Quad Pedal Car - 2025 late Xmas/early Birthday present ?
- Thread starter stormbird
- Start date
Popshot
0
The top seat mount doesn't need to be as high as it was from the point of view of using it as a seat. To avoid standing on the seat on entry why not hinge the top portion of the body thus allowing access to get the feet directly to the ground in front of the seat. You'll probably only need 18" or 2' of the top body hinged. From the middle of the seat back run two diagonal braces to the rails. They don't need to be large at all as the forces will be perfectly along the tubes.
You were right about that weld too though I've done worse.
You were right about that weld too though I've done worse.
Last edited:
I don't want the seat any higher , and they will sap power as they will allow the seat to rock forwards and backwards with the pedal strokes.Some stiff rubber donuts to mount the seat, might be a nice addition
Paul
The sides of the body are very high , so trying to straddle them AND touch the floor will not be possible.
To get in before you rested your hand on the back of the seat to steady yourself climbing over the side and getting both feet onto the seat base.
Then you could grip the sides of the seat [ now mostly trimmed off ] or the extra chassis rail that carried the seat mount and steering lever mounts [ also mostly trimmed off ! ]
Then you put both feet on the bent steering link protector , hoist your ass up and extend each foot in turn to reach the pedals , drop in the seat and you are done.
I realised about 2 days ago this may now be difficult
I doubt I will have any time to change the body work , I need to make the alloy frame unbolt-able from the chassis rails whilst still having the correx body attached to it , not possible before.
Whilst I though the surfaces were clean I have had bad porosity with some of my old steel before , and also I see a purple glow around the arc on surfaces I though I had ground all of the zinc off of ?
This happened when welding the hex coupler into the box section for the rear mount on this car.
I may try toilet cleaner in future and see if chemical removal does a better job ?
Paul
I think you're talking much softer rubber than I'm thinking -
Your seat is curved in every direction, and if you don't have some kind of conforming mount, it might crack.
I love TIG welding, but its Achilles heel is that you really need it cleaner than clean, for perfect welds.
I've yet to achieve that level of cleanliness........... forget about Godliness.............
This was how it was mounted originally
The seat is many layers of fiberglass and a couple layers of Kevlar however some numpty cut 1/2 of it off !
I have 2 more holes at the front I was hoping to come off the lower mount with some narrow 3mm[ish] bar and pick those up.
At the back I was thinking of putting a band around the top joining the 2 upper bolts holes then adding the X piece like the original had to the band, except 10mm x 1mm wall tubing and made adjustable at it's frame mount ?
Do you have a link for me to see what you are alluding to ?
Paul
No specific link, although most industrial suppliers have machinery mount bushings like this, in the hardness of your choice.
I was thinking of something like pieces of car tire sidewall - Something tough like that, but with a little give.
Anyway, if you can't raise the seat at all, a moot point.
Replacing the seat frame with lighter tubing is good - You might not need the whole X brace construction, though.
I think, that as long as the 2 outer tubes are angled outward from the seat back, to the frame (NOT just straight back, parallel), they will brace it from any sideways movement. You might then need only a simple cross brace, halfway down, H-frame style.
Oh, and a cross piece at the bottom, if you need to make the whole thing as a moveable unit - Although, maybe not, as the main frame is there?
Does that make sense?
Disclaimer(s) - I am NOT a structural engineer, YMMV, etc, etc ...........
Last edited:
Popshot
0
I think you may have an issue with the lack of that extra bit of chassis. It looks like it was doing more than one job and the most important one was adding some triangulation to the main chassis at the point where it bends. I think the whole point of the bend in the main rails is so it can be triagulated. Straight rails would offer no such option. You may find you have added some flex into it without that.
Maybe flex is not a bad thing IF it returns to where it started from ?
The previous car I had when unloaded sat on three wheels , the wheel on the outside of the predominantly right hand corners was slightly off the floor.
However it was ok when I sat on it , that car had been racing hard for many years
Paul
So new seat mounts made for the upper rear fixings
I had all-sorts of fancy ideas pivots , 10mm x 1mm tubes with 3mm ends welded to them etc etc etc....
In the end I went for the simplest [ read lightest ] option ?
As I doubted I could weld the 10mm x 1mm round tubing to a 3mm plate I opted instead to add a short sleeve of 12mm x 1mm to the outside and then simple hammer if flat on the vice tail.
For the upper mountings that worked a treat , however the other ends proved to be a bit harder ?
First try on the left and second on the right , so I was getting better honest !
Tonight I flipped the chassis upside down added 1" weld to each seat mount , finished the welds where the steering controls were
and welded the other 2 sides of the rear utility mounting.
So next up bolt up the lower seat mount without the seat and try and size the chain , unsure where to start with this as it is way out of my
comfort zone.
Usually I start big crank ring to big on cassette and add 4 links ?
After that I need to look at the steering levers and see if I can fit a 10 speed bar end shifter or put back on the 9 speed trigger shifter and
be a gear short ?
Paul
I had all-sorts of fancy ideas pivots , 10mm x 1mm tubes with 3mm ends welded to them etc etc etc....
In the end I went for the simplest [ read lightest ] option ?
As I doubted I could weld the 10mm x 1mm round tubing to a 3mm plate I opted instead to add a short sleeve of 12mm x 1mm to the outside and then simple hammer if flat on the vice tail.
For the upper mountings that worked a treat , however the other ends proved to be a bit harder ?
First try on the left and second on the right , so I was getting better honest !
