Rebuild BM2 green...

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Re: Rebuild BM2 green...

Postby Burgerman » 03 Oct 2015, 07:51

Close tyre in metric? How wide? What diameter?

Closest to a 3.50x8 is just that!
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Re: Rebuild BM2 green...

Postby Burgerman » 03 Oct 2015, 07:55

120/70 8 is same diameter.
Or 130/70 8?

110/80 or 100/80 also options.

But all need a wider rim.

You work it out like this:
3.50 x 8 is: 3.5+3.5 (top bottom sidewalls) + 8 rim. So 15 diameter.

120/80 for eg means 120 wide, but 80% of this sidewall. So each sidewall is 80% of 120,,. Which is 96mm top, + bottom.
Thats 192 div by 25.4 to give inches. + the 8 inches rim diameter. So about 15.8 inches. So a bit bigger.

Same diameter as my 130/60 10 or 145/50 10 tyres. A ride height increase of only 12mm unless you lower the pressure some.


These are the same diameter, but need a 3.00 or 3.25 to 3.5 wide rim.
http://www.shirebikes.co.uk/collections ... eless-tyre

Fitted

http://i74.servimg.com/u/f74/11/66/30/96/img_2926.jpg

Same. Fitted to a WIDE rim, http://www.gm-moto.jp/item/duro8120/ 4.75 inches.
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Re: Rebuild BM2 green...

Postby shirley_hkg » 03 Oct 2015, 14:04

Got it . :D
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Re: Rebuild BM2 green...

Postby rustyjames » 03 Oct 2015, 15:50

What's Greenie going get for a control system?
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Re: Rebuild BM2 green...

Postby Burgerman » 03 Oct 2015, 15:52

Its my old BM2 so the same old 100A pilot plus it has had for the last 3 rebuilds.
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Re: Rebuild BM2 green...

Postby Burgerman » 05 Oct 2015, 12:48

I am off my bed.

A photo for those interested.
Rim = 10 inch diameter. 4j inches wide. Tubeless.
Tyre = 130/60 - 10 Tubeless.

This rim is "wide" for the tyre. Almost as wide as the treaded part. So it opens it out and has a flatter profile. If you prefer the 145/50 - 10 tyres also fit, and you get a normal rounded profile. And is 15mm wider. If I could find these 145/50 - 10 tyres in UK I would try a set. But shipping from the US is scary... £$£$ And customs can be a fight unless shipped as low value/gift etc.
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Re: Rebuild BM2 green...

Postby hank » 05 Oct 2015, 16:23

They look amazing in your picture. Do the wheels come polished or have you
had buffer out.lol. :ugeek:
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Re: Rebuild BM2 green...

Postby Burgerman » 05 Oct 2015, 16:52

Not touched them yet. Straight out the box. The spokes are grey/silver and painted. Rims are (were) polished. I am about to get the Silvo out and re polish them!
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Re: Rebuild BM2 green...

Postby hank » 05 Oct 2015, 17:05

Not going down monkey bike or quad mudguard route, Now tarmac spec
with running solid suspension setup.
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Re: Rebuild BM2 green...

Postby Burgerman » 05 Oct 2015, 17:06

Another
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Re: Rebuild BM2 green...

Postby hank » 05 Oct 2015, 17:10

Lovely wheel choice. :ugeek:
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Re: Rebuild BM2 green...

Postby Burgerman » 05 Oct 2015, 17:29

Choosen because of, tubeless, and width, and offset (1 inch inboard). And price! And because that centre makes it easy to cut a 108mm disc with 4 holes and polished to finish off the centre.
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Re: Rebuild BM2 green...

Postby Burgerman » 06 Oct 2015, 20:27

http://www.lasermaster.co.uk/metal-laser-cutting

For those looking at these wheels and rims.
And I just ordered 4x 120mm aluminium disks, from above online. (see quick order on left.)

2 are 6mm thick, and will sit on the recess at the front after polishing with 4x wheel bolts visible.
2 are 8mm thick and will sit behind the wheel in the opposite recess, and these will be drilled to suit the old wheel adapters. And the 3 existing bolts for the old rims, hidden. So it will all look pretty.
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Re: Rebuild BM2 green...

Postby hank » 06 Oct 2015, 21:14

What grade of ally John for discs is it.? Dural
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Re: Rebuild BM2 green...

Postby Burgerman » 06 Oct 2015, 21:32

No idea. As long as it polishes! Its 8mm plate, and more than strong enough as an adapter plate regardless of alloy. Unless its super, super, soft... Even if it is, it will just deform.
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Re: Rebuild BM2 green...

Postby hank » 06 Oct 2015, 21:49

Like you say will polish up nice to match wheels :shock:
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Re: Rebuild BM2 green...

Postby Burgerman » 06 Oct 2015, 22:25

Why shocked? Dont worry it will be stronger than the rims or the output shaft!

