Amylior R3

[BCrip71]

We are all well aware of the lack of choice for rear wheel drive chairs in North America. After much deliberation, I decided the R3 was my best option, after Amylior assuring me that I would not get rear caster flutter. Well, guess what? Yes. I am getting rear caster flutter. They are sending a new caster bearing kit. We all know this will not solve anything. Do you think I could lop off the rear casters and replace the with anti-tips that are off the ground?

https://amylior.com/en-ca/hybrid-tracti ... r3-series/

[LROBBINS]

Can you just get smaller wheels to mount there?

[BCrip71]

Probably, I am wondering if the suspension relies on the rear casters?

[Burgerman]

They are sprung ino contact with the ground to make a 6 wheel chair. Much like a normal centre drive but with the seat on the other way. If you fit wheels instead of casters they will skid when turning in place. If you just added smaller caster wheels then you might be able to get them clear of the ground but this will let the chair tip back a bit.

[BCrip71]

How small would you go. 9" right now.

As is, do you think they can stop the flutter - actually more like a wobble?

[Burgerman]

Without looking at it I dont know. Can they stop the wobble? Well I could. I dont know how till I try. But I was never defeated yet! Probably just needs a hacksaw and a hammer. But if yours does it so does every one they sold.

[Raro]

As a test without cutting anything, you can try removing the wheels you have, then place a threaded rod that passes from one fork to another so that they do not rotate, and place some small wheels at the ends. If you do it while testing it on a steep slope, have someone assist you from behind until you see if it is stable, you may have problems with the suspension.

[Burgerman]

I think that its much too close to a normal mid drive chair for that. Look at the pics, the drive wheels are almost central and the casters stick a long way out of the rear.

[Raro]

Yes, it may not be suitable but there is no problem in trying, you can always leave it as is and the cost of the materials is not very expensive.

[martin007]

I think that its much too close to a normal mid drive chair for that. Look at the pics, the drive wheels are almost central and the casters stick a long way out of the rear.

I think the same.

[Burgerman]

I think just fix the flutter problem and it should be a reasonably good chair. It wouldnt suit me but they are reasonably capable outdoors by the look of the design. But I would still rather have a rear biased rear drive than a hybrid personally. But whatever the reason you cant get one in the US.

So its the best of a bad bunch of options.

Anti flutter kits?
Add more sprung weight?
Lower rear caster pressures?
Different tyre size/profile?
Some combination of the above will definitely stop the flutter.

I would be tempted to use the very flat slick 8 inch but wider "square" tyres as I fited to the Q700R front casters. Those have a large area of rubber on the deck. That means a lot of damping, very hard to get those to flutter or shimmy.

Like these:
https://www.terraintyres.co.uk/golf-law ... mooth.html
A set of those, with a little careful adjustment of caster barrel for damping - maybe a nylon washer/spacer and damping grease - and you probably get rid of it completely. Will THEY be able to do this? Who knows... I could.

[BCrip71]

Thanks! I have flat free tires all around. My first time. Very rough ride. Not sure if the benefits are worth it.

[Burgerman]

They are terrible!
But also heavy. And this makes them shake... So may actually cause the problem.

[martin007]

Thanks! I have flat free tires all around. My first time. Very rough ride. Not sure if the benefits are worth it.

I'm very happy to use them.
I go for a run with a calm mind.
Nothing stands in my way.

[Burgerman]

Excpt for the terrible ride. And endless back problems. And shorter tyre life. And faster battery wear. Shorter range. More difficulty controlling. Other than this they are great!

Watch all the traffic on a road go by. Give it an hour. Try and spot one with solid tyres... Then answer me one question. Why are non using solid tyres?

Then ask yourself roughly how many punctures a car has over its (100,000 mile?) lifespan. Most cars NEVER suffer a puncture at all. Most scrap yards or car breakers will show you this. Check all the spare wheels. Most of them are never unused. Still have the moulding "hairs" on... Now ask yourself why this is?

[Raro]

everything has its pros and cons a solid tire does not have to be inflated maintenance-free you do not have the risk of puncture it no matter how remote the probability of doing so is a car does not use solid tires because it is not suitable for them its hardness would be uncomfortable and would destroy the suspension even the chassis apart from the fact that they would be more than twice as expensive. It is also true that wheelchair tires and similar tires do not have the quality of a car or motorcycle tire; they puncture much more easily. The air ones have the advantages that you already mentioned.

[Burgerman]

But they do not need to.
Theres no reason that powerchair tyres have to be tubed. Or weak. All of my powerchairs are using much stronger tyres. Proper roadgoing scooter tyres. Or kevlar reinforced puncture proof tyres. And they are tubeless. Just like the car.

Theres not just 2 choices.
The manufacturers only give us two... But they do not offer tough, puncture roof, or runflat tyres. They could. Its simple enough.

My Salsa for e.g uses these strong, tubeless, tyres.

[Raro]

Yes, those are good, I know them, the pit bikes have them, they roll even without air but they are quite hard. a bad example, a while ago I did nothing more than buy tires from the wheelbarrow, it doesn't matter what brand or where I bought them, they are of terrible quality and they don't last at all, one day my brother changed the tires on a Vespa motorcycle, we fitted one of them to the wheelbarrow because it fits on the disc despite not having a drawing and being cracked for years and has never been punctured or burst.
The ones on the chairs are very similar and even worse if they are gray.

[Burgerman]

Those tyres above, with a massive 190KG chair sat on them and my weight on top are not "hard"! Far from it they need 25PSI in them so as to not look "flat". And at that pressure the ride is much much beter than the stock skinny tyres. Why? Because its gor around double the cross section. These give a great ride.

Anything weaker is inadequate on a heavy rehab chair. Like stock tyres are... They are actually bordeline overloaded if you look at the rating.

