Upcoming 1st Build Puerto Rico Faster would be Safer II, Shift Kit Or Not

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AmericanRoadwarrior

New Member
Nov 28, 2013
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Boston, MA USA
Okay, with everyone's help I've achieved quite a lot.

Current plans are to build a China Girl 66cc using a Walmart Special Huffy Cranbrook. I received my motor today and have yet to open the box and familiarize myself with the parts as well as make sure all the parts are there. Most of the information I've seen shows bikes without the chain guard so I may remove that one part before I pack the kit for the plane ride to Puerto Rico. I also have my powerful Cree headlight, bar end mirror and a cheapie tail light.

The big question is:
Do I buy a JackShaft or ShiftKit?

Being able to keep up with traffic will be much safer in Puerto Rico where drivers are very aggressive and the roads don't have much of a shoulder.

My concern is that I'm getting into a much more lengthy build where I can run into mechanical snags when time is very limited during my 3 week stay.

I noticed a note on Sick Bike Part's Shift Kit page that says to make sure I measure the seat post shaft to order the right kit. Do most cheaper mountain bikes have the same size seat post shaft size?

What about a build using a 3 speed (internal rear hub shift) bicycle with a JackShaft kit?
Would a 3 speed give me enough of a speed variability to be worth it?
Would it get me up to say 40mph?
I'm thinking it would.
 

AmericanRoadwarrior

New Member
Nov 28, 2013
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Boston, MA USA
As I'm looking at Walmart's bike options online I'm not finding a 3 speed.

I was in a Walmart the other day and coulda swore I saw some 3 speeds though their price might be too high to consider.
 

BarelyAWake

New Member
Jul 21, 2009
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Maine
Jus' as a heads up... it's a somewhat common misconception that a jackshaft/shiftkit will enable a higher top speed but with our bikes this often isn't the case - provided the final gear ratio is the same a shiftkit equipped build can't be any faster than a single speed as there's no "extra power" gained from the added friction and complexity, if anything it's ever so slightly slower due to the drag of it's chains & bearings.

The additional complexity & thus maintenance of a jackshaft is often accepted by builders not for a top speed gain, but for improved acceleration and lowered RPM at cruise speeds, making for a more comfortable & efficient ride...

...but if you want absolute top speed & maximum reliability, a shifter bike just can't quite compete with a single speed geared tall and pedaled on takeoff.

Food for thought ;)

http://youtu.be/U10xLqTekOw

http://youtu.be/_GTS0xG8BPM
 

AmericanRoadwarrior

New Member
Nov 28, 2013
31
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0
Boston, MA USA
Jus' as a heads up... it's a somewhat common misconception that a jackshaft/shiftkit will enable a higher top speed but with our bikes this often isn't the case - provided the final gear ratio is the same a shiftkit equipped build can't be any faster than a single speed as there's no "extra power" gained from the added friction and complexity, if anything it's ever so slightly slower due to the drag of it's chains & bearings.

The additional complexity & thus maintenance of a jackshaft is often accepted by builders not for a top speed gain, but for improved acceleration and lowered RPM at cruise speeds, making for a more comfortable & efficient ride...[/url]
I see. I WAS under the misconception that all I needed was gears. I returned to a prior thread post by HuffyDavidson and noticed that he did indeed state he is running an advanced motor with his shiftkit.

Thank you for clearing that up.

I will definitely stick to my stock China Girl setup for this build this year.
I may get by without incident, we'll see.

I think I might order a smaller rear sprocket to bring with me.

On ebay I'm seeing 32, 36, 39 and 41 tooth sprockets mainly by a seller who happens to be in Puerto Rico which is very convenient. I noticed most of these do not have a convex to them.

Any input would be appreciated.
 
Last edited:

Russell

Well-Known Member
Apr 19, 2009
1,276
155
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MA
Some of the most amazing bicycle builds come from Puerto Rico can't wait to see yours!
 

AmericanRoadwarrior

New Member
Nov 28, 2013
31
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Boston, MA USA
Ordered a 32 and a 39 tooth sprocket to take with me.

I'll gradually remove chain links with the heavy duty chain breaker I bought.

With that brings another question:

The chain breaker model I bought has a finer thread than others which means it will have more force on it's pin to push out the chain pin. Some recommend grinding the head off the chain pin to be removed.

Is it recommended that I bring a dremel tool?

I would imagine it might even come in handy for even more than just the chain.
 

Huffydavidson

STREETRACER/MANUFACTURER
Jan 29, 2012
1,076
4
38
st.louis,mo.
It took me along time to get mine right, but I love it. I built single speed bike so my friends would quite whining that I always leave them behind. hail to the shift kit
 

Powertool

Member
Jul 8, 2012
229
0
16
Bradford,TN.
Just stay with the stock set up to start off with your 1st build , you'll learn much , 2nd build try the jackshaft - shift kit. ------ Learn and be wiser .
 

AmericanRoadwarrior

New Member
Nov 28, 2013
31
0
0
Boston, MA USA
Just stay with the stock set up to start off with your 1st build , you'll learn much , 2nd build try the jackshaft - shift kit. ------ Learn and be wiser .
I agree. And HuffyDavidson thanks again for your input.

I think I'm all set for this years build....

1. 135.45 66cc Silver China Girl Motor Kit

2. 41.15 TurboBuick Chain Tensioner

3. 79.99 Projected Price of Huffy Cranbrook from Walmart
----------------------------------
$256.59 Total 66cc Motorized Bicycle

BICYCLE EXTRAS

1. 44.47 Cree 5000 Lumen Headlight

2. 2.84 Cheapo LED Tail Light

3. 16.95 39 Tooth Rear Sprocket

4. 16.95 32 Tooth Rear Sprocket

5. 10.34 2x GoPro Handlebar/Stem/Seat Post Mounts
----------------------------------
$91.55 Total in Bicycle extras

EXTRA TOOLS

$12.69 Heavy Duty Chain Breaker
 

AmericanRoadwarrior

New Member
Nov 28, 2013
31
0
0
Boston, MA USA
For next year's build right now I'm thinking "possibly".....

Add JackShaft / Shift Kit

Replace Rear Hub with a 3-Speed Hub

A few minor mods to motor for power (head, carb, exhaust)

NOTE: Right now I'm wondering about anyone using hand-brakes....

Using a hand clutch lever now takes the place of your second (front?) Brake?

All this having only one wheel brake sounds DANGEROUS! brnot
 

AmericanRoadwarrior

New Member
Nov 28, 2013
31
0
0
Boston, MA USA
Has anyone mounted a front brake on a Huffy Cranbrook?

If so.... what type or brand brake should/could I buy?


I'm rather concerned about having only rear coaster brake on my upcoming Puerto Rico stock China Girl/Cranbrook build.
 

CTripps

Active Member
Aug 22, 2011
1,310
1
38
Vancouver, B.C.
Some don't like them, but all of my builds get the brakes switched over to a dual-pull lever (replacing the right hand lever), making room for the clutch lever on the left side. I did try for a while to use seperate brake levers, but I found it was just a bit too crowded on the left side of the bars for quick responses to traffic etc.
 

CTripps

Active Member
Aug 22, 2011
1,310
1
38
Vancouver, B.C.
Sounds interesting. So you have both front and rear brake cables hooked to one right hand "dual-pull" lever.

With a little thought I can't think of anything better. Sounds like a great option.

Thank you
Yep. The dual handle works well for me. As mentioned, some folks don't like them, but I do. The main reason for me came down to how awkward it was to grab the clutch lever and use the brake effectively in traffic.

Here's a pic of my Beast's handlebars..