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

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So this is the sanity check ?

Are we heading in the right direction - will it work - before we spend anymore time cleaning - cutting - grinding and welding ?



By jove I think it will , I have 2 different height BB's to insert , this is the shorter one the other is considerably longer so I can try a couple of BB heights however we will easily achieve level with seat base and 5" above.



Top of seat base marked on square post , rest is 3 3/4 " so I marked and trimmed that down to seat top + 1 7/8" .
I then fully welded the post to the front gusset.
I drilled 2 x M8 holes 90' apart in top bit to hold BB post at desired height.
Whilst I want the 2 stays I realise I can't weld them to the square post as it could distort and then the BB post won't fit.
Best option may be to make BB end of them tabs with M8 holes in and use upper BB holding screw for stays as well , only a little more work ?

Paul
 
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So this is the sanity check ?

Are we heading in the right direction - will it work - before we spend anymore time cleaning - cutting - grinding and welding ?



By jove I think it will , I have 2 different height BB's to insert , this is the shorter one the other is considerably longer so I can try a couple of BB heights however we will easily achieve level with seat base and 5" above.



Top of seat base marked on square post , rest is 3 3/4 " so I marked and trimmed that down to seat top + 1 7/8" .
I then fully welded the post to the front gusset.
I drilled 2 x M8 holes 90' apart in top bit to hold BB post at desired height.
Whilst I want the 2 stays I realise I can't weld them to the square post as it could distort and then the BB post won't fit.
Best option may be to make BB end of them tabs with M8 holes in and use upper BB holding screw for stays as well , only a little more work ?

Paul
Looking good on the raised height BB.
You might have trouble cold-setting those "stays" to match your main frame.
If the original main-frame didn't fail with the existing BB it won't in this new deployment either and you could do a much shorter (but still very strong) triangulation to the front section (as long as you can get a clean chain-line in all cassette/chainring combo's.
 
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You might have trouble cold-setting those "stays" to match your main frame.
They just want hacking to length ?

If the original main-frame didn't fail with the existing BB it won't in this new deployment either and you could do a much shorter (but still very strong) triangulation to the front section
The triangulation is to stop the new post collapsing forward ?
They will probably be trimmed to meet the botched plating over the forward cut and shut upwards ?

You are right nothing will be done on that part till a chain has been tried and we have spinney wheel (y) fell for that one before !

Paul
 
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Are you going to move the derailleur mount further around the cogs? Without moving it you will loose wrap though it should still be ok but the mechanism may not have the range of movement to work in that position relative to the BB. Again I suspect it will be ok but I'm by no means certain.
 
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Are you going to move the derailleur mount further around the cogs? Without moving it you will loose wrap though it should still be ok but the mechanism may not have the range of movement to work in that position relative to the BB. Again I suspect it will be ok but I'm by no means certain.
Popshot

DannyC's experience is exactly that , however as you say it ' may ' work or it ' may ' not.
So next up is to add a chain and try it .

Paul
 
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Popshot

DannyC's experience is exactly that , however as you say it ' may ' work or it ' may ' not.
So next up is to add a chain and try it .

Paul
Paul, for what it is worth.... Mine appeared "fine" on the bench but as soon as it got a heavy load on it the chain climbed off the rear sprocket teeth because of insufficient chain-wrap.
 
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Tilter #3 = 170 miles

Engine seemed happier today , slight head wind no sun drizzle etc etc

trike did as advertised on the tin ?

Did some Pythoning
................Tilting
................Got me there
Picked a shorter route as I was late leaving , did a detour for some shopping
................Got me back

Slogging up a hill gives time for cogitating , I realised the social ride and when I had the thorn were rides where I was distracted by chatting to my companion and trying to stop the tyre coming off the rim and rode the trike without giving any though to it be a tilting trike or having to make any conscious actions to ride it nice.

Paul
 
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Tilter #3 = 170 miles

Engine seemed happier today , slight head wind no sun drizzle etc etc

trike did as advertised on the tin ?

Did some Pythoning
................Tilting
................Got me there
Picked a shorter route as I was late leaving , did a detour for some shopping
................Got me back

Slogging up a hill gives time for cogitating , I realised the social ride and when I had the thorn were rides where I was distracted by chatting to my companion and trying to stop the tyre coming off the rim and rode the trike without giving any though to it be a tilting trike or having to make any conscious actions to ride it nice.

Paul
This "Slogging up a hill" usually has my knees and eyeballs popping and sweat on my brow, so no time for cogitating. ;)
 
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This "Slogging up a hill" usually has my knees and eyeballs popping and sweat on my brow, so no time for cogitating. ;)
Cogitating takes your mind off the pain , as the pain is only in the mind :whistle:

Paul
 
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So that did not go well :((n)



No pictures yet as the front is still laid on it's side on the workmate , however I can illustrate where the chain interference is ? the blue square.

