Inner tube 12x1.75 valve 70x45°

Size

12x1.75 inner tube, ETRTO 47-203: 47 mm wide, 203 mm rim diameter. This size fits electric balance bikes, children's bikes and machines with compact wheels.

Beware of the two meanings of 12 inch

The 12 inch designation covers several rim diameters, including 203 mm and 254 mm. The 203 mm is used on balance bikes and children's bikes; the others belong to different families.

That is what the ETRTO code is for: 47-203 removes the ambiguity that "12 inch" leaves open.

70x45° valve

The valve is angled at 70 degrees on its first segment and 45 degrees on the second. This angle is dictated by the rim and mudguard geometry: it gives access to the valve with an inflator head where a straight valve would be unreachable.

On a small diameter wheel, the space around the valve is limited — the angle matters all the more. Check the one on the original tube before ordering: this is the leading cause of error on this product family.

Fitting

Sold individually. Inflate the tube slightly before inserting it into the tyre to avoid folds, and make sure it is not pinched between the bead and the rim before bringing it up to pressure.