A full 4 minutes in Crab II at the end of this topic

just for fun i'd like to build a different version of the Crab.

I'm gonna call it: 'Coast-line Cruiser'
this one is a mirrored version with the steering axle in the back.
therefore when you ride it the single front wheel will probably not be visible for the rider because of the footboard.
so this might give the feeling of low flying because of that.

and the goal of a better trailing because 2 steering wheel can easelly give friction and therefore cause speed reduction wich Crab 1 has slightly. not much, but slightly.... and if i can reduce that..

maybe the weight disrtribution with this setup will give a better
result and easyer high speeds, also the goal of weight reduction is a priority.

this version is allready made by more guys so i am not taking any credit for the idea..

keep you posted

I like this
Excuse my lack of knowledge but might it be easier to use the single front wheel for steering ?

edit - I think I see the mistake in my suggestion above. You'd be going around in circles. :D

Quote: Originally posted by RedSky

I like this Excuse my lack of knowledge but might it be easier to use the single front wheel for steering ? edit - I think I see the mistake in my suggestion above. You'd be going around in circles. :D

:D:D:D
The other way around in fact, I will not be able to steer at all..

But keep coming with input, comments or suggestions.
I'm only human and can also easily miss something...

Interesting idea

Quote: Originally posted by jantie

Quote: Originally posted by RedSky   I like this Excuse my lack of knowledge but might it be easier to use the single front wheel for steering ? edit - I think I see the mistake in my suggestion above. You'd be going around in circles. :D :D:D:D The other way around in fact, I will not be able to steer at all..

That is true! Don't ask me for any advice.

thanks Khaakon,

the reasons for a curved axle are:
1#
it's something else than just a straight pipe and bend ant the end on both sides.
and it needs to be bend because of clearence for the tires that are in line instead of a 90 degrees angle like a 'normal' buggy because they need room to steer.
2#
i'm probably going for a 50mm pipe so it will be rigid enough and no further stiffening is needed.

i'm trying to make the steering and the rest of this creation as light as possible.
Crab 1 is kinda heavy, and the weight distribution is not perfect.
when i get lifted only the rearwheel get's airtime,but in my 'normal' buggy all 3 go 'up and away..'
:D:D

and when starting to drift a little but equally with three wheel in line costs less speed.
So this rear-steer setup hopefully also translates in a better allignment when i ride this new creation a little overpowerd. because there are 2 wheels that steer instead of 1, there are always 2 wheels that might drift wich causes decrease in speed.
with making that better i try to prevent that.

important: I do not want to make a copy of Crab 1
everything and every part if possible is gonna be reversed, up-side-down, mirrored or completely different.

so far i've got the tires, rims, a lot of nuts and bolds left from previous projects.
i've calculated that the radius has to be about the same as the length of the steering axle,
now finding a way or someone who can do that nicely.

for the footboard on the Coastline Cruiseri've got also a nice and different idea..


keep you posted when progress is made..

the setup to paint a picture in realtime of how it's gonna be:

the middlesection (seat) is a part of Crab I.
i'm using it without modifying so it's compatible for both Crabbies.







steel is ordered so now wait for the phone to ring..

that's it for now.

This type of crab makes more sense with less drag from two wheel steer. Maybe also include an optional fork and rear axle kit to convert from crab to regular buggy.

Quote: Originally posted by RedSky

This type of crab makes more sense with less drag from two wheel steer. Maybe also include an optional fork and rear axle kit to convert from crab to regular buggy.

it hopefully does have less drag but time will tel..
and as for a conversion-kit:
i already have a 'normal' buggy so there is no need for that
:D


15 years old and well over 26000 km on it..



today's progress is small but better than nothing:

found leftover material wich is perfect for the ballbearing head's to hold the upright's:
it's stainless steel and even better: it's for free..!!

my uncle has a steel Lathe/miller to make the bearings fit perfectly.


this is the rear-end from crab I wich will be multifuncional:

this part can be removed:



and now it's also suitable for the Cruizer.
fortunatly the supports for the roll-bar can also be used
so i don't have to make that double.








at both ends the axle (50mm) will be extendend with 1 size smaller (42mm) pipe wich will be bend in a 70 degrees angle inward.
so not a complete curved axle but that was gonna be to costly..
and this rear-axle was the one that was used to widen and extend the original Libre V-max this buggy was before i converted into Crab I

so that's it for now..

today's progress:

made the rear-axle separable for easy and compact transport
cutting, grinding, welding, grinding again, sanding and painted with zinc-spray










to be continued...

