WheelchairDriver

There's a switch on the boundary to unlock the brakes so you can roll it, but the switch requires power obviously and my bounder has no battery in it at all. How do I unlock the brakes without using that switch?

Thank you

Mine has levers near the motors.

That's weird to go free wheel by power.

https://youtu.be/ovIx_3f7VEU?si=vprFeafIcFynVQBk

I watched dans vid. You dont need to contact or persuade your provider or bounder.
Those sprockets are just standard cheap industrial stuff that you can buy on any industrial estate from a transmssion or conveyer or bearing supplier as used on food machinery, cranes, conveyers etc. They are cheap, easy to get and even online (a link below for e.g. As long as you know what to order. If not just take that front sprocket to the nearest industrial estate. They will sort you out. Get one with a few extra teeth for more speed. Or a few less for better control and range.
No real reason to even change the rear larger one.

So you can experiment at will.
Also count the number of teeth on your new front sprocket. If its got say 3 more than the old one, then order a new chain from the same place with that many extra links. Then it will fit and are cheap. I cant measure it but those are either 3/8th", 1/2" or whatever (use a ruler) stock sizes.

Beware. His warning about heat, wear, less torque etc is very very valid!
If it was me I would do the exact opposite. I would get a SMALLER front sprocket and reduce max speed a little. Why? I like control, range, easy battery life, and ability to climb hills/curbs/steep ramps etc. Over an extra mph or two. If you ask me 8mph is already a compromise too far.

E.G.
https://www.mcmaster.com/products/sproc ... rockets~~/

Easy to play and experiment. Dont worry about the rear big sprocket. But if needed those are also available. Bounder dont make much, they buy all the parts in like other manfacturers do. They just make frames and assemble bought parts and add a huge premium. New keys are availabe too. Probably 1/4 square?

I just got a smaller sprocket for mine. It's just a standard #35. $10 for 2 sprockets.

So to answer my question, there is no lever on these older models. You have to undo the clutch lever at the beginning of the chair and then unhinge the chain if there's enough play

If there's not enough play then you have to physically remove the brake system On the newer models they just have a button you can press, so as usual Bounder updates about 20 or 30 years after everybody else does

Jay_x wrote:So to answer my question, there is no lever on these older models. You have to undo the clutch lever at the beginning of the chair and then unhinge the chain if there's enough play

If there's not enough play then you have to physically remove the brake system On the newer models they just have a button you can press, so as usual Bounder updates about 20 or 30 years after everybody else does

Easiest way would be to ask Bounder themselves. They'll tell you the easiest way to do it.

The newest model has a break lever release

emilevirus wrote:I just got a smaller sprocket for mine. It's just a standard #35. $10 for 2 sprockets.

Thats good. Dont forget the shorter chain. Count how many less teeth. Get chain with that many less. And a link with clip.

The tension is adjustable. No need to change the chain.

Wait and see. You will find that even 1 tooth makes a huge difference. 2 will be much more than you expect. I have much motorcycle chain experience! Your chain will be too long, tensioner will not cope. In any case you shouldnt really run old chain on new sprockets.

Not sure if yours is 1/4 or 3/16th, 3/8ths pitch?

Looked it up. This. 3/8ths. I think. 5 meters or 6 yards. 17 feet! Enough to do both sides twice. £27.
https://www.thebearingcompany.co.uk/pro ... 3-8-pitch/
They do SINGLE link joiners, and double (normal) link joiners too.

But if you know what you are doing you can shorten a chain easily too. But now is the perfect time to replace with new anyway as industrial chain is really cheap like the sprockets.

Tell me what reasuringly expensive price do bounder charge for their sprockets and a chain?

Back in the day you could buy flat tins that looked like a frying pan that was full of very solid high melting temperature grease. Sold as chain grease treatment.

