Klein Mantra Meets BHT!

[nutnspecial]

hello!
want to put a gng small block on a dh bike for a single chain reduction. thinking 11t/66t? would like to keep the voltage lower....so i can use a prebuilt 14s pack, however going lipo is no issue as i have 18s16ah multistars but like to get rid of lipos altogether with the new safer 18650 setups.
only issue is mounting the motor...small block is good for 3kw so I think i can do 30mph with HELLA torque. 30mph would be fine, 35 ideal. however for that i need the big block I believe?
how do you use your gears on pedal side? single speed on each side would keep it very simple, but gears are nice on a 60lbs bike if something happens.
cheers

Got a pm that wasn't particularly private imo, so posting and answering here- name ommited, and when I get a chance.
Answer is pretty much "yes", but plan to go more in depth, and will of course notify sender so they are abreast of my reply.

 

[nutnspecial]

Hehehe I ran into a telephone pole the other day- I bet it looked f'n hilarious. My jaw took the hit like a champ, but still sore along with shoulder/back. I was driving a bit quickly, and changed my mind mid-corner, and I just couldn't miss the pole lol. I'm usually a pretty good biker. Barely even slowed down, these mech 160mm brakes are junk compared to the vbrakes.
Anyway, don't do that :lol:

Answering the pm I posted above: I suppose a small block would do 30 and up, it will just be less torquey the longer you gear it. 11/66 is way too low for 30mph on bht, even at 83v.
What kv is the motor you're talking about? Just figure how fast it spins @ desired volts and then use a calculator to figure gearing based on wheelsize and at least one sprocket size preference. I think 35mph should be fine on 3kw. Try it and find out!


Mine's still setup with rear deraileur and full gear range of 11-36t and 48t on the front. Would love a 54t chainring someday for pedaling at 35mph+. Yes, a lighter bike is really great to be able to pedal/use like normal and then add motor power whenever you want/need. I really prefer it, but dual freewheeling is more challenging than mounting the motor imo, so I'd start with that and a direct sprocketed hub?

 

[nutnspecial]

SPRINGTIME UPDATE

I've dropped 4s from the 20s2p, reigning bike back under 70lbs, but losing speed. (2x 4s packs were underperforming)

@ 16s I am lucky to hit 31mph hot off charger. I could regear, but the #35 sprockets and chain are holding up great, so what the hell. The 50t aluminum rear sprocket is showing a little wear in the direction of power, but the hub, wheel, adapter, and white HD fw are holding up excellent.

Anyway, even though I've upped amps to 100/200phase (ca shows 107a max) the 6kw+ with 16s sag is EXTRA fun for the lower 0~25mph it's now geared at, so I'll leave it for now. Damn thing could climb a tree, or put you through one.
Since my hub is holding up, I still have the 11-36t range across the modified (to 7spd) 8spd cassette. Imagine a >70lb mountain bike you pedal as normal and dump the freewheeld 6kw (geared low for 25-30mph) when you want- it's ridiculous. Geared for 40mph was fun but this is crazy. I do admit I miss the 6kw above 30mph though.

I wonder if I'll be able to keep from frying the bht if I move to 22-24s and +100amps (which would regear back to 40mph+ and give nearly 10kw to bht). . . Maybe use ca3 for torque throttle and/or motor temp amp rollback could really help, but no need to worry about it right now. The crap brakes are more adequate for >30mph, the 22-24s 2p is way more weight/mass than I want, so screw spending the money right now. Super pleased with it nearly a year later, and will keep @ 30mph max for awhile.

I'm actually surprised there hasn't been more bht action lately on the sphere. Pretty much just Bzh with the Lmx now finished for sale. I guarantee it's a more stout frame and build, but I really wonder how else it compares. (power, weight, bike gears, freewheel).

