ABike PLus Noises

[itpjohn]

Hi,

Just bought my Abike Plus this week and have been using it for some time. As I have been using it, I noticed creaking noises coming from my right crank arm and a knocking sound from my rear wheel as I pedal. Has anybody experienced this with their Abike? I would appreciate any suggestions that could eliminate these noises?

[rongood]

The noises from the rear wheel are most likely caused by the chain hitting the housing. You can correct this by shaving off the ridge formed on the inside of the housing parallel to the chain. See my other posts, for example: http://abikecentral.com/forum/viewtopic.php?f=2&t=225&st=0&sk=t&sd=a&start=15
As for the creaking noise, I don't know.

[rongood]

It is also very possible that the noise from the rear wheel is caused by failing bearings. I just replaced bearings on one of my A-bikes. There was a rhythmic tapping noise not dependent on my pedaling, which got worse as I rode and could not be reproduced by just spinning the wheel. It was only noticeable with my weight bearing down and after the bearings got warmed up. Then the noise stayed in rhythm with the wheels. (If the noise is more of a clapping and rattling sound and varies according to how you pedal or lean the bike, it is probably the chain.)

To change the bearings, note that the housings for the left set and the right set are different. You can get just the bearing insert and re-use the housing, or request Mayhem to send you the entire set including the housing and the screws. Be very careful when removing the bearing housing from the bike. You cannot take shortcuts, and must open up the crankcase and remove the rear wheel to get proper access to the bearings. Then it is crucial to take extra care with the small bolts and nuts that hold the housing onto the crankcase. They are regrettably easy to damage. The nuts are held in by what looks like a good design, but in fact the plastic housing is no match for the torque you need to apply to loosen the bolts from the nuts. You need to use something like a thin bladed jeweler's screwdriver to jam in beside the nut as you back out the bolt from the other side.

Sorry for the long report, but I will say I succeeded and did find that the tapping was indeed from failing bearings.

[itpjohncardenas]

Hi Rongood,

You were correct when I found out that I had a defective bearing on my rear wheel which caught me by surprise as the bike was fairly new. Anyway, I decided to do the repair myself following your instructions and replaced the defective bearing with a new one.

The knocking sound from the rear wheel is gone and the bike is as new except for the creaking sound that I still have on my right crank arm. So far, I've tightened all bolts and pedals on the crank arm but to no avail. Any suggestions? Thank you by the way for your solution, that really did the trick.

John

[job]

I just got a new a-bike plus, and noticed rattling sounds from the rear wheel as well.

In my case it looked like the bearings were ok, but the chain was too loose. So I decided to change the tension from medium to high.
After removing the rear wheel I found one of the screws holding the bearing/tensioner assembly was already rounded off (rounded out?) during production..
So I had to carefully drill it out, which was easy. Indeed these little screws seem to be made from a very soft kind of steel, and are therefore very liable to get damaged.
Especially if you don't open the crankcase, but just stick to the paper manual that was included in the package.

But I found the perfect solution:
Buy 8 M4x10 (or M4x12) Allen head countersunk screws/bolts (hexagonal hole, we call them 'imbus' here in Holland)
Install these instead of the original philips head screws ('kruiskop').
Now you can use the small Allen key included in the tool kit.

So changing the bearings or adjusting the chain tension is now easy, without the risk of damaging the screws!

Btw, it turned out the high tension wouldn't assemble, so I had to mount it again in the medium position.

Now I still have some rubbing noises. It seems the chain runs against the flexible plastic lip inside the crankcase.
This lip seems to keep the aluminium rear tube from striking the chain in the folding process, so I'm not keen on cutting that (yet).
Or does anyone know this can be cut without adverse consequences?

Job

[rongood]

No you should not remove the flexible plastic piece inside the crankcase housing, but: Yes you can safely file down the lip, or ridge, that is formed at the base of the housing parallel to the chain. I have done it on 4 A-bikes. it is the first thing you need to do to improve an A-bike, since getting rid of the lip actually makes the bike safer. The lip interferes with the chain's smooth functioning, causing the often mentioned rattling and clunking, and can (and has for many A-bikes) cause the chain to get stuck between the housing and the tyre. Severe tyre damage can occur, and worse it can cause the pedaling to freeze up in mid-stroke, tearing up the bearings. I used a Dremel power rotary tool to completely remove the nasty lip.

[job]

I saw the pictures of the removed lip in another post of you, very neatly done!
I also saw a picture of the spiral shaped damage to the tyre on someone elses a-bike.

Your warning that the chain can get jammed, and the resulting damage will be severe makes me want to remove the lip also.

