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Saturday, October 2, 2021

New Bike Part 9: tailbox and new forks

1 Attaching tailbox frame to fibreglass seat. A soldering iron was used as well, for marking drill positions on the set.

2 That bit of the tailbox finished

3 Scored corflute for lower back half of tailbox

4 Bit blurry, but this is the setup for bending the forks to suit a front wheel.

5 New dropouts held square and roughly alligned with a rear wheel axle, ready for brazing

6 Jig for keeping back v-brake bosses in place. It helps chain clearance that they are close together.

7 Checking v-brake fit, all good

8 painting, working parts of the fork are masked off.

9. A zinc splodge. I had left a zinc screw bearing cap on the thread when I was brazing and it melted. Oops but no harm done.

10. Assembled

11. Not much chain clearance but enough!

12. The bike with the new fork

13. Steerer is now shorter so exerts less torque at the stem.


I've been working on my new bike, and at first I started in on the tailbox, firstly making a 5mm surround for the seat which I can mount the back of the tailbox on. Work included drilling the seat and attaching the corflute with tape and cable ties. Next I scored and bent a larger 3mm corflute sheet which will be the lower back part of the box.

At about that I realized I wasn't happy with the front fork arrangement, mainly the brake. The Performer fork only had one brake, for a disc, and I didn't like it that much. The existing 2-v-brakes-one-front-one-back has worked fine for a while and I didn't need to change it. Also I wanted a screw on headset, the Aheadsets have never properly worked for me on this style bike.

As well I realized that the stem could probably be swivelled through 180 degrees. If there was enough clearance to the crank, then this would save 100mm or so of steerer material. Lastly the 3 cables from the handlebars wouldn't have to go through a big angle with the new arrangement.

To solve all this I started by ringing my local bike shop to see if they had the fork I wanted which comes from a 451 Byk bike. They didn't have just the right thing but suggested something else. After a shop visit, I found their suggested alternative no good because of the dropout type, thanked them and went on my way.  In the end, shed fossicking revealed I not only had the 451 fork, but also something (20" folding bike fork with short 1 1/8" threaded stem.

A few mods were needed to the fork, these were

Widening the blades using pipes slipped over the tynes as levers.

Removing dropouts and replacing them with custom laser-cut ones

Adding bosses for an extra set of v-brakes behind the fork

Lengthening the distance to the thread from the lower bearing mount

Lengthening the thread length. I'm mixing things up by having a threaded bearing and clamp on stem.

Whew, quite a bit of work!

After checking, I painted it the only colour I have, black. After an afternoon outside, and night inside, it was dry, and this morning it was ready for fitting. That's what I did today, I'm very happy with the resulrs as shown above. 

I managed a test ride late today and tomorrow can shorten part of the steerer (scooter fork at the bottom) to save weight and do some more paining.


Steve Nurse

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