correcting spedo by changing diff ratio

[brad 93hilux]

g'day i have a ln106 hilux and was recently clocked by the cops doing 20kms over the speed limit.

My question is i have 4.3 ratio diffs in the truck (with 33's) can i correct the spedo by putting in like 4.8's or something...
At the moment my low range gearing is up to shit and had the idea this might put it back to normal??

Any one done anything like this and what ratio did you use???

Cheers
brad

[Shadow]

what speed did your speedo say when you were 20k's over. Need a ratio...

Assuming hilux comes standard with 29's, and you now have 33's fitted.

33/29 * 4.3 = 4.89

so yes 4.8 or 4.9 diffs would go a long way to putting your speedo back to standard, and would fix your low range problems.

[brad 93hilux]

i was doing 94 and was told by the cop'a that i was doing 114.

thanks heaps

[brad 93hilux]

and my next question is, is i have a lockrite in my diff centre and am gonna get a airlokka for the front, if i get 4.8's will i jst be able to swap the open centre in a 4.8 to one from a 4.3...

I am guessing that both ratios will fit in the same housing??

Is this correct.

Cheers

[diesel028]

From the speeds you have just quoted your speedo is out by 17.6%. going to 33's with std ratios should only put your speedo out about 10%....
go and find one of those 5km odometer check zones, clear your tripmeter as you start, once finished the 5kms see how far you have driven. I reckon your tripmeter would read around 4.12kms. Unless the cops radar was out.......

[Shadow]

From the speeds you have just quoted your speedo is out by 17.6%. going to 33's with std ratios should only put your speedo out about 10%....
go and find one of those 5km odometer check zones, clear your tripmeter as you start, once finished the 5kms see how far you have driven. I reckon your tripmeter would read around 4.12kms. Unless the cops radar was out.......

33's should put it out by about 14% (4/29)

114 when he thaught he was doing 94 means the speedo is 21% out. (20/94)

going from 4.3 to 4.8's is a 12% reduction, (0.5/4.3).

The bottom figure in a ratio is always the current spec, the top is the new spec (or difference).

Im no diff expert but the 4.8 ring and pinion should bolt straight to the lockright centre AFAIK, and yes, if you get 4.8's from a hilux (or hiace) it will fit your housing.

[diesel028]

From the speeds you have just quoted your speedo is out by 17.6%. going to 33's with std ratios should only put your speedo out about 10%....
go and find one of those 5km odometer check zones, clear your tripmeter as you start, once finished the 5kms see how far you have driven. I reckon your tripmeter would read around 4.12kms. Unless the cops radar was out.......

33's should put it out by about 14% (4/29)

114 when he thaught he was doing 94 means the speedo is 21% out. (20/94)

going from 4.3 to 4.8's is a 12% reduction, (0.5/4.3).

The bottom figure in a ratio is always the current spec, the top is the new spec (or difference).

Im no diff expert but the 4.8 ring and pinion should bolt straight to the lockright centre AFAIK, and yes, if you get 4.8's from a hilux (or hiace) it will fit your housing.

....i was never real good at Maths

[grott]

My ln107 read 4.2km on the 5k speedo checks with 33" tyres and standard 4.3 diffs. ie 94k=100k

[Shadow]

My ln107 read 4.2km on the 5k speedo checks with 33" tyres and standard 4.3 diffs. ie 94k=100k

5km/4.2km = 1.19, 19% overdrive. It should mean that about 85KM/h on your speedo is 100km/hr.

[Bumpy45]

Know anyone with a portable GPS unit? Stick it in the car and go for a drive, most of the units give a speed reading. Grab a felt pen and mark the relevant speeds on the speedo dial, or take the clear cover off and mark it direct.

[bastard]

ln106 4:3 gears with 33 and your speedo should read 88kmh to give you a true 100kmh,tested on the wekend with hand held gps and 2 other new cars.

[dirty harry]

i have a ln106 hilux, i'm running 4.8's with 35's and my speed is spot on.