Rear Diff ratio's

[m9fdb]

Would it be possible to fit a differential with a different ratio to lower the RPM at speed in my MOD stag ?

I don't know what ratio is in it at them moment though so if someone could also explain how the ratio number work i would be grateful as its a minefield to me.

I find that my Stag is revving to high at say 60 or 70 MPH and want to lower the RPM - Its probably me being used to driving a modern car but i find that the RPM's are high even when I put it in Overdrive.

I don't think there is anything wrong with the stag as it drives fine but i would prefer it to be lower when on a motorway if possible.

Cheers

Darren

[Jeff]

Loads and loads of info on here.

Standard dif ratio 3.7.

Most change to 3.45.

[mole42]

If you get a diff from a 2500 estate it should be 3.45 and will fit straight onto the diff nose extension. Your speedo will be inaccurate!

[Lingen]

Darren. As you will have read, a 3.45 diff is easy to fit, and a big improvement on an automatic car. However, and it is only my opinion, when I fitted one to my manual/overdrive car, I found the ratio too high. The car was struggling on motorway gradients in overdrive top. Probably because the Stag engine doesn't develop its maximum torque till it is doing 3500 revs. Even with the correct diff this is over 85 MPH!
Mike.

[GDPR]

Running a 3.45 diff in my ZF auto car, straight from a 2.5 PI mk2 estate - mounts directly to nose extension and diff mounting beam. 2500S speedo brings speedo to near as damnit correct, and I have no issues with running out of steam on gradients. BTW it is 30mph per 1000 rpm on top/lockup

[m9fdb]

Interesting you say about the speedo as that is out by about 10mph I noticed the other day.

[m9fdb]

Interesting you say about the speedo as I noticed that it was about 10mph out the other day it's showing about10mph slower than the actual speed.

[GDPR]

Try a 2.5 PI speedo if you have a mk1 or a late PI or 2500s if a mk1.5 or 2

[m9fdb]

I was going to get Alan at the Gauge shop to calibrate the speedo for me

[pollystag]

Hi darren,
have a look here,
http://www.club.triumph.org.uk/prefix1.htm,
then crawl under your stag and wipe all the grease and oil off the bottom and on the flat bit in the middle you can just make out the number, it should be ld----- which is 3.7 and a stag one,
i have just found out that my replacement diff which is cd, is from a triumph tr250 export model but is still 3.7.
steve.

[m9fdb]

Hi darren,
have a look here,
http://www.club.triumph.org.uk/prefix1.htm,
then crawl under your stag and wipe all the grease and oil off the bottom and on the flat bit in the middle you can just make out the number, it should be ld----- which is 3.7 and a stag one,
i have just found out that my replacement diff which is cd, is from a triumph tr250 export model but is still 3.7.
steve.

Cheers Steve I'll have a look

[thebadleys]

These are the ratio's for the different models, its stamped on the bottom, length ways.
The stamping is very faint usually, you need to clean it up then catch it in the right light, ask me how I know, I've been looking at diff for the last few weeks.

Triumph Ratio Ratio
Model Manual Auto


2000 Mk1MB 4.11 3.7
2500pi Mk1 MD 3.45 3.45
2000 Mk2 ME/MF 4.11 3.7
2000 Mk2(post 1975)ME/MF 3.7 3.7
2500 Mk2 MG 3.45 3.45
STAG LD 3.7


The paint colour on an output shaft could also tell you,


None 4.11,

[mjheathcote]

Standard diff with the auto is high reving, however it does mean she is right in the powerband when you want to go!

[simontink]

Does the MOD rev high with the standard diff?. Thought this was more of a problem with the auto.

[staginmacc]

is a diff used with auto the same as that used on manual with overdrive?