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[jamesb]

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they had their chance mike

[ukrobotics]

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Im struggling to find a cheap but effective brake solution for this soapbox.

Ideally Id like to go for disc brakes, but they seem to be prohibitively expensive. A front & rear brake disc set-up for a mountain bike seems to start at about £100 on ebay. Is there a cheaper way of doing disc brakes, or an alternative that will be just as simple and nearly as effective ?

Last year I used bike wheels and was able to use the V/caliper brakes that came with the bike. This year I want to move away from the bicycle wheel idea as they have to be supported from both sides which means the chassis has to be much larger , heavier and less rigid than it would be for use with wheels supported from one side only.

Does anyone have any suggestions for building/obtaining a cheap but simple and effective braking system ?

[simon]

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what wheels are you using ?

[killercarrot]

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the traditional soapbox brake is a wooden lever that acts directly on the tyre... if you fitted two you could have tank steering!

[killercarrot]

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get that rotten constrictor thing off your profile pic, and put up a pic of your racer

[ukrobotics]

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Si: Not 100% sure about the wheels. The £5 sack truck wheels from northern tool seem like the ovbious choice though im a little concerned the small 10 diameter might reduce my top speed too much.

(That is assuming that the wheel diameter affects the speed in a gravity kart in the same way it would a powered one)

Rob - Tried the skid steer idea last year on the grounds of minimal moving parts and maximum simplicity but it didnt work!. When one wheel stopped all 3 others did too.

Im thinking the lever on the tyre might be the better appoach ..the more I look into it the more I realise discs are complicated and expensive.

As for calling constrictor a rotten; how dare you! :P Ill remove it if you remove the rotten carrot from yours.

I actually have nothing to show right now as everyting is just in my head or scribbled on paper. Once ive made some progress ill share some photos.

[simon]

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What if you used two moped wheels on the rear, then you could use their drum brakes.

[simon]

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PS, how long is the course ?. A heavier cart might be slow on the take off but would be faster later in the course

[ukrobotics]

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Finding a cheap scrapped moped might be difficult and I guess it would be excessivly heavy.

Course is no more than 200m.

[woody]

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This approach seems simplest..
http://www.gravityengine.co.uk/redbull/viewer.php?id=153http://www.gravityengine.co.uk/redbu...wer.php?id=153

Tiller for steering ...std push bike brakes ...reclined seat.

Perhaps you could get clever and add a lean mechanism?

[ukrobotics]

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Someone made one like that last year - it was very unstable and buckled two of the 4 wheels.

Heres the video from the 2006 event: http://www.youtube.com/watch?v=AgLngG9rUychttp://www.youtube.com/watch?v=AgLngG9rUyc

[aliboy]

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Another idea for brakes is just the flinstones method . Just cut a hole in the floor and put your feet in to stop or alternatively just something that would create friction .

[woody]

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it was very unstable and buckled two of the 4 wheels.

Sling yourself LOW ,reclined with bum just off the floor....cut the frame and cant the rear wheels in a little at the top ....make a foot rudder bar to steer.
Edit :- A long hand tiller and foot operated brakes might be better ... a lot of probs seem to come with oversteer.

Come on your an engineer!

Or just get a racing wheelchair.

(Message edited by woody on March 31, 2007)

(Message edited by woody on March 31, 2007)

[woody]

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LOL ....A similar design at approx 4 mins in to the video didnt do very well!

His rear wheel buckled under the side strain before he crashed.

(Message edited by woody on March 31, 2007)

[ukrobotics]

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- The kart at 4mins into the video is my kart being driven by me!