The idea was that you took off the top, to reveal a 12 inch tin of grease about 1 inch deep. You put your new chain on the top, put the whole thing on the cooker ring and watched the grease melt, the chain sink to the bottom. The hot thin melted grease was as thin as oil now, so you jiggled the chain around a bit to make sure that this melted grease entered the pins and bushes in the centre of the chain. Then you lifted the chain out of the tin and held it up while the exess ran off back into the tin.

Leave the chain someplace to cool. Leave the tin to cool on the cooker.

Now your chain has cooled and it has heavy chain grease inside all of the bearing/pin/bushes internally. Then you fit it back on the motorcycle. That was by far the best way to garantee your chain lasted a long time.

No longer required as motorcycles use 0 ring chains and thee already have grease and its sealed in.
But your chair doesent.

So take an old frying pan.
A camping gas "stove" outside and fill it about 1/2 inch deep with heavy high melting point grease. And do the very same thing! Well I would. Then the chains will run better/longer. From new.

Heres an EMPTY tin. Designed to do this.

https://www.wheelchairs.com/resources/p ... r_form.pdf
Mine is brand new. Came overgeared. In snow it just won't move at all.

Chain 225 for 2 meters. Instead of $27 for 5 full yards!
Front sprockets 220 instead of £10 a pair...

Those prices on that list all appear to have a extra ZERO added. Those are rediculous prices. For every single minute chair part!

Yep but at least all parts that need to be serviced are industrial, standard parts so should be cheap to service.

As long as you dont buy from bounder!

Pair of motors, all same price, $7,100 or £3550 each! That doesent include brakes, sprockets, tensioners, wiring, etc. JUST basic motors. And they are not even very good. 65mOhm.

I can get a set/pair of 4 pole motors inc brake, and gearbox and hubs, 40mOhm, 8.5mph ready to fit for £860 brand new delivered at full retail. Thats TEN TIMES cheaper. Again bounder seem to have inadvertently added an extra zero or the price of a full chair for giggles again. They seem to be charging for 20 motors instead of 2.

Sunparts website for an 8.5mph Q700R for e.g:
 1-11 22710010-023 Motor, 4 pole, 13 kph, Motor P/N: 250292 RWD = right, (Identify the order number via the P/N on the motor) £ 433.25
 1-11 22710010-024 Motor, 4 pole, 13 kph, Motor P/N: 250293 RWD = left, (Identify the order number via the P/N on the motor) £ 433.25
RETAIL (and I can get 30% off that! So 600 delivered.)

Heres a set on the shelf as spares.
8.5mph or 13kph Linix motors as new still in the plywood box... I paid 220? "used"... Brushes are not yet even bedded in. So basically unrun or almost so. These fit ALL of my chairs. 30 to 35mOhm.



Heres a set of AMT 8.5mph motors. German made, £270 each delivered.
Sat on my bed... 40 to 45mOhm.



I have others too. ALL of these motors can be fitted to all of my various chairs. All the 6 and 8 mph motors are standard fitting. They would just need some compensation tweeking in programming.

How can anyone afford to keep 7k+ bounder motors on the shelf, especially as that doesent even include brake, sprockets, tensioner, chains, etc. That adds another 1K plus!

But since it's not direct drive, no brake. Do you think it'll be easier to find spare motors? Can I basically search for same size, same RPM?

Yes theres a brake. It fits over the small sprocket side. Its extra whan that wears out

Those motors are very old style. They are physically huge, 6 pole but pretty low impedance so not very powerful. As you can tell in the snow where it doesent have the torque needed.

Someone manufactures those, probably in the US. Can you find them? Who knows. But they like most motor manufacturers will make them and fine tune things like connecting cables/plugs, or actual winding resistance etc to suit a manufacturer needs. They will not be geared up to selling retail in groups of 2... So even if you found them they wouldnt likely sell to you. As that would upset their primary customer - bounder or whoever else uses them.

They probably are used in industry someplace like conveyor belts systems or farming etc where speed control is important. So DC motors are used.

