pinging noise

[Draggin]

When I looked down I knew something was wrong.  Of course I had to try the throttle to see what it was.  Lifting the front up and spinning the wheel to show my buddy. Worked ok.  When I put it down it tugged harder on the wire, then it stopped working. Buddy had a set of channel locs in his truck so I unwound the axle and tightened the nuts.  It worked ok and I got home.  Thats when I decided to weld up the forks.  I have a couple hundred km since and had no problem.  So I'm sort of pretending that the whole thing didn't happen.  Do you think that this will come around and bite me in the but?         

[myelectricbike]

So the motor power lead, sensor leads and their power leads got wrapped around the axle until they were so tight they stopped the axle from turning ...great excuse to buy some new Teflon insulated silver 16 AWG and some 22 AWG to replace the sensors leads and their power leads in preparation for doing a 48 volt mod. They are ebikes on steriods and well worth the time and effort! Just stay off the public roads.

[Draggin]

     myelectricbike, I hear ya.  I just can't justify the 48v mod.  I ride to commute to work.  I don't ride on my days off.  I think that I might pull in a new set of wires this winter when I can't ride.  That is only for reliability.  I look at this thing and I can't really find anything that I might improve.  It works pretty good.  I really want to see if I can wear it out.   

[Draggin]

   Oh and if I were going to do the 48volt thing I wouldn't start with a Raliegh bike.  I think I'd want something a little beefier.  I do like the Idea..... Lets see 48/36v thats 48/36km/hr.  With the right gearing thats 50.  I bet if you had a fairing you could do 80.  My insurance company would kill me.   

[myelectricbike]

  Yes, you do have to be careful and a beefier bike is the place to start. The bike I used had an oversized frame so the issue was beefier spokes, rim and tires. I carry 4- 18AH SLA/AGM batteries mounted in side baskets at 12 lbs each - or 4 times the weight of a single 36 volt 15AH LiFePo4 pack. That's 48 lbs. I'm also normally returning from the store with a 60 lb back pack. Add everything up and I should probably have an industrial bike with 2.5 inch tires in addition to a trailer.

I think that's why the "still a bike" limit was set at 20 MPH and 750 watts no differenet than 21 being the legal age age for drinking. Although you can do 24 MPH with 48 volts its the pulling power (with the beefed up motor wiring) that is the main reason for this mode. 24 MPH is just fast enough to get you into twice as much trouble even without a heavy load, skimply breaks, etc. so for now without sturdier rims and spokes I rely on knee and elbow pads in addition to a crash helmet. Previous accidents on regular bikes keep safety (or danger) always on the mind.

[Draggin]

     That sounds like allot of effort for a couple of Km/h.  Most of the time now I cruise at 34-35 km/h.  24mph=38km/h.  but it makes sense too. My mountain bike before the conversion cruised at 26 km/h.  I can put out about 100 watts on the excersize bike in the gym.  It takes an additional 600watts at 36 volts to go not quite 10 km/h faster.  Anyway you look at it its is 25 percent more speed and It sounds like 25 percent more power.  It must look funny when you take off from a stop light.  Do the tires squalk when you give-er.  That set up sounds like it would be ideal for a custom built bike. Maybe purpose built like a pedicab or load hauller.  I think I could get the same performance as you by lacing my 36v motor into a c700 wheel and loose 30 pounds off my gut.         

[myelectricbike]

Personally I rather deal with unintentional spinning than a wheelie although with a Tandem or Tadpole wheelies are not a problem. But remember 48 volts is strickly an off-road mod no matter how you do it. (In the US at least.)

If an excercise bike is your application, however, you can use the new regen comtroller (36 or 48 volts) to charge your batteries while you excercise. 

[Draggin]

Frig it's back again.  Worse than ever.  Got back from holidays and went to ride to work.  A couple of pings when she rolled off the stand.  About 5kms into the ride I hear this jjjj sound.  By the time I get to work its so loud I need ear plugs.  I'm guessing that the guy who turned the axel had a bit that was as sharp as a sledgehammer.  Thats only 250kms on a new set of cheap 6202's.  Maybe I can find a spherical contact bearing.  I'll let you know how the rerebuild goes.   

[myelectricbike]

Dalecv has a picture of a 20" wheel for his Bike Friday where the flats are NOT 180 and I've got a wheel that has a cast or forged iron or steel yoke spoke that is so quite at speed you can not hear it run except for the tires on the pavement and another with a forged or cast alloy yoke spoke that chatters so bad from torque vibration it sounds like its coming apart. Sure would like to take a trip to China.

