JimL recommended LPS 1 for brake cables. I ordered some. It arrived and I put it on the shelf until I could think of a use.

Sixteen months ago I installed a drain with a popup stopper. At first it worked great. Then it began to act as if badly corroded. It would resist being pushed down. Often the sink would drain slowly because it hadn't popped open quite all the way. Once I used a syringe to empty the sink because I couldn't pop the stopper open.

This would be my first task for LPS 1. I removed the stopper, dried it with a hair dryer, and cleaned what I could with a toothbrush. It wouldn't come apart further, so I gave it a quick spray. Almost immediately, the mechanism worked smoothly, and my hands felt gritty. Apparently, part of the problem was that grit had bonded to the metal surface. LPS 1 had gotten it off immediately.

I should have masked the seal. Some solvents make some plastics swell temporarily. The seal on the plug was wavy as if swollen. I shouldn't have put it in the drain because I had to remove the trap to push it back out from below. In a couple o hours the seal was back to normal.

More than a year ago, I got a Bolton controller for my Radrunner. I rode every day and it worked until one recent morning, when sometimes the PAS wouldn't switch off or wouldn't switch on. The day before, I'd ridden on pavement after it rained. I figured water had gotten into the controller. My  $100 Radpower fender is pretty useless because it stops 11" off the ground. Any water thrown off the tire at that point will be rising with a velocity equal to the forward velocity of the bike.

I found crusty sand on top of the controller, which meant it had landed wet. The front cover had a grommet. I found a dirt trail where dirty water had run along a cable through the grommet. I left both ends open for three hours for the controller to dry. After screwing them back on, I used RTV to seal the seams on three sides. I didn't put RTV over the bottom seam because I thought the water hadn't come up from the bottom.

Next, I used 1mm polypropylene, sold as cutting boards, to make a fender extension down to 5.5 inches from the ground. To reduce the possibility that it would strike an object, I used a heat gun to bend it close the the tire. I wasn't able to test the fender until the next time I rode on wet pavement. The bottom of the bicycle frame got wet. That was a bad sign because it's 2" above the bottom of the controller.

I thought the RTV had protected the controller until the next morning, when I had trouble switching the PAS on or off. I left the ends off for an hour, blowing compressed air through it three times. This time, I sealed the end plates on four sides. I also made a fender extension extending to 4.5" off the ground. I bent it pretty close to the tire, so it probably won't hit anything. If it does, it will probably flex because it's attached only where the fender brace screws to the fender.

The next day I had more trouble with the controller. This time, I noticed at least once when everything worked but the speedometer. That happened at least once when the controller was new, so I guess it picked up moisture then, too. Now to dry it better, I opened it up and warmed the inside with a heat gun three times in two hours.

Later, there was a thunderstorm. Afterward, I tested the extension by taping on a cardboard shield to the frame. It was 6" behind the fender extension and 6" ahead of the controller. Besides wet pavement, I rode through puddles and along rivulets. I was limited to 15 mph. If I went faster, the cardboard would blow out of position.

The fender extension protected the cardboard down to a point 5" off the pavement. The bottom of the controller is 8.5" off the pavement, so it hadn't been wet through the gap in the cardboard. I wouldn't have thought one inch could make such a difference. Apparently it catches water from the tire down to a point where its vertical velocity is only 1/12th the bike's forward velocity.

Today when I mounted, the freewheel ratchet in my Radrunner 1 didn't catch. I backpedaled, and it caught the second time. A moment later it missed again. It was okay for the rest of the ride.

I guess it needs cleaning and lubing. A few months ago when there was a bit of noise on each wheel revolution, I found globs of excess grease at the ring gear driven by the motor's planetary gears. (I think that's what they're called...) I wiped away the globs and the cyclic noise was gone.

I don't recall getting into the freewheel. I don't know if it's the same on all models. How do I open the freewheel? How should I lube it? Should I lube the planetary gears?

I've read that brake cables need adjustment to compensate for stretch. That didn't sound right. Bicycle and motorcycle brake cables used to be soft enough for diagonal cutters, and they didn't stretch.