But I mean the brake is external, no gearbox. It's just a motor with a shaft. What would prevent me from fitting a different motor?

Nothing prevents it.
Its just engineering. I fitted a 4.5 litre alloy V8 from a range rover, hotted up some, to a ford car where a 4 cylinder motor came out... Major engineering!
Is all just mind over metal. If you are stubourn anything is possible.

If you have a few tools and some knowledge and experience everything is possible. Its more a matter of is it worth the trouble! Will it be better when done. And how capable YOU are.

Bear in mind that the reason they use large diameter motors is because they have no gearbox. So the larger the diameter the lower the RPM and the greater the torque. Meaning they can get away with a simple single chain reduction ratio as a gearbox. So the motors you choose will need to be either VERY power hungry (to get the torque) or large diameter physically.

The reason modern chairs dont need massive looking motors like the bounder is that they have much higher reduction ratios in a simple gearbox now. To get the torque needed and then some, from a smaller more compact motor unit.

Try looking like this:

https://duckduckgo.com/?t=ffab&q=DC+IND ... iax=images

My old V8 car starting up outside the pub.

https://www.wheelchairdriver.com/gopro/V8.wav

But I've always wondered. In RC cars you can get a 2000kv motor or a 4000kv motors. Is it better to get lower kv and gear up or higher kv and gear down considering it's the same voltage?

Again it all depends what and why.

If we are using propellors we have an additional consideration. A larger prop all else equal is more efficient. So for propelling a plane a slower turning higher pitch larger area prop gives greater efficiency. So in that case we need a low KV motor.

If we use a high KV motor on a large prop then it will draw a HUGE current due to its lower impedance/higher load and so eat the battery. We want the KV that allows us to use 100% pulsewidth to get the desired thrust and match the load.

Thats why a helicopter has a huge rotor. A small propellor could do the same thrust needed to lift the mass. But you would need to feed it about 10x the power.

In a chair we are not worried about propellor efficiency. And we are just trying to get:
Adequate STALL torque.
Correct speed at 100% pulsewidth (battery votage).

If we were to use a higher KV motor, to drive the chair we would get the same result at the same current, and the same seeds if we then correct the output speed by using a suitable gear reduction.

But gears are wasting energy. So losing efficiency. And a motor spinning at double the speed wasted energy as it moves air inside the casing called windage losses. So to keep the losses low enough to make sense we use motors that turn around 3500 to 4500 rm in a chair. Or 9000 in my BM3 at 45V...

We could increase efficiency slightly more by using bigger diameter or slower turning motors. But not really enough to make a difference.

Theres another thing to consider here that we have not touched on.

The lower the impedance of the motor, the less battery power is wasted. So a 4 pole may draw more current (and make proportionally more torque) at any particular voltage. But its INCREASES range and overall efficiency hugely! Do you kow or care why?

emilevirus wrote:

Jay_x wrote:So to answer my question, there is no lever on these older models. You have to undo the clutch lever at the beginning of the chair and then unhinge the chain if there's enough play

If there's not enough play then you have to physically remove the brake system On the newer models they just have a button you can press, so as usual Bounder updates about 20 or 30 years after everybody else does

Easiest way would be to ask Bounder themselves. They'll tell you the easiest way to do it.

I did, that's what they told me right there

emilevirus wrote:https://www.wheelchairs.com/resources/pdf/pricelists/replacement_parts_service_order_form.pdf
Mine is brand new. Came overgeared. In snow it just won't move at all.

your bounder doesn't move in the snow at all?

Just power the system via its charge port. Dont drive the chair... Or jump cables to the battery. Or directly connect to the brake wires and add power.

your bounder doesn't move in the snow at all?

I added wider, agressive tires as well so all that combined. It barely moves.

Burgerman wrote:Just power the system via its charge port. Dont drive the chair... Or jump cables to the battery. Or directly connect to the brake wires and add power.

what do you mean power via the charge port? The batteries are 100% dead