Quad Pedal Car - 2025 late Xmas/early Birthday present ?

[Trickytrike]

It sounds like you could add fifth retractable caster wheel at the front for short turns and parking in town...

More seriously how are the frong wheels steering arranged ? The kingpins etc don t appear too clearly on the pictures, are they attached to the side beams of the chassis ? Do they tend to apply a twisting force so ? For a tadpole trike there is a cross beam btw the front kingpins but it does not look present here.

 

[stormbird]

It sounds like you could add fifth retractable caster wheel at the front for short turns and parking in town...

More seriously how are the frong wheels steering arranged ? The kingpins etc don t appear too clearly on the pictures, are they attached to the side beams of the chassis ? Do they tend to apply a twisting force so ? For a tadpole trike there is a cross beam btw the front kingpins but it does not look present here.

Yes not really got involved in them yet , simple they are attached to an extremely short stub that is welded directly to the side of the chassis:-

Bit blurred however this is the right front wheel the correx sides are 4mm and as can be seen the kingpin barely clears them.
It is possible the sides at this point could be narrowed by about 2.5" per side I have yet to calculate how much more turning angle
I would get , currently I have about 14' before the rear of the front wheel attacks the body work !

There is some cross bracing both in front of the kingpin mount and behind it as can be seen in this picture.

Kingpin is bolt head almost bottom right corner of picture

Paul

 

[Trickytrike]

Ouch so hard welded in place no tie rod with end bearings like in velomobiles that could have been tuned. Looks like whoever built it had a talent for welding stuff with spot on angles and no adjustment possible... so the body modification seems like the only way. A very crude idea of how much turning radius could be gained can be estimated by trigo. I could be wrong but : let Turning radius = R, wheelbase = W, wheel half diameter = HD ( 10 inches ) and clearance between body and wheel be C, then T/R = approx C/HD. Which means than an increase of clearance should reduce turning radius in inverse proportion. Say you go from 3 to 4 inch wheel clearance, the turning radius should be 3/4 of what it is now. Hope this helps.

 

[stormbird]

Ouch so hard welded in place no tie rod with end bearings like in velomobiles that could have been tuned. Looks like whoever built it had a talent for welding stuff with spot on angles and no adjustment possible... so the body modification seems like the only way.

The rod end bearings do not really give the adjustment you imagine ? as if you try and alter them you change the angle of the kingpin axle so giving the wheel either camber inwards or camber outwards ?

A very crude idea of how much turning radius could be gained can be estimated by trigo. I could be wrong but : let Turning radius = R, wheelbase = W, wheel half diameter = HD ( 10 inches ) and clearance between body and wheel be C, then T/R = approx C/HD. Which means than an increase of clearance should reduce turning radius in inverse proportion. Say you go from 3 to 4 inch wheel clearance, the turning radius should be 3/4 of what it is now. Hope this helps.

My best calculation estimate would be the steering angle currently 14' could become 24' ?

So dark red is current set up green would be great and yellow I may have to live with ?
If I chose to chop it about [ inches/feet are the radius of the turn from the outside of the wheel on the outside of the turn ]

Paul

 

[Popshot]

Looks like the chassis rails just behind the body are in the way of much more turning. That leaves little room to muck about. One of the big drawbacks of a perimeter frame. The front wheels being a long way forward make matters worse too.

 

[stormbird]

Looks like the chassis rails just behind the body are in the way of much more turning. That leaves little room to muck about. One of the big drawbacks of a perimeter frame. The front wheels being a long way forward make matters worse too.

Yes you are right , however we work with what we have , so first up is a plan to lop 6" out of the wheel base in the centre to disturb as little as possible , should take 1.5 ft of the turn radius.
It will be out of the rear of the car effectively bringing the rear wheels closer to the seat.

Paul

 

[undertoad]

It's too bad you can't widen the front track, by re-welding the kingpin mounts a bit further outboard.
That would give you more steering angle, before hitting the body.
Probably not practical, though.

 

[stormbird]

It's too bad you can't widen the front track, by re-welding the kingpin mounts a bit further outboard.
That would give you more steering angle, before hitting the body.

I had though of getting some new stub axles made with a 1" spacer , placing the wheel 1" further out only that seems a no go either.

Probably not practical, though.

Looks like they were never really meant to be played with , however I have a plan C which I shall investigate shortly

Paul

 

[Popshot]

The problem with cutting the kingpins off and moving them out is it increases leverage the wheel can exert on the frame rail. Again a perimeter frame issue. The perimeter frame rail wants to twist as force is exerted from the wheel and has only any cross members to use to resist that. This one effectively has only the front one. A single spine chassis has one wheel bracing against the other. Ie good resistance to twist. If the front wheels were far enough back a crossmember could be placed between them but where they are that would want space the feet need.

