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swalker

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I went for a magnificent wheelchair ride over the weekend in my Permobil C500s VS wheelchair. I rode the Gondola to the top of Vail Mountain and took the ride down Village Trail. It is about a 7 mile trail all on dirt roads. The weather was great and I truly enjoyed myself.

During the ride, I decided to backtrack up the hill for about 2 miles. While doing this, I started to have some wheelchair problems. I have scheduled a visit to the service folks at NuMotion, but thought it would be wise to check with my friends here to gain any insights you might have.

During the ride, I heard a sound like a pebble caught between the wheel and shroud. It was intermittent and repeated at irregular intervals. There was no rock or pebble. My best guess is that I was hearing noise from one of the motors' gear boxes. This is the first time I have heard that noise. The noise has occurred on all subsequent rides, but is very irregular.

After going uphill for about 2 miles, the wheelchair became sluggish and hard to control. The turtle icon illuminated (indicated the wheelchair went into a degraded mode of operation). Presumably, the wheelchair was overloaded and went into turtle mode while it cooled down.

After reversing course and heading back down the mountain I discovered that the wheelchair was pretty uncontrollable. It drifted hard to the right and required full left on the joystick to go in a straight line forward. The wheelchair would not turn left, so left turns required making a 270 degree turn to the right.

Letting go of the joystick resulted in a sudden 130 degree turn to the right as the wheelchair came to a stop.

This behavior persisted for about an hour as I made my way downhill at reduced speed and then the wheelchair started acting more normally, though not completely normal.

The descent was interesting, to say the least. I made it home OK, but it tested my wheelchair driving skills.

The next day, the wheelchair behaved more or less normally at first. I took it on a test drive up a smaller hill and the same symptoms recurred. I can reproduce the symptoms at will now by simply driving the wheelchair for a half an hour on flat terrain.

Two other items to note that I suspect are unrelated are:

1. I have significant flutter in both rear casters. I suspect worn bearings there.
2. The right shock is apparently blown, as there is an oily substance all over it. I noticed this as I was checking things out after the wheelchair started making the weird noise described above).

I sure appreciate any insights you may have so that I can more efficiently work with NuMotion to get the wheelchair fully functional again.

Here is a picture of me during the ride (before the troubles started).

Thanks for your help.

Steve
 

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KimT

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Steve,

You probably know more about wheelchairs than the rest of us combined! You probably know more than the techs at NuMotion. I hope it is something easily fixed. I'm glad you have more than one chair.
 

KarenNWendyn

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I know absolutely nothing about power wheelchairs but am so inspired to hear how you live so fully with this condition. This is why I subscribe to this forum.
Sounds like you have some reasonable theories as to what's wrong with the wheelchair and what to do about it.
 

bigmark1954

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sounds like a bearing issue to me.
 

swalker

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Kim, thanks for your vote of confidence! I am actually pretty comfortable with some of the folks at my local NuMotion working on the wheelchair. Of course, I like to be there when they are doing it;)

Karen, I am glad you enjoy reading about some of my wheelchair adventures. I think having the opportunity to be outside really keeps me going.

Mark, I think you are likely right. I was pondering whether it was a motor problem or a controller problem. Initially, I was leaning toward a controller problem because the initial symptoms were evident when I put a heavy load on the chair. But, the problem has progressed, which I don't think would be the case for a controller.

If it was a bad bearing (as you suggest), then I would expect to see the behavior I have observed. As the motor is used, the worn bearing heats up, causing it to be even worse.

Since NuMotion only replaces parts (they do not rebuild them), that means I will most likely be in line for a new motor. Those are expensive and take awhile to get. I hope they can get one installed before the next trip to Yellowstone.

And, of course, it is fairly important the motors be well matched. I have read it is better to replace both motors when one needs to be replaced. It should be interesting to have that discussion with the insurance folks!

In the first 800 miles of the chair I went through both a left and a right motor. Now that I have 1800 miles on the chair it looks like another pair of motors is in my future. Hard to believe that motors only last 800 to 1000 miles.

