A2B Metro - www.ultramotor.com - Video Page4

[wymjymn]

the + 6V sounds like something I will do, thanks.

as to the rear, I counted the small cog....=11teeth
large = 28 teeth

is yours different?


wj

[Ypedal]

I had to replace mine back some time ago, i'm currently using a shimano and my smallest rear is 16t, you are correct tho , the original one had a smaller gear ... will have to dig it up and double check..

[joepah]

That's an interesting thought Y... Adding a 6v in series with the A battery sounds like a good idea.

I went to a 46t chainwheel, but it didn't help much.. I can get to 21 mph with pedaling.

[Ypedal]

Gotten quite a few emails about this so here are a few pictures ..

Using 10ah PSI cells, ( lifepo4 )

a2b-6v-2.JPG (43.99 KiB) Viewed 848 times

Wrapped in crazy-carpet ( thick flexible plastic ), 2 cells in series .. 3.2v each = 6.4v ~ 6.0v operating voltage at this discharge rate..

a2b-6v-1.JPG (51.39 KiB) Viewed 848 times

I charge the 2 cells seperately.. with single cell voltphreaks chargers and anderson connectors, the stock charge plug in the frame for the A pack works the same as usual for the internal 36v pack.

Normally, the A battery fully charges to 41.8v, drops to 38v under load almost right away and fades away to 35v at the end of a long ride..

With the extra 6v, it shows 48.x volts hot off the charger, drops to 45~44v giving aprox 38~40 kph.. and 42v at the end of a ride still going 32 kph.

I need a larger chainring to help with pedaling at top speed, with the shimano 16t rear i'm unable to pedal on level ground, spinning too fast.

This is on an older version of the bike, recent models may be different, but the power wires going into the motor at the swingarm connector, are past the BMS and throttle LED's.. the throttle led's are connected to the BMS of the A pack so are not affected by the extra voltage.

[matt20]

What is the highest voltage that this will take without something catching on fire? I have a 48 volt pack I'd like to connect up, if it could take it...

[Ypedal]

A while back ( not sure what page .. ) .. i ran 16 cell PSI for 53v hot off the charger and dropping to 50v operating voltage for about 10 minutes, nothing went bang...

The soft start controller made 48v sluggish off the line for a longer period it seemed but this is something i have to test again with the CA calibrated to report back accurately.

[Gregor]

Going with a bigger chain-ring might be easier to install, but don't forget you may need to add a few links to your chain. If the rear wheel is easy to remove, then changing from a freewheel that is 16T smallest to 12 or 13 tooth would give you about 4mph more "pedalling added" assist. There are quite a few of these available on ebay, just make sure that you get a 6 speed (I think that is what was stock, tho I'm not sure) and that it has English threads. A shimano brand is probably the easiest to find a freewheel remover for, But again, that tool may have to be modified with a bigger center hole so that the axle will fit through it--I've had to grind the center out of one with a Dremel and it takes quite a while.

[deepfraught]

I didn't change the standard chain because in standard form I was only using 1 (top) and 2 gears on my commute. Now from 42 stock to 48 on the front I'm also using 3rd, leaving the massive 4 gears of larger rear sprockets still unused.

I have found my Australian 200W claimed restricted controller is speed limited to 25kph with throttle only, but does still assist while pedalling up to near zero assistance by 35kph. I don't think taller gearing will help me go higher in speed without adding more voltage like Ypedal has shown. since the standard assist at 35kph is negligible.

I've been riding it for a couple months or more now with the gearing increase mandatory for happy commuting. It is a good speed and is real cycling effort, working (e-relatively) hard to the benchmark of fast road bike commuters who do that pace. Over 35kph would be passing them into the fewer riders who do 35-40kph solo, or pairs/groups drafting each other, and would risk just being drafted by them unless able to break away for a burst with 40kph and taller gearing.

[Gregor]

Ah yes, it is a 7speed stock. A lot of it has to do with the maximum cadence that you are comfortable with--for some it is 50 rpm and for others it's 80 rpm. The higher revs are supposed to be easier on your knees.

[matt20]

A while back ( not sure what page .. ) .. i ran 16 cell PSI for 53v hot off the charger and dropping to 50v operating voltage for about 10 minutes, nothing went bang...

The soft start controller made 48v sluggish off the line for a longer period it seemed but this is something i have to test again with the CA calibrated to report back accurately.

Thanks for the reply. I put a 48 volt ping pack on the back and ran the bike for about 10 miles today. It seems to be working very well. Top speed seems faster than before. All I did was cut the black wire that goes to the auxiliary pack and connected up the +/- with Anderson connectors. The third wire I left disconnected.

[deepfraught]

Has anyone hit a wheel speed limit?

At top speed pedallling a short steep downhill, sustained pedalling shortly on the flat, no throttle use at all, the controller cuts power like a reset, battery lights on throttle flash, cut out altogether, then back on and resume normal operation.

Looking at GPS speed only.shows 34-35kph for this fast downhill/flat pedalling without any throttle.
However other flat section pedalling with motor I can get 36kph without any of this cutout.

