I have a front hub motor on a bike with lawyer lip forks ...It has been a challenge to get the motor to clamp to the dropout .. I had to grind some of the lawyer lip off to use washers big enough to hold it .. I have seen forks with thick tabs welded to them for the drop out .. I don't "need" a suspension fork ..Just a steel one without lawyer lips .. Thank You for any help/suggestions you can give me ..Don
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7Get any steel fork and file the tabs off.– Paul HCommented Oct 23, 2022 at 2:00
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2Welcome to the site Don - this kind of question falls under the "shopping" category, and tends to be of limited use in both time and location. You're probably not going to get a "buy brand X model X from website Z" kind of anwer. So they are classed as "off topic" Please read the tour to learn more about SE's Q&A format.– Criggie ♦Commented Oct 23, 2022 at 3:11
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2 Answers
Some old steel forks used a different retention mechanism - a small hole above the dropout that engaged a tab on a special washer. You could omit the tab washer.
I've had 2 forks like this, both rigid. Unfortunately one was from the early 90s and the newer one on a rubbishly cheap bike.
But it's not clear why you're having trouble. Track nuts work just fine with lawyer lips.
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I suspect the provided wheel nuts are flanged and that's larger than the recess in the fork. Its a electric motor, so there's going to be at least three wires going in through the axle too - it might not even be a standard-sized axle.– Criggie ♦Commented Oct 23, 2022 at 7:40
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And also, there may be a torque arm that needs to be secured somewhere up the fork to help minimise chew-out of the dropout's facing surfaces. A 250W motor probably doesn't "need" them but higher-wattage might.– Criggie ♦Commented Oct 23, 2022 at 7:41
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1@Criggie the flanged nuts (dynamo hub not motor) I have do fit a standard recess made for QRs. The 250W rear hub motor I've dealt with did use a standard axle. Good point about higher powered motors. I forget about them as they're illegal in most places including where I live (though easily available and seen on the roads). I would expect a torque arm to be intended to be universal given the variety of forks. Again 250W doesn't really need it, or didn't when I priced up an electric front wheel– Chris HCommented Oct 23, 2022 at 8:22
Sounds like you want a rigid fork. You'll have to look for:
A lower-headset race to dropout length measurement that is the same as your suspension fork when loaded (ie you're on it). This keeps the bike on the same angle. Too much change upsets the handling.
Note, adding about a kilo of motor to the front wheel will change the handling some anyway as will batteries in the frame. Batteries on a front or rear rack have even more effect.Same steerer tube diameter. It could be 1", 1 1/8", 1.25", 1.5" and there could be a different diameter top and bottom, which is called tapered.
Same retention method. There are threadded (older) and threadless. While its possible to convert, that will add cost.
Length of steerer - it has to go through your bike's headset and have enough exposed to retain. That means no-shorter than your current steerer tube.
Brake mounts - it is possible you might find a fork that has different mounts. There are a couple of disk brake caliper mounts, as well as V-brake/canti mounts, and the traditional center-hole for single and twin pivot calipers. Again, conversion is possible but then you'll need to buy that brake and possibly a lever to suit.
Your best option is to find a used bike of similar age to yours, and scavenge suitable parts. OR simply fit your motor to a used bike and keep your existing bike as it is.
Search locally on auction sites. Find out if there's a bicycle cooperative in your area - most of them are more than happy to help with parts-finding.
Don't be tempted to try and lock up your existing suspension fork and call it a rigid. That will weigh more, be less-strong and always have the risk of sudden failure.
