belt slipping on gebe, I cant find what the problem is!

[errolprowse]

hi everyone,
i have 1900 miles on my gebe robin suburau 35cc motored bike. Its been a good ride but i have broken the lower mount strap, gone through 3 wheels, and a ton of other stuff.

My problem that has just come up is that when i take off the cover, and just let my bicycle coast, the tension spring will "pop up" for a split second, as if the belt slipped on the gear. When i press the throttle too hard while riding, it does slip as well, same goes for going up steep hills. I can kind of feel it and hear it slipping.

I have looked it over and cant find why it would slip considering it hasnt slipped before like this.

I have just bought a new belt before this all started happening as well. Could it be the gear being worn out? how long till i need to replace it? Could it be the drive ring that needs to be replaced?

any help?

 

[bamabikeguy]

Hi Errol,

In this thread, Bumwaiter tried to fix his tension lever by tightening that nut too much:

http://www.motoredbikes.com/showthread.php?t=18928

The issue might be the same, as to too much bounce on the tension lever, and I'm presuming you haven't switched to a heavier gauge of spokes.

(I'll just copy paste)

I think I know what happened,....but let me ask, first:

Is the reason you tightened the tension lever because you had too much bounce on that lever, where it would jump off the belt? Where you would have to reach back and re-engage it?


Because if that is what happened, we should address that bounce first, that maybe your spoke ring has moved severely off-center.

Then we can remount the wheel and check the axle position/washer spacing second, and re-adjusting the tension nut would come last.

What gauge spokes are you using?

 

[errolprowse]

well, i did use to have larger guage spokes in the wheel i was using before compared to the one i have now. I usually hear it sqeaking whenever i move the bicycle because the drive ring moves around on the spokes. I guess this is my problem. I do put epoxy and super glue in the notches all the time but it never seems to hold for more than a week.

 

[bamabikeguy]

Okay, here is how I do it, on 12 g. spokes....

No zip ties on the spokes until AFTER the ring is on....

You move the ring around the spokes, 1 position at a time, until you have it where it looks to be the BEST fit.

Put the soap in the notches.

There will be ONE spoke a little bit out of alignment, that spoke becomes 6 o'clock.

Snap 12 and 6, then measure the gap....

Snap 3 and 9, measure again....

Then snap around until you have them all on there snug.

You have to look in those notches, to make sure they are in there all the way.

Then zip tie the intersections.

Then put the drop of superglue in them.

(to melt the superglue, a drop of gas will do it, to unsnap the ring put soap in the notch, and take it off in the same 12,6,3,9 o'clock method)

edit: did you frame mount the kit, or are you axle mounting the engine?

 

[errolprowse]

theres also a ton of epoxy on both sides of each notch but the spoke just slides around through the epoxy and super glue

I have the engine mounted to the axle

i did ziptie them afterwards and i also used the 12,6,3,9 oclock method

still though when i move the bicycle, the ring moves around. The rim is somewhat bent as well, will that cause it to slip too?

 

[bamabikeguy]

well, i did use to have larger gauge spokes in the wheel i was using before compared to the one i have now. I usually hear it sqeaking whenever i move the bicycle because the drive ring moves around on the spokes. I guess this is my problem. I do put epoxy and super glue in the notches all the time but it never seems to hold for more than a week.

As I understand it, you have changed the wheel more than twice, but are using the same original spoke ring that came with the kit.

If that is the case, the notches have been "stretched/bored out/grooved to" whatever size those biggest spokes were.

Switching to a lesser gauge would be the same as stripping out the threads on a bolt, you can't expect it to hold.

I looked back on some of your posts, and this rear wheel has been a problem since the beginning, and I think we can get it running right if we erase the board and start back from scratch.

There are two parts of the benefit to frame mounting the engine, a fix that costs about $15 and takes an hour or two :

1. The distance from the bottom of the engine mount to the axle is constant (357mm in my case).

2. You can work on wheel adjustments (axle washers/brakes/up-down in the slot/change a flat) without fiddling with engine removal.

______________________________

Once you get the engine mount stationary, so that part (the belt drive gear) never moves, then you need to get a 12 gauge wheel with spoke ring as perfectly centered as possible.

If you've stretched the grooves on your present ring too much, there are 2 choices....get a new spoke ring from GEBE or switch to 10 gauge (which has a different set of issues).

Those two choices would keep the fix under $75-100.

A third choice is to get Dennis at GEBE to mount a new ring on his .105 gauge wheel, which means you will be perfectly centered....and IF you do that fix, then of course you'll frame mount the engine while you wait for the wheel to arrive.

 

[errolprowse]

i see

i like the idea of getting a brand new wheel and spoke ring considering this wheel also has a bent rim on top of this issue with the present spoke ring.

The number one concern i have before ordering that wheel is that there being something else wrong, like maybe the gear was worn away and causing it to slip or something like that. As long as i know it will fix it i will spend quit a bit of money for something that will last the longest considering i use my bike every single day for school and work.

so my last question, is there a chance this could happen for any other reasons?

 

[bamabikeguy]

A belt that shows threads raveling on one side is a sign that the belt is not centered on the upper small gear, or touching the sidewall of the tire as it passes. The fix is adding/subtracting axle washers to move it right or left.

A belt that is "jumping" and "skipping" and getting unnatural wear on the inside ridges is a sign that the spoke ring is off center, and maybe the wheel is not up in the best axle slot position.

If your tension lever-the little black ball, jumps back and forth more than an inch as you cruise along, or if you measure that gap between the ring and the rim, and it is over a 1/8-1/4" off in one spot, the fix is resnap the ring.

Again, frame mounting allows you to suspend the rear wheel in the air and check the performance, then make the fix without having to remove the whole engine assembly.

What bike are you using, and do you have a picture of the rear wheel area?

 

[errolprowse]

i did put a new wheel and ring on it with a new belt and gear, seemed to need all of it after i called up julia at gebe.

ive noticed for some reason that the tension is different too, the belt doesnt go nearly as far around the gear as before. but anyways, it works great, thanks for the help

i dont have any places to frame mount and my bike used to be disk brake so it doesnt have the lugs in the back anyways.

thanks for all the help!

 

[Roy Carpenter]

I've noticed that after a few hundred miles, the belt will stretch. This also adds to slippage, because the teeth on the belt no longer line up with the notches in the gear(s), perfectly. Even a mm is enough to cause this problem. I've tried everything suggested, but after nearly three years, came to the same conclusion. I weigh in at over 300 lbs though..lol. There are many ways to "extend" the life of the belt, but I would boast that belt death is the biggest drawback to GEBE. If you search the forum, you'll find much lighter riders with the same problem. It would be nice if the belts went for $10.00, but they're $30.00 a pop. Besides breaking spokes, (which 10 guage spokes installed by "The Wheelmaster" remedied), the belt replacements have been my only issues. A lot of it is when the rider gets "lazy" and doesn't pedal enough. Remember, the GEBE is an "assist" engine, and is not intended to be the primary drive source of the bike.