Tactical Shifting

[Sidewinder Jerry]

An item which will greatly improve the riding experience for shift kits is a tachometer. This item can also help single gear ratio riders as well. For shift kits: engines have a max horse power at a certain rpm. You can then be in a gear which hovers around that range. This way you'll know if you need to be in a higher or lower gear. For single gear ratios it can help keep you from over revving your engine; such as when you're going down hill.

The tachometer/ hour counter I use you can get from Staton Inc or Northern Tools. It cost around $50. It is a simple device which has a wire that wraps around the spark plug wire. The hour counter is helpful for knowing when to clean the air filter. For 4 strokes its good for knowing when to do an oil change as well.

 

[Wild Bill]

You are correct on the peak power being the ideal shifting point but on both my China Girl and KTM clone shifters I "Short Shift" since that's where the power is on both my bikes and I have developed a feel for where to shift. During the races theres just too much going on for me to worry about shifting points using a tach so I use different markers on the track and try to get a rhythm.
You don't want to wind out every gear, the midrange power on my bikes is pretty decent and I get up to speed quicker that way. I do wind out the last gear at the end of the straight. A tach is also a great tuning aid.

 

[Sidewinder Jerry]

Yeah Bill I used my tach to set the auto shift on my bike. Are you racing on road courses or ovals?

 

[Wild Bill]

Road courses on kart tracks, but they have done some oval racing too. This is a track called The Grange, Im still feeling this one.......lol
https://www.youtube.com/watch?v=m_j5y9XDyKw

 

[Sidewinder Jerry]

Wow that was scary Bill. The RS 35 max HP is at 7000 rpm the max rpm is 8000. On my auto shift derailleur I set it to up shift at 7800 rpm and down shift at 5800 rpm. That way at full throttle I'm always between 6500-7500 rpm. The only time I reach the max rpm is going down steep hills. So I let of the throttle and coast then.

I've helped others build shift kit builds but they manually shift. I've told them to be in a gear where at full throttle they're at the max HP rpm. If they drop below that then down shift to a lower gear. If they get near the max rpm then up shift to a higher gear. I put the tach next to a speedometer. Being in the right gear is a big help when you live in the mountains.

All to often I hear of problems on here which are gear related. Too high a gear engine strain; to low over revving.

 

[Wild Bill]

The auto shift would simplify things, during a race the right side of the handle bars is a busy place between throttle, shift and brake.

 

[Sidewinder Jerry]

I've figured out a way to modify a LandRider derailleur to where it can shift an internal hub automatically. Hope to have a build soon with it. Plan to do away with the belt drive system the derailleur uses and use a direct gear drive. The derailleur works the same weather the weights turn clockwise or counter clockwise.

 

[bigoilbob]

I've figured out a way to modify a LandRider derailleur to where it can shift an internal hub automatically. Hope to have a build soon with it. Plan to do away with the belt drive system the derailleur uses and use a direct gear drive. The derailleur works the same weather the weights turn clockwise or counter clockwise.

Unpowered bikes with IGH have natural low torque periods between pedal strokes. Manual shifting powered bikes with IGH are probably shifted with the power off, like motorcycles. Your engine will be applying torque while shifting. Can your IGH stand the stress of shifting under load?

 

[Sidewinder Jerry]

Bob when I first built my auto shift bike I was told it couldn't be done. However it can upshift or downshift under full power and is quite smooth doing it.. I had to do modifications to the LandRider derailleur to make it work. I may have to do modifications to an IGH as well. Brian Kilduff has a shifter out now which shifts a Shimano Nexus 3 speed automatically. However its being done on a pedal only bike. I believe the LandRider derailleur will work even better because of the adjustment screws on it.

 

[bigoilbob]

G'luck, L.R. One of the reasons I read your posts is because of what you were able to accomplish on your auto build. Also appreciate your grown up attitude towards regs. But derailleur systems are commonly considered tougher than IGH's. Really hope that you prove me wrong. The capability and efficiency of such a power train combo, with very little added weight, would interest any MB rider who had to negotiate steep hills. Meaning many of us. Ultimately, I would like to see durable kits for "the rest of us".

 

[Sidewinder Jerry]

Bob the LandRider derailleur has some cheap crappy sealed bearings in them. I've got some metal shielded stainless steel sealed bearings on the way. I'm going to make a video of how to modify the derailleur for use on my 5 speed sprocket freewheel setup. I've got a tread or you can view an album in my profile on the 5 speed freewheel. Currently (34,28,24,20,16).

 

[bigoilbob]

L.R, in the interest of actively cheering on for your success in your IGH project, have you considered a properly sprung chain tensioner to transform the shock loading of upshifting into an increasing, then decreasing load, smoothly applied over the span of a fraction of one second? It would not affect downshifts, but intuitively I would think that those load shocks would be less dramatic. On second thought, it could reduce that impact as well! Some enterprising soul on the forum could almost supply proper spring tension calculations, given engine power/torque, sprocket sizes, gear ratios, etc.

