Size used on some high performance road and triathlon bikes especially those designed for smaller riders.
Road bike tube sizes explained.
The standard sizes are 1 inch 1 1 8 inch 1 25 inch and 1.
You can also get 26 inch mtb tubes.
The diameter needs to be the same e g.
The steerer tube of the fork is threaded and a threaded race is screwed into the top of the fork to snug up against the top bearing.
Road tubes come in different widths but not as broad a range as mountain bikes.
Tubes because they can stretch will list a range of widths.
To confuse matters further all tyres use the european tyre and rim technical organisation etrto system so for a road it would display 622 x nn with the nn value indicating the tyre width which is the same as 700 x nn.
This is the reason why you see inner tubes listed with one number for the diameter and a range for the width e g.
As the width decreases there is less rolling resistance or friction and therefore is faster.
27 5 x 1 9 2 3 for example.
A typical road tube box may say 700 18 23c or 700 25 32c.
All inner tubes will come with a recommended range for tyre width for example 700 20 25 for traditional road tyres 700 25 32 for wider road tyres.
How to get the right bike tube and valve size.
A standard road tire is 700c x 23mm indicating a tire diameter of approximately 700mm and a width of 23mm.
Thus you need to be sure any new bike tube has sizing that has a width range that aligns with the sizing on your bike tires.
Mtb wheels in particular can be further categorised by 26 inches 27 5 inches and 29 inches.
When shopping for road tires you ll look for 700c x your preferred width 23mm being the slimmest option and going up to 36mm.
700 or 26 but the tube s width will vary depending on the amount you inflate them like a kid s balloon.
A narrower inner tube will balloon out to.
As the width increases the tire will have more contact surface with the road making it more stable and comfortable.
There are a myriad of wheel sizes for road mtb touring and children s bikes.
Bike tube sizing essentially mirrors bike tire sizing with one exception.
Sizing width may vary from 18c through to 28c meaning 18mm through to 28mm.
23c 25c and 28c their width in mm.
So a 29 inch mtb tube will have the same diameter as a 700c road wheel while a 27 5 inch tube will be the same diameter as a 650b road wheel.