higher ratio diff

[dalebrignall]

i am thinking about fitting a higher ratio diff to my 1098 traveller i want to take the revs down a bit when crusing .will i loose out when going up steep hills etc ,advantages and dis advantages please .

[bmcecosse]

So - that would be a LOWER ratio final drive - the 'diff' would not be changed...... My Trav pulls the 3.7 final drive very nicely indeed - but the engine is warmed up. I doubt changing to a 3.9 would make a worthwhile or even noticeable difference (no pun intended..) .

[Stoneporch]

We have a previously mentioned Traveller, which has a midget engine producing a claimed 100 bhp. Could bmcecosse, or any other knowledgeable member, suggest the advantages of fitting a 3.7 final drive and/or a 5 speed gearbox. 3000 rpm currently gives approx 50mph. What could 3000 rpm produce with the above changes? (Which car was fitted with the 3.7 final drive?)
Thanks.

[bmcecosse]

I have the 3.7 final drive in my Traveller - but I don't have a rev counter. However it pulls that ratio very nicely, with an engine I estimate to be 55/60 bhp at best. The 5 speed box conversion is very much more expensive than just changing the final drive- but since it has an overdrive top gear, I suggest it would be best to retain the 4.22 final drive if going that route. However - if your engine really IS 100 bhp, it's likely to be poor on low revs torque, and will require to be revved hard to make the power..... so a 3.7 final drive may not be ideal for that spec of engine. Do you have any details of what has been done to the engine ?

[smithskids]

I had a 1300 engine and one way to increase the final drive ratio is fit 205X14 rears on wide wheels, keeps the revs down and the tread just fits inside the wheel arches.