Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-08-09, 05:07 PM   #1
atombikes
Senior Member
Thread Starter
 
atombikes's Avatar
 
Join Date: Dec 2005
Location: Orlando
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Posts: 302
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Cheap BMX minivelo

After studying this for a week or so, I took the plunge and started to build up my homebuilt minivelo from junk bike parts. I started thinking that I wanted to build a bike that could easily be put in a suitcase by using sleeves as referenced in another thread, and I still intend to do that. But I decided I would build it up this way first just to make sure I like the ride before I cut the frame.

Here is where I'm at now. It will be a 52 chainring/16 freewheel single speed bike with front and possibly rear caliper brakes. I figure the less stuff I add to it the easier it will be to pack. I know the handlebars will probably have to be dropped some more.

atombikes is offline   Reply With Quote
Old 05-08-09, 11:53 PM   #2
Lalato
Senior Member
 
Lalato's Avatar
 
Join Date: Sep 2007
Location: Bay Area and Sacramento
Bikes: Bike Friday Tikit
Posts: 1,159
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I like it.

That's an impressively long seat post. And is that a quick release on the stem?
Lalato is offline   Reply With Quote
Old 05-09-09, 12:27 AM   #3
caotropheus
Senior Member
 
caotropheus's Avatar
 
Join Date: Mar 2005
Location: Portugal-Israel
Bikes:
Posts: 863
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
First of all, lucky little me, I would not need such long seatpost and stem. And this build is giving me ideas!...
Second, a question. Do you consider 451 mm wheels?

Cheers
caotropheus is offline   Reply With Quote
Old 05-09-09, 05:18 AM   #4
griftereck
Senior Member
 
Join Date: Jun 2008
Location: angus scotland
Bikes: Grifter BSA 20
Posts: 600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
you might want to put the saddle as far forward as you'll be more over the cranks then
will be steadier to climb then

have you got a close up of the stem?
did you cut the quill tube from a stem and then clamp a plain tube onto it?
griftereck is offline   Reply With Quote
Old 05-09-09, 08:03 AM   #5
atombikes
Senior Member
Thread Starter
 
atombikes's Avatar
 
Join Date: Dec 2005
Location: Orlando
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Posts: 302
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Lalato View Post
I like it.

That's an impressively long seat post. And is that a quick release on the stem?
Yes, it is a seatpost clamp and quickrelease.
atombikes is offline   Reply With Quote
Old 05-09-09, 08:04 AM   #6
atombikes
Senior Member
Thread Starter
 
atombikes's Avatar
 
Join Date: Dec 2005
Location: Orlando
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Posts: 302
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by griftereck View Post
have you got a close up of the stem?
did you cut the quill tube from a stem and then clamp a plain tube onto it?
Yes, I did exactly as you said, clamped as scrap seat tube cut from a frame onto a quill that had the stem cut from it, then filed flush. Works beautifully. And allows use of a quick release.
atombikes is offline   Reply With Quote
Old 05-09-09, 06:45 PM   #7
rench123
Senior Member
 
Join Date: May 2008
Bikes:
Posts: 89
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Does the seatpost flex much?
rench123 is offline   Reply With Quote
Old 05-10-09, 07:16 AM   #8
atombikes
Senior Member
Thread Starter
 
atombikes's Avatar
 
Join Date: Dec 2005
Location: Orlando
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Posts: 302
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by rench123 View Post
Does the seatpost flex much?
Not that I have noticed- I have only ridden this bike for a short distance but I have not noticed that seatpost flex would be an issue. The wheelbase seems a bit short but nothing insurmountable.

The way I see it, this seatpost is no longer than a Bike Friday and some folders?

