Okay, thanks. Both chain and "seat" stays on mine also have S-bends.knutselmaaster wrote:No 135. It didn't cost much effort to put it in, maybe because after the "S-bent" rear stays.
Thanks for the pointer. I hadn't seen that. I especially like the simplicity of the "string & ruler" method of checking symmetry.Ozzzz wrote:I used sheldon browns lever method to bend my fat bike steel frame, one side at a time.
Indeed. The Sheldon Brown method uses the integrity of the front triangle and the floor to apply force to the two sides independently, which is great on a rigid frame; but trying to apply it to my frame, with "seat post" being independent of the front triangle, means that it would be the pivot points that would take the strain and whilst the main pivot can probably take it, those by the spring unit won't.Alan B wrote:But the problem with all these solutions is they bend the bike unequally, since the two sides never have exactly the same bending characteristics. There is a need to bend each side independently, which is more difficult.
Interesting.Alan B wrote:If you lay the bike on it's side and use the scissor jack against a long wood block on the side against both the chainstay and seatstay tubes at about the tire, and a wire from the dropout to the jack top, then to the lower "seat tube" midway between the stays you can bend one side independently from the other. All the forces are within the one side of the rear triangle, none are on the pivots.
Okay. That's tallies with the front wheel motor with disk brake. (The v-disk front is 100mm).bigoilbob wrote:what I called the "skinny" version, is, I believe, ~110mm. I was blessed with a thick, steel , front fork, and enlarged it to handle my 48 volt hub.
You're right. The different widths are purely down to external extras. A disk brake adds 10mm; a thread-on freewheel 35mm; a lock-on cassette 45mm.bigoilbob wrote:I'm no expert, but I don't think the thicker versions have any stronger innards, more windings, or anything like that.
knutselmaaster wrote:As the 2-speed motors have quite a big width at a big diameter, one should check if the fork doesn't narrow down near the axle, especially at the front. A lot of front forks get less wide at a few centimetres from the axle and that may cause the motor not to fit.
Don't only check the width at the axle, but also it needs to be 100mm wide until at least 60mm from the axle.
qwerkus wrote:Hello, I'm considering the 2 speed xiongda motor for a second build, with more torque in mind. Sadly the motor seems very wide. Is there any chance it could fit into an aluminium 135mm disc rear frame ? Cold bending aluminum is not advisable, so I guess I only have +-2mm of spare room.
As you seem to have been an early adopter of the XD2, have you over-driven one to any extent? Ie 40v in to a 36V wound motor or similar.d8veh wrote:...
Did you use your wooden plank method? Even though I got away with my steel fork spread, if I had seen/conceived of your method, that's what I would have done. I learn more from you....d8veh wrote:It doesn't do any harm to bend aluminium frames. I've done it several times even on two full-suspension bikes.
I started with a 36v version. I added some solder to the shunt to take the current up to 20 amps. That made it pull 33% more up hills. Then I tried the 48v version at 15 amps, which was just about the same as the 36v one at 20 amps, but not long after I got it, I dropped the bike and damaged the motor wire. While I was waiting to repair it, I put the 36v motor in and ran it at 48v. It ran fine, though O could tell that in high gear, it wasn't very efficient, and low gear became too fast to act as a winch. I'd say that there's absolutely no point in over-volting these motors because you lose more than you gain. The 48v one with everything standard has immense climbing power. If you need more speed, you'd be better off with a Bafang BPM, MAC or Q128 with higher current.Buk___ wrote:As you seem to have been an early adopter of the XD2, have you over-driven one to any extent? Ie 40v in to a 36V wound motor or similar.d8veh wrote:...
I'm wondering if it is the default controller the limiting factor, or the windings?
I saw a vid of some guy pushing 82V into (I think) a 48V wound XD2, but he had added a thermistor to cut off when the stator got too hot. He also seemed to be trying to blow the thing.