Bighit 8t mac

[Bill Nye the science guy]

You could grind or belt sand the diamond plate flat and then skim it with good quality body filler, then paint. done.

high build primer makes life easy.

 

[deffx]

You could grind or belt sand the diamond plate flat and then skim it with good quality body filler, then paint. done.

high build primer makes life easy.

Sounds to much like hard work

 

[Spicerack]

That does sound like hard work- because it is! I quite like the look the way it is- way neater than my dodgy Mad Max style setup. I'd ask Timma to do the same to my bike but he's selfishly nicking off to the other side of the country!

Coming on the ride on Saturday morning?

Andy

 

[deffx]

Hopefully I'll be there.
Not finished, but running some configuration

 

[Samd]

Looks good coated!

 

[deffx]

Looks good coated!

Thx Samd

Pics don't do it justice, looks great in real life

Put a new chainring, chain, freewheel and dérailleur on when I rebuilt it. Nice, gears work properly now.

Laced the Mac into the mtx31 rim myself, was easy

New front wheel, saint hub, mtx31 rim

Just need to work on some external battery and balance connections now. And a dcdc to power some lights and a cooling fan

 

[jesset33]

Looks real good mate
Does that 8t pull wheelies
And what area of perth you located I'm in fremantle

 

[deffx]

Looks real good mate
Does that 8t pull wheelies
And what area of perth you located I'm in fremantle

It wheelies if your going really slow and give it a tug on the bars when you crack the throttle, but no power wheelies at speed, The 8t Macs certainly no monster, but a good motor for its size and weight, much more torque than my crystalyte 408 dd

I'm outback Wanneroo 60km north of Freo

 

[jesset33]

Check you PMs mate need your number if we are going to ride

 

[deffx]

Lost a couple of teeth

 

[Gregory]

Oh no! Looks like you did a number on that. Fix it up and put the MAC on a lower power machine. 30A max I think.

You looking at a DD as a replacement?

 

[deffx]

Oh no! Looks like you did a number on that. Fix it up and put the MAC on a lower power machine. 30A max I think.

You looking at a DD as a replacement?

I'm using a crystalyte 408 dd, whilst I wait for the replacement gears, its totally gutless and heavy

I think I'll stick with the Mac when its repaired, its been OK for a year with my riding

It broke when I let someone else ride it, full power of a curb going slow

I have considered a decent DD motor, but the weight, extra batteries to up the voltage, more weight and the cost is kind of putting me off

Also considered the bbs02, but I believe its a bit gutless, certainly don't want anything less powerful than my Mac 8t on 15s @ 40A

I'm open to suggestions though

 

[Samd]

Yeah I found the 750W BBS uninspiring, and a PITA in shifting gears before jumps, or riding a new section of single trail with NFI what is around the corner. I've decided to put a BBS02 on the new wife bike for hauling kids.

I always keep a spare BPM in stock, and a clutch assy with new gears, for a few hundred bucks they are easy to swap out annually or so. ~63V 35a is a lot of fun down low, and the mid band torque isn't far off a DD without all the fat that comes with DD. Agile setup.

I'm toying with some large front torque bolsters on some triple clamp forks and running another geared unit up front. Kingfish's setup still inspires me for face pulling torque and the ability to switch hubs during long hillclimbs for heat load sharing. And I like the idea of climbing lots of stairs during urban freeride with the front motor pulling up.

 

[PRW]

Kingfish's setup still inspires me for face pulling torque and the ability to switch hubs during long hillclimbs for heat load sharing. And I like the idea of climbing lots of stairs during urban freeride with the front motor pulling up.

and don't forget the Duty Cycle, with Mac 8t's back and front...

 

[jesset33]

Mate why don't you do oil cooling
Help the motor tones, cooling and durability under load

 

[deffx]

Was seriously thinking about it and upping the volts a bit, before it broke

Its like new inside, I rode it for a year without breaking it, as I understand its weaknesses

But I let an inexperienced/inconsiderate teenager ride it and he broke it in under two minutes

Lesson learned, don't let dickheads ride my bike

I guess I can seal it up properly when I put it back together ready for atf

 

[jesset33]

I'm a teen who can ride it right :lol:

Be careful as some AFT oils have ingredients that ruin the windings.
I reckon 72v and 40amps should be a real hoot with oil cooling

 

[deffx]

You won't want to ride it now you got your phasor

And yes, i was wondering which atf fluid, maybe spicerack could chime in, won't destroy heat shrink, glue, and wire sheathing etc

 

[Spicerack]

Yup I ran standard dexron III or similar. Everything was fine after a year but expect some leakage. ..

