Which sprocket ratio for my Tomos?

With the gear ratio, you can very simply influence the traction or top speed of your Tomos, provided you have enough power. As a front sprocket, most models use a 26-tooth sprocket. The rear differs depending on whether it is a 25 km/h or 45 km/h model. In addition, models like a Revival and Streetmate also have a different rear sprocket. The models with small wheels like the Tomos Funtastic also have different sprocket ratios.

Below a few examples. Of course, you can also take 26 or 28 teeth as the rear sprocket, for example, if you don't want to go too fast but are looking for something in the middle to match your setup.

Flat and concaved front sprocket

Most Tomos models have a flat front sprocket, a few models like the Tomos Revival and Pack'R with a wide rear wheel have a concaved front sprocket so the chain is in the correct line.

Torque or top speed?

Do you want lots of torque / fast acceleration? Fit a large rear sprocket, but do keep in mind that this does reduce your top speed.

Do you want more top speed? Fit a small rear sprocket, this will give you less acceleration but if you have a fast setup you can compensate this.

With a large rear sprocket, you do have to make sure you don't overrev.

Tomos A3 / A35 / Flexer / Quadro / Luxe / Standard / Taxxity / S25 / Wizz'rd

25 km/h

Front sprocket 26 teeth
Rear sprocket 33 teeth

45 km/h

Front sprocket 26 teeth
Rear sprocket 22 teeth

Tomos Revival / Streetmate

With the Tomos Revival, pay attention to which rear hub you have. It is available as a 4 or 5 hole rear sprocket.

25 km/h

Front sprocket 26 teeth (concaved type)
Rear sprocket 37 teeth

45 km/h

Front sprocket 26 teeth (concaved type)
Rear sprocket 31 teeth

Tomos Funtastic / Funsport R

25 km/h

Front sprocket 26 teeth (concaved type)
Rear sprocket 26 teeth (internal teeth type, also called A3/A35 front sprocket)

45 km/h

Front sprocket 26 teeth (concaved type)
Rear sprocket 31 teeth (type with internal teeth, also called A3/A35 front sprocket)

Tomos Youngst'R

25 km/h

Front sprocket 26 teeth (concaved type)
Rear sprocket 31 teeth (type with internal teeth, also called A3/A35 front sprocket)

45 km/h

Front sprocket 26 teeth (concaved type)
Rear sprocket 20 teeth (type with internal teeth, also called A3/A35 front sprocket)

Calculating the gear ratio

You can theoretically calculate your gear ratio very easily.

Here are a few examples

26/33 = 0,78
26/31 = 0,83
26/28 = 0,92
26/26 = 1,00
26/24 = 1,08
26/22 = 1,18

28/33 = 0,84
28/31 = 0,90
28/28 = 1,00
28/26 = 1,07
28/24 = 1,16
28/22 = 1,27

31/33 = 0,93
31/31 = 1,00
31/28 = 1,10
31/26 = 1,19
31/24 = 1,29
31/22 = 1,40

If you spin 6000 rpm with a 26/22 ratio, then your rear wheel spins 6000x1.18=7080 rpm. If you spin 6000 rpm with a 26/33, your rear wheel will spin only 4680 rpm. So with a 28 or 31 front, your rear wheel will spin even more revolutions = higher speed. Based on this, you can calculate for yourself and ultimately decide what you like.

Front sprocket 27 teeth

Some Tomos riders choose for a front sprocket with 27 teeth, this is possible but doesn't fit directly. You have to grind a piece out of your crankcase to get this combination to fit. Below is an example with a 27-tooth sprocket.