What inner tube?

[hoppym27]

Apologies..im a newbie...ive bought a second hand bike but don't know what size wheels it is...the tyre says the size is 700x38c....what size inner tube do I need?

 

[vickster]

One that has 700 x 38mm on the packaging, likely will say 28-38 or 38-45

E.g. http://www.halfords.com/cycling/bike-parts/inner-tubes/halfords-presta-bike-inner-tube-700c

They are 700c wheels, the 38 refers to the width of the tyre (mm)

Does it have a presta (long skinny like the link I've added) or Schrader (fatter, like a car) valve?

 

[mjr]

Use the ISO sizes, which will have a diameter of 622 on them. Then tubes will have a width range on them and all you need to do is get one where 38 is in the range, such as 37-50.

The imperial (probably 27.5 or 28 inch) and French (700c) sizes can be ambiguous.

Also, if you've got fat valves, you can choose between Schrader (car) and Woods (old English) valves. I prefer Woods because it uses the same pumps as narrow Presta (French) valves and I think the valves are easier to adjust.

 

[hoppym27]

Thanks...so it's got city/road tyres on now..could I put 700c hybrid tyres on it?

 

[mjr]

You can probably put lots of 700c tyres on it. As long as you don't vary the width too much and the tyre fits through the frame, the bike won't care.

Edit: if the bike came with 38s on, it may have 19mm rims, so tyre widths of 28mm to 44mm will be OK on the wheels, according to SheldonBrown.com