The rear brake cable on my Radrunner creaked from the day it arrived. It was also spongy. After 16 months, I replaced the cable and housing. The creak was gone, but it was quite spongy. It occurred to me that the sponginess was in the housing. It's longer than the front housing, and it has to curve way around to reach the down tube. Then it goes through three S curves on the way to the caliper.

For two days, I kept the brake lever tied to the handlebar when I wasn't riding. (I had to switch off the battery to turn off the brake light. It would stay on another 7 seconds. Apparently, it draws very little current.)

After two days, I had to tighten the cable adjuster several turns. Now the two levers felt almost the same. I measured. Between first resistance and a hard squeeze, the front lever moved 10mm and the rear lever 15. Considering the length of the rear cable and its curves, that seems pretty good.

Laugh-in used to show an old man on a tricycle falling over. A rider's arms and spine can form a sort of tripod to stabilize his upper body. With his handlebars almost in his lap, the base of his tripod was too short for stability. With the OEM setup, the Radrunner made me feel that way. I was an accident looking for a place to happen.

I could lengthen my tripod by turning the bars forward, but, as the manual pointed out, it's dangerous to have the hand grips too far forward or aft of the steering axis. As was discovered in 1885, the solution was to move the seat aft. That helped in other ways.

I needed some pressure on the bars for stability, but in some circumstances it could be excessive. Traditionally, you could raise of lower handlebars to adjust the pressure. The OEM Radrunner seat could be raised 30 cm, but the handlebars couldn't be raised at all.

Radio Runner told me about an extender. The minimum increase was 6cm. That seemed too much. At that height, I felt that I wasn't maintaining enough pressure for stability. Swinging the bars forward can increase pressure. The grips had been 5cm forward pf the steering axis. I swung them to 7. That was too much. The pressure could be unpleasant, and the handling was a little weird. I swing them back to 6. Perfect!

A centimeter can make a big difference, and that's only 2 degrees of rotation at the clamp. I couldn't make worthwhile adjustments without measuring. The photos show how I do it. I tie a shoestring between the centers of the hand grips. Then I align my eye with the steering axis and measure how far it is from the string. In the photo, it might look like 7 cm because the camera isn't quite aligned with the steering axis. It's 6 cm, my final adjustment.

From the day my Radrunner arrived, the rear brake creaked, and it felt a little spongy. Eventually, I discovered that the jacket on a section of the cable housing appeared to have been damaged by heat. Touching this section, I could feel the creaky vibrations when I pulled the lever. If the damaged housing could be squeezed shorter, that would explain the spongy feel.

Customer service asked me to document it with a video. A video? I responded with a photo, showing how it looked as if the insulation had been melted by a propane torch. Customer service said they'd send a new cable as soon as they could verify my address. They closed the ticket. I didn't know what that was about. I'd had to provide my serial number and address to open the ticket. In the past three months they'd made at least three shipments to me.

That was 13 months ago. It looks as if Radpower lied to me. So I'll buy a cable. Does anyone know how long it should be? Is there a trick to fishing it through the frame?

After a year, the rear brake on my Radrunner failed. I had adjusted the cable but not the caliper because Radpower instructions made it sound difficult. The wear pattern showed that it had come from the factory offcenter and askew.

Corki offers resin, semi metallic, multi metallic, metal, and copper, in increasing order of heat dissipation and longevity. I ordered resin because they're supposed to be the quietest.

Installation was much easier than I'd been led to believe. I loosened the cable so that the lever on the caliper would open to the stop. I loosened the inboard pad adjustment so I'd have plenty of clearance. When I remounted the caliper, I left the screws loose enough for it to slide without much friction. I tightened the inboard adjustment to clamp the disk between the pads, so the disk would align the caliper. I backed it off enough for the wheel to turn freely.

I adjusted the slack out of the cable and applied the brake by lashing the brake lever to the handlebar. This would center the caliper for actual use. I tightened the screws. I untied the lever and the wheel turned freely.

After a couple of days, I noticed a little squeak, once per revolution, when I rolled backward out of the garage. Then I began to hear it rolling slowly forward. After a month, I looked into it. With a digital caliper, I found that the runout was 0.2mm. That doesn't sound like much, but the sector farthest outboard was the one squeaking. It must have been hitting the outboard pad. With a Knipex pliers wrench, I applied a little leverage to warp the disk flatter. I got the runout down to 0.1mm, but making adjustments just moved the squeak to another sector. Apparently warpage wasn't the problem.

