RFC: Nexus 3SPD Coaster Brake Hub - Convert to Freehub

[mwkeefer]

Hello all,

I just found a good source of 26" rears but they sadly had the coaster brake version of the 3SPD Nexus.

In teh good old days you could disable / remove the Coaster Brake mechanism (not the arm) by opening the wheel and removing the Brake Pad Unit (circular little bugger) and replacing it with hard spacing (washers) and perhaps a spring to eliminate any wobble (I always used a length of pipe - but that's me...

So does anyone know if this is feasible and similiar with a internally geared hub as I would like to remove the coaster pads unit all together to prevent possible friction heat building and intoduce true freewheeling hub.

Buying a new hub for 26" is not an option - after this its a full wheel build but I can get these for a reasonable price in fair quality so if they can be modded correctly - I'm crazy not to!

Thanks in advance for any help or suggestions!

-Mike

 

[johnrobholmes]

The coaster mech should be very similar, although getting to it not so easy. I haven't taken apart the nexus before. Maybe I will see if the LBS has any laying around today, I am going in to build some bikes for them.

 

[mwkeefer]

John - thanks I kinda figured it was going to be hard to get at, and harder to reassemble
-Mike

 

[Rayy]

I played with a Nexus 3 coaster hub last year also with the intent of making it freewheel. I took off the nuts on the non-drive side, the end cap popped off and I pulled out the brake shoes then reassembled. It seemed to function as a normal freewheeling hub, but I did not actually try it on a bike. I remember it didn't take very long and it wasn't very difficult.

If you get this done, let me know how it works.

 

[mwkeefer]

Depending on the actuation method used by the brake unit - this could work fine (providing without the shoes the unit won't go Metal to metal)... I'm fairly sure that's why a spring is always used...

Most coaster brakes have shoes which apply force on the outter housing of the hub (from the inside obviously) the trick is which way they actuate this... If it's by expansion then back pedaling could still extend the pad seats and possibly cause metal to metal...

Placing the spacers and spring in, in place of the actual brake unit solves this problem 100% cause there is nothing left to expand into the hub cylinder.

In case your wondering I've been doing my homework but it seems nobody has done this yet to any internally geared hub with a coaster brake...

I'm beginning to think maybe just leaving the brake isn't such a bad idea anyway... I don't need reverse, they are fairly weather and environment proof and with dual left input isolation, back pedaling won't / shouldn't engage the brakes (since it only seems to engage on the drive side) as it wil be isolated from the motor sprocket which won't be freewheeling and thus would cog in reverse but it would be freewheeling forward - if that makes sense?

I am hesitant to disassemble the unit yet - I want to learn more first, wouldnt' want valve bodies and bits and pieces coming out on me (I disassembled a TH350 transmission once, just once - never got it back together!).

-Mike

 

[Rayy]

For this Nexus 3, it didn't look like the camming action (from pedaling backwards) would expand the brake shoe actuator enough to cause metal to metal contact. I also didn't find any spring so nothing popped out and I didn't need a spacer either with just the shoes removed. It was just 2 nuts, endcap, remove shoes and replace in reverse order. The hardest part was setting the bearing clearance.

Rayy

PS. I think there was a C-clip as well, but nothing a screwdriver and pair of needle-nose pliers wouldn't take care of.