And another one of my chairs uses these:
https://www.wheelchairdriver.com/board/ ... &mode=view

Again tough, tubeless, and a bit bigger/stronger. The total chair width is still narrow at 25 inches.

[Burgerman]

Or these which are PUNCTURE FREE and kevlar reinforced. These run at 8PSI and are practically everlasting! But eat battery faster. So lithium...

[Burgerman]

I do this because I dont like punctures and have never had one yet in a tubeless tyre. At least not that stopped me getting home. Because unlike tbes they dont expand around a nail or hole, the tyre traps the object. If it doesent the tyre sealer fixes it every time! That doesent work on tubes. AND because solid tyres hurt my spine, set off my muscle spasm.

The manufacturers could all do exactly the same as I do. Theres many many different ways. But they dont. Because no proper competitive market exists in this area. They DO use them now on some scooters. Because people are buying those with their own cash. And the manufactyrers want that cash!

Heres another tough TUBELESS tyre. ALL of these are on different but TUBELESS rims.

[Raro]

To use those tires they would have to make different chairs, placed on a standard chair it would make it too wide for many places.

[Burgerman]

Yes - except the last one.

But I am not talking about you or me doing this, although I did. But the whole industry. Its just better. Safer. Smoother. Longer lasting as well as making punctures almost an impossibility. But they either dont care because they have no competition or are too stupid to figure it out. And I doubt that.

Its not just wheels and tyres.
Its much more efficient brushless motors.
Its lithium batteries.
Its rapid chargers.
Its useless suspension.
Its decent solid no flexible seating.
Why doesent the fancy screen on my joystick work aas a phone with a sim card.
Why doesent it have GPS built in.
Why is there no rear view camera shown on the screen?
Why isnt there a AC outlet on the chair?
All this stuff is commonplace and cheap as chips now.

Its the whole thing. In the US you cant even get a rear drive chair anymore. Everything is all sewn up, its called corruption. Caused by a lack of free capitalist markets, and crony capitalism/corporatism. In the competitive market, everything battery powered uses lithium. Brushless motors. Everything has options and choice! Driven by the market.



Oher than some fancy colours, some marketing, and som wizz bang names and videos, absolutely nothing has advanced in 25 years. No competition.

[BCrip71]

What should be my expectations be when it comes to caster flutter. I travel at 13.7 KMH wherever I go outside. Should I be ok with flutter on a sidewalk, going over a bump, on a rough road, etc. Should the caster be able to recover from a flutter without slowing down?

[Burgerman]

If it can recover without slowing down rapidly, as it should then it wouldnt flutter in the first place.
And the faster you go then the more likely you are to get flutter. Another reason that 6 to 6.5mph (10kph) chairs make much more sense on top of the battery lifespan, lack of torque, and hotter controllers rolling back power on hils etc.

But 8mph should not be an issue for shake if well configured. I used to get caster shake issues, that did go away on their own at a higher 15mph (24kph) on my BM3 which is much more violent! Made your eyes go blurred! I got that to go away on that particular chair by lowering the rear tyre pressures a little and the front ones a fair bit. Once the new rounded profile caster tyres wore in a little and so had a wider part of the rubber on the deck it never did it at all. It sorted itself out as the tyres wore in a little.

https://www.wheelchairdriver.com/gopro/caster.mp4
Watch. You can see it start over a small road hollow, then rattle like crazy, then stop by itself. The faster you go the more sensitive to this casters become. But this is twice the speed of your chair. Hence the violence of the shake.
Did it in the same spot going up this hill every time. Going up hill puts less mass over the casters. So less damping. So I put the camera on a wall and drove past again. So I could see it.

[BCrip71]

Thx!

[Burgerman]

Its also great fun overtaking push bikes slow traffic etc on the roads. But embarassing when you have to slow again if some bump sets it off... Also was fun at a show once. The guys dispaying the 8mph Q chair were telling me how fast it was in the car park as they were unloading it. I said nothing, and when he showed me how fast it was, I passed him like he was parked at double his speed. His facial expression as I shot past was a picture!

[shirley_hkg]

Smallest tubeless drive wheel for wheelchair
3.50-8

Tubeless seldom fails. Never had a flat in a decade ever since switching to tubeless .

I always ride at 16kph.

Flutter at times , when casters hit small obstacle or uneven bumps .

[Raro]

I think I asked you again Shirley, but what chair do you use and what have you done to it to make it reach 16 km/h?

[Burgerman]

I can reply quicker for him I THINK. Its brushless invacare storm, with a little programing and bigger tyres. And lithium (slightly higher voltage). A combination of those things = a bit more performance.

In my case its 13s Lithium, so double the voltage of lead, roboteq controller, and the sunrise supplied AMT 8.5mph motors run at double the volts = 16mph. Or 25/26kph which is too fast! But you can always go slower.

My 10kph 6.2mph chairs are really faster too. Because same thing. Lithium, and programming to allow more of the lithium's voltage through, and bigger drive tyres which is the same as taller gering. So they are almost the same as an 8mph chair. Say 12kph? Without the disadvantages of lead/13kph motors.

_______________
With lithium, the voltage doesent drop by approx 2 volts as you roll. Because theres no "surface charge"/increased resistance effect.
With lead they are around 26V when full. After 100 meters they are around 25.x volts. But as soon as you apply a load constantly such as when rolling at speed, you draw 10 to 15A from them. The voltage drops down more to say 24V or even less on a hill (which is partly why you slow). Lithium starts off higher anyway. And pretty much stays there!
In programming theres usually a figure of 21.5 to 22V applied as maximum. Which is correct for lead. It gives enough for some headroom and some control under load. With lithium fitted you can gain some speed by increasing that to say 25.5V instead. So the chair is faster. And with larger tyres, faster still.