I cleaned the disk, but the little squeak was still there. So I lashed the brake lever to the handlebar, loosened the caliper screws, and retightened. The squeak was gone. A day or two after installing the pads, I'd tightened the cable to compensate for break-in wear. Apparently this had left the pads just enough offcenter to squeak.

I hadn't noticed until I worked on the brake, but applying it produced a slight scraping noise like dragging cardboard, or a creaking like a vinyl saddle. I cleaned the pads with a Scotchbrite pad, then a paper towel dampened with contact cleaner. It made no difference. These pads are quiet but not silent like the OEM pads on the front.

A couple of weeks ago I began experiencing pain in tasks that required a muscle to pull my thumb in a certain direction. I checked the WWW and thought I'd torn a ligament. I took it easy on my thumb, but it got worse.

Yesterday, I palpated the area with my muscles relaxed. It's not a torn tendon but a bruised joint, where the thumb connects to a carpal bone. I could imagine only one cause: the left hand grip on my Radrunner.

Pavement around here is rough. The handgrips are designed for weight on the outside of the hand. The thumb side of the grip could transmit wicked shocks to the carpal joint.

I wrapped the grip in a folded washcloth and taped it. When I rode, the pressure was normally on the tape, but when I applied the front brake, the pressure moved to the base of my thumb. My grip was loose and padded, and I didn't hit any big bump, but it hurt. I don't know why I didn't notice earlier. I'll leave the washcloth in place and for now won't use the front brake.

Amazon has lots of grips. Any recommendations? Some clamp at both ends. Would that work on the right grip (which would have to be shortened)?

The Radrunner is primarily for the road, and bikes for the road normally have handgrips that point aft. For one thing, it keeps pressure off the base of the thumb. For another, it's easier to see past your arm in a mirror. It would also help of the bars were a little higher. If it were possible, I'd replace my Radpower bars.

The front fender on my Radrunner wasn't long enough to keep dirt and water off my controller, chain, and feet. I've had stuff like this lying around for 30 years: https://amzn.to/3Mxde2V

It's almost as thick as the fenders. I cut a piece and marked where I wanted the edges bent. To bend, I sandwiched the piece between sticks in a vise. A hair dryer didn't get it hot enough, so I used a propane torch with a flame spreader. An electric heat gun would have been better.

My pop rivet gun was made for two hands, so it was tricky to hold the washer in place until I could pull the rivet tight enough to hold it.

The fender is generally 30cm from the axle, but the bottom of the extension is 36cm out. That's partly because the bottom lip of the fender curls out. I can avoid that by bending an extension to fit under the fender, not over it.

If the handlebar is turned sharply, there's about 2.5" between the pedal and the extension. My toe doesn't seem to extend that far in front of the pedal. On a test ride, I found that I don't steer that sharply except in a u-turn. I've still got clearance. What's more, if my toe ever did hit the fender, it wouldn't get caught because my toe would be moving downward.

I got a Bolton controller for my Radrunner more than a year ago. I ride every day. A couple of days ago I set out 15 minutes after the rain stopped. As always, I avoided puddles because the front fender is too short to protect feet or the chain from what the tire picks up. Like Schwinn, Radpower seems to value fashion over function.

I prefer to pedal without assistance and use level 1, about 150 watts, intermittently. That day, there were a couple of incidents when I switched to level 0, which the display showed, but I kept getting pedal assist and throttle response for several seconds.

The opposite problem occurred the next day. At a stop sign on an upgrade, I switched to level 1 for assistance in accelerating across the road. The display changed, but the motor was still dead. I hopped off and pushed. I could cross the road faster that way. A few seconds later it worked again.

At home, I inverted the bike. All connections seemed clean, dry, and tight. I unscrewed the controller and found grit accumulated between the fins on top, at the front. It was crusty, meaning it had been deposited wet. It must have been thrown from the front tire, and the fashionable fender didn't block it.

