Bighit 8t mac

[deffx]

Bighit 8t mac

Just thought i should post a thread for my bike, as i have been following endless sphere for a while and randomly posting generally useless information

Nothing very creative in my build except maybe the battery box, which took inspiration from "timma" well the cutting and chopping not the exicution

8t mac, 12 fet 4110 infineon, 15s 15Ah zippy lipo.

2007 Specialized big hit 2, chequer plate box cut into frame to house batteries and controller

The box was a favour and a rush job, not much planning i.e we made it up that morning, but my friend is a first class welder and did a great job with the limited tools, materials and work area we had on hand that day.

A year now and the frame is holding fine, 15s was the secret for fun after running 12s for a while, I can keep up with 50cc mopeds/scooters but blow them away on acceleration, freaks them out! Not sure how long the mac will hold up 40+ amp peaks, but i only go flat out 10% of the time

Bike rides great, i previously fitted the kit to a couple of lighter xc bikes, soon realized i needed a DH/freeride bike.

Not much fun pedaling it without power, but it was not much fun to pedal before the motor

Before

Nearly finished

Freshly welded



Stealth Matt Black

Early days


.



My ghetto backup bike

 

[hjns]

Very nice kitten, I think you mentioned it in another thread as well.

I just started with a Big Hit build myself, slightly bigger motor, though.

 

[deffx]

Very nice kitten, I think you mentioned it in another thread as well.

I just started with a Big Hit build myself, slightly bigger motor, though.

Thx and yes i did mention it before, just thought it would be nice to share and document it in its own thread

I think I should put a bigger DD motor on too, before I kill this Mac

Looking forward to see your build as i really like these specialized BigHits

 

[dawrench]

A beautiful build. What thickness of plate in the battery box? Did you have it heat treated?

 

[deffx]

G'Day Dawrench

LOL "beautiful" is not how id describe it, practical and great fun is

Its 3mm plate, no heat treatment, No problems so far, I don't really jump higher than a foot if that, but have hammered it somewhat offroading. Its pretty heavy and planted

I was going to get it powder coated which involves going in an oven for a while, kind off a semi heat treatment. But it is going under the knife again, i would like to do a more refined/intergrated tank job.

Carrying a decent battery was my main requirement, it has 30Ah @ 12s or 20Ah @ 15s, thats roughly 1300-1500 Wh

Recently updated forks, stem and wider bars,

 

[Lussy]

Deffx,
I have just bought the same bike and looking to make similar mods. Will either go with the 'box' option like you have or will replace the whole bottom tune similar to timmas builds. Did you cut out the existing bottom tube or is it hidden inside the box?

Cheers
Matt

 

[deffx]

Hi lussy.

Bottom tube removed, kept half the top one to help keep the angles/length and I think its given it some strength

Was a real rush job at the time, would love to redo it one day' timma style

Great bike though, rock solid at 60 km/h

One idea is to build a complete new front section and have the option Of switching back the original frame to sell or ride. To late for me now though

Look forward to seeing yours

 

[deffx]

small update, new rear shock,a "romic" I had never heard of them

but a google search revealed they were pretty good back in the day

$50 three springs, 400,500 and 600 mint condition, worth a gamble

The big hit i bought had a 750 lb spring, on a fox vanilla r

way to hard for little me 72 kg 150lb,

So i was looking for a new spring for the fox when this turned up local for $50

What a difference, trying not to swear,

Having correct sag, compression and rebound (still need to play around alot)is frocking amazing

Ran one of my usual routes and the bike just ate it up, like floating on air

I have been running low pressures in my tyres to compensate for the hard rear end,

which isnt advisable as you can spin the tyre and tube.

I am gobsmacked how well it rides and inspires confidence,i had a couple off massive saves, it was good before but now

Need to put my Knobblies on and go for a bush ride

Sorry to rave on but am stoked with the shock and the missis just doesnt get it

 

[deffx]

just went for another run a bit more hard core, masivly impressed, this is my bad for having the rear spring rate wrong for so long.

i am getting so much grip were it would slide before, mental

 

[John Bozi]

One of these days I'll get started on my triangle. I like your fighter looking bike.

looks like a pain to get batteries in and out...

My greatest concern when going more than 2 bricks is charging and balancing

 

[deffx]

THe access hole has grown a bit since then

sneak peak of something im working on

 

[John Bozi]

Is that a norco?

Your not worried about the strength of the frame? Looks exciting if it holds up. How wide is the frame? enough for 6cm lipo?

 

[deffx]

Is that a norco?

Your not worried about the strength of the frame? Looks exciting if it holds up. How wide is the frame? enough for 6cm lipo?

