Top tube extension for chopped electric bike project is finished

December 29, 2009 · 7 comments

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topTubeExtension3The top tube extension is ready to braze. It took lots of filing by hand to fit the tubes. It’s important to make a very close fit. I positioned the existing water bottle bosses so they can be used for mounting something to the top tube extension.

topTubeExtension2
So what’s left to do to finish this electric bike? After I finish brazing the extension I need to fabricate the battery box. Once the battery box is mounted I can reassemble the bike and give it a test ride. If everything works out, I’ll disassemble, prep and paint.

I also need to order longer cables for the brakes and derailleur as well as a longer throttle cable. Waiting for parts can slow a project down so its a good idea to plan ahead and order parts as soon as possible.
topTubeExtension1Leave a comment and let me know what you want to see more of. Do you like the videos? Are they too long too short? Would you like to see more brazing or fabrication steps? Click on comments below and let me know.

{ 7 comments… read them below or add one }

1 Kate December 29, 2009 at 2:58 pm

I like the videos. I’d also like to know where to go to buy parts. Thanks.

2 Kate December 29, 2009 at 3:33 pm

And another thing, what are ‘water bottle bosses’?

3 Dan December 29, 2009 at 3:40 pm

Hi Kate, Thanks for the feedback. I’ll make a video while brazing the top tube extension.

Some day soon I will add links in ‘TOOLBOX’ where I buy my bicycle parts, electric bicycle parts and conversion kits. For this project I’ll probably order the longer cables and chain from Universal Cycles.

Water bottle bosses are the threaded inserts that the water bottle cage gets attached to. See the top most photo. The top tube extension has two screws in the bosses from the donor frame.

4 keith December 30, 2009 at 7:28 am

Nice Miters!

5 Dan December 30, 2009 at 8:52 am

Thanks Keith. A lot of hand filing went into those miters. It makes me appreciate the craftsmanship that goes into hand made bicycle frames.

6 Brian January 12, 2010 at 8:31 pm

Miters go faster once you’ve done gobs of them :) I don’t pay nearly as much attention to detail on my miters as you do though, so HUGE KUDOS to you!

So, is there going to be any diagonal bracing in that battery space? Will the battery act as a diagonal brace? I wold be concerned that it would bend. I’m not good at keeping my bike on the ground though, so maybe that’s just my problem :-P

7 Dan January 12, 2010 at 9:46 pm

Hi Brian. Thanks for the kudos on the miters. I’ll be happy when I can make them faster.

Good catch on the battery space brace. I was hoping to get away without bracing it because I’m using two tubes for the chain stay extensions. It might be alright without but I’d rather be safe than sorry so I’ll add a brace or gusset.

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