spongey

Hi all, I'm new here and purchased my first hybrid bike a couple of weeks ago. I special ordered a 2014 Trek 7.4 fx (didn't really like the 2015 colors). I visited the shop today and they were building it. So, I'm thinking about having a spare tube when riding. I think the tire size is 700 x 32c. I was browsing Amazon for that size but there doesn't seem to have one specific size. I've seen 700 x 25-32cc, 700 x 32-42cc. Also, it seems the valve stems have different sizes as well. Can anyone recommend the right size and also a good brand?

Thanks!

themishmosh

My trek dealer had inner tubes made by Specialized that were perfect. If 32 is in two different ranges, I'd get the smaller range--probably lighter. BTW, the dealer had prices on inner tubes that weren't any different than internet ordering. I'd just pick them up there when you get your bike.

headloss 

Long valves (say 48mm or so and up to 60mm if not longer) are really made for deep "aero" rims, although to save overhead, that's all that some bike shops carry now. I prefer to buy the shortest valve possible, which is usually a 42mm but sometimes I get lucky and find something shorter. Going longer won't hurt anything, it just looks ugly to have a tree growing out of your rim. I can't say what is perfect for your rim without measuring it, but an educated guess would be to go with a 42mm.

As for the tube itself, you can always go smaller than necessary but don't go larger. If the tube is bigger than your tire size, it makes mounting the tire more difficult. For that matter, tires are rarely the size they say they are. If yours is labeled 32mm, I wouldn't be surprised at all if it actually measured 30mm or maybe even 28mm with a pair of calipers... then again, it may be the right size; only way to know is to take a measurement yourself and not trust what is written on the sidewall.. That said, 700x25-32 will definitely work, there is no reason you couldn't use one that was 700x25 only. 700x32-42 will be too big, it can be used, but it will be difficult to mount the tire with a tube that big (even if only marginally bigger).

cc stands for cubic centimeter and is used to measure gasoline engines, not bike tires... you mean c, a single letter, which comes after the 700 i.e. 700c. The 25-32 or 32-42 nomenclature is mm, as in millimeter, and is referring to the width of the tire.

You can buy tubes at Mal*Wart btw.

Wanderer

I would use the 32-45 tube, because it wont be stretched as thin when inflated. Makes it a little less prone to flat easily.... they will both stretch to fit inside the tire. Mho

headloss 

FWIW, I agree with your logic... especially when patching a small puncture/hole on a tube. Still, mileage will vary depending on how difficult a given tire/rim combo is to mount the tire. When in doubt, I say size smaller; forgot to mention the other side of the coin though, thanks.

spongey

Awesome! Thanks for the replies. I learned a little more about bikes. I'm glad this forum is very active and I can learn from more experienced cyclists. I just picked up my bike today and took for a quick test ride. I had a previous engagement this afternoon, so I couldn't ride more. I'll try it again tomorrow. Thanks again!