Randy is right. I do admire people who can do this kinda stuff.
Is the translation you're looking for, a bearing press ?

this is what i mean...




edit: translated from dutch (draai- en freesbank) Lathe and milling machine

today continued on the frontside of the frame:

setup


locked in and set level


used a laser to be more accurate


result after the cut


setting the axle-pipe
the frontframe in total is still to long
but that will come on a further stage


result so far..


wheelbolt not welded yet but looks great if i may say so




to be continued...
:D:D

unexpected dry wheater today

fixed the frontwheel axle to the frame:


first i took a M20 nut, shaved the thread
and slided it over a M20 bolt,
grinded a groove


welded it


grinding an sanding


aligned it


again welding


alignment on the frame


welding


grinded, sanded and painted


drivers view.


slowly getting there...



that's it for now.

Seems to me at least, a little more intuitive to have the single wheel facing rider. This is going to be great!

Continued with the steering:

from scaffolding used 2 tubeholders an slightly modified them


use 10mm massive steel round bar
and exhaust clamps to make it adjustable



small plates welded to connect the front to the rear




setup to see how it looks


setup with tire



that's it for now..

continued with the rear-axle:

made 4 incisions in the bended piece 0f 40mm so it would fit (with a hammer) in the 50 mm pipe




times 2..



allignment on the complete frame



after welding, grinding, sanding and spray-paint




rideheight made for these tires to be used on a really smooth beach,
bigfoots will give more rideheight in case of a bumpy surface.





and got these back from my uncle,
ready to be welded on the steeringaxle



next time:
uprights en steeringrods
goal is first test-run in december

progress of yesterday:


made a drawing to see an calculate the angle of the bearinghead.
It's almost similar to the one of the Spider Crabbuggy, but he use a bigger tire and another rim.



draw and grinding it fit.



welding and more grinding.



cutting the 40mm to make the 34mm pipe fit



after measuring and setting it level in every direction,
ofcourse also a visual allignment...



again welding, grinding and some spray-paint


the complete axle


and the answer to Randy's question:
most of them are the cheapest DIY-tools here in NL.
only thing missing is a XL pipe-bender and the Lathe/milling machine to make the ball-bearingheads.


And thanks Abkayak, I'll take that as a compliment.. :D

Quote: Originally posted by jantie

and the answer to Randy's question: most of them are the cheapest DIY-tools here in NL. only thing missing is a XL pipe-bender and the rotary-machine to make the ball-bearingheads. And thanks Abkayak, I'll take that as a compliment.. :D

Thanks for showing that. The craftsman is obviously not limited by his tools!

Quote: Originally posted by rtz

I don't have a lathe yet either. The first head tube I made; I bored out the bearing pocket using one of these adjustable boring heads. Works but slow to do. https://www.ebay.com/itm/333725651886 I've since made them like Popeye did and slit the tube to put it inside another. In the future I might just use flanged bearings.

to cut a pipe 90-degrees you probably get that with big saw Carl (Popeye) used, but with a metal-Lathe it is always a 100% accurate.
if the inner tube isn't 100% accurate the bearings will not last very long.
i only have a hand-grinder with a thin cutter-blade, so that's why i asked my uncle..

progress for today:

started wih the uprights,.



it fits in the a-symmetrical rim.



then copy/paste it..



and look here: all grown up to stand on it's own 3 tyres..:D



the took a corner-piece of 25x25mm and 4mm thick.



cut it, weld it together and drilled 12 and 16mm holes.



spraypainted and it fits perfect!!




cant wait to take it out to the beach..



next:
completing the uprights and continue with the steeringrods

You are getting close to the finish line. Can't wait to see it in action.

continued with the temporary foothboard:

i'm still considering what the final shape, material and looks
the foothboard is going to be i've made this for 'inbetween'..


drilled the mainpipe to stick the 10mm solid steel pipes true.




welded and spraypaint.



used leftover ply-wood.




used seatbelt-band for foothstraps.






