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RW4 and 20 inch tires

Started by Ddaybc, August 11, 2023, 08:03:17 AM

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I have a RW4 with the stock 22 inch tires. They are only available from Rad.  :(

Has anyone changed their tires to 20 inches such as the tires on the Radrunner? The weight rating of the Radrunner and the RW4 are the same, 350 pounds so there's no issues with the weight rating, payload etc. The tire width looks like it would fit.
When I wear out my RW4 tires I'm either going to get Shinko 241 moped tires or change to 20 inch tires so I don't have to rely on one tire supplier anymore.

FWIW I also see almost every two wheeled cargo bike is now designed with 20 inch tires. Hopefully Rad has a new RW in the works with 20 inch tires? RW5? RW4a?  ;D


Isn't the wheel a 20 inch wheel? Would you replace both wheels with new 20" wheels as well? That seems like it would be expensive, especially for the wheel with the motor on it.


the shinkos will be heavy, so be prepared for that.  there is also some confusing differences between bicycle and moped tires, like a 16 inch moped tire equals a 20 inch bicycle tire, but not always, depends on brands.  Are you going to re-lace the rad hubs onto aluminum moped rims?   

Radio Runner

I believe the rims are also a bigger size. 20? tires from a Rrunner would not fit. To small overall diameter.

If you swapped the wheels out to smaller rims and tires your whole bike would drop lower as well. Turning will be different, fenders won?t work as well and pedals will most likely strike the ground on even very easy corners you normally can pedal on throughout the turn. Also the rear derailleur could end up being just an inch above the ground.


Good comments everyone. Thank you.

A Shinko 721 in a 2.75 by 18 fits the RadWagon as it's presently designed. They are heavier but designed for a moped so I believe they are built better/stronger than tires built for a bicycle. The reviews I've seen on YouTube say they are pretty good in the winter too.

Rad Runner 20 inch rims would fit perfectly as the axle sizes are identical. The rim width would allow one to use tires of various widths but it shouldn't be a concern as the tires look like they would fit. If I had access to a Rad Runner I would like to try the wheels to see how they fit. It looks like, according to the spec sheets on the Rad site, they would be a perfect fit.

The switch from 22 inch wheels to 20 inch wheels sounds like a big size difference. It's the diameter of the overall tire and not the ride height. If all other things are equal one would only lose 1 inch of axle height and 2 inches of overall tire height. It appears, however, the Rad Runner tires are larger than the Rad Wagon so I would be very interested to see exactly how much axle height one would really lose by switching to Rad Runner tires and wheels for the Rad Wagon.

I don't believe hitting the pedals while riding would be an issue as one doesn't corner fast on a cargo bike, doesn't take a cargo bike mountain biking, generally only ride rail trails kind of trail riding. If it was a big concern for someone then perhaps one could switch from 170 mm pedals to 165 or 160 mm pedals?


FYI, 22 inch tires are available here:

I plan to get these to replace my Rad tires.


jazzy_bob, those tires look good. They look like they would be smooth and they look like they have reasonable tread design. Very nice.
I especially like the white sidewall design. It's what I used to have on my motorcycles.


this 20" convertion seems interresting.
Does anyone tested it ?


The ISO number, usually on the sidewall, provides a fit by showing the bead diameter and the width. I believe the RW4 uses 62-559mm. I believe it has 45mm rims, which, according to a chart I have, will work with tires 2.35 to 4.20 inches ( 60  - 107mm ). lists 698 tires with the 559 mm bead, and too many to count are between 60 and 107 mm wide.