Drum to Disk brake conversion - help!

[fodio]

I have a Viper STX with a 4 1/2" drum/sprocket and want to upgrade the brakes to disk (see image).

I'm thinking in this option (with the right hub):

http://www.ebay.com/itm/Footbrake-M...Parts_Accessories&hash=item3381a9d116&vxp=mtr

I would like your opinion, specially if the ebay option is significantly better than the mechanical ones like:
http://www.ombwarehouse.com/Posi-Stop-Disc-Brake-Assembly.html
http://www.mfgsupply.com/gomini/gominibrakes/gominibrakesdisc/4-9306-manco-9597.html

 

[Half-breeder]

W/ my conversion of brakes, I went w/ the last link option (Mechanical disk). It stops my 16" wheels at 50mph quite nicely. Just be sure when mounting a disk brake assembly, you take into account that one of them 'should' be floating. Either the brake caliper's mount or the disk. On mine I firmly secured the caliper and got the hub for the disk that was floatable(not secured to the axle/shaft and able to 'slide')

 

[supermanotorious]

so Half-breeeder, the caliper keeps the hub/disc combo in place then? how do you keep the axle key from sliding out of the hub?

and why does BMI want so much more for THIS? I assume for the eBay kit, you'll still need a reservoir tank?

 

[Half-breeder]

so Half-breeeder, the caliper keeps the hub/disc combo in place then? how do you keep the axle key from sliding out of the hub?

and why does BMI want so much more for THIS? I assume for the eBay kit, you'll still need a reservoir tank?

I personally use zipties to retain the key. But they sell retaining rings keyed.

 

[ML-TOYS]

Or you can use hose clamps

 

[mckutzy]

Hose clamps, zip ties, locking collars, they all work.
If floating the disc, lightly oil the hub on the shaft, so it don't seize and helps keep moisture out.

 

[Young One With A Manco]

Not trying to thead jack, but whats the difference between the ebay, and the bmi option. I know generally the chinese parts are pretty awful, but what actually is the difference?

http://www.ebay.com/itm/Footbrake-M...Parts_Accessories&hash=item3381a9d116&vxp=mtr

and why does BMI want so much more for THIS? I assume for the eBay kit, you'll still need a reservoir tank?

 

[Half-breeder]

Not trying to thead jack, but whats the difference between the ebay, and the bmi option. I know generally the chinese parts are pretty awful, but what actually is the difference?

The ebay one is a 'universal' setup (for pit-bikes)... where as the bmi one is setup for specific karts, supposedly bolt on, no fabbing necessary.

 

[Young One With A Manco]

Not worth it for +$60 in my opinion. Just my $.2

 

[rmm727]

Not worth it for +$60 in my opinion. Just my $.2

I'm with you on that. They both are Chinese setups.

 

[fodio]

The ebay one is a 'universal' setup (for pit-bikes)... where as the bmi one is setup for specific karts, supposedly bolt on, no fabbing necessary.

Not worth it for +$60 in my opinion. Just my $.2

I'm lost with your opinions. Please confirm if I'm understanding you correctly.

Both seem to be Chinese parts, not big difference price/performance except the ebay one requires an adaptation.

But I stil have a question. The ebay one is hydraulic and the others are mechanical. I guess the hydraulic one requires less effor on the pedal to stop the kart.
Could you please clarify?

Are there a better options?

 

[supermanotorious]

Fodio, hydraulic brakes are more powerful and efficient than mechanical ones but are more complicated, more expensive, and require more maintenance.

Also, I'm communicating with the eBay seller to find out the bolt pattern for the rotor. That setup won't do any of us any good if we can't put a hub on it. I know some of you have fabricated hubs but that's something even I wont take on.

Not trying to thead jack, but whats the difference between the ebay, and the bmi option.

You're not thread jacking, these are great questions which will help fodio make a decision.

 

[fodio]

...hydraulic brakes are more powerful and efficient than mechanical ones but are more complicated, more expensive, and require more maintenance.

Crystal clear! Thanks!

...I'm communicating with the eBay seller to find out the bolt patte rn for the rotor. That setup won't do any of us any good if we can't put a hub on it...

