A wide crank that will not fail

C

cobrafreak

New Member
I've been quiet in the background lately. I have been making and selling locally on the side basic 4-stroke motorbikes based on new Schwinn frames with springer front ends. The engines are new Chinese 142F's, basically copies of a Honda GXH50. Good transportation bike and it pays for my board track building hobby. People like 150 mpg. Anyway, the 3 piece cranks that come with China kits are not strong enough. If you stand on the pedals such as when you are going over a bump, the axle sags. If you pedal too hard, same thing, axle bends. #1, the company that makes these things don't know enough or don't care enough to make it out of tough enough steel. What have you people used for cranks when you needed wide ones but you needed strength? This must be a common problem. There is Pat's Sportsman flyer crank that is wide and he assures me it is tough enough not to bend. I also see there is a "one piece" wide crank out there as opposed to the "three piece" crank. Anyone have experience with these?
 
I added a wide 3 peice crank when i installed a centrifugal clutch on my China girl. It has much more play than my standard 1 piece crankset. We generate a lot of additional leverage with a wide crank. I don't think there is a remedy for it except to weld a wider bottom bracket tube into the frame.
 
I just received a wide three pc. unit because everyone was out of stock on a one pc. wide unit and I required more width than could be gained by heating and bending the original one pc. crank.
First off the supplied sprocket is kinda flimsy and does not align with the rear sprocket, secondly the kit came with two left hand arms and they both have left hand threads for the pedals.

I am planning on adding some additional external support to the shaft by adding some thrust bearings and a close fitting heavy wall external collar fit tightly between the crank bearing retainer nuts and the crank arms.
 
I've been using the 206MM SBP spindle and cranks, no complaints. I'm a pedaler, too. You can set it up so it doesn't freewheel.

The distance between crank arms is 9.5". You can increase that with different arms, ofc!
 
Here is what I have been using. Fits standard 2" bottom brackets like on olds Schwinns, Worksman, and any cruiser style bicycle.


Sportsman Wide Pedal Crank by Sportsman Flyer, on Flickr


Pedal crank by Sportsman Flyer, on Flickr

2" bottom bracket with sealed bearings
3/4" steel shaft
Small diameter 28t sprocket
Adjustable offset billet aluminum sprocket hub for perfect chain alignment
Offset forged steel pedal crank arms only 4 1/2" long
10 3/4" I.D. between pedal crank arms
 
sportscarpat said:
Here is what I have been using. Fits standard 2" bottom brackets like on olds Schwinns, Worksman, and any cruiser style bicycle.


Sportsman Wide Pedal Crank by Sportsman Flyer, on Flickr


Pedal crank by Sportsman Flyer, on Flickr

2" bottom bracket with sealed bearings
3/4" steel shaft
Small diameter 28t sprocket
Adjustable offset billet aluminum sprocket hub for perfect chain alignment
Offset forged steel pedal crank arms only 4 1/2" long
10 3/4" I.D. between pedal crank arms
Click to expand...

OOOOH i like that, i think i will be getting one of these when the need arises. Love your work!!!!
 
@cobrafreak
That's great you are having some luck selling some bikes locally, I have had some interest in mine as I ride.

@sportscarpat
That crank set looks great Pat, are those going to be listed on your site for purchase soon? Also, are they set up for 9/16" or 1/2" pedals?
 
Sportscarpat ? You have beautiful builds.. What would a Sportsman 200 sell for with the 4 stroke you have ? What is displacement of that 4 stroke ? Thanks
 
Received my crankset from Sportscarpat (Sportsman Flyer) and it rocks. The install went fairly easy considering my lack of tools/experience. I just needed to purchase a new set of 9/16" pedals and some #41 chain. After securing and getting the chain fit, it works great. I now have plenty of room for Clutch kit and pull start on my 2-stroke or can use for any future builds maybe even a Sportsman 200 one of these days :)
Thanks Pat!
 
am interested in the PRICE of the 3 piece crank but you don't seem to want to let people know the price so do you really want to sell this particular item?
clfxwill
 
clfxwill said:
am interested in the PRICE of the 3 piece crank but you don't seem to want to let people know the price so do you really want to sell this particular item?
clfxwill
Click to expand...

No secrets. It's $100 plus $5.95 shipping. Email me if you need one. I try very hard to answer everyones requests. It's not always easy. I sold what I had and have more coming in late next week. This item is new and currently not updated on my web site.
 
Hey Pat. Whats the story with the sprokets? Can any sprocket for a one piece fit or do you have to use chain rings from a three piece, or is it strctly propriatary?
 
Velodrome said:
Hey Pat. Whats the story with the sprokets? Can any sprocket for a one piece fit or do you have to use chain rings from a three piece, or is it strctly propriatary?
Click to expand...

Hey Velodrome,
All my sprockets run standard bolt patterns, Sportsman standard that is. Seriously, though, the patterns have industry standard numbered bolt patterns but not for bicycles. This pedal crank uses a three bolt pattern and comes with the crank assembly. I cut for 415 chains on all my sprockets, bicycle side, motor side, sprocket adapters, hub adapters, all of them. I then run 41 chain on everything I build and everyone else can run 415. Sometimes I cut 41 when I know the application, like on my Sportsman 200. Confusing? Welcome to my world.

I can also cut wider bottom bracket shafts and different tooth counts on the sprockets. Problem is there are so many different combinations, so I am attempting to just standardize and stock certain sizes. I'm swamped guys, buried, burning it at both ends, all of the above. If I don't answer someone in an email or on here, just try again.
 
Does the 3/4" steel shaft have snap rings on it, or is it machined to not slide through the crank bearings?
 
You must log in or register to reply here.
Back
Top