how to attach mounting bracket to mechanical brake caliper?

[Bluebeagle]

Hi,

I'm working on an electric go kart. I just got a kit with a mechanical brake disk, caliper, and caliper mounting bracket. I know you attach the bracket to your frame first so you can put the screws in and then slide on the caliper, my question is how to fix the bracket to the caliper when its on so it doesn't slide around. Suggestions appreciated!

thanks,
bluebeagle

ps here is a picture of the kit

 

[Denny]

You weld the bracket to the frame.

 

[Bluebeagle]

Thanks so much for confirming that! I kind of had an idea that was it but just couldn't find anyone to confirm it. thanks!

 

[Denny]

Glad I could help!

 

[Functional Artist]

Ooh, an electric kart

I wanna see more

Please share some pics

 

[panchothedog]

The caliper is supposed to float inside the bracket. The disk will prevent it from moving more than about a 1/32" in either direction. If you notice once caliper is inserted into the bracket it can't move forward or backward but can move side
to side. It is designed to work that way.

 

[madprofessor]

The caliper is supposed to float inside the bracket.

That's exactly the way it looks in the picture. Bracket still has to be secured to the frame though, welded, or drilled and bolted.

 

[Kartin’ kid]

I have the same caliper on my kart except it’s bolted directly to a vertical piece of metal that acts as the bearing hanger without the bracket. Is this a problem? I don’t have any pictures of the area and I’m currently traveling internationally so I can’t take any but I have attached a picture of the other side. The area circled in red is where the caliper is bolted to the frame. I bought this frame off of FB marketplace

 

[panchothedog]

I can't see why it wouldn't. Might wear one pad down a little quicker than the other. I think that's the reason why the caliper floats in the bracket, to keep even pressure from both sides. If you are using the system as designed, with the caliper IN the bracket it won't work unless the bracket is solidly attached to the kart, weather bolted or welded I am sure it makes no difference.
Just as an aside I only have this kind of brake on one kart and I am not impressed with it at all. Doesn't grab very good. O K for out in the desert, but
for street use almost not safe. Would like to hear from Kartin 'kid or
Bluebeagle or anyone else how does yours work. Doesn't seem to matter how hard you push on the pedal stopping power just not there.

 

[Kartin’ kid]

I can't see why it wouldn't. Might wear one pad down a little quicker than the other. I think that's the reason why the caliper floats in the bracket, to keep even pressure from both sides. If you are using the system as designed, with the caliper IN the bracket it won't work unless the bracket is solidly attached to the kart, weather bolted or welded I am sure it makes no difference.
Just as an aside I only have this kind of brake on one kart and I am not impressed with it at all. Doesn't grab very good. O K for out in the desert, but
for street use almost not safe. Would like to hear from Kartin 'kid or
Bluebeagle or anyone else how does yours work. Doesn't seem to matter how hard you push on the pedal stopping power just not there.

I’ll post the results as soon as I finish the build and get some road testing in

 

[Denny]

I have the same caliper on my kart except it’s bolted directly to a vertical piece of metal that acts as the bearing hanger without the bracket. Is this a problem? I don’t have any pictures of the area and I’m currently traveling internationally so I can’t take any but I have attached a picture of the other side. The area circled in red is where the caliper is bolted to the frame. I bought this frame off of FB marketplace

That looks more like it is a setup for a hydraulic disc brake than for a mechanical. The Airheart mechanical takes a totally different bracket so the caliper instead of the pistons will float.

 

[Kartin’ kid]

Yes, definitely. When I bought the kart it didn’t come with the bracket but was instead bolted directly to a section of the bearing hanger and so I was wondering if that was a problem but according to panchothedog it’s not

 

[panchothedog]

Mine is on a Manco Intruder kart that I bought just this last February. Other than a bigger engine ( predator 301 ) everything else on the kart looks stock and original, including the mechanical disk brake.

 

[Bluebeagle]

Wow guys thanks so much for the discussion here and sorry for not replying sooner. It appears notifications are off and missed these replies! Thanks Panchothedog, that makes way more sense because the assembly design would suggest it's supposed to float. We bolted the mounting bracket to the frame and will test that set up.

Functional Artist: Here's a photo of progress so far. Suffice to say we're aware of the clunkiness of our design (masterpiece!) but it's our first build and we used the materials and skills available to us, including the gifted motor you see. We're very excited to have the motor mounted and aligned with the sprockets and the chain installed.

 

[Functional Artist]

Kool creation

Let's start off with, what gear ratio are you running?

Also, it looks like it has some kind of a gear reduction
...if so, have any idea what reduction?

