Cheap BMX minivelo
#1
Senior Member
Thread Starter
Join Date: Dec 2005
Location: Orlando
Posts: 301
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
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.
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.
#2
Senior Member
I like it.
That's an impressively long seat post. And is that a quick release on the stem?
That's an impressively long seat post. And is that a quick release on the stem?
#3
Senior Member
Join Date: Mar 2005
Location: Portugal-Israel
Posts: 863
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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
Second, a question. Do you consider 451 mm wheels?
Cheers
#4
Senior Member
Join Date: Jun 2008
Location: angus scotland
Posts: 600
Bikes: Grifter BSA 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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?
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?
#6
Senior Member
Thread Starter
Join Date: Dec 2005
Location: Orlando
Posts: 301
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
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.
#8
Senior Member
Thread Starter
Join Date: Dec 2005
Location: Orlando
Posts: 301
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
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.
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.
#9
Senior Member
Join Date: May 2008
Posts: 89
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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!
#10
Senior Member
Thread Starter
Join Date: Dec 2005
Location: Orlando
Posts: 301
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
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).
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.
#12
Senior Member
Join Date: May 2011
Location: GMT +8
Posts: 230
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
very nice build. i have been toying with the idea of building a formula 1 BMX too. this diamondback BMX will be the guide.
#14
Banned
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 ?
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.
#15
Senior Member
Thread Starter
Join Date: Dec 2005
Location: Orlando
Posts: 301
Bikes: homebuilt FWD recumbents, Genesis 20" folding bike, 1986 Schwinn Tempo, Cannondale Beast of the East, 70's Peugeot
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
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.
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.