Why oh why am I building a ' very low ' racing bike called 10% , when I am the wrong side of 65 ?

Take solace in that it can always get worse - how many forks do you have left?

2 unmolested although one is the fat straight legged fork , possibly not so useful.

There is another bike free on FB Market place , not sure I have enough brownie points to get that as I have been on this build almost every afternoon since back from the Netherlands.

Currently slowed down as this bike [ as some of the others I got for free ] has been left in the rain with flat tyres and the water has gotten into the rims, ends of spoke nipples very rusty and a odd white corrosion hold them tight onto the rim and spoke thread , about 2/3 swapped out the end is in sight :)

Paul
 
So Saturday post #35 was a disaster
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tyre-right-DSCF7222-sm.jpg


however Sunday/Monday and today and we have turned it around ?

I have already found the big pulley in front of the head tube does not work the chain drags on the back of the fork legs , so now trying behind the head tube.

good-pulley-poor-mech-DSCF7221-sm.jpg


Tried a higher quality [ than the usual SIS stuff I use ] rear mech , completely pants insufficient Low adjustment to get the jockey wheel in line with the high gear.

good-pulley-good-mech-DSCF7232-sm.jpg


However a SIS one works a treat and short cage as well to help avoid heal strike.
So next up make an adjustable mount for the big pulley so that I can adjust the position with respect to the boom centre line.
Make a permanent mount to the SIS mech.
Looking at the small pulley wonder if this may do the job ?

small-pulley-DSCF7229-sm.jpg


Some Shimano think I have had for years , because it looked like it might be useful ?

Paul
 
So garage tidy up including getting Python #5 into the bike shed to make some room decided I needed to get the beast outside so I could try sitting on it with pedals/pulley and handlebars..

out-with-pedals-no-chain-DSCF7233-sm.jpg


So I can get on the seat [ just ] pedals as predicted about 2" to 3" to far away , pulley will need to be closer to frame to get out of way of knees.
front-view-DSCF7234-sm.jpg


Easy to see pulley to far from frame 62T teeth about 1" from boom so pulley needs to be same[ish ]

pedals-DSCF7238-sm.jpg


Possible boom will have to be raised a little as pedals head towards the back they may class with tyre.

Now this is interesting.

porter-FWDDual-Susp9.jpg


It is a low racer by Tom Porter from the WISIL site projects page ?
So it is a little like the Beano where there are 2 chains and not a single chain , this is more complicated as he has 2 gears and a changer at the mid drive.
So I will add another 28T on the back of my pulley and drive that from the pedals [ with a seperate tensioner ] and use the front 28T to drive the wheel using the rear mech to tension it.
That's the current plan....till I change it again ;):D;)

Paul
 
So more to report.

First up after lots of fettling and cursing I have the boom able to slide in and out [ just ] so it was time to clamp it.

clamps-DSCF7240-sm.jpg


Now it would have been much quicker to use Brads method , however I always seem to have problems where I over tighten the bolts [ usually chasing a squeak ] and find I bend the plates stopping it either being easily adjusted or remove , so tube in boom it was to be.
One [ or both ] of the tubes are slightly oval and the outer has a seam to deal with , having struggled for a couple of days there are 2 places it will slide in [ 180' apart ] of course the loosest position is with the BB axle @ 90' and NOT 180' grrrrrrr.
So there was no way I was going to weld or brace the clamps on , I just used these U clamps 1/2" from end 1" apart and 3/4" before end hole drilled in slot I cut , they are bolted up however not been pedalled in anger yet so will it work ?

rear-mach-DSCF7246-sm.jpg


Rear mech mount tacked to fork leg , currently it is held by the wheel nut and there is an anti-swivel bolt through the existing hole in the mech arm.
If this works the bolt will be changed for a welded pin.
All this will do is mean the wheel nut will have to be removed and then the mech lifted off the pin before the wheel is removed, not an arduous task.

rear-meach-1-DSCF7247-sm.jpg

At the moment there looks to be plenty of room ?