 

[stormbird]

Some of the pedal cars are based on tadpole trikes , not in itself bad , however it does dictate the shape of the car :-

It means the pedals are way out front and to stop the cars being unacceptably long they tend to have a short w/b. This also makes body work harder to add.
My car was 7.5 ft I hope to get it down to a more manageable 6.5 ft [ or less ]
There is a length limit in the rules raised to 2 meter to let Quatro Velomobiles enter , I doubt if anyone with one of those would be mad enough

The 2 teams currently running the most cars : -
Apollo - peripheral frame single tubes
Royce - peripheral frame complicated space frame


Paul

 

[Popshot]

The 2 teams currently running the most cars : -
Apollo - peripheral frame single tubes
Royce - peripheral frame complicated space frame


Paul

They are presumably race vehicles only so any limitation on road manners is not relevant. There's no reason a perimeter frame has to have the front wheels far forward. It won't affect overall length to pull them rearwards.

 

[stormbird]

They are presumably race vehicles only so any limitation on road manners is not relevant. There's no reason a perimeter frame has to have the front wheels far forward. It won't affect overall length to pull them rearwards.

Road holding at race speeds becomes questionable if w/b to small.
However there is no definition of ' to small ' although a car last year was considered dangerous and pulled from the race.
There were several incidents with it before that happened.

Paul

 

[stormbird]

So I have raised the car to running height without the wheels being in the way :-

This allows me free access to the innards and will allow the whole lot to be wheeled into the sunshine for a spot of surgery.

I then got busy with the hacksaw [ safe in the garage unlike the grinders ] and remove these redundant parts.

They amount to 680gm and none of these will be going back on.

The T piece at the bottom came from here , when we have 6" out of the chassis middle the smaller tube will be trimmed and cleaned up and inserts in the bigger tube for welding.

So small progress , still trying to source a light seat ...

Paul

 

[undertoad]

Excellent removal of ugly bulk

 

[stormbird]

Excellent removal of ugly bulk

It is very easy to get carried away

Paul

 

[DannyC]

Excellent removal of ugly bulk

Don't say that..... If my wife hears words like that I am a dead man.

 

[stormbird]

So first up get the body work frame off:-

Now actually this came off fairly easily about 12 small bolts with only 2 under the frame and hard to get to , so me thinks if I can improve their access I can add all the correx panels to this and just remove the whole lot for maintenance ? it's a though.

Rearranging one of the bike sheds got it a home for a rest whilst ......

Surgery is contemplated weight of above 18.92 kg does include complete rear end and king pins , but scant little else.

So whilst last cutting removed some unwanted fat , this has removed front and rear seat mounts and chain management chassis components oops

So we have a big hole and now we weigh 15.33 kg so I have removed 2.79 kg .
how much of this will have to go back on I am unsure it would be nice to think only 1.79 kg , well we can all dream

Paul

 

[DannyC]

So first up get the body work frame off:-

Now actually this came off fairly easily about 12 small bolts with only 2 under the frame and hard to get to , so me thinks if I can improve their access I can add all the correx panels to this and just remove the whole lot for maintenance ? it's a though.

Rearranging one of the bike sheds got it a home for a rest whilst ......

Surgery is contemplated weight of above 18.92 kg does include complete rear end and king pins , but scant little else.

So whilst last cutting removed some unwanted fat , this has removed front and rear seat mounts and chain management chassis components oops

So we have a big hole and now we weigh 15.33 kg so I have removed 2.79 kg .
how much of this will have to go back on I am unsure it would be nice to think only 1.79 kg , well we can all dream

Paul

Good Luck with the trimming of the surplus and reassembly.

 

[Popshot]

You could get more turning circle by relacing the wheels with some offset. Just an inch of offset would equal a lot of extra turn. Same effect as moving the kingpins on the chasis stress though.

 

[stormbird]

I had tho

You could get more turning circle by relacing the wheels with some offset. Just an inch of offset would equal a lot of extra turn. Same effect as moving the kingpins on the chasis stress though.

I had though of getting DannyC to turn out some new axle stubs with a 1" spacer at the kingpin end till I saw they were not simply welded in as the vertical face of the kingpin isn't !

I reckon I can try that with a bodge that would not stand much riding , however it only has to perform a semi-circle on the grass as before and i can walk it there.

Paul