Square Four gearing

[leonc]

I had an interesting day on the primary side of the 52 4G long term project.
When I pulled everything down, I found several sprockets that had been welded and I assumed repaired, during this bikes long hard history. A tooth count showed that this has in fact been modified to give it significantly higher gearing.
The engine sprocket is a 29 tooth (unsure of standard?), the clutch a standard 44 and the gearbox 21, not 19.
So longer legs, however for my intended general use when back on the road, i am inclined to go back to standard.
Any comments or observations appreciated.
Leon

[brenton.roy]

I think standard gearing is a bit low for current roads, particularly if you are doing any highway riding.

[GuyWalton]

I bought one from a Vincent HRD comet which is exactly the same if you have any difficulty getting the one you want . Seems to be more of the available at a reasonable price £32 if I remember correctly .

[simon.holyfield]

I think standard gearing is a bit low for current roads, particularly if you are doing any highway riding.

Me too. I guess it depends where you ride - for me, it is mostly open roads without much traffic. Remember if you ride a lot in town with low engine speed, you may not charge the battery effectively.

[JohnnyBeckett]

HI if you was riding on open roads i would leave as it is now if you was doing a lot of slow riding i would change it to standard to keep the revs up and run better

[leonc]

Yes the easy option is to leave it alone and see what the real world result is like. Typically I ride the open road, so charging around town will not be a significant issue.
In saying that the gearbox sprocket is a bit ropey and could do with replacement anyway!

[JohnnyBeckett]

HI it looks like drags do not do the sprockets you are looking for you will have to look at other models of motorcycles to find them

[paul.jameson]

This is considerably higher than standard, which has a 25T engine sprocket for solo use (26T on the Mk II). I am surprised that a 29T will fit in the cases. As others have said, it all depends on the type of riding you do. Many riders increase the gearing these days but the downside is lack of charging, especially if you go 12 volt without Bennet Longman's alternator conversion and actually use the lights. I had standard gearing on my 1953 MKII and 12 volts but after a long ride in pouring rain at about 55mph the bike stopped due to lack of charge in the battery at the traffic lights close to home. This was using the standard dynamo.
I did a lot of miles on my 1948 4G with a fairly light sidecar on standard gearing. There is plenty of power available for this. My current 1936 4G is also on standard gearing which feels a bit high for club runs but is still fine for a long run at 55-60mph. If I wanted to ride faster than this for long distances I might raise the gearing - but I don't have any such desire. If I was going to do a Club London - Edinburgh run (400 miles in a day) - I would do it on standard gearing.

Just to make you aware of my preferences, my RH500 has a 22T engine sprocket rather than the standard 23T. For everything other than motorway cruising, the lower gearing is, in my view, better. And it keeps me off the boring motorways.

[JohnnyBeckett]

you can use LED lights you can run a very long time with out it charging like i do and they are brighter

[david.anderson]

I think that the gearing is way too high. My mk2 is fitted with a 26 engine sprocket and I have also run with a 25. The 26 involves a bit of clutch slipping to take off up hill, two up and I would not want first gear any higher.
The fitting of a 21 gearbox sprocket means the speedo will be incorrect. The final gearing must not be altered or the speedo reading will be out.
David