argggh...i'm so mad. Remember, measures twice and buy once.

[ngocthach1130]

So...about a week ago i decided to lower the rear by changing the wheel from 26" to 24". I figure it was an easy task. Planned out everything. ordered 24" rim,spokes , tube, tires. Rim brake won't work anymore so ordered disk brakes. Front and rear just so they match. OCD can be annoying sometime. Got new fender to accommodate larger width tire too. Got double leg kickstand cuz with smaller wheel the bike will tip over because the current kickstand is too long. New rear rack so some of the battery weight will be put on the rear swingarm instead of seatpost. Everything came to about 300 dollars in parts. Both brakes alone was about 100 something already.

Stuff came yesterday. I was so gungho about it i spent the day removing wheel, rim spokes. Ugh trueing a wheel is a bitch. Got it to wobble as little as possible but still pulsate. Respoke to new wheel and mount on the Schwalbe big apple. Then it hit me. Damn Schwalbe was so big even though it's 24", fully inflated it is almost the same as my 26" knobby. Okay so no ridn' low yet. I also notice i somehow dished the wheel offset to the right a bit. *sigh* got to fix that later. Installed other stuff, rack, fender, kickstand. I was going to leave the brakes for last. Took off the front disk brake off. Mount the Avid BB5. No problem. Then i move to the rear and OMG damn caliper won't clear the hub. I don't have enough clearance for disk. Fack fack fack. It never occur to me disk brake won't clear the damn hub. Shit, now i'm stump. Either i work up a huge rotor and custom mount for the disk like hal9000 did, which mean mucho money, or i need some resistive brake system which short the motor to some coil. i could run with front brake only. But dunno if i have the balls too since i ride average 28mph down a hill on the way to work everyday.

Moral of the story is. Don't order all the shit before you measured everything, then measured again. Crap.

 

[Link]

Pwnt.

See if you can find a smaller caliper...?

 

[ngocthach1130]

dunno. I measured and from the inside of the dropout to the face of the hub is less than an inch. 3/4th of an inch to be exact. Shit i should have measured before.

I think i have a plan though. I'm going to have a huge torque plate made. I will bolt the torque plate to to the frame using those preexisting disk brake mount. Then the torque plate will extend a little bit and i'll have new disk brake holes to mount the disk brake. Might need a slightly larger rotor. But the nice thing is that instead of being mounted behind the inside of the drop out which shove the caliper closer to the hub motor the disk brake will mount to the torque plate so it will be on the same plane as the dropout. I can clear and side plate of the hub.

Think i'm going to drive to school and go to the machining center see if i can get some prof to mill me some freebie LOL. I'll tell them it's for a school project or something.

 

[Link]

Hmm, that is a little small. I don't know of any brakes that'll fit. :?

You should be fine with only a front. I had to go with only a rear v-brake for a while.

Might wanna try Fechter's regen/plug setup? :wink:

 

[Sturdly]

I've been doing my research to possibly upgrade from my current 250w BB drive to a BMC rear hub motor. One of the issues is the disc brake fitting. The 160mm size, which I currently have on my ride, seems problematic. There are adapters for the 51MM IS caliper to 51MM IS that will allow the fitment of a 203MM disc. That will move your caliper about 1 inch further out from the axle center. However when you add up the cost of using the existing caliper plus the adapter and larger rotor it is just seems to me like a better deal to go with the 203MM BB7 which includes the adapter.

Kind of stuck you are with the 24 inch wheels as for the V brake option on the rear or the Xyster V brake/ disc brake on the front combo. If an extra inch of caliper clearance will give the clearance needed my suggestion is to return or Craigslist the 160mm BB5 and get a 203MM BB7.

Good info to share so others won't have to learn the hard way.

 

[Ypedal]

How many mm's do you still need ?

You have plenty of axle threads left, can you strech the frame by adding spacers to the inside of the frame..over the axle ?

You don't need alot of extra room.. it's supposed to be a tight fit ! + or - a few millimeters.

The caliper bolts to a plate with egged holes.. loosen those bolts up and push it as far back as you can as well.

 

[Wile E. Coyote]

This may help you out. I purchased one off e-bay and it works great.
View attachment 1

 

[monster]

you could get a front fork with both disc brake and rim brake tabs. then you will have two brakes.