BT inspired columbia build

Lay'emLow · #1 02-18-2010, 02:34 PM

Finally, after seemingly endless frustration, Ive finished my first build. Now, the next logical step is to start a new one, right??

I few days ago I bought a few old and beat up bikes (2 columbia road bikes, a raleigh, and a ladies schwinn breeze from '77). If anyone has any knowledge of any of these being a collectible please tell me because the next free weekend I get theyre getting chopped up.

I plan on building a board track-ish MB. Im not too concerned with staying with the original style, but there are a few design elements that Id like to incorporate, namely being looooowww! haaa

I also want to build a leaf springer front end. Ive already got a simple design in mind. (see 'painted' photo) where i will build a bracket to mount it to the top of the split in the fork and use a piece of the rear stays to connect the spring eye to the wheel axle. My only concern is how far forward this will put the axle in relation to the fork's rotating axis (red lines in painted photo). I have a lowrider bike now with almost 90 degree bent forks and its a ***** to control.

For the frame I plan to unbraze a few of the joints and put a slight bend in the middle of the downtube (and keeping the bottom few inches straight for engine mounting purposes) filling the empty space behind the wheel, similar to a BT. This will angle the seattube back and along with bending the toptube towards the rear, will allow me to sit very low.However, I dont like all the empty space in front of the rear wheel behind the seat tube this creates. I may not make the bend in the downtube so extreme to help with this.

You guys can see where im going with the photos. I just wanted to share and see if anyone has any ideas, tips or forewarnings before I really dive into this build. I dont have any friends who are into this kind of thing, so I need you guys!! haha

Thanks for checkin out my post,
L'eL

h0tr0d · #2 02-20-2010, 09:33 PM

L E L,

Your enthusiasm is great, but slow down a think it out. Please don't take my advise like i drank a bottle of HATER-ADE. Since no one has responded in 2 days I thought I'd say what I thought.
Looks like your front tire will hit your toes when you turn. In my opinion the frame looks better for motorbycling the way it is. Im a little over 6 feet tall and still wouldn't want to ride very long chopped out like that. Take a look at some of the boardtracker bikes in the gallery and everything except a stretch has the pedals in the rear. It's better if the pedals could stay where they are on the Columbia. The front forks dont look like the bottom bolt will be enclosed, remember it's not going to be fixed after you add that suspension. and the trail setup you have is too little and will wobble at post bicycle speeds. I don't want you to get to chopping and then run into a few problems and get discouraged.

Keep us updated

Lay'emLow · #3 02-25-2010, 05:58 PM

hey hot rod,

thanks for the input. im happy for any outside thought as ive just about gone mad turning this over in my head.

I dont think im going to move the pedals as far foward as depicted, but i am going to put a slight bend in the downtube... i just dont like all that empty space and i also want to angle the seattube back a tad.

as far as the forks go, ive thought long and hard about how to make the linkage and what fasteners and bushings to use. after a few trips to the hardware store, i think ive got i nailed. i should have time to finish it up over my spring break (right around the corner) and will post pictures as soon as i do.

what do you mean by trail setup being to little? im not too familiar with bicycle lingo

l'el

h0tr0d · #4 02-27-2010, 10:08 PM

Here is a quick lesson in bicycle handling.

CalfeeDesign
The easiest way to correct your trail issue is to increase the head tube angle while you are moving things around. Ive seen people on here simply lengthening the area between the crank and rear wheel stays. Doing this increases headtube angle and leans the seat post back at the same time while only altering one small section of the frame.

I mentioned the part of your fork that is currently a slot for the axle, it really should be an enclosed hole if it is going to be an active part of the suspension.

Keep thinking it out and it will come together.

Lay'emLow · #5 02-28-2010, 08:39 PM

thanks hotrod, that diagram and explanation completely cleared things up for me.... turns out i have negative trail. also explains why i cant ride with one hand on my lowrider.

theres a couple design elements i was to maintain, like a horizontal top tube, and the cleanliness of the brazed joints that make changing tube angles difficult. not sure what im gonna end up doing yet.

oh the sacrifices we make in the name of style....

Lay'emLow · #6 03-11-2010, 05:07 PM

A few afternoons in the books and out comes a leaf spring front end. The only thing that I wish is that it had come out a little more precise, but considering the conditions I was working in, Im okay with the end result. Its ugly as all ****, so Ive decided to keep that theme and just build some sort of ratbike (even though I hate the 'rat' term... I cant think of a better word to describe). The pictures here show it near completion. The only thing left to do was weld on some washers in the stay slots so in order to locate the axle and pivot points, and also add a few lock washers and whatnot.

Yea theres a slight issue with trail being just about non existant... but i decided to just run with it and test it as a bicycle for a while before I throw a motor on it.

Next up is frame work. Hopefully the next time you all hear from me Ill have a finished bike!

K.i.p · #7 03-11-2010, 06:29 PM

Just my humble opinion, but I think you sell yourself short. That's pretty cool looking. I think it could work with a variety of MAB styles.

h0tr0d · #8 03-12-2010, 04:17 AM

Send it to me.
You can fix the trail by changing the head tube angle.

Keep sending progress pics, don't wait until your finished!

kla63 · #9 03-12-2010, 09:23 AM

Quote:

Originally Posted by Lay'emLow

A few afternoons in the books and out comes a leaf spring front end. The only thing that I wish is that it had come out a little more precise, but considering the conditions I was working in, Im okay with the end result. Its ugly as all ****, so Ive decided to keep that theme and just build some sort of ratbike (even though I hate the 'rat' term... I cant think of a better word to describe). The pictures here show it near completion. The only thing left to do was weld on some washers in the stay slots so in order to locate the axle and pivot points, and also add a few lock washers and whatnot.

Yea theres a slight issue with trail being just about non existant... but i decided to just run with it and test it as a bicycle for a while before I throw a motor on it.

Next up is frame work. Hopefully the next time you all hear from me Ill have a finished bike!

very nice back yard craftmen ship keep up the good work !!!!thumbs up on you creativety!!!