Gear cluster/chainring recommendations for 20"/24"
 

Hi there. I took a friends Ezirider 20" wheel for a ride today, and it was simply awful. Either the rear cassette or chainring were not set up properly; he has 2 of these bikes and complains about the crazy high speed he has to pedal and I totally agree.

Im purchasing several Ebikes 20" and 24" and I dont want the supplier to chuck on a gearset which is fitting for a 26" wheel which I suspect the Ezirider does.

Can anyone recommend a resource that will give me the correct specs for these smaller wheels? Or make recommendations?
Thanks kindly, Alistair.

You can use simple math to determine the relationship between pedal rpm, gearing, wheel size and bike speed. Look it up online possibly at sheldon brown. If you can't locate it in a couple of days, I'll work it out and post.

You probably need a 52T front gear with an 11T small gear on the rear freewheel to get a comfortable cadence for 20 mph on a 20" bike. These are about the limits of what is commonly available too,

The only maker I know of that sells 11T freewheels is DNP. I put them on my 20" electric folders. One came with a 52T chain ring and 20 mph is attainable with the pedals. The other has a 46T chain ring and it maxes out around 18 mph for comfy pedal cadence.

Hi the first reply - its all very well working out using a calculator, but actual in use is the thing. I built a recumbent 20" many years ago and we worked out what should have been the right combination F/R but in the end needed a higher cogset chainring.

Im not sure what you mean by 11t freewheels? I thought shimano smallest gear (7 shifter) were 11t as de-facto standard, or am I wrong? Ive asked the chap who owns the Ezibike (a generic NZ/China make) to give me the details F/R teeth and crank length, but he hasnt done this yet.

Just to be clear, your 2 bikes are both 20" right? and their smallest cog is 11t? and you have 46t and 52t and prefer the 52t?

Thanks so much for advice. Fortunately, this first shipment is small number of samples, and hopefully, with me drawing attention to the Ezirider problem they will be proactive, and supply the right bits for the 20"/52t and 24"/46t inch bikes.

Sure, reality will trump theory in the end.
But what a gear calculator does is help you compare bikes with a considerable accuracy. Have a bike with a drivetrain that you like, write down the specifics and a gear calc will let you replicate those characteristics in another bike with a minmum of fuss.
You'll probably need to do some tweaking due to differences between bikes. If going from a full-sized bike to a small-wheeled folder, you can probably lose some top end w/o missing it much. And you may appreciate some lower gears to reduce the flexing from standing riding.

Well, 'bents are quite a bit different than uprights in several aspects. W/o knowing what your reference bike was, it's still no surprise that you needed to do some adjustments.


There are two different designs that are used in derailer gear bikes, freewheels, and freehub/cassettes.
Freewheels have the sprocket stack and the freewheling mechanism integrated into one unit, which screws onto the hub. Usually, these come with a 14T smallest.
Freehubs/cassettes treat the sprocket stack and the mechanim as separate units, and can generally use an 11T as the smallest.
There are "specialty" f/w that goes down to 11T, but they're far less common than the 14T variety.
There's also the Shimano Capreo f/h that goes down to 9T.

I didn't know an EZrider was a recumbent. . Don't you guys fly at 25 mph routinely?

I'm thinking of powered hubmotors that use free wheels . If you can use cassettes, there is more availability of smaller gears, but the DNP brand is what .we're looking at for regular bikes and the angle of the frame brackets limits many regular bikes to 52T/53T for the chain gear,

let's see your bike
 

Nature of a factory build parts pick is typicality based on best cost .. if you are contracting directly with the manufacturer and getting a big order, you may be able to specify..
buying from the Importer-distributor as a retailer, or at retail as the consumer, it's up to you and the dealer to change parts ..


yes calculating ratio math is simple..

with only 2 posts the OP will be needing (8)more posts before submitting pictures.... since a search for EZ rider bikes gets you Peter Fonda's movie bike..




....

You could be right, but the supplier has been very cooperative verbally anyway. If the wheels fall off I do have 2 boxes of parts I got from a Taiwan Bike show about 20 years ago. Includes clusters, chainwheels and even 20" mag wheels; quite a collection which may help me get the best out of this batch of sample bikes.

As for the Ezirider here is a Ezirider dot nz
Im not allowed to post url or pictures :bang:.

This tool is great for comparisons, if you know a combination that works, you can compare: Bicycle Gear Calculator

Here is an example Bicycle Gear Calculator

I know for my riding conditions at 48T chain ring with a 12/36 9 speed cassette works well with 35-622 rear tire. To achieve comparable with a 50-406 tire would take a 60T chainring and a 11/34 cassette.

Here is a 58T chainring, with a bit more searching you should be able to find a 60T which are not uncommon on folding bikes.