Tonight I flipped the chassis upside down added 1" weld to each seat mount , finished the welds where the steering controls were
and welded the other 2 sides of the rear utility mounting.
So next up bolt up the lower seat mount without the seat and try and size the chain , unsure where to start with this as it is way out of my
comfort zone.
Usually I start big crank ring to big on cassette and add 4 links ?
After that I need to look at the steering levers and see if I can fit a 10 speed bar end shifter or put back on the 9 speed trigger shifter and
be a gear short ?
Paul
I wonder was the original overly glassed seat and cross member also adding stiffness and reducing torsional flex of the frame ?
Probably ?
I met the guy who designed and built this chassis and asked him why they were now driving a round tubed chassis of a different design.
In his words this chassis was far to stiff , they even tried drilling loads of holes in it , gave up and built a new chassis.
Like a fool I never asked the symptoms of the chassis being to stiff ?
So answers on a post card ?
Paul
Perimeter t
Perimeter tubing looks like 1"x2", or metric equivalent - It looks pretty stiff in one direction, at least.
Kingpins way out on long arms, though - Localized twist, there?
Perimeter tubing looks like 1"x2", or metric equivalent - It looks pretty stiff in one direction, at least.
Kingpins way out on long arms, though - Localized twist, there?
Maybe as you said earlier flex allows to keep all 4 wheels on the ground without suspension, with your weight ? Especially if you intend to use your quad outside of a racetrack with less than flat ground
So I have weighed it again looking similar to the right picture however with seat mount & pulleys etc etc
weight of above 18.92 kg does include complete rear end and king pins. We have a big hole and now we weigh 15.33 kg
Oddly it weighs 14.86 kg so obviously these weights are not accurate and now I am unsure which weight is incorrect and how much I have really removed ?
Leaving that I struggled most of the day trying to get the gears to behave , it was sold as a 9 speed car however that was not the whole story ?
It had a 10 speed cassette with a 9 speed trigger shifter , this combination only partially worked apart from not getting all the gears it was very haphazard when changing and did not always give 9 speeds and the 10th speed you could not get was the lowest gear grrr the one I need the most.
I did however have a 10 speed bar end shifter , champion I though attached to existing cable it was unable to work and could actually get less gears than the 9 speed !!! I was resigned to the fact the rear mech a short cage Shimano 105 was probably not up to the job [ even though it was the most modern of the available stuff ? ]
As a last ditched attempt before a go at getting the rear mech off I tried a old Shimano 7 speed friction only thumb shifter , I have used these for over 10 years on the Python and perform flawlessly.
You could have knocked me down with a feather [ without touching any of the mech settings ] I had all 10 gears no over shifting and in fact the thumb shifter could move the mech faster than the chain could move through the gears
So I do need to change one of the front rings from a 32T to a 38T and keep the 48T it came with as the mech has a little difficulty with the amount of spare chain between the two [ 16T is it's stated limit ] . Then on to the brakes.
Paul
Well done the non indexed shifter was a good solution I was told if derailleur shifter and cassette dont match well even if they are supposed to be same nb of speeds one can have issues.
So the seat supports that came off in the process of loosing weight were also useful in stiffening the frame ?
So the seat supports that came off in the process of loosing weight were also useful in stiffening the frame ?
Yes compatibility is a big issue when you just use stuff found on scrap bikes and want to mix and match , even trying to stick with Shimano their Road and MTB parts are no compatible and old stuff just adds to the problems.
In all honesty I don't think they added any think to stiffen the frame looking at where they were welded to it ?
Paul
So this morning I searched my cranks box right to the very bottom and the last crank I pulled out had 4 arms , correct BCD and 38T , so I swapped that over.
In the afternoon I refitted the chain , shortened the shifter cable and was prepared to be chuffed ? progress at last when ...
I discovered have a problem of my own making boohoo .....
this is looking forward ............................................................................and this is looking aft
Can you see the chain twists over on the return side , then because the side of the chain is shaped like a dogs bone it locks over the chain keeper
and stops the chain dead even though it is still in the pulley valley.
Observations :-
Now have swapped the chain's position to be under the opposite pulley
I have marked the chain and it always does it in the same place
It only does it on the 38T and not on the 48T
It only seems to do it on the 28T sprocket and not on the others , although having typed that I have not really lingered much on the other sprockets.
Very puzzling , I think there could be a couple of solutions ?
Make the chain keeper a flat plate instead of a Q/R skewer ?
Make it much bigger in diameter ? say a M8 or M10 bolt ?
Any other thoughts
Sorry for blurry picture , however it is to show how much the chain angle has to be to get through the pulleys.
Paul
In the afternoon I refitted the chain , shortened the shifter cable and was prepared to be chuffed ? progress at last when ...
I discovered have a problem of my own making boohoo .....
this is looking forward ............................................................................and this is looking aft
Can you see the chain twists over on the return side , then because the side of the chain is shaped like a dogs bone it locks over the chain keeper
and stops the chain dead even though it is still in the pulley valley.
Observations :-
Now have swapped the chain's position to be under the opposite pulley
I have marked the chain and it always does it in the same place
It only does it on the 38T and not on the 48T
It only seems to do it on the 28T sprocket and not on the others , although having typed that I have not really lingered much on the other sprockets.
Very puzzling , I think there could be a couple of solutions ?
Make the chain keeper a flat plate instead of a Q/R skewer ?
Make it much bigger in diameter ? say a M8 or M10 bolt ?
Any other thoughts
Sorry for blurry picture , however it is to show how much the chain angle has to be to get through the pulleys.
Paul
Last edited:
