Specialized Big Hit FSR

rodgah said:
izeman said:
26" wheels
Click to expand...

24" with 3.0 tyres, and dont quote me but I think my middle speed is programmed as 100% and probably 50a. All things considered I dont see why it wouldnt wheelie...
Click to expand...
ok. i didn't consider you're riding a 3525 which is the torque version, and 24" is better than 26". i set my 3540 to 60a and removed the heavy battery from the box, but still no real danger of uncontrollable front wheel lifting ;) or should i say :(. it maybe the longer wheel base which moves the cog more to the front.
your bike is a real beauty. nice welds, and looking good. only thing that would make me mad is the battery wiring madness - a thing you can't avoid which a lot of lipo.
 
I bought a cheapo shock pump off ebay for the forks as they are air-sprung......



result......
WOW, if you need a shock pump dont waste money on brand name ones, just buy one of those and save your $$$ for more electrical goodness.....it is excellent quality and cost a half to a third of the big brand ones ($30). I adjusted sag and played with the dampening and rebound and fiddled with the shock as well to match the front and I am blown away, the bike feels so much like a motor bike now. If anyone is in the market for forks and is looking in the single crown air/spring area choose rockshox totem air, they are a brilliant fork.

off to jump something......
 




went for a long ride today. Since I have no CA or anything to tell me where my pack is at I pedaled most of the way with a bit of assist, and a few spirited runs through the forest. I ended up coming home with 65% left to go....and I only charge to 95%....30% damn. I gather I probably could of run the whole distance on speed 1 on the 3 speed no pedaling and still only have used 40-50%. I couldnt imagine wanting to ride much further, but maybe some more antics in between so there is plenty of head room for that :wink: . I am going to get a CA, but also on the horizon is this russian controller adaptto?, that has taken my interest more, but still not for sale.
 
nice!
What kind of metal was used to build the box? How did you TIG it to the existing frame? Would MIG work? Thought it was hard to weld to aluminum?

I guess the only downside to this setup is that your frame could crack where the box is and not know it? On the plus side the box adds maybe only 5-10 lbs? and is a little more fire proof than a bag, if the lipos hate you one day.
 
Haste said:
nice!
What kind of metal was used to build the box? How did you TIG it to the existing frame? Would MIG work? Thought it was hard to weld to aluminum?

I guess the only downside to this setup is that your frame could crack where the box is and not know it? On the plus side the box adds maybe only 5-10 lbs? and is a little more fire proof than a bag, if the lipos hate you one day.
Click to expand...

its all at the start of the thread....aluminium, tig though mig would work but its hard to do a nice job an not warp it. its not hard to weld aluminum people just get their nickers in a knot about it. If it were to crack I am sure I would see it. Whole bike weighs in at 35kg.
 
I have been looking for good 24" tires. What are you running, and - more importantly - where did you buy them?
 
the big hit was from crazy downhill days with weird ideas...like 24" rear wheel and 26" front (if you look closely at the first picture of this thread you will notice it). 26" doesn't fit at all and 24x3 is a squeeze in the rear but works. I like the big tyre look anyway, little more protection for the rim from that hub is gotta be good.

I buy just about everything that is new through http://www.chainreactioncycles.com/, though the tyres must be a hot item as I had to wait a while for them on back order. They are halo contra. They are absolutely awsome on dirt and grass but wont last long on the road :( .
 
really nice uphill bashing. i love this :)
you say you run 50A (5000W). i think you didn't install a CA (yet?), so i also assume you have no heat probe installed. correct? so you don't know it this thing runs hot ... i found that my 3540 gets really hot @4kW. some minutes riding like in your video and phase wires are at 120°C.
did you do any modding on the 12fet controller? i have mine installed in the same place as you, and it seems to handle 4kW+ quite well if you're up to some speed, even though it''s said to handle 2.5kW only.
watching your videos my fingers start to itch again - i NEED to build a new bike - my wife will KILL me ;)
 
the only riding that makes the motor hot is stop start full throttle action. If i keep my momentum up the motor and controller stay dead cool, I could imagine going full throttle up very steep long hills would heat it as well, but i have yet to find a hill big enough for the motor to even get warm, plus I have a bit of sympathy if I am climbing slowly.

No CA yet, i just feel the motor every now and then and it hasnt even been what i would call hot, just warm and that is rare, most of the time it is cold. the 3540 is a lot faster wind than mine so I would assume it would get warmer riding like that. The 12fet is modified by Hyena, i dont know how. I leave mine on the middle setting of the 3speed since the top speed suits me and the power is fine, I guess it is probably less than 5kw, I wouldnt know.
 
