Tracer trike Conversion from fixed to 6 gear.

[Ajax Bay]

You may find this Sheldon Brown page worthwhile reading with some technical specs. Please don't take some of the comments above as 'adverse': I'm sure they're not meant like that.

 

[stearman65]

You may find this Sheldon Brown page worthwhile reading with some technical specs. Please don't take some of the comments above as 'adverse': I'm sure they're not meant like that.

My god that's a lot of reading, might tackle that just before I go to bed, should help me sleep, only kidding.
I used to use an AV forum (Audio Visual) daily, one of my favourite expressions was "there's always more than one way to skin a cat" which upset some people who didn't think that way, & always assumed their way was best.
Since my last post my heavy duty jubilee clips arrived, I plan to use 3 of these to fasten my fabricated hanging bracket to the mounting tube. If the set up works, the job could be made permanent by welding on the bracket & removing the clips.

 

[stearman65]

You may find this Sheldon Brown page worthwhile reading with some technical specs. Please don't take some of the comments above as 'adverse': I'm sure they're not meant like that.

"hi , all modern bikes have a 35mm threaded part , unless you've got something unusual this will fit no problem cheers", was the answer a seller from Ebay gave me when I asked the question, a brief read of Sheldon Browns page doesn't say this exactly, so we'll have to be careful matching the hub to the freewheel.
This is the seller who gave the 35mm size.
http://www.ebay.co.uk/itm/272119271919?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDXT

 

[TheDoctor]

The issue is that you don't have a hub. You have an axle with a wheel on one end, and a sprocket bolted to the other. I'm sure you're not going to listen though, so I'm out of here.

 

[Tim Hall]

The issue is that you don't have a hub. You have an axle with a wheel on one end, and a sprocket bolted to the other.

This is the important bit. Or as your ebay seller says

unless you've got something unusual

. So your tame mechanic will have to source a hub, with its "35mm part", fix that to the existing axle, then screw the freewheel on to that. From the photo it looks like your axle has an M16 nut on it (24mm across flats) or possibly M12 (19mm across flats), so I see an amount of welding in your future.

Edit: The "35mm part" is in fact 1 3/8" x 24 tpi.

 

[stearman65]

The issue is that you don't have a hub. You have an axle with a wheel on one end, and a sprocket bolted to the other. I'm sure you're not going to listen though, so I'm out of here.

Well it wouldn't be a bad thing if you were out, your negativity is depressing. However, for the benefit of those who want to know, the hub is to be modified by turning off the threaded end flush with the rear of the spoke plate. That will then be clamped / bolted to a replacement sprocket collar, minus the sprocket. The new 6 cog freewheel will be threaded onto that. I'll try to show a mock up of the proposal for those interested.

 

[TheDoctor]

You asked for advice. If you don't like it that's your lookout. However, I'd love to hear how this works out.

 

[raleighnut]

The existing sprocket will be fixed by a keyway machined in the axle, either by a woodruff key held by the grub screw (best) or by the visible grub screw fitting into the keyway (not as good but effective) the nut on the end of the axle does not secure the sprocket to the axle, it secures the axle within the bearings (that's why it is a nylock nut for adjustment of play on the shaft)
The bike rear hub will not have to have bearings in it (once modified) as it does not rotate on the axle it will simply act as a freewheel 'carrier' but it will need a keyway 'broached' through and/or be drilled and tapped to take an appropriate grub screw (to transmit drive to the axle)

 

[stearman65]

Well it wouldn't be a bad thing if you were out, your negativity is depressing. However, for the benefit of those who want to know, the hub is to be modified by turning off the threaded end flush with the rear of the spoke plate. That will then be clamped / bolted to a replacement sprocket collar, minus the sprocket. The new 6 cog freewheel will be threaded onto that. I'll try to show a mock up of the proposal for those interested.

Well, while searching for suitable components to P/shop into a mock up, I came across a series of Atomic Zombie pictures which explain how I intend to modify my trike. Unfortunately they aren't manufacturing the threaded collar/ hub or I may have taken the easy way & sent for one. If you click the link at the bottom of the AZ page, they do supply drawings which could be modified to suit my dimensions.
http://www.atomiczombie.com/FDAX34 Trike Axle FreeWheel Adapter.aspx

 

[raleighnut]

You only need the flange if you're bolting a disc brake on, a modified version of that should serve the purpose though.

 

[stearman65]

You only need the flange if you're bolting a disc brake on, a modified version of that should serve the purpose though.

Been having a chat with the Aussie trike manufacturer, the one I thought his rear end may be an option. He said my set up with two brakes on the front wheel wouldn't be allowed in Aus'. The problem fitting gears & a rear disc is the control cables, if the controls are fitted on the handle bars, they would have to be removed every time I put the trike in the car. The speed I'll be doing wouldn't warrant a rear disc brake, so that's on the bottom of the priority list.
Regards. S.

 

[stearman65]

My proposed bike ride this afternoon was curtailed, partly the weather but mainly as my rear r/h tire had deflated, the pump supplied with the trike wouldn't, so the only exercise I got was assembling then dismantling the trike. This was countered by the rum & raisin cornet my wife bought as compensation.
So I came back & knocked up a couple of drawings.

 

[TheDoctor]

 

[raleighnut]

My proposed bike ride this afternoon was curtailed, partly the weather but mainly as my rear r/h tire had deflated, the pump supplied with the trike wouldn't, so the only exercise I got was assembling then dismantling the trike. This was countered by the rum & raisin cornet my wife bought as compensation.
So I came back & knocked up a couple of drawings.

I'd go with the first drawing set up, just remember that the derailleur needs to sit at a perfect 90 degree angle to the bar you mount it to.

 

[Ajax Bay]

Four points for you to consider:
1) The sideways travel of the derailleur cage is limited so in its 'relaxed' (ie no tension in gear cable) state it must be close to being directly under the closest sprocket.
2) Chainline - limits to angle for safe changing and avoiding chain drop (off chainwheel).
3) Bar in way (not in your drawing).
4) I said earlier (it would be good project practice to) determine what spread of gear ratios you want (rather than just getting what the 14-28 block gives you.. There are other blocks besides the ubiquitous 14-28 (which I have for normal road cycling with a 54-40 chainwheels). With a 20t on the front and a 26t at present on the back, I don't think you'll use anything lower than an 18t, so effectively only 3 of the 6 sprockets (and all three of those with poor/poorest chainline). If you replace the 20t chainwheel with a 30t, that will bring more into play.

the derailleur needs to sit at a perfect 90 degree angle to the bar you mount it to.

Think actually the hanger needs to be in a plane perpendicular to the axis of the block of sprocket / driven wheel axle, rather than in relation to the bar onto which it's mounted.