Tilter mk3

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The weather has stopped play on the Drypod as I need to be outside to hinge the body up and down (the big disadvantage of a tilt body) so I've committed a cardinal sin and started my next project. If I get this right it will be a tilting tadpole along the same principle Alan Maurer built his. It will use caster as the steering mechanism in that a heavily castered wheel will steer when tilted. Steering and tilt will be separate functions though in that it'll be able to tilt without any steering but the opposite is not true, ie it can not steer without tilt. Here's a video of the inspiration.


This will be my mk3 as no.1 was a complete failure and scrapped and no.2 was my green one which works fine but on different principles. Progress is somewhat limited in that all I've done so far is to sort the rear end for it. The swing arm came to me as an unknown Whyte unit as part of a deal and languished in my pile for years. It weighs almost nothing which is why I want to use it. On looking for a dropout for it it became identified as a Whyte JW2, made about 20 years ago and attached to a very low volume forkless mountain bike. Even Whyte don't sell the dropout any more - marvellous. On scouring the net for anything similar it appeared a Marin unit may fit and £21 later indeed it did. Quite why Whyte don't say this on their website when Whyte and Marin are under the same company is beyond me. The pivot on this is a pair of real actual bearings - a first for me. The bearings in the arm were of course seized so I pulled them out with the time honoured trick of a bolt and socket. It turns out they are imperial which surprised me given I believe they were made in the UK. By a stroke of good luck I had several such bearings I'd been hoarding for years on the off chance I'd ever need them so pressed them in. This is why you never throw anything away. A mount to the chassis would be needed and I've used some 1" 16swg tube as a bearing holder with some 3/4" tube in the middle to seat another pair of the same bearings against and a pair of oilite flanged bushes at the outer edges to help rotation and protect the swing arm. It all slotted together nicely to make the mount.

The swing arm origin.



Somewhat odd dropout needing bolts to hold it in. I need some longer bolts.


The parts for the chassis mount


And assembled and in place


Sufficient room for a 10 speed freewheel


The brake mount utilised a front 160 to 203 adapter wrong way round and with an extra hole drilled and tapped into it. I have no idea what those holes are originally for in the swing arm. Clearly they are not std disc brake mounts and they are replicated both sides. At a later date I'll kiss the adapter with a flap disc to de-blue it and grind the spare hole off.


The rear brake will be very much needed on this unlike many tadpoles. Applying the front brakes means that the steering mechanism wants to steer further as you brake as the caliper mount has to be attached to the caster arm. This desire to steer further has to be resisted by the rider applying pressure against the bars. Not ideal but pretty much every tilting taddy I've ever seen has some compromise.
It's not much to show for 3 hours work but you have to start somewhere. The chassis will be built from round stainless and I have a stainless reel for the MIG. Yes it'll be a pain to work but most of that work will be done with powered tools such as a chop saw. I'm hoping not to need to paint the bulk of it. Certain parts will need to be painted such as the rear swing arm mount which is mild. I do expect to need to dry it after any rain and oil it regularly. This won't be a daily rider though so such demands can be accommodated for the sparkle provided. If it does start to rust I can always paint it later.
Next job will be attaching the main beam to the swing arm. I have a 1" drill so will see if I can get that through the 45mm tubing to slot that swing arm mount through. I expect that to be my first cursing session against my stainless choice.
 
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Nowt wrong with a change of direction of the Time/Effort available for making stuff. :)
Good Luck with this one, it looks interesting.
 
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Nice project. I like the second version from him a lot, where he added the airodinamic upper arm.
Can't wait to see what you make from it.
It is more a race trike and not one for in the city, but as an extra trike, it is great to have.

Nice donor bike. Many nice parts that you can use.
 
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I don't have the whole donor - just the swing arm. Wish I did have the whole bike - it's cool as heck.
Been back in the garage since the 1st post and actually got a 1" drill through the 45mm stainless tube! I marked the tube and drilled each side separate as it seemed like the better way to get things square as opposed to drilling straight through. I wasn't wrong either, the hole is dead straight and the pivot assembly fits in very snugly. The main tube is perfectly in line first go - I ought to buy a lottery ticket whilst my luck holds. Still needs welding which should be easy given the perfect fit. It's usual for me to make a large tack at this point and then club and whack it into alignment. It's rather nice not to be doing that.







I was going to go for a mesh seat this time but my usual Polish supplier is now knocking the VAT off for UK sales so I ordered another of the usual ones. The next few days will tell whether I have to pay the VAT at the import side of things. I thought it worth the risk.
 
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It is a nice swing arm.
Those things make it very easy to build a trike with rear suspension.

As he puts a lower value on it, you will pay less VAT as they check it.

It is a trike I would love to ride to see how it rides.
 
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Popshot

Hmm another one ?

