My life with Python trikes Mk1 , Mk1.5 , Mk2 ?

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Why didn't you go for the rear part of a bike frame, for the front?
Like the first one I built ?

Well there are a few downsides to using an existing rear end ?

If taken from a 20" fully suspension MTB the rear frame is very compressed at the BB and so limits the size of the front rings ? I cannot go above 48t as even with a 48t ring the chain saws it's way through the underside of the seat stay's

It proved to be the weakest part of the build and has broken 3 times in first 4 years.

It is very small to try and fit everything in especially if there are two brakes and 2 gear changers - speedometer - lights etc etc

regards Paul
 
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Is that not a teensy-weensy bit HEAVY for a weight weenie like you? ;)
The tubing is 40 mm x 20 mm x 2 mm , there was not much choice when looking for rectangular tubing that was also thin walled.

If I can get this design to work it will be enough and as long as it is not much heavier than the Mk1 and don't fail well that's a win for the first version ?

Better than this ?



regards Paul
 
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The tubing is 40 mm x 20 mm x 2 mm , there was not much choice when looking for rectangular tubing that was also thin walled.

If I can get this design to work it will be enough and as long as it is not much heavier than the Mk1 and don't fail well that's a win for the first version ?

Better than this ?



regards Paul
I am just teasing. It is really surprising how much all the steel weighs (well, it surprises me).
I think I shall be a coward and go with round tube and triangulation (if I can); as it seems to be what most commercial forks, rear-triangles are made from..
But I do see the value in using rectangular tube in that orientation. I certainly cannot see it distorting.
 
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I am just teasing. It is really surprising how much all the steel weighs (well, it surprises me).
I think I shall be a coward and go with round tube and triangulation (if I can); as it seems to be what most commercial forks, rear-triangles are made from..
But I do see the value in using rectangular tube in that orientation. I certainly cannot see it distorting.
I was worried about weight when I had all four pieces complete and laid on the top of each other , they seem more normal now chopped.

Although I really would have used 30 mm x 10 mm x 1.5 mm if I could have found it.

Paul
 
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So had a bit of time to tackle the joining of the 2 pieces.

I chopped them both off one end square then the other ends at a slight angle then files them till the gaps were within TIG welding tolerances ;)

Applied some glue and got this:-



and next to the old front end ?



Wow you say that looks clean !



Maybe in the interests of lean and clean , no clutter etc I may just make this a Nexus 7 speed with no front mech post ?



and the money shot ? the one where the person with the short fat hairy legs had no faith ?



and if I go 7 Speed I will only have 1 x 40t IIRC ring on the front , then just need simple chain tensioner ?

Next I need to carve out for the BB when I can find the one destined to be on the front , probably in that don't lose pile me thinks (y)
 
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Off to mothers again today with 761 miles on the clock since the rebuild/rear brakes mod when a troubling maintenance problem reared it's ugly head ?

The right hand brake lever was hard to pull and the right brake seemed very ineffective and locked on.



In an effort to stop road dirt etc entering the cable end I had mounted them vertically [ maybe not my best idea this century ? ] and on freeing the cable I could see corrosion at the wheel end ? however there was also signs of corrosion at the lever end ?

I rubbed them vigorously with wire wool and brushed on a little engine oil , hopefully that will keep them working for a few weeks ?

I think it could be bad luck as the left hand one is still fine and it did the same miles and visited the same places as the right hand one :ROFLMAO:
 
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So had a bit of time to tackle the joining of the 2 pieces.

I chopped them both off one end square then the other ends at a slight angle then files them till the gaps were within TIG welding tolerances ;)

Applied some glue and got this:-



and next to the old front end ?



Wow you say that looks clean !



Maybe in the interests of lean and clean , no clutter etc I may just make this a Nexus 7 speed with no front mech post ?



and the money shot ? the one where the person with the short fat hairy legs had no faith ?



and if I go 7 Speed I will only have 1 x 40t IIRC ring on the front , then just need simple chain tensioner ?

Next I need to carve out for the BB when I can find the one destined to be on the front , probably in that don't lose pile me thinks (y)
Looks good.
A simple trick that I use, is drawing the angle on a piece of paper and cut it in half. Than you have something to draw the angle on the parts. This way, you can cut it in the angle you need.

Your welds look good. Mine are getting better and better now I weld more. Still not how it should be, but I sand the old ones away, and put where needed new ones.
I have a stick welder. Bought it to build my bike.
 
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There are rubber slaves that you can put over the opening of the brake cable. That keeps also durt out of it.
 
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and the money shot ? the one where the person with the short fat hairy legs had no faith ?
How very dare they! :eek:
You just tell me who this miscreant is Paul and I will go and sort them out for you PDQ.
 
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A source of 40x20 thin wall tubing is the dog / children gates , available at your local recycle centre. Mostly coming in power coated white.
Regards Emma
Only if you can buy stuff from your LRC ?
 
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You just tell me who this miscreant is Paul and I will go and sort them out for you PDQ.
Do you have a mirror in your house ?
 
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Do you have a mirror in your house ?
No, they all shatter when I stand in front of them. Something to do with the lack of an "ugly-filter". ;)
Good to see that the cranks miss the frame indeed. Where/how will the 4" of mandatory adjustment be implemented?
 
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With this iteration the seat.

However that is a pain to implement which is why I am exploring designs where the BB moves instead.

Next up is a in life service upgrade for the Mk1 rear end ?

Better seat mount
Rear brakes

I have realised I don't need the Mk2 rear end to carry my camping gear , just a cunningly designed rear rack for the Mk1 ..........
 
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Thanks for all the pics, one of these days I am going to have to let the snake bite me as well!
Brad
Thank you for those kind words , it remains a pleasure to be part of the Zombie family.

I am sure if you do build a snake it will be full of ideas worth nicking copying :LOL:
 
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I have realised I don't need the Mk2 rear end to carry my camping gear , just a cunningly designed rear rack for the Mk1 ..........
A demountable rack system (2 sizes maybe?); one for local shopping trips and a larger one for expeditions. 🙃
 
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A demountable rack system (2 sizes maybe?); one for local shopping trips and a larger one for expeditions. 🙃
Hmm maybe cage like current but lighter & pannier rack for 3 or 4 + tent ?

.. and then it will fit in the car !!!!

ain't it great when the brain actually works :D
 
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Hmm maybe cage like current but lighter & pannier rack for 3 or 4 + tent ?

.. and then it will fit in the car !!!!

ain't it great when the brain actually works :D
Yup! QR clamps are your friends. 🆒
 
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