Yes, as Fred said, it is (appropriately) the first piece of data on that row. For the Cb250RS it is 2.464. This is the calculator we are using. http://www.gearingcommander.com/
First thing I checked was which values were different and corrected them. Would have been an easy mistake to make the assumption that as they use very similar engines that the gear ratios as the same. This is definitely not the case, as the CB250RS has several improvements from the original XL250 engine it was based on. Also the front wheel sizes were significantly different!
Now that we have both done the calculations, what does your tacho actually show? I was hoping that at least one of your CB250RSs was running and registered.
Yeh I get that, I was responding to this: To do that you need to convert the rotational velocity of the drive shaft to the rotational velocity at the wheel which will be a conversion of RPM to RPM through the gear chain. Then it's about converting the RPM at the wheel to a km/hr figure, the rotational velocity to linear velocity conversion etc. Thinking about it, it shouldn't be that hard really. I can convert velocities through a gear chain where the teeth are meshing... I'd have to look up how to do it across a chain though as the relative speeds of the gears may be different if they're meshed. Translating the velocity from the rear sprocket to the tyre is simple enough, but I'd have to really brush up on my physics for that... it's been a while.
Stu, I believe that the gearingcommander website that I linked to earlier and that Fred and I have been using does the same calculations you are describing. One thing I can't figure about about that gearingcommand calculator is why it asks you to enter the chain pitch and chain links. It isn't required for the calculator to work and I can't see how it would make a difference.
It makes no difference it is just the ratios that I described before. Perhaps they were going to use that for some other reason.
Have a look down the bottom of the page - it gives you "Chain geometry changes due to sprocket & chain changes" and "Relative sprocket & chain wear due to drive train changes" Useful if you're converting from one chain pitch to another (say, a 520 conversion from a 428 chain and sprockets) or gearing up or down dramatically...
Thanks Fred. Once again I have been caught looking at only part of the page. I just looked at the part you used to answer my question. It makes sense now.