Don't expect great and clear answers from rose326a (ebay vendor), I asked if the reservoir was included and got this "great" answer: "It is a replacement part. Please verify your used part matches this one and read the return policy before you bid on it, thank you". With this kind of replies I won't experiment with this vendor. Could you imagine trying to get spare brake pad in the future?

There are several Chinese motorcycle parts shops in Costa Rica, I'll try to stop by and find out the details of the kits they carry. So far I know they have all the parts for about $80 and they have several rotors.
What will be a good bolt pattern for a 1" live axle? (I guess 3 1/8")

 

[fodio]

Not worth it for +$60 in my opinion. Just my $.2

What would be your recommendation then?

 

[supermanotorious]

the hub bolt pattern entirely depends on the rotor's. THIS hub works with THIS rotor for example (and is 3 1/8" just by coincidence).

 

[OzFab]

I assume for the eBay kit, you'll still need a reservoir tank?

I asked if the reservoir was included and got this "great" answer: "It is a replacement part. Please verify your used part matches this one and read the return policy before you bid on it, thank you".

That type of setup doesn't have an external reservoir, it's a sealed system...

One problem you will have with it is, due to the design, the master cylinder needs to be mounted vertically for best results, mounting horizontally may cause brake failure...

My 2 cents: Go hydraulic! Some cheap, chinese setups work quite well; for my kart, I modified a front M/C as the sealed reservior sits above the M/C...

The biggest problems you will face is sourcing a hub to suit the disc & your axle & you will need to fab a custom bracket to mount the caliper

 

[supermanotorious]

Here is my conversation with rose326a so far

Dear supermanotorious,

Sorry I do not have its size so far, today is Sunday, and Monday is a holiday then I will check Tue. at our warehouse if possible,thanks

- rose326a


From: supermanotorious
To: rose326a
Subject: Re: Details about item: supermanotorious sent a message about Footbrake Master Cylinder Rear Brake Pads Disc 110cc 125cc Dirt Pit Bike #221218722070
Sent Date: Oct-12-14 09:27:05 PDT

Dear rose326a,

Thank you but those are not the specifications I was asking for. What is the bolt pattern? What is the diameter of the circle on which we find the center of each of the 4 bolt holes?

- supermanotorious


From: rose326a
To: supermanotorious
Subject: Re: Details about item: supermanotorious sent a message about Footbrake Master Cylinder Rear Brake Pads Disc 110cc 125cc Dirt Pit Bike #221218722070
Sent Date: Oct-11-14 11:12:04 PDT

Dear supermanotorious,

black Wavy Rotor 190mm ( 7 1/2inch ) Rotor ( disc brake),The outside diameter is 7 1/2 inch ( 190mm). Thick 3mm. Offset 11mm(the space between two surfaces).The space from the mounting bolt hole center to the mounting bolt hole center is 66mm.

thanks


- rose326a


From: supermanotorious
To: rose326a
Subject: Details about item: supermanotorious sent a message about Footbrake Master Cylinder Rear Brake Pads Disc 110cc 125cc Dirt Pit Bike #221218722070
Sent Date: Oct-11-14 07:56:26 PDT

Dear rose326a,

What is the bolt pattern for the disc?

- supermanotorious

 

[Young One With A Manco]

What would be your recommendation then?

I meant ebay over BMI. Like i would go with Ebay because it's $60 cheaper than BMI and thats my $.02. Sorry if I confused you.

 

[Unit 91]

W/ my conversion of brakes, I went w/ the last link option (Mechanical disk). It stops my 16" wheels at 50mph quite nicely. Just be sure when mounting a disk brake assembly, you take into account that one of them 'should' be floating. Either the brake caliper's mount or the disk. On mine I firmly secured the caliper and got the hub for the disk that was floatable(not secured to the axle/shaft and able to 'slide')

not trying to hijack, but why excatly does one of the items need to be floatable? i would assume its to make sure the pads and rotors hit evenly on both side am i correct in that assumtion?

 

[fodio]

not trying to hijack, but why excatly does one of the items need to be floatable? i would assume its to make sure the pads and rotors hit evenly on both side am i correct in that assumtion?

Yes, your assumption is correct! If pads / rotor contact is not perfect braking efficiency is impacted.