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Mounting Techniques for Bicycle Motors Every frame is different. Share and ask questions about mounting your engine kit to your frame or rack

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  #11  
Old 01-29-2013, 02:11 PM
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bairdco bairdco is offline
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Default Re: How To: Spreading Your Frame for Clearance

the two top "forks" are called "seatstays," and the bottom two tubes are called "chainstays."

a torch wouldn't hurt (besides melting the paint, if it has it,) but it's probably not necessary.

there's not too much lateral stress going on while riding. most frames break at the welds near the bottom bracket or the seat tube.

obviously, if you bend the crap out of your frame it could weaken it, but as long as you don't crease or buckle the tubing, it should be ok.
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  #12  
Old 01-29-2013, 06:36 PM
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Default Re: How To: Spreading Your Frame for Clearance

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Originally Posted by bairdco View Post
the two top "forks" are called "seatstays," and the bottom two tubes are called "chainstays."

a torch wouldn't hurt (besides melting the paint, if it has it,) but it's probably not necessary.

there's not too much lateral stress going on while riding. most frames break at the welds near the bottom bracket or the seat tube.

obviously, if you bend the crap out of your frame it could weaken it, but as long as you don't crease or buckle the tubing, it should be ok.
thanks for the advice, even though I'm a machinist I haven't worked on bikes
for about 40 years, the problem I'm having is that every time I take the rear
wheel off the frame springs back which makes it impossible for me
to change rear tire on the road without spreaders.
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  #13  
Old 01-29-2013, 07:30 PM
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Default Re: How To: Spreading Your Frame for Clearance

You need to over spread them so when springback happens it is at the width you need
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  #14  
Old 01-29-2013, 08:29 PM
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Default Re: How To: Spreading Your Frame for Clearance

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Originally Posted by chainmaker View Post
You need to over spread them so when springback happens it is at the width you need
Did that almost to the point of kinking frame and they still popped back to original measurement after 200 miles on the road, and just in case you are
wondering I have the huffy panama jack frame
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  #15  
Old 01-29-2013, 08:39 PM
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Default Re: How To: Spreading Your Frame for Clearance

3 inches? Why would ever need to spread the frame 3 inches? That seems excessive unless you're trying to use a motorcycle rear hub. You're asking a lot of your frame. I'd keep my eye on it if I were you.

Tom
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  #16  
Old 01-29-2013, 09:02 PM
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Default Re: How To: Spreading Your Frame for Clearance

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3 inches? Why would ever need to spread the frame 3 inches? That seems excessive unless you're trying to use a motorcycle rear hub. You're asking a lot of your frame. I'd keep my eye on it if I were you.

Tom
This is the axle I'm using, and by time you mount it you do have to spread your frame quite a bit.
http://www.bicycle-engines.com/Freew...t-w-Brake.html
when I bought it I didn't think I would have to spread the frame that much but there you go, oh and I'm mounting a 79cc and ezm to it
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  #17  
Old 01-30-2013, 07:36 AM
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Default Re: How To: Spreading Your Frame for Clearance

Like most bikes that originally came with coaster brakes, mine had 110MM spacing.
Most the non-coaster rears are 135MM, so that 50MM is about a 2" difference overall.

I used my tool to get most the spread, but I actually have just enough left to make
installing/removing my rear wheel a 2-person job unless I use the spreader tool

As I use a quality tube, Slime, and a tire liner, flats aren't something I have to worry about, thankfully.
My bike carries it's own footpump
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  #18  
Old 01-30-2013, 11:37 AM
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Default Re: How To: Spreading Your Frame for Clearance

Here's a little tool I made quickly from an old aluminum turn buckle. I didn't make it very pretty, just functional because I needed it 'now'. It was made to fit the seat stays on a Nirve Switchblade. I can spread the frame just enough to make removing or installing the rear wheel easier. I have chain adjusters that fit between the frame and the cone nuts and they take up some space that makes getting the axle into the dropouts difficult.

It's the same principle as Aleman's but doesn't use the dropouts.
Tom
Attached Images
File Type: jpg Frame Spreader, 1.jpg (115.8 KB, 170 views)
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  #19  
Old 01-30-2013, 12:07 PM
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Default Re: How To: Spreading Your Frame for Clearance

Not as fancy, but effective;

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  #20  
Old 06-30-2013, 07:12 PM
5-7HEAVEN 5-7HEAVEN is offline
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Default Re: How To: Spreading Your Frame for Clearance

Your advice is timeless, bairdco.

Here's my problem.

Dropout width is 130mm, so I can get a multi-speed hub in there w/no probs.

I need more tire clearance for my motorcycle tire. I'm estimating less than -1/16" on one chainstay to +1/16" on the other side's seat stay.

Do I have to cut off the fender bracket/cross brace on the seat stay?

Do I have to cut off the bike stand bracket on the chain stay?

To my thinking, that's the only way the stays will spread where the tire will be. I can secure the stays with C-clamps. That way, the welds on the seat tube don't get stressed during the spreading process.

Thanks for help. I'll prolly use a Toyota jack or all-thread and washers.
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