Maybe sometime I'll work on the new yellow ebay st3 xc frame build, shaving off some weight and changing geometry towards big plush suspension (my main goal), or I'll finish the eastgem spartan steel build. I think I'd really like that one, the added weight of frame coupled with all the battery would either burn the bht or make it feel underwhelming compared to a 60-70lb bike and battery.

 

[gman1971]

What is the chain life on this bike?

G.

 

[nutnspecial]

I half assed my speedo connections when wrapping up the electronics, and it's slightly intermittent lately but I certainly have between 1000 and 1500 miles of mainly high draw play.

4th back tire, front is pretty worn, ready to replace bb5 brake pads again, and the #35 drivetrain is still pretty healthy. The 11t steel front and 50t al rear are starting to get curved teeth, but the drivetrain should last a while more. Something like 50-70$ to replace the 3 #35 components, and the rear tires I use are dh-ish 24x 2.3 for 20$ a pc.

 

[gman1971]

Very nice dude. I love how you took the more RPM mantra to the absolute limit.

Now you need gears!!

G.

 

[nutnspecial]

absolute limit

Nah, just 20s so far. I'm thinking of 22-24s as mentioned above. Others have done similar I believe.

I agree, one speed is fun but electric motors still can benefit from variable gearing. There's a thread on that here somewhere heheh "gearboxes are awesome". No plans here for any gears here though - that's a whole nother ball of wax beyond bike gears, and I'm perfectly happy with the creation.

 

[gman1971]

absolute limit

Nah, just 20s so far. I'm thinking of 22-24s as mentioned above. Others have done similar I believe.

I agree, one speed is fun but electric motors still can benefit from variable gearing. There's a thread on that here somewhere heheh "gearboxes are awesome". No plans here for any gears here though - that's a whole nother ball of wax beyond bike gears, and I'm perfectly happy with the creation.

At 20S you should start worrying about being electrocuted hahaha....

Yeah, in your case you probably need a go-kart gearbox... or something crazy.

G.

 

[chas58]

Hehehe I ran into a telephone pole the other day- I bet it looked f'n hilarious. My jaw took the hit like a champ, but still sore along with shoulder/back. I was driving a bit quickly, and changed my mind mid-corner, and I just couldn't miss the pole lol. I'm usually a pretty good biker. Barely even slowed down, these mech 160mm brakes are junk compared to the vbrakes.
Anyway, don't do that :lol:

Use V-brakes instead of 160mm disk brakes?
WTF. You know you are going against popular ES lore? Sacrilege. Everyone knows you should use disk brakes.

I mean, you are right. Good V-brakes rock, and are much better than many disk brake setups. But don't let that secret out here!
Would you rather be right, or follow the crowd?

I use calipers and V-brakes on my two bikes.
Your Disk brakes are 160mm in diameter.
My caliper brakes are 2,000mm in diameter. LOL.

 

[gman1971]

Hehehe I ran into a telephone pole the other day- I bet it looked f'n hilarious. My jaw took the hit like a champ, but still sore along with shoulder/back. I was driving a bit quickly, and changed my mind mid-corner, and I just couldn't miss the pole lol. I'm usually a pretty good biker. Barely even slowed down, these mech 160mm brakes are junk compared to the vbrakes.
Anyway, don't do that :lol:

Use V-brakes instead of 160mm disk brakes?
WTF. You know you are going against popular ES lore? Sacrilege. Everyone knows you should use disk brakes.

I mean, you are right. Good V-brakes rock, and are much better than many disk brake setups. But don't let that secret out here!
Would you rather be right, or follow the crowd?

I use calipers and V-brakes on my two bikes.
Your Disk brakes are 160mm in diameter.
My caliper brakes are 2,000mm in diameter. LOL.

LMAO...

160mm is inadequate for a bike that can run 40 mph. You need 203 at the very least.

I think V-brakes are better in a handful of situations, maybe when new and when the wheel is true and round, but when its raining too hard, or snowing, or you're deep in the mud then you'll be glad you have dics brakes. Also, you don't want to lock the front wheel, you want modulation and is something the disc brakes do much better.