I like this guys mock-up very useful to be able to sit on it and pedal it , but harder to work on when on the ground.


he also posted a great video of his FWD working


Paul
 
So current hold up to riding the thing is the mid drive pulleys:-
mid-drive-DSCF7249-sm.jpg


Currently working on 2 neither of which are either really suitable [ one on left ] or straight forward [ one on right ]
On the left is a screw on free wheel [ pawls removed ] with 2 x 28T sprockets which are an easy fit.
However because these free wheels are stepped it means they have to be mounted on the wide bit which then must stick out towards my fleshy bits and be outside the frame , which limits how far apart they can be and leaves a large amount of free wheel stuck out ready to gouge chunks out of my legs ! not ideal.
I could fix this by welding a smaller diameter sprocket to one of the big ones allowing it to be mounted on the narrower part , thus the bulk of it could be behind the head tube over the frame thus reducing it's height?
Else
On the right a single speed free wheel [ pawls removed ] and a front chain ring welded to it , it is very hard to weld to a single speed as the teeth taper in 2 directions and disappear with heat 😢 also any welds on the body could ruin the bearing races however the welds shown would probably hold a single chain [ the first plan ].

Now as I want to do it differently I need 2 sprockets on here and so the welds are inadequate as well as ..
The other identical sprocket as 4 holes the same , easy peasy just bolt them together and weld where you can ? well no.
The factory they were produced in either drilled those holes by eye or had a lob sided jig and turning one through 180 means only no holes line up !!!
So that means filling all the holes in one one and re-drilling , then I really need an adaptor ring that can pickup the free wheel teeth with 4 x M8 bolts and then these 4 M6 holes....
Even more work.
Result well it would be slimmer than the first option however probably heavier.

This is without even making a mounting for the pulley , oh and a chain slack tensioner for the BB to pulley chain ....

Paul
 
To remove seams from the inside of tubes I use 12" or so of the fattest tube that my drill can take and superglue a bit of aggressive sanding belt to it. It's worked many a time.
 
So it's a game of 2 halves ?

First half I am winning 1 - 0 ?

2-sprockets-DSCF7250sm.jpg
pulley-back-small-DSCF7251-sm.jpg




Found a very simple answer to this problem , no grinding or welding just 20 minutes with a hand file , the unused holes in the upper ring where in a better position on the back ring to be filed out from M6 to M8 where the bolt sits neatly inside a tooth valley , needs socket head screws and some locknuts however bolted together well enough to try some chain on it ?

However in the second half we are now trailing 1 -10 !!!
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When I first laid this out I used some 16" x 1.75" tyres that came on the free bikes , 1" gap
I have since bought some Schwalbe City Cruisers which are bigger profile where's my 1" now !

hard-DSCF7255-sm.jpg


I now have hard contact between the tyre and the crank that is even without the pedal being on it.

I don't currently have the seat on so I don't know if:-
I have the boom to far in for the current seat position
The seat will have to move forward and the boom come out
Or I will have to notch the boom outer tube and raise it ?


answers on a postcard please...

...and the answer is ?

I am an old f*rt and had a senior moment :rolleyes:

space-DSCF7257-sm.jpg


In the sanding of the boom and tubing to get a sliding fit I had almost sanded away the insertion mark , when I slipped the boom in and clamped it I used one of the fresher ' it will insert to here marks ' which as at least 2.25" to short , may even be more once sat in the seat !

Phew and double phew

Paul
 
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Ok so finally got to sit in it with pedals and a chain pulley at my leg length and it's pants IMHO !

front-hit-stuff-DSCF7259-sm.jpg


I have collisions in the following places:-
Knees hit bars - an easy fix
Bottom of knees hit top of fork - not so easy
heal hits rear mech - also not so easy

Good bits ?
pedal - seat distance good
I easily clear the pulley , although it is not far enough from the frame for a good chain run to pedals so easily de-rails at either end , tis without any chain keepers though.

More bad bit's
This boom in boom is a PITA it is now not possible to weld to it for fear of either distorting the outer or welding the 2 parts together ?
So any chain management needs to be either attached to non-boom parts of which there are exactly 0 in the right place
or
will be hung from a succession of clamps both ugly & heavy or is that heavy & ugly ......



Only solution will be to move boom and seat at least 3" forward , effectively making it longer still [ w/b is already 47" ] least there is room to move them.
Probably have to chop the 3" out of the main boom from behind the seat , more work....

Paul
 
Ok so finally got to sit in it with pedals and a chain pulley at my leg length and it's pants IMHO !

front-hit-stuff-DSCF7259-sm.jpg


I have collisions in the following places:-
Knees hit bars - an easy fix
Bottom of knees hit top of fork - not so easy
heal hits rear mech - also not so easy

Good bits ?
pedal - seat distance good
I easily clear the pulley , although it is not far enough from the frame for a good chain run to pedals so easily de-rails at either end , tis without any chain keepers though.

