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

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imamedik

yes you are right , and I do have some which at some point I intend to use.
I really wanted to be confident I knew how it behaved before I added them , rather than altering a bunch of stuff having problems and not being sure what caused them.
I understand I need slightly different ring sizes as well , not looked into that yet.

Paul
 
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Ok so I need to tackle the to high BB and get it closer to the seat , this would provide a solution ?



It would also get rid of the current second chain ring needed for chain guidance :whistle: by cutting the whole of the front off to the left of the joining plate seen just above the derailleur ?
However there is




The green lines represents moving the BB back 3" towards seat , the blue line is dropping the BB 2" from it's current position ?
However that is just a spot in space , if I start to dismantle for the cut with no wheel in if I cut across the yellow line on both sides where is that point in space then ?
Ideally I want to cut the drop out off the white frame and still use the existing one then joint the 2 white tubes [ after a bit of straightening ] to the light blue points ?

Question is how ?

Paul
 
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How about re-creating your seat mount? I mean, if you move the nuts 'n bolts on the front of the seat a bit more to the rear, then you should be able to get the seat a bit closer to the BB.
 
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How about re-creating your seat mount? I mean, if you move the nuts 'n bolts on the front of the seat a bit more to the rear, then you should be able to get the seat a bit closer to the BB.
it would seem to be the easiest option [ however I am not know for doing easy :giggle: ]

I would rather get rid of the mess of having to have the second chain ring to get the chain management to work ?

See below.

Paul
 
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Ok first off I have a new toy :-



This is BIG it is 22" long and weighs ? an eye watering amount like OVER 35kg ! , that is a normal pedal sat on the back of it , that workmate is fully open on it's biggest setting !




that's a 750ml paint tin with a 500ml on top !
These are odd on Ebay ? Collection only they only seem to fetch between £40 & £60 offer to post @ cost of £30 and suddenly they can fetch up to £140 !!!



So on to the Tilt#6

In July I did this to the front part :-



Now I have measured the front after I plated over these gaps :-



This shows that now the seat is lower [ about 16" from the floor ] the original BB position is now much closer to where I want it to be ?
The BB is at 15" from the floor and only 28.5" from the seat front , crikey I could almost ride it if the pedals were moved over and the chain shortened !

So the plan is to open up that joint and move the BB closer to the wheel it will then also become higher - should be win - win.
So I have 2 side plates to grind off each side and one bottom plate each side , I will then groove the top plate and bend the front upwards , then simply re-plate it.
There is of course a slight risk it will throw the chain line out or the tyre will hit the front however there is room to grind some clearance for that.
This will allow the upper crank to be removed completely , or used for a different purpose ? [ watch this space ]

Paul
 
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To tilt the front BB why not just cut a V in those strengthening plates (the opposite way up to the cut pictured) and tilt it up and back to close the V for welding. You then go back to using the lower BB and cut off all the iron above it. You'd probably loose a couple of Kilos of dead weight too. If you want it back at the current height then lop it all off and extend it.

Hard to beat a stiff six incher (vice that is). I have a similar sized unit that's had the best part of 100 years of abuse already. It'll probably still be around for the Y3K celebrations.
 
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To tilt the front BB why not just cut a V in those strengthening plates (the opposite way up to the cut pictured) and tilt it up and back to close the V for welding. You then go back to using the lower BB and cut off all the iron above it. You'd probably loose a couple of Kilos of dead weight too. If you want it back at the current height then lop it all off and extend it.
I suppose the same reason I gave the first time I said I was going to do it like this ?
Your way requires 4 accurate cuts and no room for error if you take out to much it is harder to go back , if you take out to little you need another 4 accurate cuts etc etc
Doing it this way you just bend it till it meets the dimensions you want then plate it over.

I did briefly look at leaving the plates and doing as you suggested , however I think there would be no plate left at the top when the cut was made big enough to achieve anything ?

A web site by Knight Rider a Pythoneer has the following ?

I cut the first bend by trial/error method, but it took to long, so I derived this simple equation:




H*B
W = -----
L

It can be applied for angles small enough to have roughly sin(x) = tan(x) = x.

the plates are off mine and I need to stabilise the joints enough to add the wheel and derailleur and a bit of chain to see if it works or not....
Then on with the plating :)

Hard to beat a stiff six incher (vice that is). I have a similar sized unit that's had the best part of 100 years of abuse already. It'll probably still be around for the Y3K celebrations.
Well it is mounted , as there was no where to store it !

Paul
 
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Ok got somewhere I think...



Took some measurements from frame before disassembly , the 25.75" was from the pivot end of the straight tube to BB centre , the BB was also 5" high from the underside of the straight tube.

Now the same point is only 24.25" from the BB , giving me the needed 28" seat front to BB
BB also raised to 10" giving me a healthy 4-5" above seat from [ best power output for me [



We also have all the chain clearance we need , that is on the smallest cassette sprocket and small front ring , so now we need to plate the beggar !

Paul
 
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No ride to mothers today as weather pretty bad first thing , so pedaling time became welding time 👍

Filling the hole ....