I use double 180mm rotors on my two front wheels of my 60mph trike. on my 40mph eBike I use 203 mm front rotor and a 180 on the rear. All Avid BB7 brakes. I have to be careful not to flip the eBike when I slam the brakes...

G.

 

[nutnspecial]

Vbrakes aren't (an easy) option now with extended swingarm and newer fork. . . and I do see a fair amount of mud. Will do hydro with 8" or 180/203 rotors when I get around to it- these bb5 knockoffs really suck

 

[gman1971]

Vbrakes aren't (an easy) option now with extended swingarm and newer fork. . . and I do see a fair amount of mud. Will do hydro with 8" or 180/203 rotors when I get around to it- these bb5 knockoffs really suck

now you're talking... I have BB7 and so far they've worked very well... I don't do mud tho... so I can't say there...

G.

 

[nutnspecial]

Still watchin for some decent used brakes, so I can save my others for the other build.

I did decide to go back close (slightly under) original rear shock length though. Now I can put a foot down with susp unloaded, ride weight is lowered, and rake is more aggressive.
The trade off is lower bb and less rear travel, but so far I really like the change and will deal with the costs. Will make some vid after I fix the camera mount which broke when I crashed and burned on groundhog hole the other day

 

[izeman]

Go for some 203 rotor and 4 piston avid code-r or shimano saint. Front wheel flip at any speed with one finger braking!

 

[gman1971]

Go for some 203 rotor and 4 piston avid code-r or shimano saint. Front wheel flip at any speed with one finger braking!

LMAO ....

G.

 

[nutnspecial]

Those were the days lol.



A brief overview using hozan thread for the first time last year
[youtube]S2-614xURM8[/youtube]

Short vid showing bike and basic acceleration on 16s 100a
[youtube]iqA4Rd6b99U[/youtube]

Random 3rd person of playing in grass gulley
[youtube]retkThM2RBY[/youtube]

Gotta get that camera bar mount fixed, modify the harness mount, improve my 'skills', and maybe go back to 18 or 20s. Oh yeah and brakes, tho brakeless or worthless brakes is an interesting riding style to attempt mastery :lol:

 

[macribs]

Middle video is marked private so not possible to view.

 

[nutnspecial]

Whoops, thankyou -fixed. That's the latest with 100a 16s.
I'm really itchin to try the 100a with some better speed again (20s, 38-40mph).

 

[RageNR]

All this talk about bad brakes...
Mine has the stock Avids on it. They are MUCH better than I expected. Almost on par with my Cannondale w/mech discs.

But I say, why not both? Rim Crushers + Shinys = Stop on a dime.
My Cannondale is not a high end bike, so the discs are not topline either. Still, it will throw you ass over end if you squeeze too much.
An additional set of levers and brake components on a 70lbs bike is going to add another 5lbs.

 

[madin88]

most bicycle braking systems provide more than enough braking torque (usually 100-150Nm), so you should be always able to flip over if you press the lever strong enough.

the real problem is the brake fading which occurs if the disc and brake caliper gets too hot. the force than fade away..
IMO the best way to prevent fading is using the largest and heaviest rotor you can find.
it would not be smart to pay premium prices for a very lightweight braking system because it's just the opposite you want to have on a higher powered e-bike -> high mass for better heat absorption
Dual disc braking systems would be also a good idea^^

 

[nutnspecial]

Good tip on bulk being a bonus.
Friction and heat dissipation is why v brakes can work so great, coupled with the fact your drag is on a huge rotor by comparison. . .

Mine suck because
#1 I ran all cable for the rear (no stops), so much more housing compression
#2 especially with proper adust, when pads get thinner the caliper lever just 'gives' when you grab on them = no brakes.