But, my a-bike is brand new, and the chain is not reaching the lip yet.
Before I do any serious mods, I want to check that everything works as it should.
Modding will probably make it harder to excert any warranty claims.
So I am keeping a close eye on the chain, and will not do the mod yet.

I found another way of addressing the lip-chain problem:
While I was trying to adjust the chain tension by turning the chain tensioner I noticed there is a fourth possible position (apart from L, M or H).
This position is unmarked, but has the same tension as M.

There is one interesting difference though:
In the unmarked position the rear axle sits in a position 2mm higher than in the M position.
So the chain will be higher too, and thus further away from the dreaded lip.

So by putting the chain tensioner in this position it should help to avoid (or at least postpone) the chain getting caught by the lip.

PS: If your tensioner is in position L or H, the height of the rear axle is exactly in the middle. So no interesting options there.

Job

[Job]

Yesterday I noticed I have spiral grooves in my rear tyre as well..
And there is a (real small) scrape in the lip, exactly opposite the thickest part of the stricken tyre.
So that proves to me that the chain does get stuck in between the lip and the tyre to cause spiral grooves in the side wall of the rear tyre.

Today I checked my chain:
I put the bike upside down, and varied the chain tension by turning the chain tensioners (without tensioner retaining screws, just with both bolts in the axle):
In this way you can adjust the tension infinitely (but frustratingly you can't fix the tensioners in the desired position).

Even with an almost perfect chain tension the chain 'jumps' on certain links.
The places were it jumps are the same everytime.
Closer inspection reveals some links are stuck, or very hard to move (so the chain wants to stay straight).
This is easy to see once you run the chain slowly around a screwdriver instead of the rear wheel.
Normal, supple links:

chain normal links

chain normal links.jpg (164.84 KiB) Viewed 23562 times

Stuck links:

chain stuck links

chain stuck links.jpg (148.92 KiB) Viewed 23594 times

I think this is the prime reason for the clanking noises!

Because of these stubborn links, the chain won't go around easily, but will stick in either straight or bent shape.
And then it will straighten out suddenly according to power applied by pedals / rear wheel.
And the jumping of the chain because of this may lead to the chain getting caught between tyre and the lid of the gearcase / rear fork. And thus lead to the spiral scrapings on my rear tyre.

I suspect the chain was faulty since production, because I noticed these clanking sounds and jumping chain from day one.
(But it's still possible the clanking noises have another origin, and the catching of the chain between the lip and tyre damages the chain, so the links get stuck.)

Both cases explain why it would help to replace the chain for a new one, even if it has exactly the same length as the old one.
As long as the new chain runs smoothly, things will run better (and hopefully without getting caught between tyre and lip).

I've contacted abike-shop.nl and hope they 'll help me out with a good chain.

Job

[Job]

Unfortunately the tech guy from abike-shop.nl is on vacation.
I could wait two weeks, or try other options.

So I took the gearcase apart and went to my local bicycle repair man.
He was very interested in the bike and the design.

When I showed him the chain he had some helpful comments:
-that chain is way too slack, you need to tighten that first
-the frozen links are quite normal, the chain will 'wear in' soon if you correctly tighten it.
I explained the method of A-bike chain tension setting, and that it was like this in setting M, and too tight in setting H (with no settings in between).
-then you need to add a chain tensioner yourself!

We discussed some possibilities, the most promising would be to put a tensioner under the chain. This gives the extra benefit of physically keeping the chain from getting caught between lip and tyre (spiral scraping).

However, since my Abike is still really new, I still don't want to perform any irreversible mods yet. So I'm looking to clamp something on there, like a shaped block of polyethylene.
Cause I don't think I could get a tensioner wheel in there..

So tomorrow I'll go hunting for materials!

Job

[Job]

Last night I made a simple tensioner from some materials I had at home.

Side view (abike upside down), with spiral grooves in tyre:

tensioner and spiral grooves.jpg (21.28 KiB) Viewed 23566 times

Looking from underneath into the gearcasing:

makeshift tensioner.jpg (18.3 KiB) Viewed 23516 times

The bushing doesn't turn, to avoid the gearcase/fork getting damaged. I don't care about the bush wearing down, it's easily replaced.

The bolt is a bit too long, so I'll get a shorter one when the shops are open again.

The plastic bush, metal arm and spring came from an automatic umbrella.
Seems quite appropriate!

After a testdrive I can conclude:
-still a bit noisy:
The chain rubs the plastic bush, which makes a 'rrrrr' noise. Not too bad for now, and far better than the clanking sounds before. But I'll have to get a better tensioner before this drives me nuts.

+ the thing is small enough not to be in the way when you want to get the wheel out. Excellent!

+ this tensioner is very effective in keeping the chain from getting between lip and tyre: so no more spiral scrapes for now.

At least I'm riding again!

Job