Can 9mm dropouts be enlarged to 10mm?

fphowell

10 µW
Joined
Nov 30, 2014
Messages
6
Location
Salem Oregon USA
I have an old JC Higgins 3 speed that I want to convert to a front hub electric wheel. The wheel has 10mm axles and the dropouts on the bike are nominally 9mm. Can they be enlarged using a file and still be strong enough to do the job?
 
file them out to fit - and use a torque arm... regardless of power.
 
A stinky old American department store bike like that probably has dropouts that are too thin and flimsy to hold up regardless of slot width. Most such bikes don't even have fork tips per se; they just have slots cut into the squashed fork tubing. If you choose to file them out, be careful to file the slots evenly, so the wheel will sit straight in the fork. Don't leave any notches on the inside of the fork tip slots. Definitely use secure, well-anchored torque arms.

I have to say, a bike like that is not well suited for higher speeds than you'd achieve with pedal power alone. The brakes are terrible, the wheels have weak steel rims that don't provide a decent surface for any brake, the frame alignment is probably poor, and the frame is weaker and less rigid than that of even a cheap and nasty modern bike-- so it will shake and shimmy when you hang the extra weight of a battery on it. Almost all the available tires in that wheel size are archaic, cheap, and crude. Don't plan to go faster than 20mph on a bike like that. You'd be much better off with a sleazy MTB, because at least that would probably have linear pull brakes and alloy rims. You'd even be better off using a recently made beach cruiser, as long as you add a passable front brake.
 
Chalo said:
You'd be much better off with a sleazy MTB, because at least that would probably have linear pull brakes and alloy rims. You'd even be better off using a recently made beach cruiser, as long as you add a passable front brake.

What's a "sleazy MTB". I wouldn't make blanket statements about beach cruisers. I rode someone's as just a pedal bike a while back, and it was the worst pedal bike I've ever ridden. The geometry was simply off.
 
By "sleazy MTB" I mean a cheap bike from Bikesdirect.com or (God forbid) Walmart. Yes-- even a misbegotten, barely functional Walmart MTB would make a better platform for an e-bike than a misbegotten, barely functional Sears 3-speed from 40 or more years ago.

Beach cruisers of recent manufacture may have all kinds of functional issues (I hate their handlebars so much), but at least they are pretty sturdy, and equipped with fat tires in a common size. A JC Higgins made by some Eastern European low bidder is not sturdy. It's probably a much better ride than a beach cruiser if you're using only pedal power and moseying along, but add a HP and double or triple the speed and it will get real hairy real quick.

For what it's worth, when I picked a starting point for a propane motorized bike conversion a few years ago, I used a Dyno Glide cruiser frame. It had a longer wheelbase, more stable steering geometry, and more substantial frame tubing than any other bike I could easily get my hands on. It's very easy to set up for different sized riders, too.
 
Any cruiser I sit on gets compared to my grandfather's mid 60's Schwinn Heavy Duty. It was heavy but cruised like a dream even riding it when I was a little kid. My Stingray got all the abuse, but that Heavy Duty was much better for cruising. :mrgreen:
 
I would get the newest model bike I could find, sure in Salem Oregon there could not be much to chose from, However you are just down the Hwy from Portland where there must be many used bikes on Craigslist.
Also
In Portland , Universal Cycles has parts for sale, they are a very big mail order company for bike parts and even frames. including Cro-Moly forks made for kids that jump their " dirt jumpers "
Those forks would be very strong, and some can use V-Brakes or Disc Brakes.

What front hub kit are you going with ?

>



fphowell said:
I have an old JC Higgins 3 speed that I want to convert to a front hub electric wheel. The wheel has 10mm axles and the dropouts on the bike are nominally 9mm. Can they be enlarged using a file and still be strong enough to do the job?
 
http://www.universalcycles.com/shopping/product_details.php?id=4122

or if you brake this one v it is cheep enough to buy another http://www.universalcycles.com/shopping/product_details.php?id=35881

Or a whole bike
http://portland.craigslist.org/clk/bik/4795221458.html
>


quote="fphowell"]I have an old JC Higgins 3 speed that I want to convert to a front hub electric wheel. The wheel has 10mm axles and the dropouts on the bike are nominally 9mm. Can they be enlarged using a file and still be strong enough to do the job?[/quote]
 
The drops may be comparatively thin and weak, but I seriously doubt filing off 1mm will weaken them that much.

For a motor wheel, you should add a torque arm on at least one side.
 
Chalo said:
A stinky old American department store bike like that probably has dropouts that are too thin and flimsy to hold up regardless of slot width. Most such bikes don't even have fork tips per se; they just have slots cut into the squashed fork tubing. If you choose to file them out, be careful to file the slots evenly, so the wheel will sit straight in the fork. Don't leave any notches on the inside of the fork tip slots. Definitely use secure, well-anchored torque arms.

I have to say, a bike like that is not well suited for higher speeds than you'd achieve with pedal power alone. The brakes are terrible, the wheels have weak steel rims that don't provide a decent surface for any brake, the frame alignment is probably poor, and the frame is weaker and less rigid than that of even a cheap and nasty modern bike-- so it will shake and shimmy when you hang the extra weight of a battery on it. Almost all the available tires in that wheel size are archaic, cheap, and crude. Don't plan to go faster than 20mph on a bike like that. You'd be much better off with a sleazy MTB, because at least that would probably have linear pull brakes and alloy rims. You'd even be better off using a recently made beach cruiser, as long as you add a passable front brake.

Well this bike is for my grand daughter who has no transportation. Since my granddaughter weighs about 105 lbs, I'm hoping that this will work. agree this is a very marginal bike for converting to an E Bike, but that's what I have to work with. I bought this kit from the LA shop in California which is really Yescom USA, Inc, who I have heard good words about.
 