A ~2,000W motor ran @ 24V should draw ~80A (continuous) (The math 2,000/24 = 83.33A)
...& it may draw double to triple that (peak) (especially, like if connected directly)
(may have been really hard on your batt pack)

* Running a motor "direct" off of a batt pack is a bad idea (on a few different levels)
Here are some test's, I did a few years ago (direct with no controller)
FYI: A 1,000W motor ran @ 48V should draw ~20A (The math 1,000/48 = 20.83A)

 

[Bluebeagle]

Great video. That built in gear reduction you asked about is 20:1. We have a 45 tooth axle sprocket and 19 tooth motor sprocket. I wouldn't begin to know how to figure out what that amounts too. Thanks for the amp specs. We were woefully underpowered and subjected the batteries to significant current draw which likely blew the BMS on the LifePO4 batteries. Lots of steep learning curves here. In essence trying to power a Tesla with a 9v battery! I've since learned we will need on the order of a 24v 100 ah battery to sufficiently power this motor. That puts LifePO4 off the table so we will either go AGM 100ah battery pack or save this motor for something else and go for something more manageable. We don't need to go fast or for very long. If we could get 20-30 min. that would be great. Ultimately it's about the build and achieving some measure of success. I've guesstimated the cart will come in at about ~100lbs. with the current motor-probably 10lbs. less if we switch motors. And with the main rider, my son, ~125lbs. Based on a motor guide we could get away with 36v/500 watts on the low end and 48v/1000 watt on the higher end. Any more and I think we'd be wasting money with batteries in the mix. Any preferences?

 

[Functional Artist]

Thanks!

For a kid or young adult, I'd go with a 48V 1,000W brushed motor

Here is a video of an average size kart motivated by a 48V 1,000W motor (~$125.00)
...& powered by (4) 12V 12AH SLA batteries (~$100.00) ...& No BMS required

 

[Bluebeagle]

Ha! Nice ride! And thanks for noting the amp hours. That’s often left out of builds. Agree that would be the way to go! Just got the spindles back from the weld shop so will hopefully have some progress to post soon. Curious if you know the ballpark weight of your cart?
Thanks again for your help.

 

[Functional Artist]

Thanks! & your very welcome (teamwork)

I'd say probably ~125lbs
...or maybe ~250lbs with me driving

Torsk is another kart that I designed & built that's motivated by a 48V 1,000W brushed motor
...& powered by (4) 12V 15AH SLA's

Here is the build thread for the Torsk. It has lots of interesting info
https://www.diygokarts.com/community/threads/torsk-backbone-chassis-kart.38905/

...& here is a video of me & my daughter Desteny riding around.

I'm driving the Torsk kart & she is riding a little yellow/green kart I built for her before the Cotton Candy kart

 

[Bluebeagle]

Thanks! & your very welcome (teamwork)

I'd say probably ~125lbs
...or maybe ~250lbs with me driving

Torsk is another kart that I designed & built that's motivated by a 48V 1,000W brushed motor
...& powered by (4) 12V 15AH SLA's

Here is the build thread for the Torsk. It has lots of interesting info
https://www.diygokarts.com/community/threads/torsk-backbone-chassis-kart.38905/

...& here is a video of me & my daughter Desteny riding around.

I'm driving the Torsk kart & she is riding a little yellow/green kart I built for her before the Cotton Candy kart

Hi again FA,

Unfortunately the custom NiCd batteries that were specific to our motor have reached end of life. So rereading through your comments a couple things to clarify. According to the formula you mentioned-Watts/Volts= Amps you estimated we'd have ~80 amp continuous draw for our ~2000w/24 volt motor. Matching a battery, we would presumably need something in the range of (2) 12v/100ah batteries. Looking at the specs for your Torso, you use (4) 12v 15 ah SLA's for a 1000w/48v motor. However, using the same equation/ 1000/48, you would draw ~21 amps continuous. The slightly lower 15ah batteries clearly work for you so could you help me resolve this discrepancy so we can get "just enough" battery thereby reducing our cost. And again, if we got 20-30 min. we would be very happy!

To further clarify, what I'm trying to understand is what seem to be two aspects of battery power 1. related to the ah(capacity) as it relates to runtime and 2. the potential for the battery to deliver current. Example; reading through r/c forums and videos, a model airplane will have a ~14v/ 2200mah lithium ion battery that can delver 50 amps to a 700w motor. The equations to determine amp draw are the same you've listed here watts/volts. 700w/14v = ~47 amps continuous draw. What's fascinating is the battery for this setup. To determine the battery amp rating in the video he uses the equation mah x C rate/ 1000 (2200 x 25/ 1000= 55 amps) to give you the amp rating on your battery. This means a 14v/2200 mah or 2.2 amp battery can deliver 55amps!