp. upshift downshift ? and what is final drive ? sorry but i struggle with this for a long time , never manage to understand that http://www.mdracing.co.uk/gear_ratios1.xls Share this post Link to post Share on other sites
sutol 0 Posted January 8, 2007 It's easy 3.31 means 3.31turns of the input shaft (gearbox to clutch) equals 1 turn of the relavent gear cog in box. 3.4 to 1 diff means ........What does it mean ? well on a Mini it means 3.4 turns of the crank = one turn of the road wheel so on a Pug it would mean.....Help Share this post Link to post Share on other sites
DamirGTI 342 Posted January 8, 2007 bloody mathematic so it means crank turns ? ok , and how can i tell which gerbox ratio is best by that ? Share this post Link to post Share on other sites
sutol 0 Posted January 8, 2007 First you need to measure the circumference of the roadwheel allowing for tyre deflection by weight. This will tell you how far the vehicle travels per wheel revolution (handy for later) Then you need to count how many turns of the roadwheel to turn the engine one revolution in selected gear That will give you a 00 to 1 figure If you want more max road speed in that gear then you change the ratio e.g. dump 3.33 to 1 and insert 3.01 to 1 (ficticious figures) etc I'm of to bed now Share this post Link to post Share on other sites
whizzer71 0 Posted January 9, 2007 (edited) Take a look at http://www.mckeown-enterprises.co.uk/downl...tiosGti6.xls,It really is very usefull giving ratios,allowing you to insert you own ratios(providing you have the relevant gears) to build custom box etc,Also give final drive ratios ,relevant road speeds and speeds per 1000 rpm in any one given gear,Also allows you to insert tyre size ! Edited January 9, 2007 by whizzer71 Share this post Link to post Share on other sites
Baz 421 Posted January 9, 2007 Broken link that is! Share this post Link to post Share on other sites
smckeown 1 Posted January 9, 2007 http://www.mckeown-enterprises.co.uk/downl...5ratiosGti6.xls or check my sig Share this post Link to post Share on other sites
smckeown 1 Posted January 9, 2007 I think i'll update it soon to calculate the useful transmission output torque and appropriate shift revs per gear to maximise acceleration. If I get a spare evening this week i'll do it.. Share this post Link to post Share on other sites
whizzer71 0 Posted January 9, 2007 Broken link that is! Sorry m8,I seem to have added some letters to Tris Share this post Link to post Share on other sites
Baz 421 Posted January 9, 2007 http://www.mckeown-enterprises.co.uk/downl...5ratiosGti6.xls or check my sig Cheers Sean! Very handy! Share this post Link to post Share on other sites
DamirGTI 342 Posted January 9, 2007 Thanks on advices ! cheers Share this post Link to post Share on other sites