The grit was against the back of the front end plate. There was a gap between the plate and the rubber gasket because the assembly was designed with too few screws. The back plate was the same way. When I removed the plates, I saw that dirty water had seeped in through the grommet, along the cables.

For moisture protection, circuit boards are often potted. This one wasn't. To pull it out, I would have had to unscrew a row of heat sinks. That was a potential assembly hassle, so I left the board in. In case any moisture remained, I left it in the breeze for two hours. The humidity was low that day.

The solution was quick and cheap. I sealed around the plates, around the grommet, and around the cables with Flex Shot. Some Bolton customers must ride through a lot more wet stuff than I. Why didn't the instructions warn the installer to seal the unit with RTV? Why does Radpower sell inadequate fenders?

Radpower says you have to add air to bicycle tires every few days. That was not my experience with butyl rubber tubes. For some reason, I had to add air to my Radrunner tires every ten days or so. Eventually, the front improved, while the back got erratic. It could hold pressure for weeks and lose a lot overnight, even going flat. I thought it had to be the valve. Replacing the core, cleaning, greasing, and screwing on a metal cap tight didn't cure the problem.

I removed the tube, pumped it up, and held it under water, section by section. I didn't see any bubbles. When the problem persisted, I replaced it with a Velo tube. Again, I pumped up the old tube and held it under water. I didn't find anything, but it lost pressure overnight. This time I found bubbles from two holes an inch apart, too tiny to see even with a 20x microscope. I'd never seen leaks so tiny. I thought the tube must have been faulty.

With a 4" tube in a 3.3" tire, maybe the tube can shift within the tire, so that some times it can be pushed shut and other times stretched wide open.

In a week or so, the new tube began losing air. When I swapped tubes, I checked the inside of the tire by looking and feeling. I didn't find anything. When I checked the tube I'd removed, I found a tiny hole near the centerline of the tread, like the other holes. I must have missed something tiny when I checked the tire. externally, I checked the center of the tread carefully. All I found was a sort of grain of sand embedded in a lug. I got it out with a little screwdriver and tweezers.

The third tube soon started losing air. This time, I marked the sidewall of the tire on the sprocket side at the valve. I also marked the tube on the sprocket side. That way, when I found the leak, I could lay the marked tube on the marked tire to see exactly where to look. It was another Velo tube, and with that brand I could see the tiny holes with a 20x microscope. I saw a tiny bit of metal lodged in the hole.

I found the exact spot in the tire. There was a discolored spot, and I felt a pinprick. On the lug, I saw something tiny. With a wire, I pushed it enough to grab the inside end with pliers.

It was 1/4" of wire as thin as sewing thread or the wire used for window screens. It was so exceptionally fine that I wanted to measure the diameter. I had it on my fingertip with my hand on a white counter as I turned on my caliper with my  other hand. The wire fell off, and it was so tiny I couldn't find it.

If I'd run onto 1/4" of such thin wire, it would have bent or broken without penetrating even a millimeter. The only way I can imagine to stick it through the thick part of my tire would be to grip it with pliers a millimeter from the end, shove it in, slide the pliers back a millimeter, and repeat, one millimeter at a time.

Sometimes my front tire still loses a little air. That's not normal for butyl rubber. I'll mark the tire and the tube. If I find a leak in the tube, I'll know where to look in the tire.

The assembly manual that came with my Radrunner said nothing about putting the front wheel on. I couldn't get the rotor between the pads until I backed off on the inner pad adjustment dial. With the wheel on, I tightened the dial until it seemed about right. That was about 1500 miles ago. The brake has always worked well.

Lately, I found that the rear brake had no effect against forward motion. It still worked fine to keep the wheel from rolling backward when I turned the bike upside down. I ordered new pads. One old pad was worn away at one end. The other pad was fine. Except the cable, I hadn't adjusted the rear brake because the Radpower instructions weren't clear to me. It must have come from the factory off center and misaligned.

I installed the pads and went to the Radpower site for adjustment instructions. They're for the birds. How could I see the pads well enough to know if the caliper was centered and aligned? Visually, how was I supposed to judge the right spacing? I didn't understand how to use the adjustment tool.

