Fixed gear Mountainbike, Shift Kit ???

Cafe Racer

Cafe Racer

New Member
Hello,

As mentioned before, I still have not strted my first build but I do have the motor kit sitting in my shop ready for the start. But before I begin I will have a few more questions for you seasoned folks.

Are shift kits primarily Mt Bikes or are they for single geared bikes too? I was thinking of converting my mountain bike to a single gear before adding the motor. Thoughts?

As for the "why" questions. Simplicity. And I think it looks beautiful.

Mountain Bike History 101 and the Single Speed | Mountain bike product reviews, bike builds, trail reviews, forum, and tips - MTOBikes.com

Miguel
 
I can't think of any reason why it wouldn't work, heck if you used a fixed rear sprocket it would let you bump start it.
 
One chain, no tensioner, cleaner looking install, easier to do maintenance on rear wheel, and maby other reasons I can't think of right now. :)
 
'Cept ofc you'll have three chains, a tensioner for the second chain in particular would be a wonderful thing, the engine becomes slightly more awkward to remove, ...and I think that's it lol

Don't get me wrong, I dearly love my shiftkit and wouldn't build another w/o one - but if you're attracted to the simplicity of a fixie then perhaps a shiftkits' added complexity isn't for you.

For a clean, simple looking install - have you considered a mutli-speed rear hub? An engine w/gears is a wonderful thing :D
 
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Hello,

Thanks for the comments. Polite comments I should add. Actually, I made a couple mistakes. I was thinking of a single speed mountain bike. I dont know why I said fixed gearing.

And I suppose that since I wouldnt be shifting I wouldnt need a shift kit. I guess that was a silly question.

My plan is not to use the bike offroad much. Here in Northern California I think that I would stand out too much in any of the bike trails. And that would be a really bad thing. I am planning a 90/10 application bias towards the street.

Anyway, I hope to get this on the workbench soon. To be honest, the reason I have not started the build is because I am building a workbench and tooling area. I want to have a proper area to work on my bikes (and motorcycles). I just bought a house in San Francisco and have been rebuilding for the family. The garage phase started about 2 weeks ago. Currently working on a 13'x18"x3' work bench with cabinets underneath. Once complete things will start to happen.

Thanks again folks.

Miguel
 

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Nice shop space man *drools w/envy* (^)


Not to worry about "mistakes" bouncing ideas both good & mebbe not so good is exactly why we're here as I see it - heck, even having a jackshaft on a single speed isn't "silly" - just different is all... ya might even wanna give it a go jus' for giggles - you could always add gears later if ya wanted.

You've no idea of some of the truly odd things I've daydreamed up lol it's all part of the hobby I figure ;)
 
I have to agree with BarelyAWake, there are quite a few benefits to using a shift kit,

Single drive chain.

No tensioner

Ability to go to a multi speed simply adding a different wheel and dérailleur

No sprocket adapter (if one is even available for your chosen wheel) needed

Ability to run a rear disk brake with no adapter
 
you......are a genious!!!That is the most brilliant idea I have ever heard of!but wait!how about a fixed gear 7 speed!now THAT WOULD ROCK!!!!!!
 
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kevyleven007 said:
you......are a genious!!!That is the most brilliant idea I have ever heard of!QUOTE]

Thanks... I am new in this game so genious is a bit premature. But, non-the-less thanks! But I figure that if I can teardown vintage sportbikes and buidl them up with modern components this motor+bicycle thing should be easy enough. Hmmmmm?

Thinking that I will give both methods a try. First, I will install the tensioner. Then I will work on shortening the chain and going with a direct drive without a spring loaded device.

I will also give the "Jackshaft" method a shot. I think it is important to learn how each of those methods work. I will have another new topic shortly... get ready!

Miguel
Click to expand...
 
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kevyleven007 said:
you......are a genious!!!That is the most brilliant idea I have ever heard of!but wait!how about a fixed gear 7 speed!now THAT WOULD ROCK!!!!!!
Click to expand...

Thanks... I am new in this game so genious is a bit premature. But, non-the-less thanks!