Yes an old Norco shore vps 2002

Worried? Hell yeah! I'll get it rolling without a motor and make up some bolt on side covers. Then test it out

Width is 40mm internal at the moment so 4s packs, 10 Ah at 12s should fit

I was inspired by this build

http://endless-sphere.com/forums/viewtopic.php?f=3&t=39746

I think I may probably have to chop it a bit wider, it's early days

 

[Lussy]

Deffx,
Finally finished my build (nearly). Didn't end up welding to the frame but used epoxy to attach a alloy box.
Bighits are a good donor bike.


http://endless-sphere.com/forums/viewtopic.php?f=6&t=56221
cheers Matt

 

[Bill Nye the science guy]

My welded frame has taken a good beating without any problems, no heat treating. a machinist told me that a quelch in water will harden the aluminium. the aluminium welded on is alot thicker than the thin light weight tubing of the original frame. I haven"t let my bike do any ghost rides down any hills but I throw it into alot of rocky areas. my opinion is heat treat is a non issue as long as the whole frame doesnt reach a very high temp while welding.

Bikes look awesome. vids always appreciated.

 

[iovaykind]

That thread with the Norco would be mine Good to see it inspired you. After riding the ebike for quite awhile, and taking it off curbs and small jumps.. I have to say that even with the two panels taken out, it didn't feel like there were any issues whatsoever. That being said, I think if I were to do it all over again, I wouldn't. It really was a lot of work to get all the batteries and controller in there. What makes it worse is that once its all done, I didn't have access to the guts. If a cell were to go bad, I would be stuck with really no solution. Hope you can figure out a way to fix the issues I encountered.

Anyway, I long sold that bike and made a good profit off of it Happy ebiking and be safe!

 

[deffx]

Deffx,
Finally finished my build (nearly). Didn't end up welding to the frame but used epoxy to attach a alloy box.
Bighits are a good donor bike.


http://endless-sphere.com/forums/viewtopic.php?f=6&t=56221
cheers Matt

Thats awsome Matt, at least you can convert it back to a normal bike if needs be

Yes good solid bike for a fast and offroad capable ebike, heavy as fuk though and terrible to peddle unassisted

 

[deffx]

That thread with the Norco would be mine Good to see it inspired you. After riding the ebike for quite awhile, and taking it off curbs and small jumps.. I have to say that even with the two panels taken out, it didn't feel like there were any issues whatsoever. That being said, I think if I were to do it all over again, I wouldn't. It really was a lot of work to get all the batteries and controller in there. What makes it worse is that once its all done, I didn't have access to the guts. If a cell were to go bad, I would be stuck with really no solution. Hope you can figure out a way to fix the issues I encountered.

Anyway, I long sold that bike and made a good profit off of it Happy ebiking and be safe!

I got the frame cheap, but building it up is going to cost $

It will need some welding work too, as i need to remove the indented panels both sides to accomodate 4s batteries

Wanting to put a bafang bbs02 on her, but a bit short on funds at the moment so its going to take a while to complete

 

[deffx]

My welded frame has taken a good beating without any problems, no heat treating. a machinist told me that a quelch in water will harden the aluminium. the aluminium welded on is alot thicker than the thin light weight tubing of the original frame. I haven"t let my bike do any ghost rides down any hills but I throw it into alot of rocky areas. my opinion is heat treat is a non issue as long as the whole frame doesnt reach a very high temp while welding.

Bikes look awesome. vids always appreciated.

Yes no problems here either, fingers crossed, touch wood,

Was worried and checked it alot at the beginning, but i have totally abused this thing for almost a year and no problems

the big hit frame is 2mm ali and the box 3mm ali, its even hard to drill a hole in the box.

This is what was cut out

 

[jesset33]

very nice big hit and another perth ebiker
how do you like the mac motor

 

[deffx]

very nice big hit and another perth ebiker
how do you like the mac motor

Hey Jesse

The big hit is awesome. Heavy and not a "pedal" bike. but it never was even before electrocution

Love the Mac. It's an 8 turn run at 15s on a 12 fet infineon at 45 amp peaks. 60+ km/h. That's right on its limit. Over its limits really. Just been lucky I think, but I rarely run flat out for long unless it's late at night or I'm drunk. In retrospect I probably do run it flat out often but just can't remember .

Defiantly worth considering especially now Paul offers the new upgraded stator version. Should be even better.

If you would like to try it pm me

 

[Samd]

Nice work fella! It would look even better with a coat of paint all over. But who am I to criticise

Good job.

 

[deffx]

Nice work fella! It would look even better with a coat of paint all over. But who am I to criticise

Good job.

Thx Sam

I was holding off on powder coating thinking I'd redo the box. But as it's proved to be strong I think I will live with it. Ugly as it is. Pretty close to putting together a second bike so this one can be stripped and get painted. For some reason I'm thinking white even though Black's stealthier

 

[Samd]

My fabricator doesn't T6 heat treat any more on his buggies for what it is worth, so I haven't on my frames. The harmonic vibration is much nicer in the untreated frame than my T6 6061 aluminium pub bike - that thing rings like a bell when ridden even with a little Q100 hub.

Most high cost bikes I see now aren't T6 heat treated either. I think times have changed for the better.

I used some matt black plastidip spray on my first frame. All the boy racer types seem to do their bonnets now and peel it off when they change their mind for another colour. I like the rubbery feeling of it - mud brushes off. Worth a try IMHO. it does scratch much easier than powdercoat and peel at edges, but its easy to patch so who cares.

Cheers fella.

 

[jesset33]

Got a link to where you got the plastic dip spray ??