Chainlube
Well-Known Member
Can you switch nuts from the old trans to the new one and get more clearance?
Dual Chain Transmission Won't Fit
- Thread starter phil4989
- Start date
5-7HEAVEN
Well-Known Member
Hi phil. I like to think of these devices as gear reducers too. Calling them transmissions is like calling French, Brits, Italians, Spanish to be Europeans. Semantics and generalities, I guess. No biggie.
Did you check how many teeth your reduction box has? Your ratio seems high; ya might want to shoot for 18:1 or lower.
Let's say your gearbox is 3:1. That means you need 6:1 more when you reach the rear wheel.
If the gearbox has a six-splined output shaft, finding a 9t/#35 sprocket to use is extremely difficult.
You'd need that 9t and a 54t rear sprocket, to attain18:1 ratio.
If you do have a six-splined output shaft on your gearbox, you can use T8F sprockets and chains. These are used on pocket bikes and are readily available on ebay or Dax.
Then you can use 11t and a 72t sprockets.
That'd lower your gearing to 19.64:1 and climb your hills better.
Did you check how many teeth your reduction box has? Your ratio seems high; ya might want to shoot for 18:1 or lower.
Let's say your gearbox is 3:1. That means you need 6:1 more when you reach the rear wheel.
If the gearbox has a six-splined output shaft, finding a 9t/#35 sprocket to use is extremely difficult.
You'd need that 9t and a 54t rear sprocket, to attain18:1 ratio.
If you do have a six-splined output shaft on your gearbox, you can use T8F sprockets and chains. These are used on pocket bikes and are readily available on ebay or Dax.
Then you can use 11t and a 72t sprockets.
That'd lower your gearing to 19.64:1 and climb your hills better.
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5-7HEAVEN
Well-Known Member
I've dealt with clutch bell interference before.
Once I machined off .125" from the edge of the bell.
I've spaced out the gearbox with washers, on other occasions.
5-7HEAVEN
Well-Known Member
5-7Heaven: We were going for a low gear ratio. There are a lot hills around here, several have stop signs right in the middle. He would pedal assist from a stop, but it still wasn't enough. The clutch kept wouldn't fully engage due to the high torque and low RPM. The other benefit to a low gear ratio is his top speed is lowered at bit, which makes my wife feel better about him riding it.
phil, the ultimate hill climber, aside from a bigger engine, is the shift kit.
Once I used it, I've never considered anything else.
A shift kit entails connecting your gearbox to the bike's 7-9 speed cassette or internal gear hub(IGH).
Then you end up with a centrifugal clutch and a 7-speed manual transmission.
One of my bikes had a low of 46.36:1, with final drive @ 16 .36:1.
Connecting your gearbox to a shift kit would lower your gearing to 27.82:1 in First and 9.82:1 in high gear.
Something to consider.
Wow, that's a lot of advice! Thanks so much. Our build is on a beach cruiser with a coaster brake. This was intentional, because we wanted it as simple as possible for my son's safety. Gas to go and brake to stop, nothing else.
I've thought about putting washers on the four bolts to pull it out a bit, but then there would be a small gap between the gear box and the engine. Also, I'm concerned that the entire depth of the clutch hammers (not sure what you call the three arms that come out) would not strike the bell, thus reducing the frictional grab.
I thought about taking the bell off and possibly putting on a smaller center nut and bolt, however if that doesn't work then I can't return it.
Final thought, should I just return it and get a belt drive? My son is chomping at the bit to go, go, go.
I've thought about putting washers on the four bolts to pull it out a bit, but then there would be a small gap between the gear box and the engine. Also, I'm concerned that the entire depth of the clutch hammers (not sure what you call the three arms that come out) would not strike the bell, thus reducing the frictional grab.
I thought about taking the bell off and possibly putting on a smaller center nut and bolt, however if that doesn't work then I can't return it.
Final thought, should I just return it and get a belt drive? My son is chomping at the bit to go, go, go.
5-7HEAVEN
Well-Known Member
phil, before you do anything else, install a front brake!
www.sportsrec.com
If the pedal chain breaks or slips off, you have absolutely no brakes!
And have your son practice using both his shoes to clamp down on the front tire, before the emergency arises..
LOL, I've used my boots as an extra brake on my cruiser bike.
It works!
It won't hurt anything if there's a gap near the clutch, because you've put spacers on it.
You could put a piece of duct tape, if it bothers you.
No worries if you lose a bit of clutch surface area from the clutch shoe pads.
It won't matter.
The big matter is having such a low gear ratio, that it destroys clutches.
In all my years, I've never burnt a single clutch.
How to Put Front Brakes on a Cruiser Bicycle
The majority of cruiser bikes come with a single coaster brake at the rear wheel. The casual nature of cruising possibly has resulted in status-quo production by manufacturers. But, there are places, such as steep hills or quick-stop situations, when additional braking is beneficial. Installing...
www.sportsrec.com
If the pedal chain breaks or slips off, you have absolutely no brakes!
And have your son practice using both his shoes to clamp down on the front tire, before the emergency arises..
LOL, I've used my boots as an extra brake on my cruiser bike.
It works!
It won't hurt anything if there's a gap near the clutch, because you've put spacers on it.
You could put a piece of duct tape, if it bothers you.
No worries if you lose a bit of clutch surface area from the clutch shoe pads.
It won't matter.
The big matter is having such a low gear ratio, that it destroys clutches.
In all my years, I've never burnt a single clutch.
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Frogslayer
Well-Known Member
If he wants to ride right now why not just put the transmission that came with the engine back on and ride it till she goes?
5-7HEAVEN
Well-Known Member
Phil, would you consider reinstalling the engine in a mountain bike? Besides having better brakes and maybe a suspension fork, your son would be able to help the engine by pedalling uphill.
I know that's something he can't do with a single speed bike.
I know that's something he can't do with a single speed bike.
Frogslayer
Well-Known Member
You totally can pedal single speed bikes up hills. I've done it. It's a spandex myth but even if you're not in "peak cadence" the bike will still move forward.
5-7HEAVEN
Well-Known Member
Yes you can. But I remember how tough it was for me, as a kid, to pedal my ballon-tired cruiser up hill, as compared to my classmate's English racer.
Maybe that's another reason why Phil's son is burning up clutches.
