Help needed for a Z cank ?

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Yes that makes sense for Paul's design Danny but I hadn't thought of putting a BB there at all so the floor stayed completely free. Don't know why I thought that except the design Paul put up in another thread for the mini camper thingy had a clear floor which just looked so nice and uncluttered.
That's what I really love about this site. Just so many inventive ideas put out which really get the braincells sparking.

John
 
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John

Don't hold your breath , this is next on the build list I think [ things may change by the end of tomorrow ;) ] however I need to finish the Python fairing first.
This does need brainstorming to see which shape the frame needs to be .
Looks like I need to build a full size jig , maybe add some friction [ like a trainer ] and see what happens ?

Paul
 
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Just to mention Paul, I'm ordering some A32 filler rod so as to prevent creeping welds when welding chrome moly and T45 (T45 should be ok anyway) steels.
I thought I was going to weld some EN16T (605M35T) as I've made steering tube & collars out of it (because it begged me too!).
On looking up the pre heat and post heat requirement, 250°c & 40°c cooling per hour, I decided to bolt it on as the design lends itself to this too.
Yes we may not get creep on thin stuff, mine is 35mm square.
I would be careful welding crank arms too. Yes you may get away with it, but...!
Unless you know what the material is you are guessing.

We don't do crack detects MPI or ultrasonic do we!!
So overkill but...
Just a caution on materials used.
Surmon over.

Martin.
 
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Hi Martin, what you say about materials to be found in cranks is doubtless true and maybe caution is very much warranted.
If we don't "KNOW" the crank composition (other than a magnet sticks to it) would we be best advised to TIG Braze instead of TIG WELD?

Braze is often called the marriage guidance counsellor of dissimilar or warring metals, and I understood brazing was often the answer to the joining of unlikes in matrimony. :)
 
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Hi Danny,
TIG braze would eliminate the creep but is it strong enough used in certain areas?
The best pedals for welding will be the none chrome moly. Probably a grinding wheel sparking test may reveal some info.

It would be hard to distinguish still with sparks.

Can't help wondering if those failures Paul mentioned was due to creep or poor design.
Martin
 
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Ok anyone tried this ?



I could not find any drawings for the arc's a shoe/pedal makes when being turned ?
So I tried a 170mm crank and old shoe and a guess as to where my ankle may be on the pedal stroke ?
The outer black circle is for pedal axle path for 170mm cranks.
In this I have assumed 2" heel ground clearance , is that enough in the real world
This gives a BB height of 14" allowing the seat to be at 10" to 12" and the pedals to still be slightly above the seat.
This gives a shoe height at the top of the stroke @ approx 24" so the body will be quite low at that point.

Anyone have any real world experience that is applicable ?

Paul
 
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I would suspect that your seat is going to be higher than most enclosed trikes so you'll enjoy a better view over the body than most.
 
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Ok anyone tried this ?
Yes, but only with pencil & string and not crank and shoe. :)
Nicely Done, it certainly gives you a good idea of clearances required/space needed.
 
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Yes, but only with pencil & string and not crank and shoe. :)
Nicely Done, it certainly gives you a good idea of clearances required/space needed.
Doubt mine is anymore accurate than yours as have to guess the angle of my ankle
Interestingly I have triked with someone who's ankle is at 90' the whole of the way around the circle ?
My ankle changed the angle almost constantly ?
is this seat/bb geometry or body geometry , how do you others pedal out there ?

Paul
 
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I suppose it depends on whether you put the ball of your foot or the middle of your foot on the pedal. As a kid I used the middle as it was more comfortable, particularly when bouncing up and down kerbs. Later I realised that doing so left my calf muscles out of use and swapped to a more ball of the foot action. If using the middle of the foot then your ankle is pretty much locked in position for the duration. If using the ball then your ankle is going to move.
 
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I suppose it depends on whether you put the ball of your foot or the middle of your foot on the pedal. As a kid I used the middle as it was more comfortable, particularly when bouncing up and down kerbs. Later I realised that doing so left my calf muscles out of use and swapped to a more ball of the foot action. If using the middle of the foot then your ankle is pretty much locked in position for the duration. If using the ball then your ankle is going to move.
So if you model both, then you have a best-case/worst-case set of orbit lines I suppose.
 
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Yes, probably a good idea to measure both as I am still want to swap my footing about depending on the terrain. Probably not necessary though if you intend to clip in.
 
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Hi both

Can't think that will be necessary i suspect I will have either clip ins or more likely some form of platform pedal that has a heel keeper and elastic strap over the top of the shoe thus allowing normal shoes to be worn.

If I build the platform then I will mount it in a similar position to a cleated pedal as I find that position most comfortable and gives the most power.

On a normal bike I could never ride it with the pedal up against the heel of my shoe my foot had to be further back so I rode on the ball of the foot.

Paul
 
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