Converting an old mountain bike into a city roadster

Building a City Roadster

This is a little blog on my little experience with this small Raleigh MB20. We pretty much got it from thrash and had some family fun in the garage to turn it into a city bike.


Saving it from garbage

I got this from a student here who was ready to throw it away. It is a good ol' reliable Raleigh MB20. Raleigh makes great bikes. This one was not a very expensive and fancy model, but what I liked about it is that it comes with a steel frame.


As it can be seen, there was lots of rusty parts, flat tires, and pretty much nasty condition. The bike was "parked" outside in bike rack and beaten up by rain and humidity (you got to love Texas).


Major "issue" with "da machine"

The biggest issue with this bike, however, was the fact that the seat post was replaced with a thicker one that was hammered into the frame.


As it can be seen here, there is no screw to hold the seat post. I thought it was not going to be a problem, but I later learned that wrong sized seat post hammered into the frame is one of the hardest things to fix. I found several articles about it on the net.

Suggestions

Some suggested use of penetrating oils such as WD-40. It did not help. A good advice I found is to actually use the seat as a tool when trying to move and remove the seat post. Unfortunately, in this case it did not help. The seat post was aluminum and the frame is steel and it felt like they become one. I read that there are some issues with different types of metal and their thermal characteristics. Honestly, not sure if that was the case here.
Some people suggested use of vice and bike frame as a lever. I did not try that but it did not look like it would work.

Solution

Finally, I found a solution where guy suggested a "radical" measure of cutting the seat post. The "trick" is to cut the seat post about an inch above the frame. Then to cut the seat post vertically from inside. So I got me some tools and started working on it.


Cutting it vertically was not a big deal... the adventure is yet to come...


I started working on the vertical cuts. You need to make at least three cuts and then try to pull out piece by piece. The funny thing is you never know when you really did cut through and you have to be very careful not to mess up the frame.


Little "play" with chisel and "gentle" touch with a hammer. And more sawing. I finally came up with a tool made up out of "standard" parts. You break one metal saw insert in half, screw it to another one and put all that into the holder. This worked nicely for this kind of job.


I never had enough time to work it through in one shot so I do not really know how long it took. I worked on it at least 2-3 weekends 15 minutes there, 15 minutes here. Anyhow, it takes a long time.


I got some help from time to time. These were my high profile "consultants" on the subject.


Finally, the old seat post gave up. Once I took out the first piece it all happened in few minutes.


I inserted the new seat post that was selected to match the diameter. It went in pretty easy.

Preparing it for the paint job

Now came the fun part of dismantling the bike. I first took several pictures just to have a reminder on how to assemble things back. It came apart pretty easily. I bought some paint stripping tools to be used with electric drill. It worked pretty well on the frame and fork.


Finally, the thing was ready for some sanding and and primer layer. gasoline worked nicely for cleaning up the dirty corners. Please be careful with gasoline. Fairly flammable I hear.




Painting

I bought some spray paint at Home Depot. Got 2 cans of primer (one was enough) and 4-5 cans of the color. My family members picked some crazy yellowish greenish tone. I went with their choice.


After the primer, it is good to use wet sand paper to further smooth it out before applying the final color.


I used 2-3 coats of the final paint. I think I did little too much. But it did not look bad so I kept it that way. The last coat I put was glossy finish (no color). I used one can of that for the whole frame and fork. It gave it little more shine and some protection.

Putting it back together

I did lots of searching on eBay, Amazon, and other places for some replacement parts. I got new seat post, seat, tires, and a crank set. Also got new break pads and tubes.


I picked those tires at Amazon. Pretty inexpensive and have cool slick look and are very comfy for regular asphalt roads. I think the tires defined the new look of this bike completely.


We painted all the metal parts ("trim") into black mate finish.


I later decided to paint those rusty screws into black mate finish as well.


I got a small "computer" speedometer at Walmart on sale. That was pretty much the final touch on the machine.


The machine is pretty much ready for the test drive.



Good thing about "tuning" is that online you can find lots of documentation on Shimano. I downloaded instructions on how to adjust front and rear rails.


I did not put much effort in removing the rust from rear gearbox. I cleaned it with gasoline, put a new chain and lubed everything. Now, after few months of use all the gears look much cleaner.

Disclaimer

Kids do not try this at home. At least, not alone. I am not suggesting or implying that all this was easy. However I enjoyed it. Wear protective gear if you playing with tools, be careful with gasoline and other flammable stuff. Blah, blah, whatever, etc...