I have a 90s era Cannondale Killer V 900., Believe it has the Headshock fork with the shock directly below the headset.

I am converting the bike to an electric commuter (please dont hate me or just dont send me hate mail). I have a few other bikes - just dont like to get to work sweaty.

The ebike motor kicks out so much torque the recommend a steel fork. I am a noob on bike maintenance and its tough to tell much info on the boards.

Anyone have a recommnedation for me. Based on what I have gathered I can get a 1.5 to 1 1/8 conversion piece and get a steel fork.

Can someone confirm this? Also not sure on if I get threadless or threaded and if any differences exist in lengths? (i.e. do I need some spacers or something else.) Someone also mentioned that it might look goofy going from a 1.5 thick headset to a skinny fork - - oh well.

Anythoughts much appreciated - - as indicated I dont know much so any specific detail or product link is awesome.

Love this sight.

Thx Tom tom_mccarthy@me.com

  • If the motor puts out so much torque they recommend a steel fork then a 90's aluminum frame is not a good choice. So you have a few bikes? Does not make this a good project bike for conversion to electric. – paparazzo Mar 27 '15 at 18:22
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    Unless the motor is on the front wheel, the comment about steel forks and torque doesn't make a lot of sense to me. Where did this advice come from? – Fred the Magic Wonder Dog Mar 27 '15 at 18:35
  • @FredtheMagicWonderDog Torque on the crank flexes the whole bike down to the wheels. – paparazzo Mar 27 '15 at 18:40
  • Yes the motor is on the front wheel. As aluminum breaks - the torque on the fork can snap the wheel mount. So its just at the torque point. You can put on torque arms - but does not entirely eliminate the issue. Steel bends and it stronger. The same issues exists if I put on a rear motor (both the frame and fork are aluminum) - so if I put – Tom McCarthy Mar 27 '15 at 18:48
  • The same issues exists for a rear wheel as the frame is aluminum - you can put in some steel plates to reinforce the wheel mounts - -but in the rear there is limited room to do this - -so its much simpler to put the motor in front. – Tom McCarthy Mar 27 '15 at 18:49

Yes, you can use a 1 1/8" fork with a 1 1/2" frame. I did it on one of my bikes. You just have to get a special "reducer" headset. It doesn't look goofy at all - you can't even tell unless you look closely.

You'll have to get a threadless fork. Nobody makes reducer headsets for threaded forks.

Most new forks come with an un-cut steering tube - that means it's a few inches longer than most people need, and you have to cut it to the right length.

Make sure that the crown-to-axle distance is approximately the same as your old fork. If not, it'll change the bike's handling characteristics, maybe drastically.

| improve this answer | |
  • Thx much - will check it out – Tom McCarthy Mar 27 '15 at 20:10

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