Folding Bikes - Mini-Velo Project ?

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SSDD
12-31-06, 07:14 AM
Hi !
The following is not a folder related issue but I think that some of you can help me with the project.
Here goes:
I've seen a Peugeot mtb (??) bike with 20'' wheels.
Seems to be in good condition (It does need to be cleaned and lubricated).

I was thinking about modified it to be a Mini-Velo bicycle - A long term project
What do you say ??
Any directions ?
Guy


MnHPVA Guy
12-31-06, 08:17 AM
A possible downside may be that the top tube may be too short for you. You may need an offset seat post and/or a very long extension on the stem to get a comfortable position.

Some of these kid MTBs have very heavy frames, but probably no heavier than my Twenty's.

Please show us how it turns out.

SSDD
12-31-06, 08:29 AM
Well ....
The bike is cheap (around 45$ and I can try to bargain) and in addition I already have the parts (For the R20 project):
A long stem post (I might need to install a second stem - Seems to be too short)
Good back wheel
Decent front wheel
Brand new crank and BB

Where can I get that special seat post ?
How long should be the stem post ?

Thanks for the help :)


LittlePixel
12-31-06, 10:14 AM
SSDD - The seat post you want is probably found at a BMX specialist - they are essentially 's' shaped so that the post is offset a few inches back from the original position. This will buy you a few more inches of reach. You could also fit a longer stem - very easy if it has an a-head headset which will improve things further - A 45° upwards angled stem of say 200mm will help increase the size of your 'cockpit'

But you should remember that this is a kid's bike, and is essentially a scaled down adult's bike so even with these changes the geometry won't be ideal. The bottom bracket may be a little low, and using a bmx post that buys you reach will mean your legs will be further forward in more of a 'cruiser' style that may not suit you - especially on hills.

But it could well also be fun - it's something I've considered myself to be honest, and if it's an MTB style bike it will have all the brazeons and correct hub spacing for some pretty fun gear upgrades I'd imagine too.

Let us know how you get on. One other warning - French bikes like Peugeot's sometimes have some strange not-quite standard sizing on things like stems, bars and seatposts. Just a warning in case you end up finding nothing will fit!

Huw :)

SSDD
12-31-06, 10:42 AM
Its probably a late 80's bike and since my daily commuter is also a 80's peugeot - I dont expect any problems

I'll post some pictures upon the kick-off

james_swift
12-31-06, 04:45 PM
Don't forget that you can get an additional 2.5" in rise by using riser MTB bars (http://pricepoint.com/detail/12713-195_SETDR4-3-Parts-62-Handlebars/Mountain/Bar-Ends/Sette-Duo-25.4mm-Riser-Handlebar---2014.htm).

SSDD
12-31-06, 08:36 PM
Guys,
What do you say about a 24'' fork (and still using the 20'' wheels) ?
What effect will it have on the handling of the bike ?

SSDD
12-31-06, 08:38 PM
Don't forget that you can get an additional 2.5" in rise by using riser MTB bars (http://pricepoint.com/detail/12713-195_SETDR4-3-Parts-62-Handlebars/Mountain/Bar-Ends/Sette-Duo-25.4mm-Riser-Handlebar---2014.htm).

@James: Thanks, thats an option to consider :)

caotropheus
12-31-06, 11:49 PM
Guys,
What do you say about a 24'' fork (and still using the 20'' wheels) ?
What effect will it have on the handling of the bike ?

If you show us a picture of the bicycle, we can forecast the effect of any changes of components.

LittlePixel
01-01-07, 12:12 PM
Guys,
What do you say about a 24'' fork (and still using the 20'' wheels) ?
What effect will it have on the handling of the bike ?

Not sure what the benefits of that would be apart from raising the head-tube about 2" upwards and the bb by maybe an inch or so.

It'll pivot the bike up and back from the point at which the rear wheel touches the road so will give a less upright postion in some senses as the bb goes upwards and the seat post arches back slightly. Steering will have a lazier rake too which will give a more relaxed but less precise-feeling steering action.

Braking might be a problem unless you opt to go for forks with a disk mounting or a hub drum brake. Otherwise you'll have to get some new v-brake bosses brazed on 2" lower or fabricate some sort of extender to fit callipers 2" below the drilling below the crown race. Or really long reach callipers :)

alecw35
12-18-07, 02:05 PM
Its likely that the bike has a lazy seat angle. So when a long seat post is in there. The seats quite far back

Ive built a 15" boys MTB. Its got 20 X 175, 3 speed alloys. Ive got a shopper bike seat pin in there. Not a raleigh one, just a regular 25.4mm Oh its a 6 speed bike. 2 chainrings to the 3 speed hub

http://i29.photobucket.com/albums/c296/Alecw35/79bluebike.jpg

SingleSpeeDemon
12-18-07, 08:08 PM
I'm building up a Frankenbike of sorts along this line using a BMX bike as my donor. A Euro BB conversion kit, road cranks and 700C fork with the 406 wheels is in order. I don't expect anyone to take it too seriously as I don't either. I have no idea how it will handle.

For a seatpost, I am having a custom 600mm one fabricated.

alecw35
12-19-07, 03:15 AM
hi singlespeedemon is the BMX got a 22.2mm 7/8" seat post diameter.

If so you could maybe go to a motor bike shop. They might have Drag bars Absolutely straight bars.
They might be cheaper than getting a post made.
Seen them in a custom catalogue. They had them in Chrome steel, Stainless steel, or anodised alloy.
Most motorbikes use the 22.2mm diameter bars. Just some bikes that use a bigger size.

SingleSpeeDemon
12-19-07, 08:46 AM
That's a great idea, but the post is 26.0mm. We have a local framebuilder that can weld aluminum like nobody's business. He's always up for working on odd side projects like this.

-Andrew