Type 9 speedo ratios

[chrisryder]

I've always been led to believe that with a standard late 1098 minor, fitting a ford type 9 with a 8*22 speedo drive made the speedo pretty much spot on.

I also thought, and had been told, that the 8* was most commonly in type 9's so all you have to do is change the driven gear to a 22 tooth.

In enquiring about a recon box for Bluey today, i asked if it could be fitted with an 8*22 in the recon process, and have been told that 8* is very rare, and he can't source one for me.

Is 8*22 correct? or have all of these type 9's with 22 tooth drives fitted actually been fitted into some other number (7* or 9*?).

If it's true and 8*22 is correct, and 8*'s are unavailable, is there any other ratio that comes to the same or close?

Does anyone know the speedo ratio of a standard rib case box that i can try and find ford gears to suit?

Or does anyone know what ratio they've got in their box and how innaccurate it makes theirs?

Help! I need to come up with a ratio soon to get my box completed!

[win]

Hi Chris
Sorry I know nothing about type 9 boxes.
The speedo reduction in a standard ribbed morris box is 2.6/1.
1 rev speedo cable = 2.6 revs output shaft.

Regards Win

[chrisryder]

thanks win, that's really helpfull!

so 2.6:1 is what i'm aiming for.

with an 8 tooth drive, ideally i'd want 20.8 tooth driven.
with a 9 tooth drive, idealy i'd want 23.4 tooth driven.

I wonder if there's a 10 tooth drive, as then a 26 tooth driven would be perfect!

or if there's a 7 tooth drive, 18.2 teeth would be right, so if there's a 7*18 that could be pretty close!

thanks for that win! you might have just cracked it!

[daveyl]

You could always try speedy cables for your speedo to be recallibrated. Unless you can get the correct drive cheaper.

[chrisryder]

apparently 8* is the highest available, and 22t is the lowest available, so 8*22 is the closest i can get to 2.6:1, with a ratio of 2.75:1. It'll have to do!

He's managed to 'pull in a favour' and find me an 8* drive, i had no idea they were so hard to come by.

The speedo will be out, but not by much hopefully. I can't see me going to the trouble of getting the speedo recalibrated, Bluey's speedo has never been right, but has always been close, and once i work out how 'out' it is i'm fine, and can mentally recalibrate. At the moment the speedo is way out with the 5 speed, so i'd like it to be closer, just to get my mileage somewhere near right!

I might have a go at working out the optimim tpm for the speedo and see if i can find a speedo to suit, but i'd rather keep her original speedo, even if nothing else is original!

[win]

Better leave a generous safe braking distance, if your going to be dividing your speedo reading by 5.76923%. on a regular basis.

I am sure you will cope.

Regards Win

[win]

oops it should be multiply, your speedo will show lower, I think.

Regards Win.

[chrisryder]

once i work out what my speedo says at an actual 30, 40, 50, 60 and 70 then i just have to remember that, and it's quite easy after a few days!

5.7% will be a lot better than the ~20% at the moment!

[Neil MG]

If you know the speedo requirement (from the numbers on the front or from the original spec) and you have the gearbox output (can be measured by moving the car over a set distance) you can order the correct angle drive or converter:

http://www.speedograph-richfield.com/ht ... arbox.html

No reason not to have both speed and distance reading correctly!