As is obvious, I do think that much shifting under power will shell your IGH. But any forum experience to the contrary would be well regarded.....

 

[Sidewinder Jerry]

Here are the adjustment screws on the LandRider derailleur: a high, low, B indexing and a cadence adjuster. For an IGH you wouldn't need the B indexing adjustment at all. The h/l adjustment would set the range of movement. The cadence adjustment will determine what rpm it changes at. KC has also told of how motorcycles use a cushioning system. That too may be something to explore. I'm going to buy a used IGH to do this before trying it on a new one.

 

[greaser_monkey_87]

Correct me if I'm wrong, but isn't it more tactical to shift before the rpms drop below peak? For example, let's say you're approaching a hill, and you know you need to downshift in order to crest it. If you wait to shift until your rpms drop below peak, you'll almost certainly have to shift under load. Isn't it better to shift before you start climbing the hill, so you can reduce rpm, shift while not under load, then give it gas again and you'll be in the right gear before you start climbing? This seems more tactical to me then waiting till rpms drop and shifting under load.

 

[Sidewinder Jerry]

You're correct if its a large hill you're aproaching. However with the small engines under 50 cc. Even slight hills can show up on the tach. Here in Tennessee we have grades which may be several miles long. I have a pedal only bike which I set up for riding hills here. Its set up is: (22,32,42) crank and 8 speed freewheel (34-13). I've found it to be very easy to downshift going up hills. I use a cadence meter on the pedal only bike. I do understand where you're coming from. If its a steep hill you may have to drop several gears really fast. My auto shifter often does this for me.

So to conclude it depends on the hill you're approaching as to when and how much you should down shift.

 

[The_Aleman]

I have over 8K miles on a shifter Huasheng 4G setup. I have found the greatest tactics to be manual shifting and pedaling.

Automatic shifting? Asinine. Completely Asinine, IMO. I wouldn't even call that bragging rights. I can't even respect it.

One who has put thought into their setup doesn't need a tach. A speedometer will tell you what RPM you're in in any gear.

 

[bigoilbob]

I have over 8K miles on a shifter Huasheng 4G setup. I have found the greatest tactics to be manual shifting and pedaling.

Automatic shifting? Asinine. Completely Asinine, IMO. I wouldn't even call that bragging rights. I can't even respect it.

One who has put thought into their setup doesn't need a tach. A speedometer will tell you what RPM you're in in any gear.

Auto shifting has the advantage of keeping me legal in Missouri. Many states, including yours I believe, have this requirement. I might have been able to fly under the radar for years otherwise, but I hope you can at least respect that.

But I do hear you. My NuVinci auto shift is heavy, uses a relatively complicated shifting system, and is less than 90% efficient. The derailleur system seems to be the way to go, but I must admit that with manual shift you can lower rpm's for a quiet ride on long stretches of flat, smooth city streets.

 

[The_Aleman]

The "legal" requirement is really semantics at best when it comes to our setups.

The SBP kits have always been single-speed crank-assist devices. The fact that the bicycle itself has gears really has no bearing on legality.
Some bicycles simply have gears and some do not.

That all said, I understand your desire to try to follow the letter of the law the best you are willing and able to, and for that, I respect your decision fully.
The last thing we need is to draw the wrong kind of attention to ourselves!

 

[Sidewinder Jerry]

Yes Bob it sure feels good being legal. Unless you change a speedometer into a tach you'll have no way of knowing what rpm the engine is running at. Like I said my RS engine max rpm is 8000. You can't really hear that its over revving until around 9000 rpm. The max HP rpm is 7000 I personally am not gifted enough to hear the difference between 7000 and 8000 rpm. Speedometer wouldn't let you know that you could easily be doing 8000 in a gear at a certain speed and need to be in a higher gear to where it would be doing 7000 rpm.

 

[bigoilbob]

I don't doubt for a minute that plenty of manual shifters have been riding around for years in auto shift states, without being hassled. All we need to do is to read through the legal thread to understand how ignorant our law makers and law enforcers are about these machines. Sometimes it works to our benefit, sometimes not. But manual shifting is not auto shifting, no matter how we finesse it. My preference is to be legal if I ever do get pulled over. Better for me, and even better for the scofflaws who get a freer ride on my rep.

And to unhijack - I like my tach. Sometimes, starting out, my shifter doesn't keep up for a second or 2 and I see it and back off a little bit, momentarily. Also, my tach helps me monitor my shift performance throughout my range. In high, it becomes a functional speedo, when I sometimes need one, like in school zones. It is the one instrument that is worthwhile for a MB.