Gear Shifting

[cayuse]

I don't have a tach (yet) and I've never been sure of my rpm's so I thought I would exercise the noodle and came up with these charts.

There are some interesting figures here:
It confirms the tach results some are reporting in 5th gear: rpm's are ~10x mph
If you want to hear 8000rpm's go to 50mph in 3rd gear (!)
Seems to be OK, at least for short periods, to go 65mph in 4th (ie redline is just below 70mph)
Stepping up to 16-tooth gearing will bring you down below peak HP and torque at 70mph so don't expect to go faster with that mod.
I've always been impressed with the accel I get with this little motor when I let it wind out a little. Now, I've got some peace of mind that I'm not over-revving.

[alanmcorcoran]

Thanks for info. I regularly do 65 mph in fourth. In most of my driving conditions, fourth is the only gear I can hold speeds above 60. I have no tach on my Geezer either. I sort of figured - if it don't blow up, I guess it's ok, which is obviously not a recommended form of figurin'.

[Pete7874]

alanmcorcoran, how much do you weigh? I can hold 70 mph in 5th rather easily on flat ground if there is no strong headwind. I weigh 150 lbs though.

[cayuse]

Size has something to do with it, too. At max speeds your drag coefficient is going to matter a lot more than your mass. If you are heavier it will take longer for your 20hp to get you up to speed but if you are taller in the saddle and lighter then that max speed will be less, because of the extra wind drag from the taller rider. Pete, I think you'll find if you could put 50 lbs of lead in your tank bag you would still hold 70mph because your wind resistance won't be any different, yet your 'weight' would be 200lb.

[alanmcorcoran]

Originally Posted by Pete7874

alanmcorcoran, how much do you weigh? I can hold 70 mph in 5th rather easily on flat ground if there is no strong headwind. I weigh 150 lbs though.

I was 185-190 when I bought the Geezer, but I'm now 155-ish. If the road is flat and no head wind, I might be able to hold 65 in 5th. I live in Anaheim Hills where it is neither flat nor wind free. I'm located near the Santa Ana Mountains which are known locally for the "Santa Ana" winds, and nationally for being on fire every fall. Although there are flat areas to be found, in general you are usually dealing with some sort of grade, and wind is pretty common.

Also, I have a large windshield and saddlebags, neither of which help with top end speed.