14 replies to this topic

[PACINO]

Hi guys! Anyone know if is there a final drive between 3,44 and 3,647:1 (17/62) ?

Cheers in advance!

[Spider]

There's no factory one that's in between those.

You could fit a 3.64 and change the drop gears to one of the 'Economy' sets.

 

You can fit them up in the following ratios;-

 

1.034:1 resulting in 3.53:1 overall
1.035:1 resulting in 3.52:1 overall

1.071:1 resulting in 3.40:1 overall

[ACDodd]

As Moke said using the A+ Helical economy drop gears you can fit a 30 tooth primary gear or a 28tooth input and make 3.52:1 using a new 3.647:1 crown wheel and pinion.

Ac

Edited by ACDodd, 09 November 2022 - 07:46 PM.

[Northernpower]

Hi guys! Anyone know if is there a final drive between 3,44 and 3,647:1 (17/62) ?

Cheers in advance!

Just out of interest, what's the reason for the question?

[Cooperman]

There is very little noticeable difference between 3.44 and 3.67. Between 3.44 and 3.76 is another matter, but for general use in a road-going 1275 a 3.44 is generally the ratio of choice for mildly modified engines running standard ratio gearboxes.

[PACINO]

Hi guys! Anyone know if is there a final drive between 3,44 and 3,647:1 (17/62) ?

Cheers in advance!

Just out of interest, what's the reason for the question?

The reason is that I am going to remove the engine to fit modern diff outputs and modern drive shafts.
My engine comes from an MG 1300 S and the final drive is very short with a 10" wheel, since originally the MG circulated with a 12" rim.

So I'm thinking of a 'slightly longer' group. That's why I asking to the masters Nicklause, ACDodd and Coperman if there is an intermediate one between 3,44 and 3,65. I just want it SLIGHTLY longer.

Is it clear to you now?

[PACINO]

There's no factory one that's in between those.

You could fit a 3.64 and change the drop gears to one of the 'Economy' sets.
 
You can fit them up in the following ratios;-
 
1.034:1 resulting in 3.53:1 overall
1.035:1 resulting in 3.52:1 overall
1.071:1 resulting in 3.40:1 overall

These ones Spider?

[nicklouse]

 

There's no factory one that's in between those.

You could fit a 3.64 and change the drop gears to one of the 'Economy' sets.
 
You can fit them up in the following ratios;-
 
1.034:1 resulting in 3.53:1 overall
1.035:1 resulting in 3.52:1 overall
1.071:1 resulting in 3.40:1 overall

These ones Spider?

 

Yes but the standard helical cut ones are what he is on about.  If those are yours then you will need to have a look at what the makes produces as most straight cut one you can not mix and match.

[Spider]

 

There's no factory one that's in between those.

You could fit a 3.64 and change the drop gears to one of the 'Economy' sets.
 
You can fit them up in the following ratios;-
 
1.034:1 resulting in 3.53:1 overall
1.035:1 resulting in 3.52:1 overall
1.071:1 resulting in 3.40:1 overall

These ones Spider?

 

 

Yes, but the ones I was referring to as Nick mentioned, are the factory Helicals. The standard set is 1:1 with 29 teeth on the Primary and Input Gears. There was also 'Economy' Gears made, which had 30 Teeth on the Primary (there was also a very rare 31 Tooth too) and a 28 tooth Input Gear, considering the 30 and 28 tooth gears, that gives you 3 combinations (as I mentioned above).

HOWEVER,,,,,,,

You say you'd like 'slightly longer' final drive and assuming you have a 3.44 in there now, fitting these drop gears with a 3.64 final drive, will give you a shorter final drive (except if you fitted the 30 / 28 gear option). Forgetting about Drop Gears for now, there is a Factory Final Drive that 3.205:1 (59/19) that will give you a final drive that's 10% taller / longer.  

 

Just my own experience here, and others I know will disagree, but I found going longer than 27 kph / 1000 rpm (in 4th gear), starts to suck the life from them, to the point were at suburban speeds, rises that are normally tackled easy in 4th gear, you need to drop down to 3rd for and it lost it's nippiness off the line. a 3.44 with 12" wheels puts you right in that 27 kph / 1000 mark.

[PACINO]

Thanks a lot Spider. Brutal answer.

[Midas Mk1]

Thanks a lot Spider. Brutal answer.

Not brutal, it’s called having a search and research, ie what we all did before asking a question before researching was the norm.

Edited by Midas Mk1, 11 November 2022 - 08:38 PM.

[PACINO]

Not brutal, it’s called having a search and research, ie what we all did before asking a question before researching was the norm.[/quote]

But what would you do if I consulted everything and didn't need someone like Spider to answer me? You would not have space to write your 3 lines, make a mistake and edit it.
See what my questions are for!

[coopertaz]

you only learn by asking!!!

[Spider]

you only learn by asking!!!

 

Well,,, there's always blood and tears too,,,,,

[PACINO]

yes, blood sweat and beers.