Select to expand quoteHiko said..
Surprising you cannot find 20mm bearings they are plain vanilla world wide Even the USA I would have thought
If you must 3/4 inch is very close maybe you can get those to match wheelbarrow wheels in your area
Me too.
Maybe the bearing OD is too small for that large an axle (?).
JAronstein: Do you know the OD of the original bearings, or are there any numbers on them?
Select to expand quoteHiko said..
Surprising you cannot find 20mm bearings they are plain vanilla world wide Even the USA I would have thought
If you must 3/4 inch is very close maybe you can get those to match wheelbarrow wheels in your area
It's because to fit my wheels I need a 35mm OD. I can find 20mm ID bearings but not with an OD that small.
I found 3/4" ID bearings. they were expensive though. My wheels aren't metric so I couldn't get metric bearings for them.
It seems you have a problem with off the shelf match ups You might be forced to do some custom work for your axles
!7mm high tensile axles should be OK if you use metal tube spacers between the bearings and an end nut is done up tight
You could drill and tap the ends of the axles to take washers and setscrews or studs and nuts instead of threading the end of the axles
I have that setup on my minis Works fine
i finally upgraded my wheels. 3/4" bolts for axles. I made some mounts out of 1/4" steel plate. i didn't realize that the wheels are somewhat wobbly until i installed them. swapping in something of higher quality is simple now that the mounts are built. any recommendations on what to do for brakes?
Most dont bother with brakes
If you feel where you sail you need them then probably the easiest for your yacht would be to fit levers operated from your seating position with the outer ends
fitted with a pad that rubs on the rear tyres One each side A few people use this system
The only time I tried brakes was on the front wheel and it proved next to useless due to the little weight on the front wheel
Another system used on beaches is a drag lever that ploughs up the beach mounted in the centre of the yacht toward the rear
You might come up with your own design that you can share with the rest of us that is worth the trouble 
The best way to slow down is to steer into the wind and push your sail out to create a big air brake!
I f you feel you need an active brake use the lever onto your wheel. If made of steel tubing, bend a hook that will fit the shape of your tyre at the end and dont worry about any pads. Rig it to be applied to the back of the wheel. This method also helps when trying to turn quickly as it slows the inner wheel and you can almost pivot on that wheel. It can also help hold your yacht at a start line.
NOTE: If you are sailing at speed no brake will slow you to a stop as it would be like applying a handbrake as you drive a car under acceleration! 
Thanks! I'm not sure whether I need an active brake or not. I'll probably try to mount something.
Brakes are a godsend for our standing starts at the Sandgropers.
They make it so much easier to hold the yacht stationary, not to mention the fact they remove the need to swing the yacht into the wind to slow/stop if things get dicey.
And YES braking around markers makes for quick turns and thrills to boot.
Here are a few pics of my brakes, just mounted through the same holes the axles stubs are.
Some fellas at the club have the curved tubes that rub on the front or back of the tyres but I find these work just as well.
If you didn't want to drill holes through your frame then I imagine sleeves clamped down over the existing frame, with brakes mounted on those would do the trick.
My sister exited a rolling yacht on Lefroy back in the 80's because of the lack of a seatbelt.
Mum wouldn't let Dad take us kids sailing after that.
Food for thought.
Looking at the simplicity of that system, I think i'll definitely have to make a couple brakes for mine. I don't have lake beds to go sailing in. for me it's mostly just parking lots so brakes are a good idea. If don't want to run into something and cause property damage. My thought on seatbelts is that dissipating momentum separate from the yacht after a flip over is just as safe as being strapped in and being dragged by the yacht upside down as you dissipate energy together. 3 people have accidentally flipped my landsailer and none of them were injured tumbling out and stopping themselves well the yacht flew a couple feet without them. With that being said, those were all relatively low speed crashes as I've only got up to 24 mph so far (working on making it faster) at higher race competitive speed its possible that staying in the yacht would be beneficial.
Being a featherweight (read: amateur) I reckon I would have capsized more than the rest of the Sandgropers combined in the last 5 years.
maybe even over 100 times in my cl5 and mini combined.
I have even heard people say if you are not capsizing you are not trying hard enough,
given my track record I will run with that 
Most of my CAPS have stemmed from social sailing/hooning trying to pull 360's on Lake Walyungup's loose surface or sailing as far as I can with the yacht on 2 wheels, teetering on capsizing.
Every time I am quite literally laughing my arse off, knowing I'm safely strapped in and that the mast will take the brunt of the impact.
I have bent my cl5 mast over sheeting but never from capsizing.
Never fallen out touch wood.
JA staying in the yacht is very beneficial The mast will protect you in a capsize and as long as all your body parts are inboard you should be fine
There is a great temptation to put your hand out to fend off the ground but resisting that as above is the best in my opinion A seat belt and something to lock your feet into is a must for me Before brakes even
those are all valid points. is a lap belt sufficient or do you guys recommend a full shoulder harness?
A snug lap belt is enough on the blokart. You want it tight enough to keep you off the ground when you're hanging from it after a flip.
To give you an idea of how much of a non-event a capsize is, here's a video of one of my flips:
(don't put your hand out like I did!)
The flip is around 25 seconds into the clip...
Joining this one late...very few people use harnesses, though in the US (for NALSA events) seatbelts are required.
I think for our events your front wheel is okay as long as it fits in a box that fits tightly over the typical Wheelbarrow 400/480 x 8 . In the US, the kitebuggy sites are the best source for wheels with 20mm id bearings. Most of the 3/4 id bearings are really only good for walking speed (not precision).
Hope to see you in the dirt!
getting a seatbelt is on the list of things to do. probably a sturdier seat also. I like the box method for measuring wheels and tires! it seems like every type of tire has a different sizing system to go with it, makes it a little confusing. an absolute measurement is a great idea! Thanks for the tip on finding 20mm bearings. I'll keep that in mind whenever I make my next wheel/axle/bearing upgrade. what I have is working adequately at the moment. I live in Kansas which is a long way from any landsailing races, but i'll try to make it to one someday.
