Author Topic: New Magic Pie Edge - Vector - Wobble issue (resolved)  (Read 6447 times)

Offline Regg001

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New Magic Pie Edge - Vector - Wobble issue (resolved)
« on: August 08, 2017, 07:10:39 PM »
I'm currently trying to finish my installation - I have a bran new Magic Pie Edge (VECTOR) 700c Rear Conversion Kit.

When I tried it on my stand I noticed a issing sound. Turned out it was coming from the disk brake - so I adjusted them. Yet there was still a ''issing'' coming from the brake. Then I notice the obvious issue, there's a wooble in the wheel - it's like the freewheel is wobbling side to side as if the main shaft is bent, but the entire bike is shaking from it when he's on my stand.

I saw in previous article it was a big issue in the past with the first models.

Now what can I do to fix such wobbling issue. I saw articles talking about having to tighten the spokes - i'm really no expert on spokes... should they be tightened to the max ? Or is the problem elsewhere ?

I'm a bit disappointed, I received all the pieces and parts last week, but could only set it up starting on Sunday. We're now Tuesday and I haven't ride the bike yet as there's always something to fight with to get it properly done.

I have a second Magic Pie to install on my wife's bike, I might give a try at that one on my bike to see if it's a common problem or if it is a bad wheel I received.

Added:
The wobbling is not up/down (like a bump on the road), it is more like a side movement - here's a video from someone who had that issue in 2011. It's pretty similar to what i'm getting now. I will try to do a video of it myself.

https://www.youtube.com/watch?v=2nZ5jnkY8YQ
 
« Last Edit: August 10, 2017, 12:20:47 PM by Regg001 »
Regg

Offline Regg001

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Re: New Magic Pie Edge - Vector - Wobble issue.
« Reply #1 on: August 08, 2017, 09:15:34 PM »
I just tested the second wheel. I can also see a little wobble, but nothing as what I have with the first one.

I hope someone at GM Canada can be reached.
Regg

Offline Regg001

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Re: New Magic Pie Edge - Vector - Wobble issue.
« Reply #2 on: August 09, 2017, 02:07:20 AM »
I might have found why the freewheel (and the rest of the wheel) is wobbling. I'm still searching a solution for this..... :-\

My bike has short (not deep) dropouts - so part of the 14mm axle is standing out of dropouts. On the brake side it's not causing an issue because the washer is pressed against a plate (or a ring - not sure how to call it). But on the derailleur side the washer(s) is pressing against the freewheel - because that's the bearing housing there is an amount of slack in it. When i'm tightening everything, the washer only receives pressure from the inner side of the dropout - on the outer side there's nothing to distribute that pressure, so i'm ending up with a washer (and freewheel) with an angle.

Member Davidmnz had a similar situation (short dropouts). Here's mine.

See image attached , from left to right
1- Showing the short dropout and the way the 14mm axle fits in it.
2- Disk side where the washer is flat and at a 90 degree angle
3- Derailleur side where the washer gets a bad angle (in red) , 90 degree angle is the green line


Brake side.. washer is ''pressed'' against a solid surface, so it stays flat on it, while on the derailleur side the washer is pressed against the freewheel and it can bent a little. I need a way to set and keep the washer at 90 - maybe a thin 14mm hex nut would do the trick, as anyone get that situation. There's no place to put a plate or another tork on the inner side of the dropout as the derailleur in in the way.
« Last Edit: August 09, 2017, 02:12:28 AM by Regg001 »
Regg

Offline Regg001

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Re: New Magic Pie Edge - Vector - Wobble issue.
« Reply #3 on: August 09, 2017, 05:22:17 AM »
I installed the second wheel, and fixed the washer issue (not at 90 degrees) on the freewheel side - yet it is still wobbling.

So the installation is cleaner, but the outcome is the same for now. I'm out of solution.
Regg

Offline Bikemad

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Re: New Magic Pie Edge - Vector - Wobble issue.
« Reply #4 on: August 09, 2017, 07:04:48 PM »
A little wobble on the freewheel unit is not usually a problem unless it is excessive enough to cause the chain to jump.
If the side cover is properly seated all the way around, there is not much more that can be done to improve it, but if it is not seated properly, you may need to loosen the side cover fixing screws and re-tighten them evenly until it is fully seated all the way around.

If you read the description on the YouTube video, you will notice that he says, "it wobbles slightly but I have now more that 1000km with the bicycle and it works great".

If the rim of the wheel is running out of true, it can usually be trued up by adjusting the spokes.

GM only recommend using up to 7 speed freewheels, therefore the 8 speed freewheel shown in your photo is likely to be a bit too wide, requiring additional washers and forcing the frame apart to accommodate it.
Any washers added must be small enough to fit inside the centre of the freewheel unit, or they will continually rub against it whenever the wheel rotates.

Spreading aluminium frames is not recommended as it can eventually lead to the frame cracking due to stress over time.

If the brake disc is running out of true, it can usually be persuaded to run true with a little bit of gentle force in the right places.
A wooden, plastic or rubber mallet can be used to gently tap the high spots on the side of the disc to prevent unwanted rubbing against the pads.

Alan
 

Offline Regg001

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Re: New Magic Pie Edge - Vector - Wobble issue.
« Reply #5 on: August 10, 2017, 12:20:01 PM »
Hello Alan, I did my first ride last night (30km)- it now works like a charm  :D

I think all the issues I got were caused mainly by the type of washer and spacer I used. I replaced them and got rid of all wobbling + I installed a second torque arm on the other side. when I look at the wheel turning with a laser point of reference - there's no side to side movement anymore, it's now straight. As you said the wobbling left is very marginal and doesn't shake the bike or the ride.

The kit I got is for 6-8 speed freewheel. Only one spacer should be required for an 8 speed, but the shimano derailleur (not the chain) was slightly touching the cover of the motor at the bottom with a single spacer. Just enough that I could not get rid of it with adjustment. So I put another spacer, but that spacer did not do the job correctly (giving that wobbling - or amplifying it). Yesterday, I re-did the installation all over but this time, with the right type of spacers and washers - and all started to work as it should. Lesson learned, use recommended parts - don't screw the installation to spare $10 on washers/spacers. I think that if you have short dropouts, you better put torque arms on both side to secure the installation.

By the way, I didn't had to force the fork to set it all up. It fits easy, in fact I had to add spacer to prevent having to ''force close'' the fork too much - that would have possibly brake the fork on the long run.

Attached - image of the freewheel side showing where's located the pin on the derailleur, and where it was touching on the motor. The axel terminates ''flush'' in the main bolt, so all is secured.
Regg