diff and speedo help

**leigh 7005** · 30-05-2009, 08:51 AM

ok ive put a vl diff into my vb sle 3.45 ratio and the speedo is miles out can i just put a higher profile tyres on to compensate they are 205-65-r15 if i go to 215-75-r15 will this have much affect? has anyone fixed this problem or have a calculator so i can work it out also im gonna have to change diff as the 3.45 is not the best at 80kph it sits on 3000rpm so im gonna have to go 3.08 soon darn it

**pjdm1980** · 30-05-2009, 10:54 AM

Try your local diff or trans center they can give you a different drive gear for your speedo just sits under your speedo cable in your gear box .
there is one 10mm bolt holding it in then you pull your cable out and it should be on the end or sitting in the gear box.

**ari666** · 30-05-2009, 05:26 PM

yeah i think that speedo gear is a load of bull to be honest. i have tried a few shops and they dont know of any gears for my ratio. (3.55)

unless you have ratio's that the car came with then there is no gear to make suit. i.e borg warner diff with *blah* ratio and turbo 400 fitted to a vb that only has *blah* ratio and trimatic will never match up.

the only thing i have found is a thing called a 'ratio-box' sold by a guy in ballarat which is 200 miles from my house and he needs to keep the car...

if you descover anything please let me know.

**vkberlina** · 30-05-2009, 06:45 PM

Originally Posted by leigh 7005

ok ive put a vl diff into my vb sle 3.45 ratio and the speedo is miles out can i just put a higher profile tyres on to compensate they are 205-65-r15 if i go to 215-75-r15 will this have much affect? has anyone fixed this problem or have a calculator so i can work it out also im gonna have to change diff as the 3.45 is not the best at 80kph it sits on 3000rpm so im gonna have to go 3.08 soon darn it

I have a speedo gear chart on my site.

Also I have a full range of M series gearbox speedo gears all in good condition.

have a look at my site work out what you want and let me know

cheers
Scott

**ari666** · 01-06-2009, 01:44 PM

Originally Posted by vkberlina

have a look at my site work out what you want and let me know

cheers
Scott

please tell me you have a gear for the 3.55 in my VK?

pleasepleaseplease. i have asked sooo many places, no one has a clue.

**muttley383** · 01-06-2009, 02:11 PM

If you cannot get the correct speedo drive gear for your gearbox then it is a simple as going to any reputable automotive instrument serviceman and getting them to make up a ratio box for your particular situation.

**ari666** · 01-06-2009, 03:22 PM

"reputable automotive instrument serviceman"

you know of any?

**vkberlina** · 01-06-2009, 06:37 PM

Originally Posted by ari666

please tell me you have a gear for the 3.55 in my VK?

pleasepleaseplease. i have asked sooo many places, no one has a clue.

Yes I have a gear, i have in stock everything from 19 to 24 tooth gears.

What gearbox have you got?
What size wheels have you got?
What size tyres have you got?
what speedo gear have you got at the moment?
either -
what RPM are you doing at 100km/hr?
how much is your speedo reading out by?

I estimate without knowing the above you need approx 23tooth gear I have 3

cheers
Scott