My Lightning Rods Small Block Build - Trek 920 S Track hardtail

one4torque

Active Member
The LR mid drive is a work of art IMO.
This is a mechanical engineers romantic dream... just to oogle the parts, and drink a brew...... gotta go.... on 2nd brew ;)
 

one4torque

Active Member
Thx gents....... and Joe... probably not!
I suspect it will depend on how I apply the power and under what circumstances.
I do plan to upgrade parts in the drive-line as they break.

The man behind Lrods is a true mechanical artist'...... just holding these parts in my grubby paws makes me smile.
Loving the little details like the little lightning bolt and the small hot-rod cut-out all through the parts.
I did this kind of thing.

My buddy whom I build the dolomite budget bike for..... is an architect grad and by trade..... he is planning on a retro motorcycle e-bike with a big-block mid-drive..... concealing all elec parts... and only exposing the moving flywheels/chains...... I can't wait to see what he comes up with.

I"ll post up progress report this friday.. when I'm off..... and record top speed, accel tests... climbing capability, etc..... and comparo to 2WD sondors, and Stealth bomber :)
 

one4torque

Active Member
LR Sm Block is installed and running.

A few notes on installation -
I had to machine down the crankset hub on the frame to fit the mid-drive. No big deal with a Da Sander air powered.
I had to re-align the mid drive pulleys/gears/idlers to make it work.
The controller had 2 wires swapped for the hall sensor..... blue/green.... so I noticed the motor would just buzz...... noticed the two wires swapped in the loom..... and just swapped the blue/green wires to the motor and I test hit the thottle and the bike flew out of my hands! Holy COW some tq.

I'll tidy some things up... but here are my first impressions @ 9:30PM in freezing cold temps...:
1. oh my gosh the bottom end tq is to die for.... motor-cycle like! hill climbing is a breeze! Oh BTW do not shift while'st under power! not a happy set of gears ;)
2. the top end is sweet too......
3. the bike is super light wgt....... can't wait to hit some trails.

The kit requires some mechanical skill to install and get everything lined up right.... I'm still not happy with the amount of friction in the drive.. so I'll play with chain/belt alignment and tension tomorrow....... to get it all set up with min friction...... then I'll test this on my regular 30 mile route.

Oh did I mention you should NOT hit the throttle accidently with no one on the bike... it will go flying away.


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one4torque

Active Member
Just got back from my 1st extended ride on this thing:
1. 10 miles @ 20mph avg...... voltage down from 52 to 45.
2. top speed no pedal 31 mph.

I was able to work out the binding/mis-alignement of the drive to crank. The hose clamps that attach the unit to the down tube do not automatically center the unit... so I had a funny angle. I was able to "encourage" the unit into alignment, then tighten the hose clamps, and all is well.

There is some fiddling with belt/chain tightening... but no big deal. Some wax based lube really helped to quiet down the go-cart chain and the bike chain.

Cruising @ 26mph... I'm burning up wh's!! in a big way... this is not a power sipper...... and it's just too darn fun to rip above 25mph....... perhaps I can try a run @ 20mph.....

The power combined with the "relative" ebike-lightwgt of this system results in a sport-bike like ride. compared to my stealth and the sondors.

I can only imagine what a properly setup Big Block kit feels like!!!

Cheers, all.. .ebike on!
 

one4torque

Active Member
I'll post a better pic showing the battery bag in the frame.

So I had to dial back the Watts AFTER I ran this with a freshly charged battery!
It was putting out so much tq that the drive gear for the mid-drive was jumping the chain.
I suspect this would shorten the life of the other stock regular bike compenents as well....

So I started playing with the CA and dialed back the max wattage with the following results:
* No Limit - I hit over 2000watts at times... will jump the chain, unless I really go tight.
* 250 watts - will not go over 13mph....... super slow....... granny mode. ;)
* 500 watt - will hit 20mph with PAS.
* 750 watt - will hit 25mph no PAS....
* ended up with 1250 watts...... smooth but deliberate accel.

I set max speed @ 25mph. Plenty for the stock rim brakes.

When asked which is her fav.... wife advised in this order: Sondors, then stealth, then this hard tail mid-drive. All due to comfort.

I would say they all shine in diff ways. Different tools for different jobs. ;)
 

George S.

Well-Known Member
It is a handsome motor. I can't quite see that motor on that bike, but you just got the SB, so who knows. Early reports on the BBSHD say it runs very cool at 1500 watts, and could probably handle 2,000. They hard wire the controller (inside the motor) to 30 amps. Either would be great for cargo, deep snow, or serious sand. Not sure how they would compare, actually.

Like the pictures.
 

one4torque

Active Member
Thx George! I have no need for the Big Block..... this "little" small block has enough power to rip this stock drive train apart!
I've had to dial the max watts way back..... to keep this unit happy.
As you have stated there is a trade-off between max accel/top speed/range / and price / and reliability........

The cool thing about this sm block setup with the CA is that it offers enough power head-room to destroy your stock stuff..... there is no nanny.. so in the wrong hands kaboom :)