Better tires for Radrunner?

[handlebar]

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?

[Radio Runner]

The 2" wide tires made for BMX would indeed be to small for the Rad Runners/Rad Mini wide rims. The sidewall simply isnt tall enough so when a fat 2.0 bmx tire is mounted to a super wide rim the tire profile flattens out. Very unfortunate. I am also on the hunt for a smaller tire with taller side walls. I radical option would be to re-lace skinner rims however that could get expensive very fast.

[handlebar]

The 2" wide tires made for BMX would indeed be to small for the Rad Runners/Rad Mini wide rims. The sidewall simply isnt tall enough so when a fat 2.0 bmx tire is mounted to a super wide rim the tire profile flattens out. Very unfortunate. I am also on the hunt for a smaller tire with taller side walls. I radical option would be to re-lace skinner rims however that could get expensive very fast.

Thanks. Somewhere I found a rule of thumb about what widths should work with a given rim width. 20x3.00 should work. I've ordered an Innova Duro. I thought I'd found the specs online, but now I can't find them.

[Radio Runner]

Those Innovas are interesting. They look like slicks which would be great for the pavement. Any idea if they have puncture protection? I was thinking about getting the CST's from rad since they look better than the Kenda's for road but they may be just as fat.

There is no real standard to the numbers. One 20x3.0 tyre could in reality be slightly wider or skinnier than another 20x3.0 branded tire and you never really know until they are on the rim and aired up.

What's this rule of thumb you learned?

[Jay-Ryan]

Those Innovas are interesting. They look like slicks which would be great for the pavement. Any idea if they have puncture protection? I was thinking about getting the CST's from rad since they look better than the Kenda's for road but they may be just as fat.

There is no real standard to the numbers. One 20x3.0 tyre could in reality be slightly wider or skinnier than another 20x3.0 branded tire and you never really know until they are on the rim and aired up.

What's this rule of thumb you learned?

Interested in hearing as well!

[handlebar]

Those Innovas are interesting. They look like slicks which would be great for the pavement. Any idea if they have puncture protection? I was thinking about getting the CST's from rad since they look better than the Kenda's for road but they may be just as fat.

There is no real standard to the numbers. One 20x3.0 tyre could in reality be slightly wider or skinnier than another 20x3.0 branded tire and you never really know until they are on the rim and aired up.

What's this rule of thumb you learned?

I lost interest and $70. I won't buy anything else from Innova.

The vendor mailed it in a plastic bag. The mail carrier folded to to fit in my mailbox. It didn't look like a 3.00" tire, but Innova printed 20 x 3.0 on the side, along with 406-72 (which is about 2.8".)

I got it mounted. As I pumped it up, I monitored both sides to be sure the bead was seated. It was quiet and steered well, but in 100 feet it felt a little bumpy. In 100 yards it was so bad that I stopped. The tube was coming out on both sides. I walked it back, and a caliper told me why the beads hadn't stayed seated: 2.1" wide.

On that tire, the tread was wider than the sidewall. The ISO says the proper way to measure is to spread the casing on a ruler and read the distance from bead to bead; that's 2.5 times the width. I read 125mm, so it's a 2.0" tire.

406 x 72 is an ISO measurement, and the ISO standard allows only + or - 3mm. It was blatant false advertising by Innova and the vendor. The mishap put at least 6 pinch holes in my new tube. The vendor won't accept the $55 tire back because it's a used tire. I'm sure Amazon will have something to say about that.

Meanwhile, Sheldon Brown says that at a given diameter and pressure, wider bicycle tires have less rolling resistance than narrow ones. At 30 psi on OEM tires, I'm getting faster coasting speeds on downgrades and longer coasts. I use the motor less. My gauge says I've been 37 miles since the last charge, and I still have 48.7 volts. It reads half a volt low, so I have 49.2.

I've changed my riding position to that of the 1885 Rover (first popular rear-wheel-drive bike), the Victor Flyer (best bike of the 19th Century), and the Raleigh Roadster (legend of the 20th Century). One advantage is that my legs absorb bumps, which spares me and the bike. If the tires would hold 40 psi, I'd run them that way.

[Radio Runner]

After looking at the gap of space under the fenders when comparing the stock Kendas and the CST's in various pictures, I noticed the gap is bigger with the CST's. That tells me that they will be slightly narrower which is what I'm looking for. Thinner and a more pavement friendly tread pattern. So I ordered some CST's.

I'll post pix whenever they come. 

[CostaMoses]

After looking at the gap of space under the fenders when comparing the stock Kendas and the CST's in various pictures, I noticed the gap is bigger with the CST's. That tells me that they will be slightly narrower which is what I'm looking for. Thinner and a more pavement friendly tread pattern. So I ordered some CST's.

I'll post pix whenever they come.

How are they working out? Can you post pics?