MikeinFL

I want to convert my hybrid to electric with 48v 1000w front wheel kit but the motor requires 3.9" between the front drop outs, but I only have 3.5". Can I modify my front fork? it's aluminum and suspension.

2old

Aluminum suspension forks are not good candidates for a 1000w motor IMO. Replace with a steel rigid fork and use at least one torque arm. Front wheel maladies can be tragic.

Doc_Wui

2old echoes the thoughts of many of us who have been around ebikes for a few years. While I have never seen one fail, I've seen a few pictures come up every few months in forums. Tells me I sure wouldn't want to put a big motor on an alloy fork when there is no need to do so.

car knocker

Any recommendations for a brand? My steel ridgid fork is fitted with a 500 watt motor and two torque arms and washers and the dropouts started out at 10mm and after 400 miles the right measures 12 mm and the left 11mm.

awm72

Sounds like you might want to start pricing a new front fork. I'm thinking the bike might not be steel for that much wear in that short of a time.

Local bike shops(LBS) might be able to help you with that decision since problem is not electric, but bike frame issue. Bring it to them see if torque arms are working as well as they should.

2old

CN, I would consider replacing that fork immediately. I've had good luck with Surly forks, but my front hub motor is only 350w.

MikeinFL

thanks for the replies- I had measured the front axle space incorrectly, it is a standard 100mm, so most front e kits should fit ok. My goal is to install a front wheel ekit with a top speed 25-28mph and variable throttle. Obviously I don't need a 1000w.

Now I'm looking for a low cost ekit. Are those low cost kits on ebay ok? When not using any power I would like my bike to ride and feel much like it does now without a kit.

questions:

1. My current fork is a Suntour m3010 (alloy 700c). I understand a steel fork is recommended, and I want suspension. Do I search for a fork that is 700c that says made of steel?

2. recommendation for a low cost ekit that can reach 25-28mph without pedaling, pedal assist, and variable throttle?

thx

2old

You can use a magnet to determine whether the fork is steel, but I doubt that you'll locate one except on a "Walmart-type" bike since most (all) accessory forks aren't steel. Never hurts to look though.

Doc_Wui

You need about 600-1000 watts to go 28 mph depending on whether you're in an aero racing position with dropped handlebars or sitting upright.

What stops you from a rear mount? You have shifter gears in the rear hub? If it's just fear of messing with a derailleur, that part is easy compared to the rest of the conversion.

Most low cost kits on ebay are 13-15 pound direct drive motors. Never having ridden one, I don't know if they feel like a bike when unpowered, but I have read that some of the big ones cannot be easily pedalled because of the drag from the magnets with no power.

Geared motors are more like 6-10 pounds, and free wheel so they have no noticeable drag, although the owner of that dropped bar road who is capable of 28 mph would tell us there's horrible drag and 8 pounds is like a boat anchor. But few of the geared motors can go 28 mph unassisted unless they are big.

speedy25

While installing a front hub motor is semi-easy, the kilowatt you propose will trash a fork in short order. Do a rear hub and your life will be easier and the product more reliable.

250 or 350 should be the limit for a front hub.

-SP

MikeinFL

if I go with a rear wheel hub, say 500w, isn't my rear fork also aluminum? is that ok?

Nelson37

Mike, take a look at the rear dropouts on your bike. Notice how they are at the apex of a triangle? Now look at the front. No triangle, is there?

A powerful motor, with regen, on the front, of aluminum, suspension forks, is a horrendously bad idea. Dropout failure on the front is dramatically more dangerous than on the rear. Most accounts of the results of this are noted by the surviving next of kin. If you insist on doing this please make enough information available so we can obtain a life insurance policy as an excellent investment opportunity.

A 250W-350W geared hub, with no regen, one or preferably two torque arms, ideally on a rigid, steel fork, is much more practical and safe. Rear hub much better for more power. Steel frame better yet.

If you do locate a good quality, steel, suspension fork, come back and let us know and also what you will do with the unicorn that comes with it.

Doc_Wui

There's generally more a lot metal on the rear, and you still need torque arms, but generally the install is stronger. If it does break, you probably won't fly over the handlebars.

A suspension fork is fairly weak in comparison to the rear drop outs..



.

MikeinFL

ok I'm going with a rear hub, I'll start a new thread when I have questions.