TheMereMortal

Hello, I'm kind of new at this and really need help. I have a Trek fx 7.1. I have a flat, but I can't for the life of me figure out how tires, tubes, etc work. The bike has Bontrager AT-750 rims and H2, 700x35c tires (all stock). The problem is there seem to be many variables in knowing what too get but no information online explaining it.

* Do H2s need separate tubes? A lot of tires seem need separate tubes.
* My searches bring up forum posts implying that tires help keep the air pressure in addition to tubes (not talking about tubeless), which confuses me more.
* Tires/tubes/whatever apparently have all sorts of different ways they attach to the rim. How do I figure out what sort H2s are in the event I need or decide to try something different that will still fit my rims?

I can't find any info clearing this up for me. It seems like you're just expected to already know what products have what features and how everything works. I feel like fixing a flat should be as simple as replacing a piece of rubber. Instead, I'm so confused, buying a new bike seems simpler...

--a sad soul in need of help.

reggieray

Is it a presta valve or schrader valve?



Once you know what type of valve, all you need is a tube that is 700x35. Just about any bike shop is going to have them.

You will need

1. tire levers to remove the tire from the rim and remove the punctured tube
2. a floor pump to reinflate the new tube when it is installed.

There are a bunch of videos on youtube showing in detail how to change a flat. Good luck.

FBinNY 

There are dozens of tutorials, both text and photo and video free on the net. I've linked to some here, but there are plenty more, so I'm not going to reinvent the wheel. Also, many bicycle shops, especially bicycle co-ops off repair courses for free or at low cost, and this is a great option.

But to answer the specific question, all except the new "tubeless" tires use a tire and tube combination. The tube is basically just a rubber balloon that holds air but has no strength, and like a child's balloon will expand and burst at low pressure unless constrained by the tire which provides the structured shape it inflates into.

It's like a football, the sewn pigskin gives it the shape, but wouldn't hold air without the rubber bladder inside.

Here's a link to more basic info about tires including a sketch of a tire and tube on a rim, showing the relationship of the parts involved

Andrew R Stewart 

Many shops and bike clubs offer flat fixing clinics, I teach such at our club. On line vids can also be informative. Just don't do what a customer said happens to her. Guys offer to show her how to fix a flat, she sleeps with them but they never get around to the flat instruction. (True story, sadly). Where does the OP live? Any chance of reaching out to a group? Andy.

spdracr39

The 7.1 rims are for schrader valves. To add to the above find a buddy that rides and have them give you hands on one on one training.

Retro Grouch 

Since you asked, I'd suggest finding somebody who can give you face-to-face instruction. It's a simple process, and I have no doubt you could eventually figure it out by yourself, but there are a lot of little detail things that can make the process much easier. For example, the gear that the bike is in when you take off a rear wheel matters.