Best gearing for speed

When I was racing my 500cc Triton. I always used a 4 speed CR box. I could choose where I wanted to lose a race - at the starts of the straights or at the ends. It desperately needed 6 gears. But around 1970, my bike's total cost would have been the price of a decent 6 speed box. On one occasion, I intentionally geared low and was passed at the end of a straight by the really fast guys, only near the end of a complete lap. They got into the next corner too hot and I ran off to avoid hitting one of them. Only one good thing came for me out of those days - now I am competent. So racing for me now presents no problems, except I am probably too old and poor.

My Seeley 850 now has 6 gears close ratio. It was, at a stretch - good enough to win with the 4 speed CR box. However - for me, next time might never come.
The most difficult thing about getting old, is to keep the urge going. Most days, I cannot bear to even look at my bike - it's a grief thing. The guy who ran our local raceway died on an operating table, and since then the local car club has gone stupid. Sometimes I get to the gate of the raceway then turn the car around and go home. I know I should not be like that, but the effect is decreasing with time, so there IS hope yet.

OK. 6 speed tried out at Chimay, and wow, the engine accelerates so quickly now as the revs are always kept high! Step down and up seamless and never an issue.
Unfortunately, passenger cock up meant that sidecar ploughed into tyre wall on a sharp left hander, and he leaned right...! So only made a 1.6 lap in first practice. Nevertheless, I met so many interesting people there and got loads of device on everything from jet sizes on AvGas fuel, to one way valves in the engine breather.
Tried 21T gear sprocket with 41T Rear wheel, but when I get the jet sizes/needles sorted, I think it may be better with 21T/38T. We'll see...

The trouble with sidecar racing is that when you really fang the bike, you are likely to chuck your passenger out. You need to hire a gorilla. I found that with the close box, the Commando engine with the heavy crank is absolutely gem. I just keep my 850 spinning high and play it like a piano. When you get the jetting right, you will probably get a big boost in performance. With methanol as fuel, the difference between slightly rich and almost detonating is highly significant. With petrol the difference will be even greater. If you end up using top gear for the last few dozen metres of the longest straight, you would probably have the gearing right. But it depends on how tight the rest of the circuit is. If it is really tight and there is a lot of it, you should probably gear for that and just cruise at the ends of the straights. The trouble is the faster you ride in the tight bits, the harder it is on your passenger.

Always take good care of your passenger. My brother races speedway sidecar and lent his 600cc Jawa to a friend, along with his passenger. The guy used to be a very good racer, but got in the grip and went fir it at Broadford. As he slipped under another bike, the guy he was passing came down on him and took his front wheel. They looped the sidecar and the rider got a broken scapula, but my brother's good passenger got a broken pelvis, so can no longer race. Here is my brother and his passenger at Mildura.

You need this guy :

Here what you say, but the flip side is when the passenger totally screws up and causes an 'off' into the tyre wall. This happened to me at Chimay last weekend. Coming out of the last bus stop, which has a 90 deg right then 90 deg left before opening out onto a narrow track, my passenger leaned to the right, causing a no-steering episode. Hit the tyre wall at a 30 deg angle, causing a flip and jettisoning both of us.
Result? Bent and twisted forks, RH handlebar bent at 90 deg., scraped and impacted helmets (both of us), and a distorted and cracked frame. Passenger slinked away in the evening without a goodbye, or even a check the next day to see if all was OK.
A more modern frame now being populated with my engine and gearbox ready for Mallory at the end of August...

Have you ever ridden in the sidecar yourself ? It is not easy. You can become disorientated, if you are not experienced .

4 minutes into first practice I don't expect or accept that someone may become disorientated, especially on such a simple layout as Chimay. There are 3 basic moves on a sidecar (without discussing the fine tune aspects of positioning).
1. Centre position. For straights.
2. Right lean behind driver. For right hand bends.
3. Left lean in front of sidecar wheel. For left hand bends.
The passenger said that he had done some F1 sidecar racing. Bet he didn't lean right on a left hander. Wonder if he actually did any sidecar racing at all...
I think we should agree to disagree and leave it at that.

Some guys in motorcycling tend to sell themselves as being other than they really are. It is an ego thing. Their first really big crash usually helps them lose their ego. If he is a bullshit artist, you probably put the wind right up him when you up-ended the sidecar. You need a good sidecar passenger, they are not easy to find.