[BlueSuzy]

Hey ya'll

Just abit of research that i need some help.

Some may or may not know my project, anyway, Im looking for some diff gears that will correct the speedo to suit the tyres. Does anyone know how to sort this out? Id rather sort out the gearing to suit the smaller tyres rather than pay more for a speedo adaptor, Bit of a way to cheat then just run larger tyres anyway after engineering..

Prob try to run 31's or under (i know weird request but i have my reasons Trying to get most of my lift engineered suspension only, as limits are involved, long story.. )

I will be running hilux diff centres so there is numerous ratio's avaliable. 4.11, 4.5, 4.88, 5.12

Diff calcs are a pita, They do not show speeds of original and modified. Only revs at certain speeds, unless im missing something because its 1.20am..

Any help would be great, thanks.
Tim.

[31zook]

my stock lwb with 29s (which over 5ks is about 75meters out/checked against those counters on the highwat) does 3100 rpm @100kph. Thats the correct rpm for 100kph, so from there you can work out your drive line.

The 1L case with a switch has a different speedo drive ratio, its a touch lower, thats why my 29s and rock lobster equal out....

[Teracis]

Try using this
http://www.grimmjeeper.com/metric_gears.html

You should be able to get all the ratios from there, and work out your transfer output shaft rpm for a given engine rpm/wheel speed with stock gearing and also whatever gearing you are trying to run.

Then you just need to increase the tyre size and diff ratio until you get the speed you are looking for at the same transfer output shaft rpm.

[S13RR4]

have you tried this one?

http://www.lepayne.com/gears.html

it shows stock gear and MPH( miles I know) to compare

[BlueSuzy]

Thanks Sierra and others!

That samurai specific one i played with last night, but just couldnt get the speeds right. I shouldnt of put in the transfer gears as that changes overall speeds on that chart..

All i did was type in 4.11, 4.3, 4.5, 4.8 with 31's and they are almost spot on same mph

4.5's with 31's are within 1mph. Is that less then 10% allowance for adr's? I can always try and correct that further with the slight adjustment in the cluster.

Cheers guys!

[want33s]

http://www.marlincrawler.com/java/getspd_calc.html