#3 idk, but can barely skid rear and def can't wheelstand, even with fresh broken pads lol.
_______________________

F-it not important If I can build this bike, I can do great brakes if a priority (bolt 'em on). Like I said, it's interesting to ride with little/undependable shit brakes for the moment hehehe :lol:

 

[izeman]

So you're on par with Lamborghini who said this his cars were made for driving and not for braking

 

[nutnspecial]

After being down for a few weeks due to ultimately destroying my controller ,
I am trying hydros, more suspension front and rear, more normal stem, new controller placement and wiring technique, and fresh tires.

100 to 120mm fork
165 to 195mm shock
bb5 to 180/160 hydros
about 4-1/2" to 2-1/2 stem

initial impression is feeling a little cramped when seated in cockpit/ diminished pedal stroke with seat where I can still put my feet down. For the type of riding I like @ this power level, I think it will be better suited tho overall. Also me and the light frame will no doubt like more suspension.

When I had changed to down to the 165mm, I liked the look of the bike, but the bb went down to more like a normal height. Pedal strikes and bb clearance sucked, and the ride felt alot rougher. I ride the larger travel with alot of sag, so it still rides low enough but has alot of travel drop for my prefered riding type.

First impressions of the hydros? If these things hold up, 100$ is worth it on any and every bike.
You just bolt them up- no messing with stretchy cables and constantly fiddling with pad adjustment.
They feel AWESOME, can't wait to ride.

_____________________________
Dam it though, I wish I'd bought some 5.8ah turnigys (or zippys) earlier for 60-65$ pc to elimate these weak 4s packs and take the bike back to 18s. I can't even find them now!

http://www.hobbyking.com/hobbyking/store/__26712__ZIPPY_Flightmax_5800mAh_6S1P_30C_UK_Warehouse_.html
Ah, Uk has zippy for 52/pc. [strike]Might try ordering from there.[/strike] But can't order from there!

_____________________________
Also working on swapping CA (monitor only) for at least a voltmeter, and hopefully an ammeter too, without another shunt.
I would also love to roll back amperage on the fly to sometimes utilize some weaker 16ah multistars and/or just extend range. An external pot to mod controller's shunt reading sounds dangerous though.

 

[nutnspecial]

[youtube]XbzdGkjLpuE[/youtube]

 

[nutnspecial]

The bike performed well this year and I really enjoyed it. My battery capacity limitation is increasingly apparent as the cells age and the weather gets colder. I wouldn't trade range for the power though, a single gear with a bunch of power is alot of fun.

The custom short twist throttle has been a treat, and I haven't minded a reduced top speed of 30mph with my trimmed down (16s) pack. Again, I'd rather have the gearing over that top speed on bike components anyway.

The 100$ hydros have been flawless and the larger bb7 sized pads lasted so far. Yet another 24" rear tire is worn smooth, and it's becoming a chore to find reasonably priced knobby DH replacements.

While I'd rather build up another bike with similar drive system I've already started, I think it's time to tear down the mantra and replace the consumables. I plan no other mods otherthan maybe adjusted gear ratio and fresh battery, as the 30c are beginning to show unacceptable imbalance within a few rides, unacceptable self discharge on one string, and unacceptable sag in even 50F temps.

I will attempt to setup a decent photo op to show component wear etc. The #35 has held up great but sprockets are literally 'saw toothed' now lol. I'm also anxious to pull apart the White HD FW and check my adapter that allows for parallel cassette use.

Damn I just wish bat tech would jump ahead. I do now have a 16ah 12s 10c multistar pack and will consider using it in a backpack for longer rides. Due to target wattage, I will keep a 100a capable 10ah pack on the bike, and the 16s minimum for that wattage will be the main sticking point when swapping for 12s. Maybe I'd be okay with 12s 23mph topspeed and ~50a max draw that the multistar pack would give, just for the purposes of range.

I did get >15miles from one charge of the current worn 16s 11ah this fall. I pedalled alot to maintain speed but used >80a draws alot for acceleration and large inclines too. I wonder if the heavier and bulkier 12s 16ah would really do much more than limit top speed and draw. Depends on riding of course- might easily be 25%-100% increased range.