So the holes has grown rather large ;) so the base is a strip of 3mm
You can see where I have scored it with the cutting disc , unsure whether those need filling and smoothing first , or just weld a plate over the whole lot ?



So I have 2 3mm bases added and have plated 2 sides with 2mm plate [ same wall thickness as tubing.] Brown on right weld not good either touched down or touched tungsten with filler , easy to do as positioning not good due to obstructions (n) Tiny bit of porosity on some welds , sometimes no matter how clean you get it the metal seems sh*tie ! [ well that's my excuse !]



This is the top , last time I just welded the plates to the tubing top , probably do that again as I don't think it is stressed much although it could be in tension due to pedalling forces.

Hopeful to get the other 2 side plates welded tomorrow as the bad weather continues :)

Paul
 
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Your way requires 4 accurate cuts and no room for error if you take out to much it is harder to go back , if you take out to little you need another 4 accurate cuts etc etc
I've done it many times and it's never been any issue the MIG couldn't fill in. I'd regard it as the quickest, easiest and neatest option, negating strengthening plates and wouldn't consider cutting it the other way. I'd usually use the cutting disc in the angle grinder as no precision is really required. Perhaps the TIG would have issues filling a gap? I abandoned my TIG use rather quickly to stick with the MIG.

The way you've done it looks like a lot more work.
 
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I've done it many times and it's never been any issue the MIG couldn't fill in. I'd regard it as the quickest, easiest and neatest option, negating strengthening plates and wouldn't consider cutting it the other way. I'd usually use the cutting disc in the angle grinder as no precision is really required. Perhaps the TIG would have issues filling a gap? I abandoned my TIG use rather quickly to stick with the MIG.
But starting off you have no idea how much to cut out ? and if both sides of each leg are not cut the same the leg bends ? and if the same is not cut out of each side the whole shooting match bends ?

The way you've done it looks like a lot more work.
true but controllable ?

I really wanted to cut 3 sided inserts from some scrap frame material making a neater joint with only 2 parts to be welded , however getting it apart caused considerable damage . and after all it is only a test mule ?

Paul
 
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So been @ the metal glue gun again !



there are a lot of welds , inevitably there are some spots of porosity however not enough to compromise it's strength.



As can [ almost ] be seen here the upturn is in the parallel portion just before the joint for the sweep in to the BB.
Yes I could have combined both joints together in a compound joint , however my brain can't take that sort of complexity ....
Dressed to remove extraneous bumps/lumps however not to make the welds ' disappear ' it is now ready for painting.

So sat in my room ' warming up ' [ it is 0c and 2" of snow here ] with the paint tin on the radiator awaiting a lick of 70's brown Hammerite.

Need to paint it late at night so the rest of the family don't get a whiff of how smelly the paint will be while it hardens [ pun , did you see what I did there :giggle: ]

Paul
 
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For cutting out I simply run the cutting disc through once then bend. If it needs bending more I run the disc through again and repeat until the right bend is achieved. It leaves a thin triangular slot each side easily filled by starting at the thin end and letting the weld pool run downhill into the wider end. No complex measuring or precision work.
 
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Popshot , certainly another way of doing it , we all tend to do what we think we can make work ?

So no riding whilst we have 4" snow and -4c !
Got a chance to perform a BBectomy , seems to have gone well.



Left a short stub with remains of seat tube/BB mount



Gives me somewhere to mount a lifting handle/light/speedo mount later when this rig is reassembled.

Currently it is paint hardening in front of the radiator.

Paul
 
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Ok more done...

Tilt#2 = 72 miles - retired - dangerous
Tilt#3 = 272 miles - [semi] retired - proved tilting concept
Tilt#4 = 135 miles - [ semi ] retired - will be born again Tilt#6 ?
Tilt#5 = 70 miles
Tilt#6 = 0.5 miles
Total = 5495.5 tilting miles so far..

Out on Tilt#5 good ride , getting the hang of going down dropped curb's now , no drama or tip over nice !
Forgot to say very windy so much I had to pedal down a hill @13mph I usually free wheel down @ 17mph having run out of gears !

So Tilt#6 assembled - Hooray !!

2 very brief around the estate - snagging stuff ;)




So how does it differ from Tilt#5 ?

featureTilt#5Tilt#6
Pedals from floor15"20.5"
seat from floor15"15.5"
Top of pivot from floor9"12"
Seat front to BB28"28.5"
Handlebars to steering pivotinline3.5" forward

So a comparison



.. and the good the bad and the ugly ?
Good 👍:giggle::-
Seat height
Pedal height
distance seat front to BB

Bad (n)😥:-
seat has now moved back in relation to pivot
means moved into cargo space
handle bars now to far forward

Ugly :whistle::-
Hacked up front
Seat mounts

So to do list:-
lubricate chain - add mudguard - take it for a short ride
if ridable transfer pedals and pannier and press into service.

if I can live with bars that will be good.

What has happened is the pedals have moved back towards the wheel axle causing the seat to move back in relation to the pivot [ see bad above ]

Paul
 
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