Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: wildwood on December 03, 2010, 12:22:10 PM

Title: Gearing Math(s)
Post by: wildwood on December 03, 2010, 12:22:10 PM
Just found another equation for gearing that came out of Crawl mag

Might be useful for those going up a size or 2 and who know their current ratios...........

Works like this and I'll use my own rig as example
I am going to a spit near 40" from a spit near 35" with current 4.56 ratio

40 divided by  35 x  current ratio =

So 40 div by 35 = 1.142 x 4.56 =5.21

So picking nearest 'deeper gearing' means 5.38s thank you

Seems to work with other ration equations that are more complex..... hope it is of use :icon_twisted:

Title: Re: Gearing Math(s)
Post by: Bulldog67 on December 03, 2010, 12:36:40 PM
I have bookmarked it for a day when i get that far  :icon_winkle:
Title: Re: Gearing Math(s)
Post by: scrw on December 03, 2010, 12:58:02 PM
hey that works
stock WG, 29" & 3.55 to 32" and 3.91
Title: Re: Gearing Math(s)
Post by: JamesH on December 03, 2010, 06:13:29 PM
Seems good, and I like the advice about going to next deepest - makes up for the added weight as well as increased diameter (to some extent).
Title: Re: Gearing Math(s)
Post by: Nosebolt on December 03, 2010, 06:45:11 PM
or you could use the Birtys Gearing Guide (http://www.birtydastards.com/frm/index.php?action=ezportal;sa=page;p=14) or the Tyre and Gear Calculator (http://www.birtydastards.com/frm/index.php?action=ezportal;sa=page;p=8)  :003:
Title: Re: Gearing Math(s)
Post by: scrw on December 03, 2010, 06:47:23 PM
But its wrong, certainly for my WG
Title: Re: Gearing Math(s)
Post by: Nosebolt on December 03, 2010, 06:55:04 PM
But its wrong, certainly for my WG

are you sure,

the calc says 29" & 3.55 to 32" gives 3.917

and the chart says for 32s between  3.73 for economy to 4.56 for power or 3.91, 4.11 or 4.27 for something in between