Thinking of Going to a 22T Gearbox Sprocket

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Because in a race from , say 0 to 100 mph , both bikes identical other than gearing, the lower geared bike will have allowed it's engine to turn more revolutions to get that job done. That's the mechanical advantage at work and that is where the improved acceleration comes from.
 
worntorn said:
Because in a race from , say 0 to 100 mph , both bikes identical other than gearing, the lower geared bike will have allowed it's engine to turn more revolutions to get that job done. That's the mechanical advantage at work and that is where the improved acceleration comes from.
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Only off the line in first gear. After that we'll be revving up to the limiter, using the gears and just changing at different track speeds. You'll get to 4th gear before braking for the bend, I'll only be in 3rd and revving higher. You'll drop down and take the bend in 3rd, I'll be in 2nd.... etc.
 
The thing to do is give it a try
It's not exactly hard to pull the primary and change the sprocket back if you don't like it and sprockets are not a high price
When I was younger I hated bikes that were imo over geared and I'd soon be changing sprockets to let the bike rev
But as I've got older I'm preferring higher gearing,
Horses for courses I guess
 
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I'm not disagreeing, just not understanding. On the question, the layshaft bearing was replaced with an upgraded bearing at the time it was changed to a 23T (6,000 miles ago) and box inspected / refurbished. Oil was very clean (and magnetic sump plug) when I changed it a couple of months ago. Again, this is something I struggle to understand. The engine only produces so much torque and the back wheel sees a little bit less of it. If I'm in a sensible rev range, why is my gearbox more vulnerable?

That said, I often ride the bike with a bit of spirit, but I don't flog it hard. Not a WOT or off type of rider. With maintenance, I'm pretty confident it will last longer than me... provided fuel is still available :)

Edit: if I am likely to cause damage with a 23T, I will change it. But if not, I really enjoy the long legged gearing. The bike feels effortless when riding swiftly.
 
Mart UK said:
Only off the line in first gear. After that we'll be revving up to the limiter, using the gears and just changing at different track speeds. You'll get to 4th gear before braking for the bend, I'll only be in 3rd and revving higher. You'll drop down and take the bend in 3rd, I'll be in 2nd.... etc.
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The point is, no particular final drive ratio will be optimum under all road conditions. Racers in various types of motorsports will change FDR to suit the particular track they are running on at any given time.

Another thing. I am already riding on a 21t sprocket and finding the bike just a little more "revy" than I like.

Some are criticizing me for deciding to go to a 22t sprocket saying that I already had my mind made up. While I admit that I was leaning towards the bigger sprocket, I wanted input from those that are running 22t or larger sprockets. It seems that those that have similar riding habits to mine are pleased with the bigger sprockets and the reduction in RPM at higher speeds.

As for overtaking and the option of downshifting to 3rd gear?

On a 22t sprocket on my rubber, @ 55 MPH in 4th I'll be turning 3000 RPM. I can easily roll in a little throttle to overtake and the the TQ will be near maximum for a smooth, albeit perhaps leisurely pass. If I want to overtake more quickly, dropping to 3rd will bring me in at about 3650, same TQ but more HP. Dropping to 2nd would have the engine RPM in the 5000 RPM range, not much higher than a redline shift from 1st gear, but a bit much for most circumstances although I admit that I haven't become familiar with what Trixie might do under that type of hooliganism. YET!
 
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Dan1950 said:
Some are criticizing me for deciding to go to a 22t sprocket saying that I already had my mind made up. While I admit that I was leaning towards the bigger sprocket, I wanted input from those that are running 22t or larger sprockets. It seems that those that have similar riding habits to mine are pleased with the bigger sprockets and the reduction in RPM at higher speeds.
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Hey Dan - call me out on it, I can take it - LOL

I am sorry if I came across as critical - I am sure these conversations would be much easier at a rally with a beer in hand. Hoping that day comes soon - fingers crossed!!

Just want to help you make an informed decision.

FWIW - I kind of like the broad ability of having a wide range of speed available on 4th gear, without having to downshift. Even with a 20T, I will kick down to pass, but not always.

But that is just me....

Cheers - DW
 
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Mart UK said:
I'm not disagreeing, just not understanding. On the question, the layshaft bearing was replaced with an upgraded bearing at the time it was changed to a 23T (6,000 miles ago) and box inspected / refurbished. Oil was very clean (and magnetic sump plug) when I changed it a couple of months ago. Again, this is something I struggle to understand. The engine only produces so much torque and the back wheel sees a little bit less of it. If I'm in a sensible rev range, why is my gearbox more vulnerable?

