Outer Limits 4x4 Board

just a quick question Can you get different geared drives for the speedo in a sierra. Im running 31tyres and would like to get the speedo a bit more accurate without having to install rockhoppers or change diff ratios.

speedos can be recalibrated at many auto/race/speed type shops and at guage type shops, one in Ringwood somewhere, christover

Rockhoppers dont correct speedo anyway.

i was under the impression that a rockhopper does affect the speedo too. and if you geared down the same ratio as what you increase in tyre size all would be right again

Calibrate it!

Rockhopper changes gear ratios inside the transfer.
Speedo gear is driven off the rear output shaft in the transfer, not the gearbox.
So in effect, the rockhopper does not effect the speedo.
If you want to use gearing to correct the speedo, change the diff ratios.

Go to any instrument technition (look them up in the yellow pages) and tell them you need a "ratio box" made for your aplication, they are about the size of a computer mouse, made of die cast alloy and are essentialy a small gear box the uses a combination of tiny gears to correct your speedo they are usualy mounted at the transfer case end, however I hade mine fitted to the middle of the cable to get it up and out of the shit (I had them make a new 2 piece cable for me at the time).
When you are done your speedo will be spot on.
Peter.

so they are unlike normal cars where you can just replace the speedo drive to correct the speedo.?

droopypete wrote:Go to any instrument technition (look them up in the yellow pages) and tell them you need a "ratio box" made for your aplication, they are about the size of a computer mouse, made of die cast alloy and are essentialy a small gear box the uses a combination of tiny gears to correct your speedo they are usualy mounted at the transfer case end, however I hade mine fitted to the middle of the cable to get it up and out of the shit (I had them make a new 2 piece cable for me at the time).
When you are done your speedo will be spot on.
Peter.

sounds like a nice fix... how much did that set ya back(ballpark)??

grey zook wrote:so they are unlike normal cars where you can just replace the speedo drive to correct the speedo.?

That is correct grey zook, it is not like an old Ford that came with 3 or 4 diferant engine options with 3 diferent gear boxes and a choice of 4 diff ratio's, you cant just mix and match the cogs to get the combo you want, that would be far too easy
Peter.

I was told by a few people to go to your local RACQ workshop(only in Qld) and that they'd have or be able to get a part(some kind of adaptor for the speedo cable) to fix problem....haven't done it as yet and again, it might be for more common cars

emkate wrote:I was told by a few people to go to your local RACQ workshop(only in Qld) and that they'd have or be able to get a part(some kind of adaptor for the speedo cable) to fix problem....haven't done it as yet and again, it might be for more common cars

Emkate, 4 posts up
Peter