Rocket Sidecar Bike - The Build

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loopybike

loopybike

Über Member
[May 26, 2017]

Started to make the internal structure today. I'm not sure why, but I only took one photo of it. Basically I've made "bulkheads" that the seat base will sit on. The bolts to the frame will go through these. This means that the weight of the rider will be directly on the under-frame so there is no danger of the body deforming. Hopefully that makes sense! lol

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Next I started on the rear top piece. I'm sorry but I cant take a picture of it now without the light! lol

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I'm spending a full day on this next week ( I normally only get half an hour or so on it before I start work ) so expect some major progress!
 
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loopybike

loopybike

Über Member
[Jun 4, 2017]

I've spent a bit of time on this last week.

It was time to make the frame.

I started on the wheel carrier. This is just a rectangle of tube that the wheels fits inside. That way, the wheel is supported on both sides of the spindle. Now I could have just made it rectangle......but, well, thats not my style.....

To the tube bender!

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I'm using 3/4" thin wall steel tube. One of the bends is too tight to make with the above machine so I've used the hacksaw to help bend it.

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The cuts are then welded up and the welds ground down. I prefer to make lots of small cuts rather than a few "pie cuts" as it gives a smoother result. The above photo shows about half the cuts I used.

The other end of the wheel carrier was made into a point.

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The whole carrier looks like this.

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loopybike

loopybike

Über Member
[Jun 4, 2017]

Two connecting tubes were welded to this carrier to support the sidecar and to connect it to the bike:

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Here the sidecar is just resting on the frame. I haven't fixed it to the bike yet, but it shows the final height.

The fixing point needed a bit of thought. It needs to pivot to allow the corners to be taken without the sidecar wheel lifting off the ground, but also needs to be strong. I also don't want to permanently fix it to the bike. I've decided to bolt a bar to the bike rear frame and that the sidecar frame will be attached to.

Sidecar geometry is important if it is to ride nice. There are three things to consider:
1) The tracking, ie, how parallel the sidecar wheel and the bike rear wheel are.
2) The lead, ie, how far forward of the bike rear wheel the sidecar wheel is
3) Wheel angle from vertical

As it happens a good friend of mine ( and one of the most talented engineers I know) used to race motorbike sidecars back "in the day". He was good. Very good. He has raced both circuits and road races ( Isle of Man TT for instance). So it was Alan I turned to for advice on sidecar geometry.

So here is his advice

1) tracking : a couple of degrees toe in
2) between 150mm and 250mm "lead"
3) vertical is fine.

Of course if I get it wrong "it will handle poorly above 30 mph".......er thanks Alan, I think I'm good! :smile:
 
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loopybike

loopybike

Über Member
[Jun 4, 2017]

I went to my local rocket sidecar parts supply store to get a bracket to mount the bar to the bike frame. ( what do you mean you don't have one of those in your town?) It turns out they must have had a run on these brackets because they were all out! So I had to make my own...

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3 hours it took me just to make this bracket! 3 HOURS!!!!
It is stainless steel though :smile: But really, 3 hours! I couldn't believe it when I looked up at the clock. lol
 
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loopybike

loopybike

Über Member
[Jun 9, 2017]

I've done something today that I've never done before..........

Ridden a bicycle with a side car! :smile:

Don't get excited, it's nowhere near finished, but it is attached to the bike now. Well, the frame is at least.

Photos to follow...
 
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loopybike

loopybike

Über Member
[Jun 14, 2017]

Thank you for your kind comments.

I've had a change of mind on the front. I have decided to mount a headlight up there instead of the nose cone. I figured it needed a light at the front to compliment the rear light.
The light I'm using is a headlight from a classic fiat 500. It's about 4 1/2" diameter and has a chrome trim ring.
I'll post some pictures later.
 
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loopybike

loopybike

Über Member
[Jun 21, 2017]

I made a start on the headlight mounting. First I cut a circle from aluminium and ran it through the bead roller:

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... as the edge folds up it starts to crinkle and needs to be shrunk:

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This pinches the edge together to remove the waviness of the edge. I have to flit between the two machines until it's as I like it.

Then it's a matter of tidying it up with a "slapper" and a suitably shaped block:

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The "slapper" is actually a piece of a car leaf spring carefully shaped so it has a slight convex surface.
 
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loopybike

loopybike

Über Member
[Jun 21, 2017]

I made the rear light mounting in a similar way. However after I had welded it in to the lower panels I fitted the top rear panel to check for fit. It was then that I noticed the top panel didn't fit as well as it did. If I forced it into position it would pull the sidecar out of shape in a kind of non-healthy lopsided way! Ah.

The solution, for once, didn't involve a large hammer!

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See now, this is why I like metal. If it goes wrong, just weld a bit more back on! lol
 
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