I can imagine anyone with a mountain downhill pedalling faster than motor speed, they wouldn't want the motor to attempt to drive at RPM beyond its effective power output.

[deepfraught]

The favourite commuter continues. 6 month milestone for cycling every day to work this year, half of that now on A2B Metro.
I noticed lower performance in low to 0°C temps... or maybe it was the legs that were sluggish =P


I finally suffered the the loose rear mudguard rattle. Fixed it temporarily with some cable tie clippings jammed in the bracket gap.
Fixed it properly taking the axle nuts off, mud guard bracket bolts off, and using newspaper packing strap plastic cut down to bracket thickness in a U liner around the bracket in the swingarm to compress and eliminate all tolerance. Silent ever since.

I removed the top chain guide at one service, wife cleaned up the lounge-come-workshop, and haven't found it since. Chain would drop off to the guide going up to top gear on heavy shifts (always when passing someone on a climb, grrr!). So I have a few cable ties linked around the swingarm through an unused cable guide tab, providing vertical guide keeping the chain from bouncing off shifting to top gear.

Rear hard luggage case is cable tied solid to rack with four 7-8mm ties plus a couple spare for additional bungee cord points. I loop the cords around rear subframe and case to keep the layers of clothes as they come off warming up on the 20km trip to work.

An unused kitchen now storeroom/lockers at work where I now park it daily for charging, instead of the basement bike lockers. Without this spot, I would have a dilemma for charging the frame battery. I got a whole new Tornaro mid drive N360 drive bike featuring removable battery instead of the price of a new A2B rear battery. Bummer to carry 20Ah of battery just to be able to recharge 10Ah removable, when you only use 6Ah. A rear battery removing frame battery would give room for the 52V speed up that Ypedal has done.

Very happy with the A2B Metro, it is my favourite e-bike, and the quality in design and finish is apparent compared to cheaper options, and that counts with commuter routine and reliability.
My Norco A-Line with Hyena Hadron kit is faster but isn't as convenient a commuter bike (also isn't legal as the A2B is) and I'm only ~5min slower on journey (35min avg. to 40min avg.) but would spend more than that time saved with less convenient luggage, storage, and unique charging setup (A2B shares common charger with old chinese e-bike, and the Tornaro, so I have 3 chargers across work/home).
Thumbs up for the A2B Metro.

[Ypedal]

This week is a WET week, all day every day rain to the Metro is back in service.

ironic, the city bus service is now offline, the city locked out the bus drivers for demanding more money, bla bla bla.. everyone is pissed.. but i ride my Metro ! lol..

Ditch that seat, get a normal bike seat and you will find pedaling much more comfortable.. !!

[deepfraught]

I just removed the last pic that was out of chronological order, it was actually first/second test ride but just a pic of the stock bike to illustrate the kitchen/store room I've taken over as my own.
I think it's obvious after the first decent ride you do on that seat it's in the "LEV" bias they mention, rather than electric bicycle.
I have put the stock A2B seat over to my Norco which had a downhill seat of torture at the other extreme, with a short single speed ratio "get home emergency" backup to electric, it's more an e-trail bike.
Someone mentioned Cloud9 seats on another build thread, and my Fat Sand Bike came with one standard, that dwarfs this "ass master' that I thought was huge on the A2B.
The Cloud9 seat lives up to the reputation the others had mentioned, but the one there on the A2B is fantastic also. I used to think people were soft and needed to toughen up... I guess I've gotten old and soft myself wanting a Cadillac rather than Nascar ride =P

I did wonder today, what if someone else gets the same idea with my storeroom and there's a fight for e-bike parking/charging space... all good things must come to an end, so I appreciate it now while it lasts =D
There is some nice luggage available in the factory option notebook pannier wings and hard side and top cases I've seen around, along with the optional rear battery, I did think I should get my bike insured in case anything ever happened theft/damaged, it is $4k to replace without any optional bits. Hard to justify out of pocket when I paid a fraction of that for it used.

[wymjymn]

Some mechanical thoughts


Thought I’d share a couple UM tid bits.
I’m old (63yr) and use the UMMetro for daily ‘exercise’. 12 miles round trip, hilly terrain…..sometimes 18 miles, same terrain +/-.
I wanted to get more than leg movement from my rides so I replaced the front chainring with a larger one…it wasn’t enough…then larger…it wasn’t enough….finally found the Tempo 50/34 (arms+chainring) with the 34 t secondary sprocket removed. It made me feel as if I was doing a bit of work up to 20mph. The UM does 24mph (via gps) on the flat and at that speed (only when hot off of the charger) I’m basically ‘spinning’.
This larger front sprocket did not require a longer chain. I removed the tensioner and relocated the guides and the chain routing. I have never had any problems with the chain jumping the sprocket or it being too tight.
I have found that after 6,000 miles the rear freewheel was making a crunching sound when in high gear and pedaling hard. The problem was the inner portion of the freewheel was wearing.
I located a replacement freewheel….11t~28t, and installed it today. It is the same manufacturer (Epoch) and same gearing but the entire assembly is ever so slightly different. I needed to add a shim onto the axle so that the freewheel would….freewheel.
So, 6000 miles and so far, I have worn out one set of tires, one gel seat (on second one now), one freewheel.





wj

[deepfraught]

Thanks for the freewheel info WJ, also that's a nice clean bike =D

Where did you get the replacement Kenda Kraze 20x3" from? I have looked around a bit and not found them. I like the tyre's large radius tread profile truncated for the smaller tyre, and have pulled lots of glass shrapnel up to 5mm deep (x10mm long) from the tread.