Get a lump of 8mm alloy plate, the same size as a CD, and try bending it. You will be convinced very quickly!
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Re: Rebuild BM2 green...

Postby hank » 07 Oct 2015, 08:53

Did not think of it like that John.Like you say could not bend it on a 8mm cd size alloy disc. ;)
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Re: Rebuild BM2 green...

Postby Burgerman » 07 Oct 2015, 09:26

Get a lump of 8mm alloy plate, the same size as a CD, and try bending it. You will be convinced very quickly!


Or look at the thin 1mm steel all terrain wheel rims, or at the 2mm thick hegar rim material.
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Re: Rebuild BM2 green...

Postby snaker » 07 Oct 2015, 10:16

Can you estimate the BM2's weight (the chair only, without batteries or human :P )?
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Re: Rebuild BM2 green...

Postby Burgerman » 07 Oct 2015, 12:48

Not really. But its a hell of a lot lighter than the original F55s chair it started life as.

viewtopic.php?f=2&t=5428
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 16:24

Tyres fitted to the over wide rim, and it fattens them up just right, makes them put more rubber on the ground, and allows a lower pressure to give some ride improvement, and they look great. This is a 130/60 on a 4" wide wheel. The wheel stood upright has also had a very quick 2 minute polish, and it already looks better...

These are 5 and a third inches wide. And 16 inches and a fraction total diameter. So not much taller than the 3.50/8 tyres. But about 1.5 inches taller than the turf or 145/70 all terrain tyres.
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Re: Rebuild BM2 green...

Postby hank » 08 Oct 2015, 16:29

Want them. :D
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 16:50

This isn't inflated, and it isn't polished yet. Just put 400cc of tyre "off road" sealer in, and replaced the valve core... Punctures are not going to happen.

Tubeless tyres don't puncture easily. Especially lightly loaded low pressure wide ones. Especially 6 ply ones! And if they do then they don't deflate normally anyway. And just in case I have added a lot of the best off road sealer I know of!

OKO off road. http://www.amazon.co.uk/Off-Road-Tyre-S ... B006THGZZ2

This stuff seals massive holes. http://www.oko.com/videos/
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Re: Rebuild BM2 green...

Postby hank » 08 Oct 2015, 16:56

John did you have tyres fitted. Or you used tyre levers.
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 17:57

Took them to my local motorcycle shop. Its too hard to do tubeless 6 ply low profile tyres in a wheelchair... I let them do it on a machine.

Here's another pic, boxes of lithium cells, motors, bubble wrapped parts in the background, wheels, tyres, in the corner of my room... Expensive pile of bits to make a 6mph chair with ridiculous 4.3x as much range as a stock F55!
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 17:59

It just occurred to me that I may be a bit mad.

And may change it to roboteq while I am at it...

And that the 6.2 mph EMD motors with 14 inch wheels are now actually 7.1 mph motors with 16 inch tyres on.
A 14 percent increase in speed and a 14 percent decrease in torque.
So...
The 150A Roboteq will address that, with a huge 50 percent torque increase possible... Set to say 114A max it will be the same as before. And the Roboteq allows for full battery voltage too, so up from 22 from the lead/pilot plus, to 25.x from the lithium/Roboteq. Another 14% percent speed! So... That would now allow 8.1 mph. But at great expense... And much more work.
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 19:07

This build wont be doing anything ground breaking, its more for looks, and silly amounts of range.

It will look cool though!
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 19:59

OK. Turns to the Lithium cells. I ordered 84, will use 82.
They arrived tax free from www.evassemble.com via a well known US shipping company, in 5 days flat.
They arrived as 7 separate packages since shipping lithium is hazardous, with all the regulatory certificates etc.

Each package contained boxes with 2 cells in each. All were 3.371V (+/- 0.05) which means fully charged plus a month sitting around.

They arrive looking like this x 42 boxes:
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Re: Rebuild BM2 green...

Postby Burgerman » 08 Oct 2015, 20:09

Now, each individual cell is to be fully charged to 3.600V and sit at this CV voltage until its current falls to 20mA. At which point it then has 1000mA drained from it, and it goes into a pile in a box to wait for 1 month.

CHARGE 3.600V 5A
TERMINATION POINT 20mA.
REMOVE 1000mA exactly (at 5A Discharge)
STORE IN A BOX!

After 1 month, each will be fully charged once again, back to 3.600V and terminate at 20mA, and the actual mAh that was returned to each cell, (-1000) will be written on the cell in marker pen. This figure is the amount that the cell has SELF DISCHARGED (over and above the 1000mA we already removed) over the month.

This allows us to build 8 separate parallel groups, that have the same TOTAL self discharge, before assembling into the Series connected battery. It means that if we store the battery for a few months it will discharge each group at the same rate. So it will remain in balance.

2 at a time, takes FOREVER!
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