Rhythmic thump...

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Rhythmic thump...

Postby flagman1776 » 14 Dec 2018, 23:47

Rhythmic thump... I couldn't determine if a tire issue was the cause. Honestly I don't think it is. The TravelScoot is folded with little to no weight on the wheels between uses. The tires are 'foam filled' grey rubber. The single front tire is 8 X 2, Rear are 8 X 2.5 all on plastic 2 piece wheels.
We've talked about lint in the ball bearings before & whether that's the cause of the "thump"... I always find lint & debris in the bearings when I break it down. After service, Scoot seems to run thump free for quite a while.
I've had machine screws disappear from the seat mount... I've begun locktiting machine screws on the TS#1 on the bench now but an thinking lock washers might be better. TS #2 is in use & missing 2 machine screws from the seat mount.
W. T.HECK?
no longer able to use my TravelScoots
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Re: Rhythmic thump...

Postby flagman1776 » 15 Dec 2018, 00:19

It occurs to me that I can spin the front wheel & undriven right rear on the bench. The Left Rear wheel has the toothed drive. I wonder if any tightness the the bearing would be noticeable?
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Re: Rhythmic thump...

Postby Burgerman » 15 Dec 2018, 00:23

I think only you can diagnose this. :problem:
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Re: Rhythmic thump...

Postby rlnguy » 15 Dec 2018, 02:41

It's not uncommon for foam filled tires to develop soft or flat spots, especially, when they get older.
It's not unheard of on new ones, either, for that matter.
Sometimes, a good close inspection, using your thumb to press the tire, in different spots, will find it.
First, check if it consistent with the speed of the tire-mark a spot on the tire, with a marker, or piece of tape, drive the scooter, while watching the mark-if the mark is in about the same place, every time it thumps, you're on the right track.
In my experience, a tire is the most likely cause, from your description.
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Re: Rhythmic thump...

Postby snaker » 15 Dec 2018, 03:58

I have a similar problem on a rear wheel. It seems a fault in the rim. I am looking for a pair of replacement rims.
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Re: Rhythmic thump...

Postby flagman1776 » 15 Dec 2018, 04:25

So you are suggesting the foam might be breaking down inside the tire... leaving a spot "unsupported". It's an idea worth investigating. THX
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Re: Rhythmic thump...

Postby Burgerman » 15 Dec 2018, 10:43

Just fit a set of air filled tube type tyres.
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Re: Rhythmic thump...

Postby flagman1776 » 15 Dec 2018, 16:54

There's no provision for tubes in the 2 piece plastic wheels. It might be possible to replace the front wheel / tire: a common 8 X 2. The rear are 8 X 2.5 and the left has the drove gear molded into it. I kind of doubt that modifying these rear wheels is going to turn out well. How would I even approach it? Drill for a valve stem? Do they make tubes that small?
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Re: Rhythmic thump...

Postby Burgerman » 15 Dec 2018, 17:19

Dunno without looking. But 8x 2 and 2.5 are available. They are more likely to be 4 inch rims so any 3.00 x 4 or similar may fit.
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Re: Rhythmic thump...

Postby Burgerman » 15 Dec 2018, 17:21

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Re: Rhythmic thump...

Postby flagman1776 » 15 Dec 2018, 18:56

The sizes I gave were marked on the side of the grey tires.
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Re: Rhythmic thump...

Postby expresso » 15 Dec 2018, 22:55

i had that same issue on one of my chairs years back - its the tire - foam filled - solid tires etc, - mostly foam filled - they sit and have a lump to them as you start to ride again - sometimes it goes away after some time riding and other times - it just dosnt -

switched to Air tubes - black tires - no problems since - all my chairs are now Air Filled black tires and lithium - cant go back
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Re: Rhythmic thump...

Postby flagman1776 » 16 Dec 2018, 03:51

rlnguy wrote:It's not uncommon for foam filled tires to develop soft or flat spots, especially, when they get older.
It's not unheard of on new ones, either, for that matter.
Sometimes, a good close inspection, using your thumb to press the tire, in different spots, will find it.
First, check if it consistent with the speed of the tire-mark a spot on the tire, with a marker, or piece of tape, drive the scooter, while watching the mark-if the mark is in about the same place, every time it thumps, you're on the right track.
In my experience, a tire is the most likely cause, from your description.
good luck


THX for this & the message with ideas & pictures of your mod.
no longer able to use my TravelScoots
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Re: Rhythmic thump...