Thinking that I will give both methods a try. First, I will install the tensioner. Then I will work on shortening the chain and going with a direct drive without a spring loaded device.

I will also give the "Jackshaft" method a shot. I think it is important to learn how each of those methods work. I will have another new topic shortly... get ready!

Miguel
 
im a bit confused about the term fixed gear do you mean a single speed freewheel and just wanted to add my two cents on one thing, the reason why im reluctant to spend the 150 to200 on a shift kit is im a large man 260 lbs and w a single speed fixed drive sprocket when i climb steep hills i have to help the motor this puts the stress on both sides of the wheel to me it seems that it would be easier on the axel plus w a ten speed that i have, i pick the gear i need to match my legs power band (rpm at the pedal cranck vs engine speed) ive found that i can climb hills steeper than i care to ride down due to my lack of a disk up front. any input on the subject from any of you guys would be greatly appreciated. Just want to spend my money as wisely as i can a because ill be married in a year and a half and have a wedding to pay for and if i spend too much $$$ on my new toy the wedding may be off my girl says i spen all of my free time on here or on my bike already but its like my new and much healthier addiction
 
I am sure that the terms I use are not perfect. But basically it is a single speed mountainbike. Is there a better term for this?

Miguel
 
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Cafe Racer said:
Are shift kits primarily Mt Bikes or are they for single geared bikes too? I was thinking of converting my mountain bike to a single gear before adding the motor. Thoughts?
Click to expand...

Sorry for chiming in late to this discussion; I just registered an account today.

If you are only going to use a single gear, and the objective is freewheeling the motor and/or avoiding the rear sprocket that clamps to the spokes, consider using a right hand/left hand drive system with a right side freewheel for the pedals and a left side freewheel for the motor. This is how I built my first electric bike years ago. The installation is much simpler and cleaner looking than what you are talking about.

To do this, you'll need a rear hub with RH threads on one side and LH threads on the other. These were common for BMX bikes in the late 1990s, and there are still a few floating around out there. Note that most BMX hubs with threading on both sides are both RH threaded, but with different diameters. The same thread diameter on both sides is a clue that you may be on the right track.

Staton has an RH/LH threaded hub that fits a mountain bike without modification. I strongly dislike the way they did the axle, but at least it is a currently available item. Staton also has left hand threaded freewheels and large #25 and #35 chain sprockets to bolt up to them. (#35 would be appropriate for your application; you would have to get a #35 output sprocket to mount on your motor).

One chain or both will require a tensioner. If your MTB frame has vertical dropout slots, you'll have to use a tensioner on each side. If it has horizontal dropout slots, you can use them to adjust one chain and use a tensioner on the other.

Chalo
 
I would leave the gears on either way.

If you run direct drive on the left you won't need a tensioner and can put the bike in a low gear to make it easy to start. When you need to pedal (out of gas, etc) you have gears.

Like the rest of these guys that have used a Jackshaft I can never go back, and I just have a simple 3-speed hub shift.

As mentioned it is two extra chains (motor to jackshaft, jackshaft to pedal chainring) but they are short heavy duty chains, and by the looks of the new kits, that will be even less of problem if that is even possible as I have never had a single issue with those two chains other than my awkward build configuration.

Just use a HD 410 Z chain for the pedal side.
The KMC 'Freestyle' 410HD is wonderful.

In short, you are in a win win here with gears either way.
If you have a front sprocket derailer sure pull all that off along with its shifter control, just fit it on the sprocket you want.
That will free some handle bar space, and just move the rear derailer shifter control to left side.

Also, just a tip, get a teeter-totter self adjusting dual pull brake lever for the right for both V brakes.
Throttle and both brakes (on one lever) on the right, clutch and rear shifter on the left.
Makes for a nice control center ;-}
 
KCvale said:
I would leave the gears on either way.

If you run direct drive on the left you won't need a tensioner and can put the bike in a low gear to make it easy to start. When you need to pedal (out of gas, etc) you have gears... ;-}
Click to expand...

Tank for the excellant suggestion. Your idea makes alot of sense.

Miguel
 
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