The instructions say to loosen the pinch screw on the cable. Why? You just have to be sure the lever on the caliper can open all the way to the stop. I loosened the bolts just enough enough that the caliper could slide. With an allen wrench, I tightened the dial until the pads clamped the disk, then backed off a couple of clicks so that the wheel would turn freely. That seemed a good spacing. Now if I used the lever on the caliper or the one on the handlebar to clamp the pads onto the disk, the disk would keep the caliper aligned and centered while I tightened the bolts.

It was quick and simple and the brake worked great. Since the bike was new, I'd assumed the drag on the back wheel was from the gears and motor,  but now the drag was gone. The next day, I adjusted the front brake the same way. It went from working well to working better.  I still don't know what the adjustment tool is for.

I've ridden my Radrunner daily for over a year. Since it was new, I have occasionally experienced a jump that seemed to be from a side plate riding up on a sprocket tooth. It seemed as if the derailleur was not aligned with the rear sprocket, but it looked okay to me.

Recently, I bought a laser level to check the slopes of streets I ride. It occurred to me that if the bike were parked on level concrete, the laser plumb line of my level would show if the derailleur and the sprocket were aligned. I removed the chain from the sprockets. I set up the level behind the bike moved the back of the bike a little until the green light hit the sprocket teeth. If the derailleur had been aligned, the light would also have hit its teeth.

The light missed the derailleur teeth. It took force to spring the arm into line.

Backpedaling produces clicking, like the ratchet in a fishing reel. The next day, I happened to backpedal and noticed that it was much quieter. I guess the clicking comes from the side plates of the links, hitting the teeth of the derailleur. I guess the side plates are barely touching the teeth now.

In the 2020 Electric Bike Review of the Radrunner, the reviewer said he'd let air out of the tires for a more comfortable ride. He claimed it also made the bike more stable. The president said he was running 18 psi, as I recall, and he was riding two up with a combined weight of 330 pounds, as I recall.

The review led me to believe I was buying a bike that offered the advantages of high or low pressure as I chose. 

The manual said it's critically important to keep the tires at the pressure on the sidewall. "The RadRunner employs 20'' x 3.3'' rubber tires with inner tubes. The tires are designed for durability and safety for regular cycling activities and the tires need to be checked before each use for proper inflation and condition. Proper inflation, care, and timely replacement will help ensure the bike's operational characteristics will be maintained, and unsafe conditions avoided. Recommended tire pressure is written on the tire sidewall."

"It is critically important that proper air pressure is always maintained in pneumatic tires. Do not underinflate or overinflate your tires. Low pressure may result in loss of control, and overinflated tires may burst. Failure to always maintain the air pressure rating indicated on pneumatic tires may result in tire and/or wheel failure."

They specified a certain tire and said it was important to maintain a certain pressure, but they didn't say what that pressure is. Online, Radpower recommended 20-30 pounds for that tire. That's double-talk.

After more than a year, I found the pressure, under the reflective stripe on the sidewall: "Inflate to 30 PSI." The manual says failure to always maintain the pressure indicated on the sidewall may result in tire and wheel failure. I wonder if wear and tear from riding at lower pressure can make tires susceptible to punctures.

A video posted here showed that at 25 PSI, a Radrunner wouldn't steer on soft sand. I had similar experience on snow until I reduced the pressure to 10 psi, which flattened the footprint enough to resist sliding sideways up onto the snow. The rolling resistance is very high, and the manual warns that it could cause tire or wheel failure.

Tires with lower thread counts are stiffer, which means worse handling and more rolling resistance. Rode bikes typically use 120 TPI. BMX bikes may be ridden down stairways and jumped off objects several feet high. Mountain bikes may hit rocks at high speed. Tires for those bikes have 60 TPI, which allows the "threads" to be thicker and tougher. Riding at 35 PSI is okay for these 2" tires, but they're tough enough to handle BMX stunts at 100 PSI.

The thread count of the OEM Radrunner tire is only 30 TPI. Stiffness would explain why the manual warns not to run less than 30 PSI. If stiffness were a tradeoff for toughness, pressures well over 30 PSI would be okay. In terms of rolling resistance and toughness, would I do better with mountain bike tires? I don't know if they come as small as 20 inches.

