Kart build- brakes

[denhammotors]

Well, I am new to this forum, but decided I would post a question about my go kart build (in the style of a vintage car).

I have driven the kart long ago in August, but I had built the thing way before my mechanical and engineering skills began to take root. Everything on the kart then was done in the worst, cheapest way possible and I had obviously not done my best on building it. The steering was oversensitive as I had no idea about steering angles when I built it last year.
But lets get to the question. The brake I used was a mechanical disc, with what you guys would refer to as "the ****ty caliper", working better on minibikes. The brakes never really worked I also never like using the extremely long brake rod (about 6 feet or so) Way too much stretching and bending. This December I had began to rebuild the kart to make it a lot nicer and better to drive. I purchased these two drum brakes (not band) that I will use on the front wheels. http://www.bmikarts.com/item/Internal-Expanding-Brake-400257-5956
Does anyone here know about how powerful and effective these brakes are?? Also, Why do karts never seem to have front brakes??? It there something horribly wrong with them being used on karts? Anywhere here are some specs on the kart
Harbor Freight 6.5HP clone engine
#420 chain, centrifugal clutch
20" wheels.
No time for pics right now but will post some tomorrow.

 

[Russ2251]

Why do karts never seem to have front brakes???

They aren't necessarily needed. Sometimes 1 wheel braking is enough...assuming it is a dead axle.

 

[denhammotors]

It's a live axle, actually. Just never liked disc brakes.

 

[Russ2251]

I use a single drum brake on my setup which is live axle.
Disc would be overkill as the mechanical drum easily locks up, 'as is'.
I can stall both engines at something close to 50mph.
However, my kart only weighs 138lbs.

 

[denhammotors]

The kart would probably weigh close to 200-250 lbs when finished. I had a disc on it before, but there was absolutely no braking power. It would only be stopping the kart from 35-40 mph top speed, though.

 

[jman231994]

20" wheels :O what gearing are you gonna run?

 

[Jake.B]

What about hydraulic brakes? You can get them cheap of a parted out dirt bike or quad. I hit about 65 MPH on quad and i can hit the brakes and if i get traction i stop in probably 5 seconds and with me on it it probably weighs around 430. Live axle one brake, 2 up front. I imagine on a go-cart it would work perfect.

 

[trebormacleish]

I would love to see some pics of this machine. sounds very interesting!!

 

[denhammotors]

Well, right now it looks nothing like a go kart, so you wouldn't know what you're looking at if I showed you pictures. I'll post some later anyway, but I think I just stick with the drum brakes.

 

[denhammotors]

20" wheels :O what gearing are you gonna run?

6:1. I know it's way too high of a gear ratio for its weight, but I hope to get a torque converter when it's all finished.

 

[denhammotors]

Some photos. Brake assembly, one of the tie rods, the frame of the seat (from a folding chair), and one of the axle hubs that I made to weld onto the hub of the wheel. Not tightened in the photo, but I think I may want to put some rubber spacer between the 2 flanges to act as a "shock mount". The last picture is a big mess on my workbench.

 

[r_chez_08]

That's cool! I like the bike wheels, and how you have mounted them, and the way the new brakes are mounted.
I personally like my hydraulic disc brake a lot. Single brake, 18" wheels, 40mph downhill, no problem

Dual drums should be good though. I expect you will have more than enough stopping power.

 

[kaymo]

i like the front brakes. alot. i would love to figure out a way to do better brakes on my cart (i have a worn out band brake) and front brakes sounds like it could be very nice for when you are trying to drive it like your hair was on fire and want to keep the rear end spinning but be able to slow yourself or help alter your course.

 

[denhammotors]

Some more pictures. I welded on the new engine mount (1 1/4 inch angle). Plenty of room to get the oil drain undone, which was a major flaw the first time I designed the kart. I know some of you are welding critics, so I got the best picture I could of one of my beads (HF 120 amp stick) Still can't decide on whether or not I want to make a jackshaft or keep the 6:1 straight chain drive. If I do keep it like that, I would need to make a spring-loaded tensioner where my finger is in the photo. I really want to have the project finished soon, because I don't like the idea of a non-running vehicle taking up a lot of space in my already crowded garage. (No, they're not all my bikes, but the green KE100 is mine.

 

[denhammotors]

Small update, but finished the steering except for the precise alignment. I was just waiting on some exchanged ball joints from McMaster-Carr. I originally ordered some left-hand thread rod ends, but now there are all right-hand thread. The tie rod ends are spaced out with some rubber bushings (3/8 ID hose). It seems that the Ackermann angle is more apparent when turning left.

 

[ghostdog]

I have front brakes on my go kart.

The kart I have came with front brakes but I hadn't bothered restoring them because I needed to more than likely change the front calipers and buy a bigger MC (more $$$).

I thought adding brakes to the rear might be sufficient so that's where I started. Once you got moving though it was just too much weight to stop with one caliper.

A new master cylinder was added in the original location and that powered all 3 calipers (2 front, 1 axle). It made a huge difference over just the axle.

I would have to say if it didn't already have this setup for disc brakes I more than likely would not have bothered.

I wonder if anyone has ever done a dual rear disc brake configuration on a live axle.

If you like I could take a picture of my front brakes later.

The spindle is like this in front

Link

Calipers are like these:

Link

 

[klicky96]

In the picture with your finger holding the chain off of the tubing, you are better to go below the bar, not above it, for many reasons. One major reason that you would like, would be that there would be more room to put a spring-loaded tensioner on the bottom than the top because, by the looks of it, there is no space at all.

 

[theo]

Can you move the rear angle iron back so that it just clears the axle sprocket. Then make a motor mount plate with oval mounting holes, now you can adjust the chain by moving the engine forward. Weld to the engine mount 2 extended nuts now you can push the engine back by turning in the bolts evenly.

 

[klicky96]

Can you move the rear angle iron back so that it just clears the axle sprocket. Then make a motor mount plate with oval mounting holes, now you can adjust the chain by moving the engine forward. Weld to the engine mount 2 extended nuts now you can push the engine back by turning in the bolts evenly.

very good idea, easy too.

 

[denhammotors]

I tried to keep space between the engine and axle as much as I could. I really wanted room for some other type of drivetrain, like a torque converter. The centrifugal clutch and chain drive is only there until I get this thing going. In terms of the engine mounting, I didn't want to make it too complicated. I plan on making some sort of axle adjustment instead. After all, there are no brake discs and calipers to worry about when moving the axle.