Postby flagman1776 » 18 Dec 2018, 00:40

The TravelScoot with the thump is the one in service. The spare TS is almost ready to swap off the work table. The pictures I have of the wheels & tires are poor quality. When I bring the other in, I'll get better pictures. While much of the TS is their own parts... I'm sure the wheels & tires are off the shelf mobility products. I really like to get spares to project with.
The front wheel appears common plastic caster type wheel & could probably be easily swapped. The plastic rear wheels is more complicated because of the drive gear for the toothed drive belt & because the brakes direct act on the tires. So when I have pictures perhaps we can identify the source, so I can gather spares.
Again THX for the ideas.
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Re: Rhythmic thump...

Postby ex-Gooserider » 18 Dec 2018, 01:49

My limited experience suggests that many of the foam-fill tires start out in life as regular tires which get filled later - who knows how well, and what steps they take to make sure the foam is uniformly distributed and expands evenly .... I do know that the casters I've taken out of service had definite soft and hard spots in them...

However if they actually have tire sizes on them, you are ahead of the game, it should be possible to find tube tires in the same marked size...

Examine your plastic rims closely, they may either already have holes in them for the tube stem (every wheel I've examined has) or at least a dimple where it can be drilled out... (Even if it doesn't drilling is pretty simple... Just find a good spot - probably as close to the seam in the wheel halves as possible - and have at it...)

My Jazzy thumps a lot, which I ignore... More annoying is when it starts clcking - at which point I have to try to find the metal chunk that has gotten lodged in the tire and remove it...

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Re: Rhythmic thump...

Postby Burgerman » 18 Dec 2018, 02:48

Foam filled or so called flat free tyres be they foam rubber, foam filled, urethane, etc are all terrible!

They are heavy. Always bad.
They have higher rolling resistance. Always bad but especially so with battery power!
They have only one spot of "suspension" directly under the wheel. Rather than compressing a large volume of air over the whole tyre. So terrible harsh ride.
The extra weight encourages caster shake, lighter is better.
They dont last as long, by a large margin.
They are non adjustable. So too soft, making zero turns harder, or too hard giving a bad ride, is what you get. Somehow they manage to do both of these at the same time!
They are usually only available in the following shade: "institutionalized" grey. Which goes yellow, brown and then they start to crumble...

Why use them at all? Fear of punctures. Very overblown, and using quality rubber, and tubeless tyres I have never had one in 20 years.
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Re: Rhythmic thump...

Postby rlnguy » 18 Dec 2018, 14:23

BM-
All valid points, as far as performance goes, (as well as how overblown the real danger/fear is).
However, many users in the U.S. have no choice, as many funding agencies will not fund any chair that doesn't have a flat free tire.
I used to work with a guy who said it was the "Golden Rule-those with the gold, make the rules".
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Re: Rhythmic thump...

Postby Burgerman » 18 Dec 2018, 14:28

So a lack of free market trade (capitalism) in the US market, and here, does exactly what you would expect. It removes the driving force and value signals from the end product. So we get garbage, and price gouged, and a lack of competitive product improvement/development.

This stuff does not happen in free markets. E.G. motorcycle or car, or garden machinery or anything else. There we get manufacturers competing for end customers money. It means they must develop good/better products, at a better price to attract sales and the end users cash. Where even scooters and garden mowers have quality tubeless tyres today.

Except in socialist countries like Russia. Theres was no free market, so you get to apply and wait 10 years for a used moskavich pile of crap car if you are allocated one... That is effectively the NHS or the US wheelchair market. And the reason we pay phone numbers for 1980 technology.
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Re: Rhythmic thump...

Postby flagman1776 » 18 Dec 2018, 22:38

Now that the power is back on... I just felt the tires on the spare scoot (on the work table)... rock hard. Can one feel soft spots in a foam filled where the foam is failing?
no longer able to use my TravelScoots
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Re: Rhythmic thump...

Postby Burgerman » 18 Dec 2018, 22:47

Yes, by using it.
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Re: Rhythmic thump...

Postby ex-Gooserider » 01 Jan 2019, 07:13

flagman1776 wrote:Now that the power is back on... I just felt the tires on the spare scoot (on the work table)... rock hard. Can one feel soft spots in a foam filled where the foam is failing?


On my tires I could... Often rock hard 95% of the way around, with one or two spots that are spongy or harder than the rest... Look for any variations in tread wear as well - the odd spot will wear a bit differently...

Also squeezing can be deceiving as the tire may feel OK if pushing the sidewalls - try getting a more pointy probe like a largish flat screwdriver blade and push straight in on the tread (firm but not hard enough to damage anything) in the contact patch area...

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Jazzy 1100
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