Mountain bikers moved to fat tires for better control on deep gravel. I don't plan to ride on deep gravel. Maybe a BMX tire would be a better choice, and they do come in 20-inch sizes. Two standouts seem to be the Eastern Bikes Throttle  2.2 x 20 BMX tire and the Maxxis 2.0 x 20 Hookworm. Would a 2" tire be too narrow for the rim?

I prefer pedaling my Radrunner where possible. I wish I'd bought a model with narrower tires and a bigger rim diameter.

With equal tire sizes, rolling resistance depends partly on air pressure. There comes a diminishing return for more pressure. On a bumpy road, too much pressure can even increase resistance by letting the vehicle be thrown higher; that energy is lost. More pressure means more wear and tear on the machine. More pressure means a rounder cross section, reducing resistance to sliding sideways, up onto mud or snow like the prow of a toboggan.

Rubber hysteresis causes the rolling resistance. With less air pressure, treads bend more, and hysteresis is the tendency of rubber to absorb that energy and turn it into heat. If I knew how to choose low-hysteresis tires, I might enjoy low pressure and low rolling resistance together. For now, I'd like numbers to show my rolling resistance at various pressures.

If you coast down a slight decline and onto a flat or slight incline, your rolling resistance in pounds will be your gross weight times the difference in height divided by the distance along the pavement. On a lightly traveled street, I could use brightly colored duck tape to mark my start and stop points. Pacing the distance would be accurate enough. I'd just need to find the change in height.

Some fairly inexpensive levels with green lasers are supposed to be good for 100 feet outdoors. They produce a flat line to show what's level and a vertical line to show what's plumb. Turning off the vertical line would keep all the light close to the ground. I have a camera tripod that adjusts from 20 to 54" high. I could set up the tripod at my finish point, aim the level toward higher ground, measure the height,  and carry a white paper along the edge of the road. I'd stoop to check the intensity of the line and when it got faint, mark the spot. I'd measure the height of the line, then move my tripod to do it again.

I haven't heard of a law against using a builder's level along a deserted street. The light would probably be knee high or lower, and I'd be within 100 feet. Should I buy a laser level?

Until I was 49, I had nothing but bikes and motorcycles. IIRC, I used machine oil for cables.

I unboxed my new Radrunner three months ago. Right off the bat, it creaked when I squeezed the rear brake lever. It seemed to be coming from the lever pivot. Apparently it's coming from inside the cable a near the brake, where the cable takes a sharp bend. It seems the steel cable transmits the sound and vibration to the lever on the handlebar.

Nowadays, there seem to be lots of lubes just for bike cables. This cable is mounted differently from anything I've seen before. At the back end, the housing points somewhat upward, with no rubber boot or other protection.

I figured that without a boot, an oily cable would pull dirt into the housing each time I squeezed the lever. I tried silicone spray. It made no difference.

Do modern bike cables need lubrication? What's wrong with machine oil? Is there a way to protect the housing end with a boot? Is this a common Radrunner problem? Can it be fixed by rerouting the brake cable?

I bought my Radrunner largely on the basis of the video by Electric Bike Review, paid for by Radpower. On his demo ride, one of the reviewer's first claims was that it was stable. I think he said he was riding with no hands. When my bike arrived, I found it so unstable that even after two months of daily riding, it was hard to make a u-turn on pavement 18 feet wide. I didn't dare take a hand off the bars to return a wave. I quickly developed tennis elbow from fighting for control with my right hand when I lifted my left hand to signal a turn. I'd been riding daily for six weeks when an insect landed on my eye. I let it stay. Taking a hand off the bar to brush it off would have courted disaster.

Was I too tall? My leg length is only an inch longer than the published average for male bicyclists. I looked at the video again. The reviewer had his saddle about the same height as mine. When he turned the camera down at his front wheel, I saw that he, too, had wobbly steering. At one point, I saw Cory, from Radrunner, wobble. If they had less trouble than I, they must have been on smoother pavement.

I'd grown up on classic English touring bikes: 26 x 1-3/8" tires, three speeds, and an upright position. Steering was stable because my perch was stable, with my torso and arms forming a sort of tripod. It was 26" from the seat post to the steering head.

