2wd rear of delta or quad + suspension - will it work ?

[stormbird]

Hi all

So:-
Option 1 [ the ideal ] single sided wheels with a free wheel each - suspension pivot could lie outside and inline with drive sprockets - problem needs a free wheel on the left of the right hand wheel.
Option 2 [ easy way out ] normal rear forks and normal rear wheels - problem no longer able to get suspension pivot in line with jack shaft
Option 3 do I need a free wheel on each rear wheel in Option 1 IF the drive cassette also has a functioning free wheel - on the rear wheels one free wheel and one fixed sprocket ?

Paul

 

[DannyC]

For option 3 is it not better to put a freewheeling sprocket on each outboard end of your jackshaft, a cassette with a freewheel in the middle and fixed sprockets on each of your driven wheels?
All this means is that the rear chain(s) are always moving if the trike is in motion, but each wheel can run at the same speed on the straight while being driven and at different speeds in the turns (left or right).
Does this not also give you the option of Outboard/Inboard chains (whichever is best) and the effective benefits of 2WD?

 

[lotharko]

Option 2 is the simplest solution. However, in terms of appearance, the most unattractive. One chain outside, one inside...
I have decided for my CargoQuad for the first option.
Option 3 has the disadvantage that the driving behavior in curves will be different, depending on whether it goes left or right around.
There is still "Option 4". It will be on my second quad: remove the cassette freewheel and replace it with a fixed cassette body.

Greetings Lothar

 

[stormbird]

For option 3 is it not better to put a freewheeling sprocket on each outboard end of your jackshaft, a cassette with a freewheel in the middle and fixed sprockets on each of your driven wheels?

err no ?

don't forget the input to a freewheel is the sprocket and the output is the inner threaded portion ?

this is why I asked some time ago how do they make free wheel hubs [ in other words free wheel is built inside the hub the wheel is built on ]?

The Sinner trike has them and the UK pedal cars use them

Paul

 

[stormbird]

Option 2 is the simplest solution. However, in terms of appearance, the most unattractive. One chain outside, one inside...

True however maybe some body work can hide that ?

I have decided for my CargoQuad for the first option.

I think you have the lathe skills to make a free wheel that fits on the left of a driven wheel.
I can do it [ I think ] however it will be a welded bodge and make the wheel at the hub wider than it needs to be ?

Option 3 has the disadvantage that the driving behavior in curves will be different, depending on whether it goes left or right around.

Enough to matter ? maybe someone needs to take one for the team ?

There is still "Option 4". It will be on my second quad: remove the cassette freewheel and replace it with a fixed cassette body.

Yes just removing something not really needed

Thanks for your reply , will there be a thread on the German forum for that ?

Paul

 

[lotharko]

Enough to matter ? maybe someone needs to take one for the team ?

I think it does make a noticeable difference whether the driven wheel is outside or inside.

will there be a thread on the German forum for that ?

No, I'm doing that privately this time. If it ever gets done, maybe the result.

 

[DannyC]

err no ?

don't forget the input to a freewheel is the sprocket and the output is the inner threaded portion ?

Yes, so turn that round and the jackshaft turns the inner part, and the ratcheting mech turns the sprocket, and the chains from the sprockets turn your fixie-wheels. No?
I have one in my hand and I can turn the inner to drive the outer and the outer is free to over-run as required.

 

[Popshot]

It doesn't matter whether the freewheels are on the jackshaft or the wheels, it will function the same either way. The only difference is the chains running on freewheeling or not.

Option 3 will work fine in right hand turns but will be a dog in left handers as both wheels will try to rotate at the same speed.

Ideally the jackshaft should be on a line drawn through the two pivots. In practise this can be awkward to achieve. If it can't go in the ideal place then the next best is in the same horizontal plane as the pivots assuming horizontal arms. If the suspension arms aren't quite horizontal then the jackshaft should be on a line drawn through the axle and pivot.

1 and 2 will work exactly the same as drawn. I do not see the difference you mention in the pivot position from the drawing. I ditto lotharko's point about the aesthetics of number 2 though.

 

[DannyC]

Option 3 will work fine in right hand turns but will be a dog in left handers as both wheels will try to rotate at the same speed.

Sorry, is this because of the fixie only on the one side? This is why I said put the freewheels on the jackshaft and have both the rear wheels as fixies.

 

[Popshot]

Sorry, is this because of the fixie only on the one side? This is why I said put the freewheels on the jackshaft and have both the rear wheels as fixies.

It is. In a r/h turn the inside is solidly driven by the pair of fixies and the outer wheel travels faster and goes faster than the driven jackshaft to freewheel around. The limited slip diff works fine. In a l/h turn the inside is driven at the slower pace of the inside wheel but the outer is fixed to the inside wheel's pace despite wanting to go faster. Either the inside wheel wheelspins to catch the outer or the outer must skid along to under-rotate to match the inner. Either way it's a bad outcome.

The freewheels can go on the jackshaft or wheels or even both and will work the same. Fixies can go on the jackshaft or the wheels but not both. If fixies are on the wheels then the two chains will always rotate even when freewheeling. It will likely prove easier to put a fixie on the inside of the r/h wheel than a freewheel as the fixie is thinner and a locknut will have enough room on std threads (and probably some threadlock too and/or tack the locknut on as well). A fixie cog is likely to need zero maintenance so glueing and/or tacking is less likely to be an issue for a fixed cog than a freewheel. It means a pair of std rear 14mm BMX wheels will do nicely and be single side mounted. The chains on the inside will mean no disc brakes though. If the chains went outside (locked fixie now on other side of quad/delta) then discs could be used but outside chains will not look as nice. Given this may be a quad two front disc or drum brakes may be deemed enough or calipers on the rear may suffice if braking all 4.

