midcitybikesbr

While searching Craigslist nationally for an Oset 16 I ran across this cool custom 12.5. More of a MX type build but real neat mods. http://sandiego.craigslist.org/csd/mcy/4232019583.html

Next up is the front disc brake setup. Need to make this stock Oset rim and Shimano MTB hub into a wheel. I guess I'll fab up some aluminum spokes and find a really good aluminum welder. I hear there is a race car radiator fab shop in the area.

Took me two days to get the 2.75 knobby rear tire mounted. It isn't much wider than the 2.4 but it is a substantially heavier, thicker tire and was MUCH harder to put on a rim than the stock size.

Finaly got a pic of the sprockets to upload. They started at 420 grams. First one I did weighs 310g, it is on the right mostly out of frame in this pic. Friend of mine wanted to try and he did the one in the middle, 240g! The one on the left is his second try which was not as good, 280g.

Got the second wheelset with the motard tires mounted.

Didn't put on the Kelly controller/magura throttle/new wiring harness yet as it is my weak point and was taking too long, Really want to shorten all the wires I can and hide all wires and battery. Just ordered some wheels from Oset and a set of 12.5x 2.4 street tires from monsterscooterparts.com to use as motard wheels on the mini road course. Got an extra front to dissasemble to use the rim to weld up a mag style front wheel with a disc mount hub. The Avid front brake system is here and I have a disc mount ready to weld to the fork. Doing the wiring and front brake will probably be where I stop on this bike. He is looking big on it already, I need to start saving for a 16. Still wish I could get that Mr Tao motor and some aluminum forks on it, get it near 25 lbs would be cool.

35lbs 2oz as ridden.

Those are the stock swing arm pieces I just ground off the kickstand mount and brake cable stay and machined out the insides a bit. Still trying to get that brushless motor, using a different browser I was able to get much further along in the order process. Doesn't want to take my money but I will keep trying. Bike is all painted and just waiting on me to sort the new wiring. Just got the new Oset upgrade footpegs in. Tasty cast stainless is top grade stuff and worth the extra 1.5oz each IMO.

So I decided to bite the bullet and try to order the motor from Mister Tao semi legit looking site. Item no longer exists!!! Tried using their search but no go. I really like what the guys are doing with big outrunners over at endless-sphere.com, just found that message board, are there any other boards you know of that might interest me? Where are they talking about those brushless motors and controllers you linked me?

While I had the thing apart I couldn't help but trim away some of the excess metal from the swingarm pieces. Stock: (minus kickstand mount) I mostly cut away the motor mount plates. Removed old brake stay and welded on the new brake mount, cleaned them up in general. I haven't been doing any of the welding on this project. The mechanic at my shop is a pretty good TIG welder, way better than me. I have done all of the cutting and bending though. Just teaching myself to do this type of fab work, and this bike is the coolest thing I have done. The rear disc conversion isn't too difficult to do. Just need a freewheel to disc adapter, it's the red thing in the pics, and a slotted mount welded on. I put a 2mm bicycle cassette spacer behind the disc adapter for better fit. Swing arm pieces are ready to paint, reassemble bike, Done until I pick a motor.

Thanks for the motor/controller leads, both are very affordable compared to the stuff I was looking into. I have always wanted more programming options than the Kelly brushed controllers I have. Someone yesterday was telling me about all the options on their R/C planes controller and I guess I need to step up to brushless to get that. I was hoping for more info on that motor like rpms etc, can you point me to the kit this motor is a part of? This is lifted directly from the page the motor is on: Tips: OUR baby are many kinds, different packaging, singlet, so shipping costs will be based on the quantities and types of pro-purchased accounting pro who shot the baby before contact with the store first estimated freight, such as after delivery, combined with the actual shipping costs Duotuishaobu. Your parents are aware of.Logistics of the baby, transit time may be longer, please be patient, inconvenience, please understand.

I didn't do a before and after weight of the sprocket but it feels like it lost about 30-40 percent of it's mass. The frame mod shaved about three lbs off. Kickstand and mount about a pound. Rear brake mod is going to be good for a few ozs as well. Bike came out the box at 51 lbs, weighed 40 when I started this last round of mods, hoping it weighs about 35 when done. Just need to finish the rear brake mount and paint everything and I'll put it back together and weigh it. Getting that boat anchor of a motor off the bike is next. Thanks for the motor tip, I like the weight and power is about right for this bike, hate to have to buy brushless controllers though.

The AmpFlow is the highest perforance brushed motor I could find. Do you or anyone have any suggestions for motors for the 12.5? Not opposed to brushless. I got some new endmills and drillbits today so I started the rear disc caliper mount and drilled out the rear sprocket, that thing was heavy. Need to paint it gold.

My favorite motor, have been wanting one for some other projects for a while, is the Amp Flow A28-150. Weighs 3.8 lbs rated at 2250watts 6000rpm $300. Stock motor: Weights 7 lbs rated at 500watts 2600 rpm Would be so much power that the rpm wouldn't matter. All of the smaller motors that don't make as much power also spin much faster and would have to be geared down increasing the weight and complexity. I would just go for the AmpFlow and build a new swingarm around it. I built 20" freestyle BMX bike with the 900 watt variation of the stock Oset motor run at 48v so 1800 watts. Weighed 35lbs, went 33 mph, was built to dirt jump and ride at the skatepark (built to crash). It's biggest problem was the heavy motor and I have been wanting to redo it with an AmpFlow motor just haven't ordered one yet, now I need two. Kelly controllers in the bikes now should work fine on the AmpFlow motors and are good for 100 amps (at 50v that is a lot of power!) Link to gallery of the E-BMX http://imgur.com/a/j9kBx It is a 2007 Terrible-One Garret Brynes frame with a 21.25" top tube (they used to be made here in town). A little long and overbuilt so seemed perfect for this. Foot pegs from XR50 aftermarket.

I didn't realy think about the lack of a bash guard but we do mostly MX type freeriding around the yard so the weight loss should be more important. I HATE painting but wanted it to look good so it is taking forever. I've put nearly as much work into the paint as I did the frame mod. Problem: I can't stop making mprovements. I removed the kickstand and mount (this is a performance vehicle). Rear disc brake is going on now and while I had the swing arm apart I figured I'd cut away some extra metal. I'll post pics once the disc caliper mount is welded in place. The two biggest problems this bike faces are the 6lb motor and probably 7lb fork. If I go any further than just the brake on the back end it will mean a total scratch up swingarm and swingarm mounts to house the new motor. Fork is almost a bigger issue as there is nothing that will bolt on this small of a bike. Cutting a real fork down doesn't look to easy nor does making one from scratch. I do have an old Hanbrink gravity bike fork, double triple trees, made for a 20" wheel, 20mm front axle. Cutting it down is possible but my machine skills are not up to doing internal threading so would need a pros help. If I did the fork and swingarm this thing would be well under 30lbs.