I need to grease the idler as it can clunk around at times of varied riding, but disappears with load off and on when on a steady straight.

I'm also debating hydraulic brakes, or just more pads for the BB5. I liked the Avid BB5 manual adjustment cable brake performance, and simplicity to tweak while on the road waiting at an intersection you may have just tested the brakes leading up to. Adjustable lever position "standard" with cables, but is a higher spec option for hydraulics. Nearing end of life on the original BB5 pads, the uneven wear and maxed out adjustment means braking strength has dropped off. I'm debating whether to switch to hydraulic like the Code 5 on my 2009 Norco, as I also need a disc front brake set for another bike. I need to put fluid in the front brake of that Code 5, so will do that first as it might help me decide against the hydraulic =P

[Ypedal]

http://ypedal.com/A2B/a2b2.htm

I replaced my pads last year with these from ebay, so far so good, they hold up well, and were cheap.. the BB5 are good brakes..

hydraulics, i have very little experience with them, but seems like they always drag a slight amount, the cable disk can be set to pull away from the rotor completely for a free running brake.. every watt counts !

[deepfraught]

Thanks, I've got them dragging a little now due to the uneven wear to get better braking and the last life out of them. I just consider it a bit more forced effort for the legs.
Besides I'm supposed to have unlimited watt hours in my 200W leg motors and lifepodge264 body fat batteries.

[robohead]

Anybody running a Metro at 72V yet? I upgraded to the stealth bomber. Now when I get on the old metro I feel like I'm walking.
If you were to try and mod a metro to run at 72V, it's just a matter of putting the A+B batteries in series, replacing the throttle, choosing a motor and getting it laced, then probably putting a Lyen or Crystalyte controller on the back rack?

[The Stig]

Anybody running a Metro at 72V yet? I upgraded to the stealth bomber. Now when I get on the old metro I feel like I'm walking.
If you were to try and mod a metro to run at 72V, it's just a matter of putting the A+B batteries in series, replacing the throttle, choosing a motor and getting it laced, then probably putting a Lyen or Crystalyte controller on the back rack?

Thats what I've done. The A + B batteries are in series with Bypassed BMSs for discharge. It has a Lyen MKII 12Fet controller, BMC V3T motor, Hydraulic brakes.
Unfortunately I've had to leave Greece before I got to put the finishing touches on it... but I get to finish it before the end of this month!

[robohead]

Anybody running a Metro at 72V yet? I upgraded to the stealth bomber. Now when I get on the old metro I feel like I'm walking.
If you were to try and mod a metro to run at 72V, it's just a matter of putting the A+B batteries in series, replacing the throttle, choosing a motor and getting it laced, then probably putting a Lyen or Crystalyte controller on the back rack?

Thats what I've done. The A + B batteries are in series with Bypassed BMSs for discharge. It has a Lyen MKII 12Fet controller, BMC V3T motor, Hydraulic brakes.
Unfortunately I've had to leave Greece before I got to put the finishing touches on it... but I get to finish it before the end of this month!

The Stig:
Did you document any of what you have done thus far? I went back a few pages and did not find anything.

I did run across this however viewtopic.php?f=3&t=35078

[wymjymn]

Hi,
I searched everywhere and finally had to resort to purchasing through the UltraMotors dealer network. It seems that tire was a 2009-2010 model and wasn't replaced with anything. Maybe UM has a warehouse full of them.

I was going to post the url for the freewheel…..guess what? No longer available!
I hope it lasts a while.


wj

[wymjymn]

well, three years-three months-lots of miles and the metro motor has gone -puuuuf.
out riding the other day and all of a sudden things slowed waaaay down, pedaling was waaaaaaay difficult, as if I had the brakes on.

It got a trunk ride home and I checked the continuity of the motor leads....dead short!!!

any advice? buy a new rear wheel/motor
buy a different motor controller and have the rim laced to it


look for a used a2b and grab the motor


thoughts?



wj

[Ypedal]

Open that sucker up, rip out the internal controller, run external wires and install a 3rd party controller.. lyen or similar....

i'm positive the motor is fine, it's the internal controller that shorted out and cooked.

is what i would do.

[wymjymn]

I'll pop it apart this weekend and see what is burned up


Which specific controller and throttle would you recommend? I'm not looking for problems going forward but would like a bit more acceleration and top speed.
(if I'm going to need to spend a lot of time configuring things (since I want to get back on the road asap) then I'll consider getting the stock wheel assembly and play with the burned unit as time allows)
wj