 

[stormbird]

Popshot & DannyC

So why did we have this thread to fix a free wheel to the left side of a driven wheel Freewheel to wrong side of wheel when all I needed to do was swap the positions of the fixed sprocket and free wheel ?

a)I can see if I push a bike forward with it's handlebars at the front the rear wheel turns and the pedals do not [ well as long as a SA AW 3 speed is not involved ]
b)I can see if I push a bike forwards with it's handlebars at the back the pedals will turn in the same direction.

What I cannot guarantee is that b) does not either:-
not freewheel at all
or
does not unscrew

Sorry this is beyond my brains capability to arrive at a theoretical solution , I will have to physically build it.

Popshot - sorry showing the suspension was an after though so not properly shown , basically I hope the jackshaft can finish inside the suspension pivots [ in line with them ] and the rear wheels can be BMX single side mounted.

I ditto lotharko's point about the aesthetics of number 2 though.

You are suggesting this at someone who though he could weld two kids bikes together to make a quick and dirty quad ???

thanks all for your input

Paul

 

[Popshot]

I assumed you had decided on freewheels on the wheel to prevent the two chains always rotating. You did ask how to fix a freewheel to a wheel not how to avoid doing it.

Your only worry is that any locking mechanism does not fail under drive. Using a locking ring means the threads take the effort of preventing this rather than the actual locking ring. Tacking the locking ring is merely to stop it vibrating off and some threadlock or glue is just the braces to add to the belt. I doubt any of us can produce enough power to force a fixie so hard against a locknut as to first overcome the tightening effect of one threaded part against another and second to shear some tacks off. If worried then weld it a bit harder than mere tacks. It's a fixie so won't need to come off unless it actually wears out and are designed for single speed chain so are much sturdier than multispeed cogs. Alternatively the r/h wheel disc brake bodge I did was largely held on with just epoxy. The bolts also used were the braces to use the same analogy and brakes generate far more power than legs can so if epoxy can hold a brake disc against braking forces unscrewing it it can hold a fixie against leg power. Epoxy the fixie and run it hard on, epoxy the lock nut and run that hard on. When set apply some tacks. If that ever comes off you've probably had a massive accident and the loss of drive will not be your biggest worry.

Even if all that fails and the fixie falls off the worst that will happen is you are down to a regular one wheel drive so will still get home.

I never thought you'd actually go through with the bodge-o-matic two bike quad and just assumed you were having an aneurysm, a crisis of effort or had gas or something. Should I assume the issue has remedied itself and you are going to make a less temporary job of it?

 

[Gmhowell]

For option 1, why do the swingarms need to be mirrored instead of facing the same direction? So like option two, but with single sided arms, both on one side.

 

[lotharko]

The chains on the inside will mean no disc brakes though

That's not a big deal either. I have made the experience that brakes on the front wheels are enough.

 

[DannyC]

Popshot & DannyC

So why did we have this thread to fix a free wheel to the left side of a driven wheel Freewheel to wrong side of wheel when all I needed to do was swap the positions of the fixed sprocket and free wheel ?

Ahhhh.... well, I thought you WANTED to do that for S-n-G's
No, seriously, your most recent set of diagrams of your options just caused a lightbulb moment for me, and making the wheels fixies and putting the freewheels on the jackshaft just made sense to me all of a sudden.

The only ongoing issue I see is maintenance. If you need to change your jackshafts bearings you need to remove the freewheels too.

 

[lotharko]

 

[stormbird]

Even if all that fails and the fixie falls off the worst that will happen is you are down to a regular one wheel drive so will still get home.

yes failsafe , have you read the adventures of the Green Mamba on the German forum ? they use that popular diff [ can't remember name ] a wheel came loose and so no drive , required rescuing.

I never thought you'd actually go through with the bodge-o-matic two bike quad and just assumed you were having an aneurysm, a crisis of effort or had gas or something. Should I assume the issue has remedied itself and you are going to make a less temporary job of it?

it was envisaged as a very quick way to build a quad purely to see what would and wouldn't fit through the barriers.
If I have several competing ideas i sometimes do a simple calculation of the number of parts and number of welds.
Due to several parts of the frame being in the wrong place the parts and welds counts approached a clean sheet design with added downside of very heavy so reluctantly it went on the pile of fine ideas fatally flawed

Paul

 

[stormbird]

For option 1, why do the swingarms need to be mirrored instead of facing the same direction? So like option two, but with single sided arms, both on one side.

The idea is with single sided arms is tyre removal without wheel removal , so the tyres must clear the chains.
of course there is a price to pay , special wheels [ 14mm or greater axles ] maybe heavier.
To be honest I am not snobby about having single side mounted wheels , in some ways I find it a little harder to change a tyre with the trike on it's side and the wheel free to rotate and am quite happy to spanner a wheel out if need be.

Paul

 

[stormbird]

That's not a big deal either. I have made the experience that brakes on the front wheels are enough.

yes normal tadpole practice anyway.

Paul

 

[stormbird]

The only ongoing issue I see is maintenance. If you need to change your jackshafts bearings you need to remove the freewheels too.

I think if the jack shaft bearings are to be changed it is probably time to give the whole thing a quick eyeball to see the state of the rear of it ?
Paul