Gear ratios.

[MeggyMoo]

Hi all,
Wondering if anyone could advise on the following. I have a Mk1 Haf I am restoring with the four speed gearbox, I want to increase the road speed by changing to the higher ratio gears in the hubs, will this exert too much strain on the engine? if so I have a spare five speed gearbox & shorter centre tube which I can fit, basically are the ratio's of the four gears used in the Mk1 box the same as the one's in the five speed box other than the crawler (fifth) gear & the different intermediate shaft i.e. the gears in the larger front section of the five speed box? To put it another way, if I just change the ratios in the hubs & retain the Mk1 four speed box will the gearing be the same as a Mk2 five speed box other than the crawler gear?
I hope this makes sense! any advice would be appreciated.
Thanks in advance Bill.

[AustHaflinger]

I cannot speak to the early 4 speed gearbox as I have no knowledge of it - I do have knowledge of hub gears. Overall you will not increase road speed. What you will do is lower engine revs for a given speed, and lower your performance up hill and under load due to higher gearing.

I have hi speed gears, 14" wheels and get along quite well cruising at 4000-4500RPM (70 - 80kph) BUT my engine is larger and can pull the higher gearing but still dies up hill.

With a standard 650cc engine you will gain little if any extra cruising speed, unless you are going downhill but you will reduce engine revs for any given speed.

Also if you do go to hi speed (75kph) hub gears, only use original Haflinger gears and not reproductions as they have questionable metallurgy and can fail - I have a thread on this issue.

Garry

[MeggyMoo]

Thanks Garry PM sent.
Another approach, the parts manuals I have show the five speed gearbox, does anyone have a parts manual for the Mk1 four speed gearbox so I can cross reference part numbers of gears etc. This would give me an idea as to differences in the two.

[AustHaflinger]

For Bill - some information on Hafs with the 4 speed Krawler and the later 5 speed. You can compare this with your vehicle. As I have said - I really know nothing on the very early straight 4 speed Hafs but others may know.

Haflinger_Specs.pdf

(59.33 KiB) Downloaded 105 times

Garry

[MeggyMoo]

Many thanks for your help Garry, lots of food for thought.