ScooterMan101 said:
I would get the newest model bike I could find, sure in Salem Oregon there could not be much to chose from, However you are just down the Hwy from Portland where there must be many used bikes on Craigslist.
Also
In Portland , Universal Cycles has parts for sale, they are a very big mail order company for bike parts and even frames. including Cro-Moly forks made for kids that jump their " dirt jumpers "
Those forks would be very strong, and some can use V-Brakes or Disc Brakes.

What front hub kit are you going with ?

This one: http://www.thelashop.com/36v-500w-26-inch-front-wheel-electric-bicycle-motor-conversion-kit.html
I rode it about 4 miles to test it out and it works, but I have more work to do. I need to come up with a better container for the batteries and controller. Right now I'm using the stock soft bag that the kit comes with, but I'm going to alter it and make it more rigid.



fphowell said:
I have an old JC Higgins 3 speed that I want to convert to a front hub electric wheel. The wheel has 10mm axles and the dropouts on the bike are nominally 9mm. Can they be enlarged using a file and still be strong enough to do the job?
 
fphowell,

Did you buy the , partial kit , from the la shop ?

Since this is for a Grand Daughter, you / She, does not need 500 watts, on the flats of Salem, also it does not come with batteries,

Now that I see what / who is going to be using it, there is a much better option for you, the Complete Kit, ( Including Battery ) from Clean Republic, which is also up in Washington State .

here is the link. http://www.electric-bike-kit.com/hill-topper.aspx

This will work out better for you , since everything is there, only $ 160 more then the other one , and , it has lithium batteries and is plug and play . A complete kit starting at $ 399
 
fphowell said:
Well this bike is for my grand daughter who has no transportation. Since my granddaughter weighs about 105 lbs, I'm hoping that this will work. agree this is a very marginal bike for converting to an E Bike, but that's what I have to work with. I bought this kit from the LA shop in California which is really Yescom USA, Inc, who I have heard good words about.

Ah, you got a kit already. Yescom has good stuff for the cost, I hear.

To be perfectly frank, I think your granddaughter would probably do better with the same bike, tuned up completely, with new aluminum wheels and high quality tires but no e-assist. Whether she'd ride it that way is an open question. It seems like a moot point now, since you've already got a conversion kit.

It takes a certain amount of effort and commitment to push pedals. It takes another kind of effort and commitment to keep an e-bike conversion functioning. The reason people gravitate to cars is because they take no effort or commitment; they only take money (which in your granddaughter's case might be in short supply). In this respect, no bike is truly a replacement for a car. It takes commitment, which your granddaughter might or might not have, and which you can't provide for her.
 
ScooterMan101 said:
fphowell,

Did you buy the , partial kit , from the la shop ?

Since this is for a Grand Daughter, you / She, does not need 500 watts, on the flats of Salem, also it does not come with batteries,

Now that I see what / who is going to be using it, there is a much better option for you, the Complete Kit, ( Including Battery ) from Clean Republic, which is also up in Washington State .

here is the link. http://www.electric-bike-kit.com/hill-topper.aspx

This will work out better for you , since everything is there, only $ 160 more then the other one , and , it has lithium batteries and is plug and play . A complete kit starting at $ 399
Since I spent less then $340 for the entire bike including 3 9AH 12V batteries, I fail to see any advantage.
 
ScooterMan101 said:
http://www.universalcycles.com/shopping/product_details.php?id=4122

or if you brake this one v it is cheep enough to buy another http://www.universalcycles.com/shopping/product_details.php?id=35881

Or a whole bike
http://portland.craigslist.org/clk/bik/4795221458.html
>
Thanks for the tip, I've bookmarked it, as that just might be what I need to get a more complete bike.

quote="fphowell"]I have an old JC Higgins 3 speed that I want to convert to a front hub electric wheel. The wheel has 10mm axles and the dropouts on the bike are nominally 9mm. Can they be enlarged using a file and still be strong enough to do the job?
[/quote]
ScooterMan101 said:
fphowell,

Did you buy the , partial kit , from the la shop ?

Since this is for a Grand Daughter, you / She, does not need 500 watts, on the flats of Salem, also it does not come with batteries,

Now that I see what / who is going to be using it, there is a much better option for you, the Complete Kit, ( Including Battery ) from Clean Republic, which is also up in Washington State .

here is the link. http://www.electric-bike-kit.com/hill-topper.aspx

This will work out better for you , since everything is there, only $ 160 more then the other one , and , it has lithium batteries and is plug and play . A complete kit starting at $ 399
Since I spent less then $340 for the entire bike including 3 9AH 12V batteries, I fail to see any advantage.
 
In regards to yescomusa motor kits, I have over 5000 miles on my 800w front hub motor and have had no problems with the motor or controller. Although, I have been through several throttles and throttle repairs. The break handles can cause the motor to cut out if the tension on the break is not properly set. (like when a set of pads is getting old leaving the lever a bit loose.) Over time bullet connectors for the phase wires can melt and might need replacement.

But for the most part it has been very dependable.

:D
 
When I did this with a hard tail to fit bigger wheels I just used a car jack and jacked it open a bit widerm seems to work ok as long as you are not going vastly larger.
 
I would love a 12.6mm round file with flats ground on. It's an old standard known as half an inch. Still common in the states. I know it would have a radius of 6.3mm not 6mm but 5% out is close enough. An axle shaped file would sell wouldn't it?

I can't get a good price on such a file, but in the states it is a thrifty store item. Plateau grinding is an odd job, but the right man at the right place could make this file easily. Cheap enough that many tool boxes would want one.
 
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