Kustom Kruiser Roadster and disc brakes.

[kdubz954]

good day all, thank you for taking the time to read my post. have a few questions about a new build and super new to this. I picked up a Kustom Kruiser Roadster recently and am planning on electrifying it going to be using a Bafang midmotor i have laying around for it. Now currently it has coaster brakes in the rear with a 3 speed shimano IGH. The midmotor will negate the coaster brake in the rear. I picked up a S/A front hub that has a dyno and drum brake built in but am not sold on just front brakes. I have tested the frame and it appears to be steel (magnet sticks to it). my question is this in fact true and if so does anyone know if the rear seat stays can withstand the torque of disc brakes? Kicking around the idea of having a mount welded to the frame in the rear. Thank you in advance!

 

[twojs.bike]

Post a picture of the frame. I have seen people weld an extra brace by the dropouts to stiffen things up for disc brakes.

 

[kdubz954]

if this is not good i will try to take better/closer pictures of the seat stays when i get home

 

[Captain Awesome]

Post a picture of the frame. I have seen people weld an extra brace by the dropouts to stiffen things up for disc brakes.

This^

You can definitely add disc to just about anything. Some just require more creativity. Adding a brace is pretty common practice to keep the stays from flexing and or bending under the load

 

[twojs.bike]

You can also buy bolt on disc brake adapters. There are a few models, so it might be trial and error to see which works best on your frame. They are pretty inexpensive. You can find them on eBay. I bought the one below for less than $10. I have not tried it yet, but I think I saw the same one on a bike @OddJob built.

 

[OddJob]

Yes, twojs, I have used that mount on a couple different builds, both klunkers. They may need some tweaking and use of spacers (washers) to get a good line with the rotor, but they are very inexpensive and work for those of us who don't have a welder.

On this build in the photo below, Desert Sky, there is actually only a functioning disc brake in the rear. I just used a disc compatible front wheel from a cheap Goodwill bike buy to complete the look. A perfectly good front disc wheel for only $15.99.

It was a silver alloy color, painted it to match. Looks like it was meant to be there.

 

[kdubz954]

thank you all for the replies. definitely given me a direction to look!

 

[us56456712]

Im not a fan of disc brakes except for technical mountain biking. It’s like riding with a meat cleaver. People are getting sliced up with them, especially on road bikes. A knee cap was recently sliced complete off by a disc brake in a road bIke accident. Road racing has had its share of disc brake slices. No thanks.

 

[MattiThundrrr]

People are getting sliced up with them, especially on road bikes. A knee cap was recently sliced complete off by a disc brake in a road bIke accident. Road racing has had its share of disc brake slices.

Wow I had not heard that! A little research reveals that serious burns are happening too. I'm not convinced that it has a place in BMX racing either.

 

[RustyGold]

Discs are overkill for most applications...but, hot rodding is all about overkill.

If that pic goes viral, disc branding may become the next big thing! Looks almost Celtic!

 

[kdubz954]

thank you all very much and just to update. Got the front drum brake/dyno hub installed and with the motor cut off switch on the handles seems good so far. Here is an updated picture with new ape hangers and motor and battery installed.

 

[Starnger]

Here are my 5 cents.
Do not use those "adapters" posted up there, they will bend like tin foil under the torque generated by a heavy ebike.
I suggest you to use roller brakes. I run such a setup on my Project Firebolt build. They sufficiently withstand the load and are very easy and comfortable to use. Also they won't require a frame modifications of any kind.
Good luck with the build!

 

[kdubz954]

Here are my 5 cents.
Do not use those "adapters" posted up there, they will bend like tin foil under the torque generated by a heavy ebike.
I suggest you to use roller brakes. I run such a setup on my Project Firebolt build. They sufficiently withstand the load and are very easy and comfortable to use. Also they won't require a frame modifications of any kind.
Good luck with the build!

thank you very much and yes I was looking at them and honestly just looking at them thought better of it for the exact reasons you said. I have since installed a front hub w/dynamo and roller brakes and I also have installed a motor cutoff switch on the brake handle which kills power to the mid-drive and so far "knocks on wood" has worked out pretty well. It is definitely a different ride style than my super73 scout with dual piston hydraulic brakes. Those will look the wheels up and can stop almost on a dime. Just takes some adjusments in riding style is all.

 

[scubarunner]

thank you all very much and just to update. Got the front drum brake/dyno hub installed and with the motor cut off switch on the handles seems good so far. Here is an updated picture with new ape hangers and motor and battery installed. View attachment 218979

THIS! I have been looking around trying to formulate the recipe to put a similar bike together! I have a Slick Daddy that I want to electrify. I love how you placed the motor and battery!

Could you share the recipe that you used to put this together? Motor Kit? Battery?

Are you pleased with the performance of the setup? Any issues that you would work out in front of in the setup?

Thanks!

 

[kdubz954]

Hey SR thank you very much! Well a few things have changed since my last post. I will add some updated images to this reply. I am using a Bafang BBSO2B 750 Watt mid drive motor and a rear Shimano 3 speed internally geared hub. I had to add an eccentric bottom bracket adapter due to the BB Shell size. Included the link below for this adapter as the motor will not fit without it. Also I have upgraded to a 52 volt/ 30AH triangle battery with bluetooth BMS using samsung 50E (21700) cells. The BBS02B is a workhorse really and gets the bike up to definitely unsafe speed (35-36mph) especially with just the front brake. I have picked up a triple tree springer fork that has disc brake mounts for the front and will be switching the 3 speed IGH hub out with a 4 speed hub that has drum brakes in the back. I have also changed out the ape hangers as they were just too uncomfortable for me at my age and I love the new geometry and look with the mini moon bars. I am debating on upgrading the motor to a Bafang BBSHD from another build but want to upgrade the brakes first as this motor is almost double the power from the present one. The biggest draw back is the lack of stopping power.

If you should need any further advice or input please do not hesitate to reach out.

oh and to answer your Chain Guard question. I had to grind off the mounts in the front and havent really bothered trying to figure out a way to mount it back on. I may at some point in the future but honestly dont even really miss it.

BB Adapter-https://cycles.eco/products/eccentric-bottom-bracket-adapter?variant=32718842069074

 

[scubarunner]

Thanks for the detailed reply, link, and pictures! 36mph! WOW. What would that upgrade to a BBSHD get you to?

I spoke to another buddy over the weekend and he suggesting going to a drum brake in the back. Will start down that path next!

So cool, I cannot wait to get this together and start zipping around.

 

[kdubz954]

well honestly with the gearing the bike currently has the upgrade to the BBSHD might provide a little more speed but I am not sure. I am doing it because I have a trailer I haul occasionally to the beach and have burned out one controller so it is mainly more for durability than top speed. The BBSHD has rated amps at 30 or more amps where as the BBS02 tops out at 25 amps. I am hauling a cooler and such and my big ole fat ... up bridges and stuff so yeah. It more for durability than anything.