Just a word of caution.
I have a ht3525 on 100v 26" 60a . It gets quite hot if I push it and that's with air cooling.
Also ht3525 doesn't really have more torque. It needs more v for same rpm as hs3540. More v means more KW, so that is good but they only pull 3-4kw after 20kph anyway (with my setup, vertialy identical)
Anyway keep that hubs heat in check. Roughly double the side plate temp for the winding temp. 50-60°c on side plate is about right for rough limit.
 
pendragon8000 said:
Just a word of caution.
I have a ht3525 on 100v 26" 60a . It gets quite hot if I push it and that's with air cooling.
Also ht3525 doesn't really have more torque. It needs more v for same rpm as hs3540. More v means more KW, so that is good but they only pull 3-4kw after 20kph anyway (with my setup, vertialy identical)
Anyway keep that hubs heat in check. Roughly double the side plate temp for the winding temp. 50-60°c on side plate is about right for rough limit.
Click to expand...
by "with air cooling" do you mean drilled covers, or do you mean "just air", and not oil or something else?
i would have gone for the 3525 as well, but i would have needed 100v+ to reach 60km/h+ in a 20" wheel. and no way to fit 30s a123 pouch in any case. and i can confirm that: if your side covers are just a bit too hot to touch your windings can cook.
i have no problem running high speeds for a longer time. what heats up the motor really fast is stop and go in the city, and bashing up hills.
 
yeah thats what I mean pendragon, its efficient at a lower speed. You need the V to get the power, but the wind gives you more usability because you dont need to be going 50km/h to be nice to it before you hold the throttle open.

I can imagine the motor doesnt transfer heat very well to the outside, I have only once made it hot enough that I could just hold my hand on it, IR thermometer said 50degC, but that was from constant stop and start slow monos for more than 5 minutes, the rest of the time it is cool, ie less than 30degC after a long ride. I think the trick is to keep the speed up, and have some common sense when climbing or going slow....works for me anyway :lol: .
 
rodgah
love the video 8)
it was well worth the time sound track was cool as well as popping them wheelies
Hyena / better look out new video biker on the block :mrgreen:
keep them videos coming
 
ROG130 said:
rodgah
love the video 8)
it was well worth the time sound track was cool as well as popping them wheelies
Hyena / better look out new video biker on the block :mrgreen:
keep them videos coming
Click to expand...

thanks mate, we may have to combine our efforts one day.

Went on a great ride today, up and down hills, through nature walks with lots of erosion bumps :lol: . Found some DH single track some kids must of put in, didnt bring my gopro but I think I will go back to take some more video soon. There is more tracks than I care to go over or push my bike back up.

Big tree.....


I feel the camera did the whole make a steep slope look flat on me again, I guess you will just have to trust me, its probably around 50% grade or more.
[youtube]GF9te6Js8ak[/youtube]
 
rodgah said:
who says hubs are for boring commuters...

[youtube]4iaTW6SSNyI[/youtube]

finally starting to get a bit happier about editing. Still took me 3 hours though
Click to expand...

Very inspiring video!

bahhaha about the rubber wrapper in the middle of the sticks. :mrgreen:
 
I went for a ride yesterday with thecopterdr http://endless-sphere.com/forums/viewtopic.php?f=28&t=45409. Great to ride with someone else and have a chat. Managed to get the hub nice and toasty definitely above 50degC, climbing rough technical trails, though I am sure without motor power most people wouldn't be able to pedal the whole way up. The cyclone was only warm at the top so it was a really good comparison of eggs vs eggs. I have a suspicion that most of the heat may have been caused by the low average speed (pretty tight and technical) and not so much the climbing itself, I'll have to test this more in the future.

This is a more smoother run downhill, though youtube has made a good effort to make it nice and blurry for you. I think youtube is getting worse :shock:
[youtube]23FRSv3x_FE[/youtube]
 
Hi Rodgah!

I just started Tig Welding last year and picked up my TIG welding license last November. I really like
welding aluminum :)

I've been a musician for over 37 years and having rhythm when you TIG is important when you drop those
dimes as we call it here in Canada :)

Very Nice Fabrication Rodgah!

Tommy L sends....
mosh.gif
 
You must log in or register to reply here.

Similar threads

klotas
Specialized Big Hit FSR custom AL frame
Replies
2
Views
1,020
macribs
macribs
Quokka
NYX Quokka Build
2
Replies
44
Views
8,106
Quokka
Quokka
Back
Top