[mustangman]

 Draggin, when you buy bearings they are rated in a system with 1 being the worst and 8 being the best(8 is what they use in machine tools such as mills and lathes). Look for  5 or 6 for the wheel if it is available in your area. I am surprised the machinist that helped you did not question the quality of the replacement bearings. Anyway good luck and keep us posted.

[Dalecv]

Pinging noise or more like two drum sticks being struck together hard was what my motor sounded like. It was so loud I didn't need to warn people I was passing because they were staring at me as I went by.

I took the wheel off and opened up the motor to check the sensors out but everything looked fine. I put it all back together and the noise was gone until I road a few miles then it would come back as bad as before. The hard part in finding the problem was that the noise would quit after I took the wheel off. I thought it was a bad bearing so I replaced the bearings. The noise was still there.

I finally cured my noise problem by taking the bearings out and used some fine, 180 grit, emory cloth to polish down the axles so that the bearing could be slid on by hand. I did the same with the side cover bearing seats. I then used Tenasious oil (a sticky oil I bought from a bike shop years ago) and put that between the side cover bearing seat and the outside of the bearing. I have done about 50 miles since and no noise.

I think what is happening is the shoulders on the axles that the center of the bearing seat up against are out of alignment just as the flattened sides of the axle are not parallel. When the axles nuts are tightened down this puts uneven tension between the outer surface of the bearing and the side cover bearing seat. As the motor heats up the aluminum expands and the bearing can then slip in the aluminum side cover bearing seat to relieve the pressure. It does this in sudden jerks and you get the loud pinging noise. The aluminum side cover is a very effective sound emitter. As I was sanding out the side cover bearing seat and the fit was almost there the bearing would slide in in small steps and make a noise similar to the pinging sound.

I figure the bearing is still wallowing in the side cover bearing seat but as long as it isn't make that loud noise I don't care. My hub motor has silver side covers with black center and has the name KUAKE on it along with some Chinese characters.

Good luck with your noise Draggin.

Dale

[Draggin]

Mustangman I can't blame the fitter for my own stupidity.  Do you really think the $7.00 bearings are better than the 99 cent ones?  I weight 250pounds not 2500 and the axel is turning at 200rpm not 2000.  I'm not trying to be smart Mustangman I'm just shortening my sentences.  I appreciate what you are saying.  I now believe that there was nothing wrong with the first set of bearings that I tossed.  Back when I was in trade school I learned that the rolling element in a bearing has to have an interference fit, the not moving one does not have to be.  I put press fit repair on everything and when it hardened the missalignment is what made the noise.  So Dalecv is right.  There is a couple of bearing places in town I'm going to ask them what they think.  A couple of angular contact ball bearings or tapered roller bearings might do the same thing.  More than likely I will build up the shaft with bronze and get my buddy to turn it down true. Wait a minute If I heat up one side and remove the bearing and make it a sliding fit on the axle.  I could tap the end cover and put 3 or 4 machine screws in to hold the outer race.  It would have at least 50% chance of success.  The down side is I think its the powercord side that is buggered up.  All that soldering.  My brain hurts.  I,ll let you know next week       

[mustangman]

  Bearings as well as how they are installed makes a big difference in the final product. As far as the bearing prices, we are talking about only 2 bearings(@$7,00 each!) and the load placed upon them. The cheap bearings might do the job, but for how long will it last before you have to do it all over again, and again and again....   I worked in a big box auto parts store and they had 3 lines of brake pads all with a 'Lifetime" warranty, the cheap ones would last 20-30k, the next would last 30-40k and the best would last 40-50k miles. Personally I would not trust the cheap pads with my life and neither would I with cheap ball bearings but its your call and your life.

[Dalecv]

Since it is the tightening of the axle nuts that forces the misalignment you could sand down the axles so that the bearings slip on smoothly. Make sure the bearings are seated fully into the side covers. Take a little liquid steel or some other epoxy type product and put a little on the axle where the bearings rest against the axle shoulder. Put the motor together and let the epoxy dry. Now when you tighten the axle nuts they will be compressing the center of the bearing against the epoxy and the shoulder on the axle and the bearings should stay in alignment.

Just trying to come up with a suggestion for a cheap easy solution to solve a problem on an inexpensive motor.

Good luck in whatever you do.

[Draggin]

I talked to my buddy the fitter about all this stuff today . He made some comment about how fat I was and a 26" wheel on a bearing like that was like crushing diamonds.  And said that a better quality bearing could make a big difference.  Strangely enough thats what I found when I pulled the end cover off the power cord side.  The inner race was still holding but the outer race had ground the press fit repair into carbon.  It looks as though the end cover has enough meat for four axial retaining bolts and perhaps a retaining ring could be made out of a washer.  Then the inner race could be a sliding fit onto the axle and the outer race (rolling element) would be secure.  Thus following the rules of nature.