More bad bit's
This boom in boom is a PITA it is now not possible to weld to it for fear of either distorting the outer or welding the 2 parts together ?
So any chain management needs to be either attached to non-boom parts of which there are exactly 0 in the right place
or
will be hung from a succession of clamps both ugly & heavy or is that heavy & ugly ......



Only solution will be to move boom and seat at least 3" forward , effectively making it longer still [ w/b is already 47" ] least there is room to move them.
Probably have to chop the 3" out of the main boom from behind the seat , more work....

Paul
Clearly, the design is a movable feast. :)
I am so glad that I am not the only one with this issue. :)
We cannot all be CAD Guru's can we?
 
DannyC

CAD is over rated ;) for this ? we are bike hackers and not computer geeks.

3-inch-plus-DSCF7267-sm.jpg


Does CAD have blocks of wood or screw clamps , though not.
Seat now 3" further forward which has cured some problems and not others not fully sadly.

3-inch-plus-ladles-DSCF7271-sm.jpg


A was the old position
B is the end of the fixed boom so A is now 3"+- from B
B however is about 3" from C [ the end of the clamping slot ] and the inside is just there almost no more ' out ' adjustment left.

I have collisions in the following places:-
Knees hit bars - an easy fix
Bottom of knees hit top of fork - not so easy
heal hits rear mech - also not so easy

Bars removed - now OK
Bottom of knees hit top of fork - better however moving front out only puts pedals lower not helping
heal hits rear mech - better however moving front out only puts pedals lower not helping

So the next fix is to get pedal boom closer to horizontal ? should be a very moderately hard job ?
So slit bend and reweld ?
or
cut off and reweld ?
Still awaiting the postcards

Paul
 
DannyC
A slit, shut and weld right near the root should be good enough I would think.

Popshot
Ditto

Done I now have the boom horizontal[ ish ] decided it was better than half way and still not being happy.
Alarmingly the BB is now 20" from the deck , higher than the Python I currently ride which has 20" wheels !!!
Sorry no pictures yet it is laid on it's side whilst holes are drilled to move the front seat mount almost 3" forward.
Also 2 x M12 holes to mount the monster pulley onto the frame , then back to wrestling with chain...

Paul
 
CAD is over rated ;) for this ? we are bike hackers and not computer geeks.
I take that as an offensive slur. CAD operators aren't computer programmers. Never used C++,,Pascal or Basic to do CAD.
You are mixing things up to take a swipe at those that can CAD.
No offence just addressing the balance.

'Does CAD have blocks of wood or screw clamps , though not. '

With CAD you would not need wood.
You are designing a piece of work not throwing together items with a wing and a prayer.
Pen and paper works just as well and predates CAD, it works just as well.
Now artists just throw things together sometimes in deliberate ways. I would call you an artist.
You sculpture a bike/trike together more like.
Just my thoughts and penneth worth.

theproof.png


Three tweeks of the '5 pony beater', all done without wood and extra screws, just moved some lines.
So nothing wasted and no head bashing.
Not difficult to do. CAD is worthwhile learning and adds a new string to your bow in the big wide world.

Martin
 
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I have to agree that a basic level of CAD work can save a lot of waste. Higher level CAD is probably useful if you already have the skills but possibly gets to the point of diminishing returns if learning it specifically for this hobby. The basic stuff I use takes next to no learning and is useful for testing ideas and seeing quantities of materials etc. I've also found it useful for solving how to actually build certain assemblies with the skills and tools I have available and have discarded many unviable ways before settling on the winner. I would think wooden mock-ups and the like take up much more time.
 
To get it ridable there are lots of mundane parts to be made/fitted to change from cobbled together for test fitting to ridable status.

First up rear seat bracket :-
upper-seat-bracket-DSCF7280-sm.jpg


Now that's done 2 x M6 go where the wood screws are into back of seat and 2 x M8 go in the other holes , I now need a pair of stays with numerous ' adjustment ' holes in them.
From now on all parts need either :-
Lock nuts
Grease/oil
Adjusted to work

As though it is going on the road , first ride is almost a week late and I need to get my skates on.

Other work was done to boring to record...

Still on it Paul
 
More boring stuff ? how long CAN it take to make two plates with 4 holes in them ?
Answer about 4 times longer than I have to do the job !

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This is an implementation of Dans idea , I assume I have done something wrong ? as I can't see anyway to stop the seat back slowly sagging down and backwards ?
top-seat-mount-DSCF7288.jpg


Despite best planning and measuring the pieces are NOT parallel and all the bolts/nuts cause interference between each other the seat and the frame making it a chore to take off and do up....