How do you plan to build the front chassis tilt bearings ? looks like some familiar rod ends ? the way I was going to build my frame tilt bearing.

Paul
 
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It'll tilt on M12 rod ends. The rod ends at the end of the crossbeam will screw into M12 long nuts that will be welded to the bit that rotates for the caster steering. The middle pivot will also be M12 rod ends fastened to the end of long(ish) M12 8.8 bolts that come up through the main beam. A M12 bolt will go through the middle rod ends and through a piece of pipe welded to the centre top of the crossbeam. Where Alan uses a sub structure welded to the main beam under the front I won't as my crossbeam will be lower and therefore closer to the main beam. I need to keep 1.5" of clearance between the two main tubes to allow enough swing on the lower one as it tilts. The centre ones will be fine as they only get tension applied through them. The end ones have to hold my weight and I'm hoping M12 will do. The rod ends will be fully into the long nuts to give them every chance.



 
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Do I see it right that you changed the tank steering and moved the connection above, instead ad the bottom?

You did that, to go against the break steering in corners?
 
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Popshot

Thanks I was talking about the centre pivot on the top of the frame, I need to make some think similar ?

Steering and tilt will be separate functions though in that it'll be able to tilt without any steering but the opposite is not true, ie it can not steer without tilt.
Are you sure this is a good idea ? from my limited riding of my Flevo/Python tilter I have found situations where I need to steer without tilt.

I think for me it is just a learning exercise and some body English as tilt and steering are DEFINITELY separate ;)

If this trike is having a ' normal ' tadpole seat height and track ? what advantages does tilt bring ?

Paul
 
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Emiel - correct. It seems better to brace by pushing than pulling as your body is sliding that way anyway.

Paul - it would indeed be nice to be able to steer without tilt but this system simply can't do that. Every tilting tadpole I've seen has some compromise or restriction. My mk2 has compromised Ackerman and the entire handlebar sub assembly rotates opposite to the tilt which compromises the riders space. The big advantage the mk3 has over the mk2 is rider space. On the mk3 the handlebars are static bar fore and aft movement. The trike should corner with less tyre scrub than a non-tilter and should also corner faster. There should also be no lateral forces trying to taco the wheels.
 
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I am curious in how it will go Popshot.
I like that you ad read suspension. Sadly where I live, you need to stop a lot. That is what holds me back of building it.
But I think riding it on a road **** fast nice Smoot corners, must be great.
 
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Popshot



are the pedals not a bit high ? looks like 10"+ to me ?

Is this really a lean steer trike and not a tilter ?

Paul
 
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It's not completely to scale. Pedals will be at a regular height.
A lean-steer or tilt-steer has a fixed ratio of tilt to steering input so is only ever right for any corner at one speed only. The amount of steer on this is variable and controlled by the caster angle so can be set correctly for any corner at any speed.
 
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The crossbeam consists of two tubes, one inside the other. The outer is 45mm and the inner 25mm. To the inner on each side is a flanged bearing that sits in the outer, then a thrust bearing so it steers smoothly under load and then 3 split clamps. The clamps are all sigle at the moment but will end up welded together as the long nuts for the rod ends will be welded to them. I had to skim the 25mm tube at the ends to get the bearings on. No big deal, just the flap disc grinder in the vice and rotate the ends against it until correct.





I'll make the uprights next and then attach them to the crossbeam. Having no kingpin makes the uprights a simple matter.
 
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How dp they stay in?
Did you connect them togheter so they hold each other in, or just by the press fit of the bearings?
 
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The inside tube runs all the way through the outer and the split clamps hold everything in which is why I'm using 3 each side. Should those clamps proove insufficient then I'll either need to pin or weld the clamps though welding means grinding if I ever need the assembly apart to replace a bearing. I do expect the clamps to hold though.
 
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More work done on the crossbeam. The caliper mounts are now made and fixed. A failure of planning has lead to the calipers going on top of the discs instead of the side as hindsight now tells me that position is occupied by the M12 rod ends. Not a major issue and I suppose it will highlight the flashy red calipers. My crystal ball did however work for the long nuts welded to the clamps. I fully expected to have to run a tap down them after welding so had already bought one. Oh the joys of tapping stainless - still it was a good workout. I need to add a small arm to each end to act as the steering arm

 
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Popshot [ & Emiel ]

have you seen this French effort ?

trike-inclinable-swing-phase-ii

perhaps got a little further than you ?



This is in the French somewhere :-

phiphi07 wrote: it works perfectly except that the effort to raise the trike is always too great: I will now work on the seat position to lower the g.g.

I assume he means C of G ?

Paul
 
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That only tilts the seat, not the front wheels like Popshot is building now.
The arm steers a bit as he tilts, but the front wheels stay level.
 
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