I think I sort of still expected the lower chain run to go under the frame to the rear mech , instead it goes above it.

There are 3 possible solutions being chewed over :-
a) hack the frame about , may work however you can never predict how much needs cutting out for it to work.
b) a IGH may give the clearance needed as it can move the chain much closer to the wheel
c) put a sprocket only [ no pedal crank ] on the original BB and route the chain back where it was originally

As solution c) only requires the hacking of scrap chain rings [ I have some single ring kid's ones ] and lengthening the chain I will probably try that first.
Shame I remove the BB hardware and moved it to the upper BB , especially as the original BB has distorted and both cups take some brute force to screw in :whistle:

Paul
 
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Ok we may have to implement plan ' D ' due to interference problems between the crank arm and the boss of the additional crank and the fact the original BB appears not to be welded in square to the frame ! [ despite best efforts , oh and also it is severely warped again despite best efforts ] the chain may well object to the misalignment.

You may ask what is plan D ?

Build as per the first Python but salvage the rear end from axle backwards + pivot etc from the current mess.

So start with a MTB rear end



Prop up BB at height you want the pedals from the floor weld some plates that point towards the pivot.



Add 2 slots in the rear end [ this is the original Mk1 ] the slots are at this end in the picture , insert the plates welded to the front end jig it all up to be square and straight etc then weld the bejeebers out of it.
With a little bit of imagination I could also leave space for a 24" wheel while I am at it ? now that would be nice.

And 1 step ahead of DannyC = result !

Not that it is a race you understand ......

However strike whilst the iron is hot [ or his welder is cold as it is away for repair , whichever is easiest :giggle: ] I say.

Paul
 
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Ok we may have to implement plan ' D ' due to interference problems between the crank arm and the boss of the additional crank and the fact the original BB appears not to be welded in square to the frame ! [ despite best efforts , oh and also it is severely warped again despite best efforts ] the chain may well object to the misalignment.

You may ask what is plan D ?

Build as per the first Python but salvage the rear end from axle backwards + pivot etc from the current mess.

So start with a MTB rear end



Prop up BB at height you want the pedals from the floor weld some plates that point towards the pivot.



Add 2 slots in the rear end [ this is the original Mk1 ] the slots are at this end in the picture , insert the plates welded to the front end jig it all up to be square and straight etc then weld the bejeebers out of it.
With a little bit of imagination I could also leave space for a 24" wheel while I am at it ? now that would be nice.

And 1 step ahead of DannyC = result !

Not that it is a race you understand ......

However strike whilst the iron is hot [ or his welder is cold as it is away for repair , whichever is easiest :giggle: ] I say.

Paul
Welder returns early next week, New tyre(s) on their way too.
Telescopic rear axle is my next step. Then some jiggery-pokery to resolve the front end which may (or may not) be a pre-made rear triangle.
There is no race. :)
 
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So plan D and does it work ?



Well it appears to ? I have trouble at the moment with the bottom BB , it's a s/h cartridge and someone has screwed the threads up on the crank rings side hence the washers.
I will reverse it when I get time as it will help getting the rings closer to the frame.



So seat is about 19" and pedals 23" so nice and comfy , and yes it is ridable and no chain skipping so far despite the appalling chain line ?



The lower rings can just be made out in this picture about 0.5" out of line with the upper rings , strewth it still works !



As can be seen very messy , however I have been off the drive twice with it so about 1/2 mile and no problems , it still seems to shift although a bumpy surface may well be it's downfall , we shall see.

So do I triangulate the square post with the bronzed frame ? or do I ride it as is ?

Paul
 
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Try "as-is" and keep a very watchful eye on those welds. :)
 
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DannyC

As it is :-
unpainted
I am not currently riding it
Welder is still out
Tilt#3 has almost reached 200 miles this may have to go further ?

I will add a small 1.25" sq brace then no fingers crossed riding (y)

Paul
 
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Do you think you are getting close to a final design you are happy with now?
Interesting question.

It meets the brief for taller & narrower however as a design it suck's big time.

However with all these things it is far better to have something that almost works and just needs tweaking than a blank piece of paper ?

It is much like the curates egg , the rear part is sleek and minimalist with economic use of steel etc.
The tilting seat needs a better subframe and some work on the adjuster-ability however it works as planned.
The front looks like it was made for some other purpose and has perverted to it's current task.

I have been getting hung up on the wrong things i.e pivot plate mounted on the rear end , I should leave it be as close examination show's it needs to be like that with the current front IF it has a 20" wheel.

Lot's happened today , updates tonight hopefully .

Paul
 
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