The wheelbase could stand to be a bit longer, that would open up the "cockpit" for easier standing sprints and hillclimbing, but again, it's usable as-is.
atombikes is offline   Reply With Quote
Old 05-10-09, 11:46 AM   #9
rench123
Senior Member
 
Join Date: May 2008
Bikes:
Posts: 89
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
i was thinking of the cockpit as well. the top tube seems too short for someone with legs long enough to justify that seatpost. of course its a scrapbike project, so understandably you use what you lay your hands on. please update us on how it goes!
rench123 is offline   Reply With Quote
Old 05-19-09, 08:35 AM   #10
atombikes
Senior Member
Thread Starter
 
atombikes's Avatar
 
Join Date: Dec 2005
Location: Orlando
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Posts: 302
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
updated pics

I added chain, front brake, and am now able to take this bike on short rides. I think this will be quite a nice little bike for short trips. It took a short while to get used to, but nowhere near some other bikes (like some recumbents).

I am still waiting for the chain tugs to arrive in the mail. I used a cheap v-brake lever for the front brake, I was able to expand the plastic clamp enough to fit over the larger diameter handlebars. I will add the rear brake later for safety. The foam grips are not permanent, eventually if/when I decide this one is a keeper I will strip it all down, remove the decals, clean everything up and paint the currently painted parts. I think I will leave the chrome as-is since it is so durable.

There's alot to like about this bike- low step over height, extreme portability, very nimble handling, low weight (for what it is).






Last edited by atombikes; 05-19-09 at 12:53 PM.
atombikes is offline   Reply With Quote
Old 10-14-14, 02:59 AM   #11
alecw35
Senior Member
 
Join Date: Jun 2005
Location: Angus, Scotland
Bikes: Many
Posts: 401
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
cool bike. Ive modified some kids bikes, and rode them.
alecw35 is offline   Reply With Quote
Old 10-14-14, 04:06 AM   #12
marxmini
Senior Member
 
Join Date: May 2011
Location: GMT +8
Bikes:
Posts: 228
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
very nice build. i have been toying with the idea of building a formula 1 BMX too. this diamondback BMX will be the guide.
Attached Images
File Type: jpg diamondback_01.jpg (43.7 KB, 30 views)
marxmini is offline   Reply With Quote
Old 10-14-14, 09:52 AM   #13
DVC45
Senior Member
 
DVC45's Avatar
 
Join Date: Dec 2006
Bikes:
Posts: 3,832
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Nice build!

I've been hunting Craigslist for a 24" tire BMX for a good price for the same project build. No luck so far.
DVC45 is offline   Reply With Quote
Old 10-14-14, 10:04 AM   #14
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,086
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Put a straight edge, on that seat post.. so you are able to compare it as it bends a little bit at a time.
to plan replacing it , before its too bent.

Is that one using chromoly steel ?

Last edited by fietsbob; 10-14-14 at 10:08 AM.
fietsbob is offline   Reply With Quote
Old 10-15-14, 06:21 AM   #15
atombikes
Senior Member
Thread Starter
 
atombikes's Avatar
 
Join Date: Dec 2005
Location: Orlando
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Posts: 302
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Hey, that's my bike! haha. Well, it WAS my bike. This thread is 5 years old, and many things have changed during that time.

As I recall, the bike's handling was very nimble. It was simple, relatively lightweight, and fun to throw around.

My plan was to keep the frame intact, but braze in a second top tube and second set of seat stays along with a seat tube extension to stiffen the seat area. Similar to how some F1 bmx bikes were designed. In the end, I disassembled the bike and stored the frame and other parts for years, only to have recycled them about a month or two ago.

Here's what I like about the concept: compact frame, bottom bracket in "correct location" for 20"wheelset, if you get a bmx frame with a long enough top tube (~21") the bike is OK for adult size riders.

The challenges: the seatpost (as already discussed), need a riser for the handlebars, rear dropout spacing not correct for geared wheel.

I say if you can find a geared 20" mountain bike with a 21" or longer top tube, you might have something. Similar to the F1 bmx bikes that marxmini is using.
atombikes is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 06:20 PM.