That said, I often ride the bike with a bit of spirit, but I don't flog it hard. Not a WOT or off type of rider. With maintenance, I'm pretty confident it will last longer than me... provided fuel is still available :)

Edit: if I am likely to cause damage with a 23T, I will change it. But if not, I really enjoy the long legged gearing. The bike feels effortless when riding swiftly.
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Nortons always used a 19t until the 850 .. whether by accident or design , gearbox failure was almost unknown. I f you ride with spirit and dont lug the engine it probably keeps the torque loadings down to an acceptable level.. I have 22t on mine bit never let it run below 3,000rpm... Torque is a twisting turning force and not the same as bhp. the lower the revs the higher the torque loadings are likell to be. Consider a gearbox taking 100bhp at say 10,000rpm
it s bearings will be loaded less than if it is only rotating at 1000rpm even if the actual bhp remains the same.
 
Mart UK said:
Only off the line in first gear. After that we'll be revving up to the limiter, using the gears and just changing at different track speeds. You'll get to 4th gear before braking for the bend, I'll only be in 3rd and revving higher. You'll drop down and take the bend in 3rd, I'll be in 2nd.... etc.
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All I can say is imagine the acceleration of your bike with a 30 tooth gearbox sprocket fitted.
Do you think it would still be the same?
 
Derek Wilson said:
Hey Dan - call me out on it, I can take it - LOL

I am sorry if I came across as critical - I am sure these conversations would be much easier at a rally with a beer in hand. Hoping that day comes soon - fingers crossed!!

Just want to help you make an informed decision.

FWIW - I kind of like the broad ability of having a wide range of speed available on 4th gear, without having to downshift. Even with a 20T, I will kick down to pass, but not always.

But that is just me....

Cheers - DW
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And when you do kick it down, it will pull a lot harder than with a 23 tooth on there.
I've tried 22,21 and 20. The acceleration thru the gears just gets greater as you go down in gearing. Don't think Ill try the 19 as it will pull harder again, which is good, but will be revving a bit too high at highway speed in top.

Glen
 
worntorn said:
And when you do kick it down, it will pull a lot harder than with a 23 tooth on there.
I've tried 22,21 and 20. The acceleration thru the gears just gets greater as you go down in gearing. Don't think Ill try the 19 as it will pull harder again, which is good, but will be revving a bit too high at highway speed in top.

Glen
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Perhaps you can explain how my 2006 charger running a 3.23 axle ratio was able to turn a quicker quarter mile time and thus defeat a very similar car that was running a 3.73 axle ratio.

Granted he beat me in a 60 ft by .2 of a second which should have translated into a 0.4 of a second better ET in the quarter mile. However I ended up beating him by .1 seconds.
 
I don't know anything about 2 similar but different cars that raced somewhere.

The correlation between gearing and acceleration with Commandos can be seen clearly in the period road tests quarter mile runs.
If you insist on believing that a Norton will accelerate as quickly or even quicker with raised gearing, I won't try to convince you otherwise.
The bike won't accelerate quite as fast with higher gearing, but there is nothing wrong with setting the ratio the way you like it .

Glen
 
worntorn said:
I don't know anything about 2 similar but different cars that raced somewhere.

The correlation between gearing and acceleration with Commandos can be seen clearly in the period road tests quarter mile runs.
If you insist on believing that a Norton will accelerate as quickly or even quicker with raised gearing, I won't try to convince you otherwise.
The bike won't accelerate quite as fast with higher gearing, but there is nothing wrong with setting the ratio the way you like it .

Glen
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It's not about cars and Commandos, it's about the laws of physics and the fact that the axle, or in this case gearbox sprocket ratio doesn't always equate into a lower effective FDR in all instances.

The fact is that I finished the quarter mile in third gear with a 4.55 FDR while the other guy had shifted the fourth and was pulling a 3.73 FDR'

I went to the traps in red line. I just ran off and left him after he shifted to 4th.

I spent more time in 1320 ft at maximum horsepower than he did.
 
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worntorn said:
I'm not sure what the purpose of this thread is.
It was posed as a question, plenty have answered but you don't seem to want the information.

Out for me.

Glen
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On the contrary, I know it may be hard for you to grasp but not everyone that responded here has the same opinion as you. You don't seem to be able to accept anyone's opinion that doesn't agree with yours.
 
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