The Radrunner's seat post  was only 19" from the steering head. That felt too short for a stable tripod. I bought an Alta layback seat post. it set my seat clamp back to 26". With a more stable perch, I can make a u-turn on a 10-foot driveway. I need throttle because there's a lot of rolling resistance in turning a fat-tire bike so sharply. My stable seating allows precise throttle control.

The layback cured a worse problem. Riding with one hand, you no longer have a tripod. You sit up so your weight is divided between the seat and the crankshaft. With the straight seat post only 6" aft of the crankshaft, it's like hanging a coat on a rack with a 6" base. Bumpy pavement could cause me to lurch a bit, so I would have to apply a lot of torsion with my wrist to keep the bar steady. The layback puts my seat clamp 13" aft of the crank. My legs can provide much more stability. The day I installed a layback, my tennis elbow began a rapid improvement.

Side streets around here have lots of washboard bumps. The layback rides more comfortably than the suspension post it replaced. As with a classic English bike, when I'm not pedaling, I put most of my weight on the pedal at bottom dead center, almost like standing on one leg. On a bump, the crankshaft rises about half as far as either wheel, and my leg absorbs the bump like a spring. For a speed bump, I bring the pedals level so I can absorb the bump with both legs and both pedals. I usually maintain light contact with the saddle. I did this with a straight seat post, but it works better with the layback because the seat is farther aft of the crankshaft.

Improved pedaling is another benefit I didn't anticipate. I'd depended on motor assistance even for a 1% grade. Now I prefer to handle even a 2.5% grade without the motor. The ankle is about 7" behind the ball of the foot. If the seat was 6" behind the crankshaft, at top dead center, the ankle would be approximately under the hip joint. The ankle has a limited range of motion, so when the knee is bent back that far, the heel will be several inches above the pedal. Pedaling was like doing deep knee bends. With the layback, I don't have to bend my knees so far.

The brace didn't allow the post the be inserted more than 8" into the frame tube. I clamped it that way because it put the seat at the same height as before. After a week, I raised it an inch. I liked it even better. A week later, the post had bent perhaps 4 degrees. A bulge had formed on the back of the post where it exited the tube in the bicycle frame. It was probably the cumulative effect of hitting bumps, and it would get worse. Because of the bulge, I could no longer insert it all the way to the brace. I was going to buy a new one and accept the fact that I couldn't adjust the height.

Then I realized that a plywood brace could support my layback at any height I chose. My Radrunner frame has rails a few inches below the seat. I drilled corresponding holes in scrap plywood. I sawed the board off so the holes would be semicircles to fit over the rails. I removed the seat, clamped the layback an inch higher than before, put the board on the rails, traced around the end of the layback, and drilled a hole for it. Then I sawed off the board to make a sort of triangle. I chamfered the hole to match the way the post expands just past the seat clamp. The seat clamp holds the board on place.

It works. The tight fit on the layback holds the board so securely that I haven't even fastened it to the rails. By drilling holes in another board, I could change my seat height, but it seems just right. The seat looks level, but it's tilted forward. There's no need to touch the ground from the seat, but by sliding forward, I can straddle the seat with both heels on the ground. By sliding back slightly, I can coast with one knee straight but not locked, the ball of my foot on the pedal, and the sole level.

Riding that way, if I want to put most of my weight on my foot in anticipation of bumps, slightly extending my ankle will take most of the weight off the seat and the handlebars. It looks as if the layback would put most of my weight on the back wheel, but this shows that in my normal posture, my center of gravity is approximately over the crankshaft. For hard pedaling, I lean forward more to move my center of gravity ahead of the crankshaft. Before taking a hand off the bar, I sit back to bring my center of gravity aft of the crankshaft. Moving one's center of gravity is automatic.

The geometry between the crankshaft, the steering axis, and the seat is similar to that of a classic English touring bike.

My trouser cuffs get oil stains from my Radrunner's chain. Occasionally, the chain will snatch my cuff.

In the old days, utility bikes for adults had chain guards. They were light and cheap and worked very well. Most were on the top side to protect trousers. Some went all the way around to keep the chain clean and dry.

Has anyone mounted a chain guard on a Radpower bike?