Thanks for your encouragement and your help.

Steve
 

ShiftKicker

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This is a total aside from your mechanical woes, Steve, but if I ever end up at Yellowstone again I will keep an eye open for you. It seems you practically live there, so my chances of running into you if I go are likely!

My husband just went through Yellowstone on his solo motorcycle journey across Canada and the States and commented on it feeling like a total Shangri La. The mid summer crowds were a distraction for him and he felt guilty I wasn't there with him this time, but he still rode away feeling like he'd been given a gift just driving through.

Hope you are able to get the replacements you need quickly so you can continue adventuring. I will be interested to hear what the Numotion folks discover when they have a look at your wheels.
 

DaChief

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Steve, I got stuck at your rear caster fluttering :). Glad to see you pushing the limits though for sure!!
 

chally

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Love to be on that trip with ya.
My problems are hard to see cause I can't be in chair and look at same time.
Sounds like bearings. I am always shooting WD 40 to all moving parts as like you, I am off the roads a lot and dust grime and h2o got in everything. Good luck Steve
I am due for a tune up!
 

Colawoman

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Love the backdrop of your picture!! Sorry you were having troubles with your ride!
 

swalker

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Here is an update. I was able to take the chair to NuMotion in Denver yesterday.

They looked at it and consulted with Permobil. The consensus was that the blown shock is causing all the problems.

It will take 3 months to process the paperwork for a new set of shocks (they want to replace both, though only one is blown) and then 3 weeks to get the shocks and an hour to install them.

Now, I can't conceive of how a blown shock could cause the problems I am experiencing.

My backup wheelchair uses the same shocks, so my plan is to swap the shocks from it into my primary chair to see if it does indeed solve the problem. If it does, I can get used shocks on ebay for less than $100.

If swapping the shocks does not solve the problem, I will return to NuMotion with this information and see what they say next. I am pretty convinced it is a motor problem.

On a side note, I stopped by and looked at a lightly used Permobil C350 wheelchair that is for sale for an attractive price. It would take a lot of work and some expensive parts to make that chair suitable for me.

It has a head array, omni control system, and attendant control. All of that may be useful for me some day. For now, I need a regular controller, which I can buy used for $300 off ebay. It would require some programming by NuMotion to get that working. I would also need a new seat back, seat plate, bottom and back cushions, arm rests, and controller mounting arm.

It does not have seat elevate, but I could add that if I can find a cost-effective actuator (new, they are more than I want to spend). Still pondering if I should take on this project and add a rear-wheel drive chair to my collection;).

If I am not careful, we are going to have to a bigger house with more wheelchair storage space!

Steve
 

swalker

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We were able to swap the good shock from my backup wheelchair, replacing the bad shock on my primary wheelchair. I just got back from a lengthy test ride and here is my report.

The chair no longer makes a grinding noise. So, I conclude that the noise was caused by the shock dropping down and rubbing against the spring surrounding the brake cable. There is not much clearance there, and with a blown shock there is no rebound damping.

Unfortunately, when the chair is warmed up, it still pulls drastically to the right and also makes right turns when stopping.

I am ordering a new pair of shocks off ebay now and am trying to get in touch with NuMotion to report my findings.

Steve
 

KarenNWendyn

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You're amazing. Ride on, Steve!
 

KimT

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Steve,
Nothing will stop you! Keep us posted.
 

DaChief

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Should da man Steve! They should have to pay you for troubleshooting it yourself.
 

swalker

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I went out for another test ride this evening. The chair made no grinding noises for 4 miles. Then, about 100 feet from the driveway, I hit a very small pothole dead center with the left drive wheel. The grinding noise started immediately.

So, I need to tear into the left shock/motor arrangement and see if that shock is rubbing against the spring covering the brake cable. My friend will be here tomorrow and can help do that.

I will let you know what I find out.

Oh, and here is a picture of me on the gondola today.

Steve
 

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