I was running 62v 35a and it was still marginal for heat. I wouldn't go much more power than that our it would just heat up to quickly. It was pushing alot of weight tho. 105kg me, 15kg batteries and a heavy bike to start with. ..

When the freewheel thread broke off the side cover I put a9c 8x8 on, vented it and have never had a heat problem at the same power levels.

 

[deffx]

Yup I ran standard dexron III or similar. Everything was fine after a year but expect some leakage. ..

I was running 62v 35a and it was still marginal for heat. I wouldn't go much more power than that our it would just heat up to quickly. It was pushing alot of weight tho. 105kg me, 15kg batteries and a heavy bike to start with. ..

When the freewheel thread broke off the side cover I put a9c 8x8 on, vented it and have never had a heat problem at the same power levels.

Thx Spicerack, I reckon it's worth a try, How does your 9c compare power wise? This 408 i'm using is totally underwhelming, I even have to peddle to help it up hills it's so gutless, just running on the same 15s@40A, I guess more volts might wake it up a bit

Still I bought it as a back up, and that's what it's doing, so I'll live with it until my gears arrive, hurry up cell_man!

 

[deffx]

Actually after riding this 408 for the last couple of days, obviously it lacks the bottom end torque, which I miss, but it's got great mid range and cruising speed if the hills aren't too steep or there's no headwind

And the silence is golden

Think I'll mod it when the macs running, drill the sides, upgrade the phase wires, and run it on 18s+

Really notice the weight though, maybe drilling it out and relacing a new rim might helpa bit

 

[Spicerack]

I have three grey gears here- you can have those and I'll grab the ones you've ordered from Paul whenever they get in?

The only downside is one of the bearings is bad- has a minor click in it and I was going to put a decent bearing in before using the gear. Easy enough and if you bring your old set around we could do the whole job here. You may have to drink a beer with me tho...

Let me know- I'm in Basso. I'll pm you my mobile.

 

[Spicerack]

Oh and my 9C 8x8 is slower than my mac for the volts (15S) and maybe a little bit slower on acceleration but runs sooooooooo much cooler it's not funny.

I do 45-47km/h with the 9C and 55-60 with the mac.

 

[knoxie]

Nice Bike!

I have been running macs and BMC motors for years (nearly 10 years) , 2kw is the sweet spot, anything over that and you will quickly blow the one way bearing in the freewheel or rip the teeth out of the gears, riding style also matters as you have found out, nice smooth assisted starts and no sudden jolts.

Have you checked your one way bearing? Are you getting a complete new freewheel or just new gears? if you are just getting the gears by all means fit them but if you find the drive slips when you apply the power its likely that the one way bearing has gone as well and you will have to change the whole assembly.

My experience in running high power has been the one way bearing breaks and spits bits of itself in to the gears damaging the gears.

Running high power very often will desolder the power wires as well, the power wires are often poorly soldered to the axle power cable and will unsolder themselves at higher power, whilst you have the motor off its worth getting a 50W soldering iron and remaking them as they will in time become unsoldered.

Good luck with the bike.

 

[deffx]

Nice Bike!

I have been running macs and BMC motors for years (nearly 10 years) , 2kw is the sweet spot, anything over that and you will quickly blow the one way bearing in the freewheel or rip the teeth out of the gears, riding style also matters as you have found out, nice smooth assisted starts and no sudden jolts.

Have you checked your one way bearing? Are you getting a complete new freewheel or just new gears? if you are just getting the gears by all means fit them but if you find the drive slips when you apply the power its likely that the one way bearing has gone as well and you will have to change the whole assembly.

My experience in running high power has been the one way bearing breaks and spits bits of itself in to the gears damaging the gears.

Running high power very often will desolder the power wires as well, the power wires are often poorly soldered to the axle power cable and will unsolder themselves at higher power, whilst you have the motor off its worth getting a 50W soldering iron and remaking them as they will in time become unsoldered.

Good luck with the bike.

thx man great post and advise

i'm still gonna push it to its limit, 16s then 17s then 18s but drop the amps some as i go, should probably invest in a ca3 for thermal rollback, im just addicted to the torque

cheers