Trying to ride my old bike again - confusing rim + tire sizes
 

New poster here... :)

So I have my College Bike from back in the day...and I never really used it since college. Now I want to start using it again for leisure rides.

I'm having quite a time figuring this out. I managed to fill my rear tire with air using one of these mini bike pumps...despite the Schrader fitting constantly recessing as I pushed this bike pump into the valve...had to practically hold the Schrader valve and push the pump in to fill it with air (this is correct right?) Or should my valve not be flailing in and out of the rim hole?

In any case I tried filling the front tire's air tube..and it would not work no matter what. Long story short I think I may have ripped the schrader valve from the tube :roflmao2:

I now need a new "tube".

Rim says this: Weinmann 700c x 28/35c

My Actual TIRE on the other hand says 700 x 38c....

The tube inside says 700 x 35/43c.

I know the first number means diameter of the tire and the 2nd set means width/fatness of tire (I might be wrong).

If my rim only supports up to 35c...why on earth is my tire 700x38c. Isn't that bad?

Anyways super confused what to do.....I can simply get a tube like the one I ripped out but yeah...very lost here guys. Please help :cry:

Not a problem running 38mm wide tires.

John

Tubes will come in a range of sizes and your appears to be right in the middle.
That's a good place.
If I was looking for a replacement, that's the size I would look for. Small enough to insert easily and large enough to not get stretched too much.

Does the pump have a lock, a lever that 'grasps' the valve? If not, you have to keep on pushing on the pump head to keep it on the valve. I had one like this once. I discarded it.

How can you be unsure?



A rim has 1 width; where on it did you find this?



Check out sheldonbrown.com/tire-sizing.html to find out what tires your rim can accommodate - after you figure out exactly how wide the rim is.

But, this time, you are right.


Not necessarily

The label on your rim gives lots of good info that'll help us answer your questions:

• "700Cx28C/35C" means that you can run 700c tires, and Weinmann recommends tire widths between 28 and 35 mm.
• ETRTO 622x20 is the rim size in ISO/ETRTO notation. It means your rim has a bead seat diameter of 622 mm -- the standard diameter for 700c tires. Your rim's width is 20 mm. According to the ETRTO (European Tyre and Rim Technical Organization), a 20 mm rim will ideally be paired with tires whose width is between 28 and 44 mm wide. According to the ETRTO, Weinmann's 28-35 recommendation is very conservative.

With that knowledge, the 38 mm width of your 700c x 38 tires is fine. And the 35-43 mm width range of your tube is the correct size for the tire.

As to having to hold the valve stem, if the tube has no pressure there will be nothing keeping it from getting pushed down into the rim, this is normal. So it will need to be held in order to press on a chuck, unless you get a tube which has a threaded stem with a nut to hold it; Continental has such tubes. I how have a chuck which screws on but in the past I have used a needle-nosed pliers to hold the stem.

How about a pic of the pump head. There should be a lever to turn to lock the chuck on.
I've never heard of one that doesn't screw on on something.

This is normal. I push the valve up with the other hand then lock the pump. After that, I can use both hands on the pump.

The rim both tells you its width: 20, and recommends tire sizes. You can consult tire-sizing.html for its recommendations for a 20. It has only odd numbers; interpolating between the recommendations for 19 & 21 rims, they would be 32-47. SkyDog75 is probably right.

Thank you all :) :D

I looked on ETRTO's web site and couldn't find this info. Schwalbe publishes a chart that it claims comes from ETRTO but they must have made a mistake.

It's published in the ETRTO's Standards Manual, which can be found in PDF form, but may not be publicly available on the ETRTO web site. Schwalbe, Sheldon Brown, and others have excerpted the chart from the manual and published it on their sites. It looks like Schwalbe's updated their web site and possibly their chart. They may be referring to a newer version of the ETRTO Standards Manual than the 2007 chart that's floating around in general circulation.

And even with that aside, the OP's 38 mm tires just barely exceed Weinmann's 35 mm recommendation. They'll be fine.

Did someone with a college education really just come to a bike forum to ask how to pump up a tire?

On a bike they have owned for years?

:foo:

Maybe I just haven't had enough coffee yet this morning.

Millennial's, 84% of them have no clue how to check oil, or even open the hood of their cars. I suspect, however, they ALL know how to program their cell phones!