Oh and you guessed it , it needs to come off to mount something else behind it , drat.

Paul
 
So a whole frustrating weekend trying to get the 2 chain idea to work:-
  1. chain pulley to cranks
  2. chain pulley to rear mech

Started with the simpler one and a chain on the rear of this pulley to the cranks , it just would not stay on the pulley:-
2-sprockets-DSCF7250sm.jpg
pulley-back-small-DSCF7251-sm.jpg
this sprocket.

It seemed to go tight and slack and the return side of the chain appeared to move up and down and it certainly did not like going backwards , no amount of chain management seemed to help I tried a tube - huge drag and very noisy and several skate wheels and could not get it to work at all. In my frustration at some point I even managed to bend a tooth on the pulley !

After one de-derailment out of curiosity I put the chain on the front [ welded on ring ] wow as different as night and day it could be pedalled really fast and did not mind backwards either.
So I spent the last 30 minutes of the day hashing up a 1 chain solution , just looking for the problems.
The handle bars are held with a clamp , if not the rear mech tension pulls the wheel to the right when not on the ground.

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Now the chain will stay on [ mostly ] drive the wheel and I can hand move the rear mech between 2nd and 7th gear , it is possible I could get 1st by adjusting the stops 8th is out of reach as the simple mech does not have a B stop and cannot clear the 34T. Interesting the skate wheel has no edges to hold the chain and yet it does stay there , the wheel is free to slide out along the bolt as can be seen below and does move out a little if I try a few degrees of steering , obviously the bolt is to long for me to pedal it at present.

first-chain-run-DSCF7305-sm.jpg


So now we have something to work with ?
  1. big pulley needs 1 ring removing and chain guards/keepers either side
  2. crank rings also need chain guards/keepers either side
  3. small pulley needs to be usable not just a skate wheel on a long bolt , could be as simple as chain guards/keepers either side and a short bolt to allow some movement
  4. need to find a suitable mech , somewhere I have one with Megarange on it I think.

Once the above has been attended to I will try and turn the front wheel whilst pedalling , currently the chain just de-rails from the lower side of the big pulley.

This shows a Jive [ which is a ZOX clone ] it uses a pivoting small pulley to help the wheel turn further , I may try this also...

jive-idlers.jpg


Paul
 
progress slightly forward for a change....

As they say every day is a school day :-

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So a crude shield around the big pulley to see if we can reduce it's tendency to de-rail from the bottom , yes it works after a fashion and allowed me to try some more stuff.

second-chain-run-DSCF7310-sm.jpg

if I can reduce the chain hitting it , see below , it should be good enough to ride around the estate whilst I get hold of some aluminium to make some better ones.

The chain de-rails because I don't have the big pulley in line with the middle of the cassette , nor with the crank rings [ however they don't appear to de-rail Yet ! ] so as I move through the gears from 7th towards 2nd the angle becomes to great for [ now ] the guide plates and the chain rattles up the wood however it does now stay on.

second-chain-run-DSCF7311-sm.jpg


Next up for the big pulley then is to find some shorter screws and remove the M12 spacer nut and see how much further over I can get it , will it be enough ? who knows.

The other place it de-rails is turning right and eventually it lifts off the rear mech lower pulley and hits the cage ,oddly it does not seem to do this so much/often turning left.
So simple solution don't pedal when turning !
25hz [ Tim Hicks ] built a trike called BlackMax and he allowed the small pulley free movement of 3/4 on it's axle and said he had seen it doing that whist riding. [ I think this was the problem DannyC came up against when he tried twisting chain ? ]
DSCF7312.jpg


So I mounted mine on a set screw to see if it moved , of course turning right it did not move however turning left the chain did and fell off the pulley [ not seen that before.]
Despite the pulley having NO side plates the chain stays running in the middle if the wheel points forwards.
So next up I need something in there I can attach side plates to ...
It is a skate board wheel , can the white stuff be drilled ? I was thinking of 4 maybe M4 holes across the wheel just outside the ball race recess so I can bolt a pair of side plates to it ?
or
I make the small pulley turn with the chain , easily done I think.

Paul1.jpg


Seems I am a bit of a dark horse ? this is me on Quible velodrome probably riding a diy low racer called Cuckoo Raa made by a very talented guy from Cornwall.
However all is not what it seems ? the red bit is the flat running track and the velodrome is the grey tarmac in the back ground , this velodrome is very very steep minimum stay up speed is 15mph beyond what I could manage on the bike as it was to short for me.

Paul
 
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