Hartley on gearing

[PeterW]

Just spotted this in the letters page of The Motor Cycle.

Personally I like higher gearing for a more relaxed pootle but if you want to go fast....

[Mike Nash]

Thank you, Peter for this.

Like many I suppose, I added a tooth to the engine sprocket for a smoother and more relaxed ride and in London traffic I found the slightly higher intermediate gearing of my VB was an advantage and the change in top gear of little consequence, but I found that out on the open road a light head wind or slope knocked the speed down more than I wished. So now I’m of the Lawrence Hartley school of gearing, trying to match the max speed with the peak power revs. (But of course, on a single the vibration at your preferred cruising speed is always a consideration.)

This letter seems typical of Hartley. He seems to have corresponded with various parties and been open with his opinions and data, quite unlike later engine tuners that I knew of in the early ‘60s when I was mechanic to my cousin’s Nortons; they were a very close bunch. Since he seems to have been the “go to” man for Ariels might we not gather and encourage the publication of such documents and put them into a club website Archive Room for future reference? I’m hesitant to make more work for our website mechanics (being quite ignorant of how the gears, levers, ropes and chains of these things function) but over the years there seems to have a good deal of his advice floating around which as far as I’m aware is uncollected together. And is there a biography?

Regards from MikeN.
PS I see that “Cheval de Fer” is serializing “Birth of the Red Hunter” by A C Perryman. Might this also be a candidate for an Archive Room?

[paul.jameson]

We have a lot of information from Hartley in the AOMCC Archives. Many members wrote to him for advice and much of that has found its way into the archives. A lot of what he wrote was standard advice on tuning but some gems exist and most letters from the man offer a special camshaft or piston. Invariably, it is the last one he has so the member in question duly paid the money and bought the item.
One AOMCC member in particular has done a lot of research into Hartley's methods. This work is incomplete and unpublished but I have seen parts of it which are interesting, to say the least. Until such time as this work is published, "The Ariel Story" by Hartley's son Peter, available through the Club, remains a very detailed and instructive account of Hartley's work.

[nevhunter]

Over gearing can keep the revs down a bit but can make a bike feel underpowered as any rise or headwind makes it just die and you need to down change much more. Many think the bike will go 10% faster is the gear is 10% higher. Not so. VW Kombi vans went slower in top than 4th and many overdrives are useless on anything but an absolutely flat road with no headwind. Nev