Brake calliper rubs on the hub motor

dumsterdave

New Member
i got a new hub motor and i tried to install my existing rotors to it, but the space between the rotor and the hub is too small so my calliper rubs on the hub.. .i have 160mm rotors and avid juicy 7 callipers on a 2008 trek fuel ex 9
 

JoePah

Well-Known Member
Post a pic if you can.. The profile of the hub casing now contacts your brake caliper.

I see two options:

1 Mount a larger rear rotor, 180mm, and install a caliper adapter for the larger rotor.. You can position your caliper up 10 mm and see if that would clear the motor housing interference.

2 File the interference off the caliper, if it is a slight rub.. If you're just removing some minor material off a corner of the caliper casting it won't affect performance.. beware this does run the risk of ruining your caliper. Do not use a grinder, as they cut thru aluminum like butter!
 

dumsterdave

New Member
i bought a 203mm adapter, but then i discovered that my bike wont fit anything larger than i already have.
I will probably try to file some of the calliper, but i am a bit worried that i will file into the "juicy" part and the brake fluid will start pouring out.
Anyone know of any cheapish disc brake kits that are thin?
 

JoePah

Well-Known Member
That is a bit of a pickle.. Can't upsize the rotor, can't offset the rotor. That caliper looks pretty thick compared to my Tektro drago's.

The rub doesn't look too bad...If you have an orbital sander I'd try that with some 220 grit. Or a file.
 

J.R.

Well-Known Member
Thanks George, that's good information to keep in my back pocket. If necessary I'd go with a mechanical back brake and hydraulic front. At speed most stopping power is in the front anyway.

There's also cable actuated hydraulic brakes, where one can use standard cable actuated motor inhibitor levers that come with many kits, yet still have powerful hydraulic disc brakes. They may not work for narrow clearance. So many options available to fit most situations one may encounter these days.

Blog
https://www.cxmagazine.com/trp-hy-rd-hydraulic-disc-brakes-review-road-cyclocross

$50.70
http://www.tomtop.com/cableactuated...C-MRZiEfAbuEx3XNkK_3FLHcS4wzIRH-J0RoCurTw_wcB

Sale $119.99 (reg $149.99)
http://www.backcountry.com/trp-hy-r...ferralID=4e51c71b-1f1f-11e6-a988-005056946dac
 
Last edited:

JoePah

Well-Known Member
yeah that won't work. NO clearance and no easy way to move the caliper outboard.

Just need a thinner caliper casting, or sand it.

Can you measure the amount of interference?
 

dumsterdave

New Member
It worked! I ended up putting 3mm of spacers between the rotor and hub and then another 3mm of washer between the rotor and dropout.. everything fits perfect now.. I had to stretch out the chainstay/dropout a little (3mm), but i think its all good now. This is before i put them on.. if you want i can take another photo to show you the "after"
spacers.png
 

George S.

Well-Known Member
Thanks George, that's good information to keep in my back pocket. If necessary I'd go with a mechanical back brake and hydraulic front. At speed most stopping power is in the front anyway.
I can sort of make a matrix of problems, advantages, limits with the Bafang MD's, the DD Goldens, and the geared Macs. The mid-drives have wear, chainline, and shifting issues. The Macs are fat, but light, so disk clearance problems are common. The Goldens are thin and heavy, are shipped with rim and disk capability. But 20 pounds is a lot weight.

I think customer service in DIY is getting a lot better. With my Mac there was rubbing. I figured I needed a disk spacer and just couldn't find one. @Court J, with his machine shop, sent me a couple. I tried the thin caliper and it's pretty basic. Paul at EM3ev didn't quite lay out the issues, when I bought the motor. Paul had spacers, but slow shipping from Hong Kong. I think one guy wanted $15 for 1 mm or .5 mm.

Once you get it done, it's done, but issues like this tend to scare people off.

I wonder if this guy is in the UK and could just go to the shop? I bought some tires from Chain Reaction, Marathons, and the price was great, fast shipping. Glad he could find the part.
 
Last edited:

dumsterdave

New Member
I can sort of make a matrix of problems, advantages, limits with the Bafang MD's, the DD Goldens, and the geared Macs. The mid-drives have wear, chainline, and shifting issues. The Macs are fat, but light, so disk clearance problems are common. The Goldens are thin and heavy, are shipped with rim and disk capability. But 20 pounds is a lot weight.

I think customer service in DIY is getting a lot better. With my Mac there was rubbing. I figured I needed a disk spacer and just couldn't find one. @Court J, with his machine shop, sent me a couple. I tried the thin caliper and it's pretty basic. Paul at EM3ev didn't quite lay out the issues, when I bought the motor. Paul had spacers, but slow shipping from Hong Kong. I think one guy wanted $15 for 1 mm or .5 mm.

Once you get it done, it's done, but issues like this tend to scare people off.

I wonder if this guy is in the UK and could just go to the shop? I bought some tires from Chain Reaction, Marathons, and the price was great, fast shipping. Glad he could find the part.
Not sure if this was in reference to me, but no im not in the UK. I live in copenhagen denmark and there are more bikes here than people. Most city blocks have multiple bike shops, but a lot of them are quite limited in what they carry. The bikes here are almost all internally geared hubs (non-electric), so finding parts for derailers and disc brakes is a bit tougher, but everything is here. I ended up going to the bike shop across the road from me and they just gave me a handfull of 1mm washers that ended up working fine.