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

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Frank

I am just a sheep that follows the flock ........

Just happened to have my plans the wrong way around when I built my trike ?

regards Paul
 
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......heh heh, like the bloke who built a chimney when it should've been a well :(

Last time I used a dial gauge was year one of my appenticeship - on milling machines and lathes. Can even remember using slip gauges to re-calibrate all the micrometers. I do have a digital vernier caliper in the toolbox, but rarely gets used.........
 
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....wow, dial gauges for wheel truing - that's some precision going on there! If I get mine to 0.5mm I'm happy.....
I know it may sound (and indeed be) OTT but it really makes the job easy. Coupled with my deep-wall spoke-nipple wrench it makes building a wheel a breeze. ;)
 

SirJoey

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My cozy little nook in the corner!
....wow, dial gauges for wheel truing - that's some precision going on there! If I get mine to 0.5mm I'm happy.....
That's the way I used to true mine as well. Still have a few specialty tools left
over from my machinist days many years ago. The dial gauge is one of them.
Glad I hung on to that one!
***
 
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....before I started building my own wheels a few years ago, I used to get them made up at an old fashioned bike shop in BKK. The family run shop is an Aladdin's cave to any bike builder. The owner, in his mid eighties now, was often building up wheels when I visited, and had been doing so for sixty-odd years. His only aid to doing them was a truing stand, and was wondering what he'd think of using a dial-guage?......old dogs and new tricks :). He also sat on a tiny stool, a few inches high, whilst building - wish I'd filmed him now.

I use an old rear triangle clamped in the bench vice as my truing stand, building one or two wheels a year, so it's good enough.

If you really want the precision of using a dial gauge, I'm guessing you'd have to re check them again after a few rides when everything beds down.......
 
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It wouldn't hurt to re-check them after 100 miles, that's for sure.
What I have found is that the dial-gauge in conjunction with the park-tool spoke-tension meter means the wheels are exceptionally strong and are tightened to the specification stated by the rim manufacturer and not over-tightened (which can cause cracking and fatigue). OTT? Probably. Do I mind? No.
 

SirJoey

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My cozy little nook in the corner!
Yeah, for me it wasn't so much about extreme precision, actually. It just made it easier for me to get it "dialed in" to
start with, so to speak, as I could see how far the rim was moving with each spoke adjustment. As for the precision,
I still wanted it pretty good, usually around .005 total runout, which, of course, can be achieved with just a truing stand.

***
 
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I agree. I find the dial gauge helps me to zero-in on the required level of "true". Seeing the gauge showing diminishing fluctuations makes it easier for me. YMMV. ;-)
 
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I also use clocks to build wheels,I also have a surface table to lay a rim on to see how true it is to start with.TBH clocks allow you to make it very good but a clothespeg a bit of stiff card and a fag paper do just as well,Am sure Frank can vouch for rizla blue and touch on method LOL
 
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Hi all
So been playing with the wayward SA hub again..



Standard SA hub cut away ?

2 bearings sitting in shoulders cut into the SA hub centre tube [ Blue ] etc etc.

Where X= distance between shoulders and Y = length of centre tube ?

So we have 3 possibilities :-

a) X = Y assembly with new bearings , no drag from from wheel when spun we all ride off into the sunset ?

We have drag in one hub won't settle after swinging to and fro a bit with valve pointing down , just spins briefly and stops dead ?

So we either have :-

b) Y > X when assembled the bearings are a very tight fit and need persuading into the hub with a drift if Y is longer than X bearing 1 is put in to the shoulder in the hub. The bearing 2 tries to reach the shoulder but can't because Y is to big this takes up all the slack in bearing 1 and all the slack in bearing 2 the inner races bulging out and as the bearings are a tight fit they cannot back off till the wheel runs free ?

c) X > Y the bearings go in into the shoulders but inner tube is still loose [ Y maybe only a couple thou to short ?] so when axle slack is taken up inner bearing races are squeezed in producing binding in the bearings ?

So added a thick 12mm dia washer on top of the inner tube ensuring b) was true and hub just spins briefly and stops dead scenario b) ?
So removed inner tube altogether carefully added bearings and lo and behold wheel spins freely with some to and fro when coming to a stop !

Conclusion inner tube Y dimension is to long for X dimension ?

SA actually calls the inner tube a bushing , however there is no part number for it on any of the drawings I can find ?

I wonder if each one is specific to the hub it came from ? seems unlikely , however both my hubs [ used when bought ] have had bearing changes have the bushings been swapped over ?

Next make a new inner tube to dimension Y and try then filing it down a little...

Or of course I am barking mad ......

regards Paul
 
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In simple terms dim Y must equal dim X within a few microns but I dont think thats the problem, however you can buy shim washers to try it, I still suspect the bearing bores are not concentric orthe bearing seats are not parralel
regards
john
 
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That is really annoying as the hub shell is the most expensive part of the whole thing @ £36 ea.
The other parts are a lot cheaper. I wonder if there's enough meat in them to go up a bearing size and have them re-bored concentric & true?
 
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I still suspect the bearing bores are not concentric or the bearing seats are not parallel
regards john
Just dirty engineering talk ?
 
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So not being an engineer I did this :-

Tapped one bearing in as far as it would go , added the axle and the inner anti-crush tube then put the end of my 6" steel ruler over the end of the anti-crush tube and convinced myself that the ruler was not touching the outer race lip any of the way around ?

So made another anti-crush tube filed it to a fraction shorter than the original and convinced myself that the ruler was now touching the outer race lip all the way around ?

Bolted it up hand tight and the wheel now swung to and fro before settling hurrah I here you shout ?

So I set about making these permanent [ from the point of view of being able to ride it ] and added washers and 12mm lock-nuts to the 12mm bolt axles.

Ok now I am really pi**ed off even tightening the lock-nuts till the washers were only just gripped NEITHER wheel now swings to and fro before stopping they both stop rather suddenly !!!

So wasted all this time for absolutely no improvement at all ?

Next ?

Need to bolt Mk1 front end to this Mk2 rear [ giving the Mk1a ] add a pannier and try it out.

If all goes well then I will attempt to cable up the brakes and see if I can get them to work ?

This I feel is a ' never ending story ' for me.........
 
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Paul,
It might be worth investing in a vernier gauge, your stick of inches wont do it however good your eyesight is.
if its any consolation i had the same issue when I made my hubs
regards
John
 
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Hi all

So Holland approaches and Mk2 trike unready [ again ] so after a bit of brain storming I came to these conclusions ?
a) new pivot not required - Mk1 front can be fastened to the Mk2 rear and so will do for another year
b) rear SA hub brakes not required - could use Mk1 front end as is [ if necessary ]
c) Mk2 rear end will be no improvement over Mk1 unless it can carry the contents of the trailer I have towed in the past ?

So how to do that ?



This is a platform that will be welded to the rear end when I have filed out the square tube to meet the round tubing.

This is just the same length as rear wheel overhang , the panniers are actually a bit bigger than this however this platform will take most of the weight.



I can't make up my mind whether to just have a floor say 3mm plywood and strap all the panniers/tent to that or as in the picture above build a custom rack that maybe bolts to the platform/trike so can be removed ? and use the normal pannier fastening to fix to rack ?

Bit of filing then break out the welder

regards Paul

ps yes Dan cleaned some of that nice new paint off ;):LOL:;)
 
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