for fun painted a footprint.


the test-fase is coming, can't wait..
:D:D

Looking forward to your first ride.

first of all thanks for the comments, it is nice to read and also see the read-counter of this topic getting higher every day knowing that people here are interested..
i'm curious if this one wil exceed the Crab I number of readers.



today was a beautiful one to continue on the Coastline Cruizer




the uprights only need the steerlevers





the main adjustable steeringrod from the foothboard
all the way to the back including the extra supported bearinghead
wich will go further to the uprights.




it got to dark so time to call it a day..



so close but still a few hours of work away..

finished for testing.. YEAH...!!!!


main steeringrod with protection ( ex-racingcycle innertube.. :D)



rear axle





with tires




max downwind steering position



max upwind steering position



does it pack down is Redsky probably gonna ask?
owww.. yeah, way better than Crab I



click here for a fullsize pic


now only wait for:
wind
low tide
dry beach
good wheater
time
etc, etc...

I hope you get your list of 5 soon.

Congrats on getting the Cruizer ready for a first run, hope you're gonna have at least as much a fun time on this first ride as I've had, following you build log here. Great photo & excellent construction.

Really thoughful design of the crazy linkage. And keeping the CoG low. And making it all into such a small pack for transport.

Godspeed! Enjoy!

Thanks all for the compliments..!!

To adjust the board to someone with shorter legs i just
unscrew the 8 bolds of the 4 (exhaust) clamps and slide
it backwards to the seat. Then by screwing/adjusting in the threated rod of the main steeringaxle to (re-)set the angle of the board.



for myself it's also gonna be the question of how to set the angle of the board since the steeringwheels are in the back.
i have absolutly no idea how it is going to ride, slide, turn and break.

but what i did gain is the big weightdrop in compare with Crab I:
just under 20 LBS lighter in total, and a way different weight ratio on each wheel when i'm in it.

nice touch: after a re-measurement the triangle from the tips of all wheelbolts was near perfect, just 0,5% deviation.
but checking after allignment of the 3 wheels i got it right up to 1mm
that's 0,03937008 of an Inch..


click here
for a short movie of the build with most of the pics in it.

first time out was really good.
the advantage to allready know how to Crab comes in handy,

but still it is a different Crab.
i could feel the weight difference because this Crab tracks like a train.
the way it continues after a powerslide is more stabile than Crab I.
also i don't get lifted on the rear side like Crab I.
but run the risk of getting too confident and when i do eject.... take cover!!


only had to make 1 minor adjustment on the beach:
the main steeringrod needed to be 2 cm longer,
not to bad for a backyard preset.

conditions today weren't that great but good enough for a decent testrun.
it took more time to pack, get out there and assemble it and taking it apart and go home than the actual time i got it to run,
but it was so well worth it.

used a few actioncams to record this one.
too bad there was no one to film a driveby and the cam in the kite came a little loose.
but i got enough to look back on and make a good impression.

next time with more camera's... :D:D



click here
For a short testrun movie...

@ Windstruck:
there are more pivotpoints, hinges and linkes on the first Crab..
a total of 15 in nr.1 and just 11 in nr.2


but that's improvement:
it's the 2.0 version with less mistakes or unnessesery things.
that explains also the weight-loss..
:D

the first is a mix based on all the pics an movies i found on the internet,
99% of them with the steeringaxle in front of the rider..
there is one picture of an Australian or New Zealand rear-steering Crab,
but i cannot find it anymore...



for today:
made a slight improvement to the footboard:
the (seat)belt i used folded in sometimes but i want to put my feet blindly
in position knowing they are suppported at all times,
added some sticky-sand tape for more grip.

made 2 camerasupports on Crab II.
also ordered a 360 degrees cam, and curious about
how that is gonna look.

unfortunatly the Netherlands is of now in lockdown,
still hoping to take it out soon.



frontwheel:



with cams:



rearwheel





with cams:




overview:






for a short video

yesterday wasn't perfect, but way better than spending the day indoors.

got to try the camerasupports and most are good and some not yet..


for the short movie with a nice beat

Came here straight from youtube. xD
The top down view looks like you're powersliding a regular bug haha. Welldone on a great job!

Slick video! I enjoyed that. Especially liked the mid-air collision with the gull. :D