Trek front hub conversion

Dudlee

New Member
Region
USA
I installed a 48v 1000w hub on my 1995 Trek 850. Battery and controller cover boxes are made from Birch plywood I had.
Not much to look at but its a fun ride. Found the power meter on amazon. 90 percent of my riding is on level pavement
around town. I didn't like the Pedal Assist so after 2 test rides I unplugged it.
Mike

batbox.jpeg

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wiring.jpeg

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wires2.jpeg

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display.jpeg

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completed.jpeg
 

JES2020

Active Member
Be certain to install a second torque arm with such a big motor on the front. The front forks are known to break under such stress.
 

6zfshdb

Well-Known Member
Region
USA
City
Northeast Pennsylvania
Interesting project and a nice write up.
I'm considering something similar on one of my Trek MTB's. Do you find the rim brakes adequate for that much power & speed?
 

Merle Nelson

Well-Known Member
Region
USA
:) that's a great craftsman build.

There's a guy near me who has a home made 2 cycle motor build. I see him pedaling with no motor assist early in the morning. (Lots of vacation rentals around and his bike is painfully loud.) I feel sorry for him every time I see that bike. Ebike is the way to go.
 

harryS

Well-Known Member
I believe that Trek is steel Cr-moly frame and fork. Solid bike, but I found those center pull cantilever brakes to be useless on my 1992 Trek 800. Lots of pulling force lost in the old cable sheathing, front and rear. I swapped them to v-brakes, which fit perfectly on the frame posts.
 

JES2020

Active Member
I believe that Trek is steel Cr-moly frame and fork. Solid bike, but I found those center pull cantilever brakes to be useless on my 1992 Trek 800. Lots of pulling force lost in the old cable sheathing, front and rear. I swapped them to v-brakes, which fit perfectly on the frame posts.
The issue is that the front fork is ALWAYS smaller than the rear no matter what it's made of.
 

Zynode

New Member
Region
Other
First of all your torque arm is installed wrongly. It's supposed to be on the other side behind the forks. You will break your dropouts like this. Read more about torque arms here. https://ebikes.ca/product-info/grin-products/torque-arms.html

Secondly Grin Tech discontinued these types of torque arms and were sad that china copies kept them alive because of the problems they cause.

Also be careful if you are planning to do regen. Then you install one torque arm forwards and on the other side backwards so the forces are distributed afaik. Personally i won't do regen after i broke my Rockshox Gold TK forks. They were made from magnesium and i knew i was risking it. Wasn't pleasant seeing them shear because i installed my torque arms wrong, used regen and chose the worst forks for a front 1000W DD motor. They did hold up for ~1300 km. Ordered steel rigid forks with suspension corrected axle to crown.
 

indianajo

Well-Known Member
I've practiced panic stops from 30 mph and the rim brakes work fine. I did put new Shimano pads on.
Make sure you live somewhere that is doesn't rain then. Like California. Rim brakes are useless after I run through a puddle.
 

JES2020

Active Member
First of all your torque arm is installed wrongly. It's supposed to be on the other side behind the forks. You will break your dropouts like this. Read more about torque arms here. https://ebikes.ca/product-info/grin-products/torque-arms.html

Secondly Grin Tech discontinued these types of torque arms and were sad that china copies kept them alive because of the problems they cause.

Also be careful if you are planning to do regen. Then you install one torque arm forwards and on the other side backwards so the forces are distributed afaik. Personally i won't do regen after i broke my Rockshox Gold TK forks. They were made from magnesium and i knew i was risking it. Wasn't pleasant seeing them shear because i installed my torque arms wrong, used regen and chose the worst forks for a front 1000W DD motor. They did hold up for ~1300 km. Ordered steel rigid forks with suspension corrected axle to crown.
The torque arms on the wrong side myth has been proven wrong long ago, visit endless spear for expert knowledge.
*Endless Sphere
 
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