Bicycle Mechanics - Newbie frustrated with tire/tube!

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : Newbie frustrated with tire/tube!


JahJahwarrior
12-25-08, 11:06 AM
I'm new, and just bike a few miles to campus for classes. I do not have any desire to become a master mechanic... Bike is an old Puch Cavalier roadbike, 27" tires. One tire was replaced by a bike shop, but they did not replace the tube. It was old and often lost a noticiable amount of pressure over a day or two, so I replaced it. That was the rear tire, and I did the whole job in about 15 minutes. Getting the tire on and off was fairly easy.

Front tire looked like it was dryrotted pretty badly too and I'd put about 100 miles on the bike, so I biked to Kmart and bought myself a Bell tire...figured it was a little cheaper than the bike store, and I am not a hardcore biker so no worries, eh? Anyways, that tire was a pain in the butt to get on, and the old one was a pain in the butt to get off. I'm talking me and my brother both manhandling this thing for 20 minutes for each tire! Next morning, I go outside and the tire is very, very flat :D The tube had exploded, was ripped about 8 inches long. I chalked it up to forcing the tire on, ripping the tube somehow in the process.

So, I put on my spare tube. Bell tube from Walmart, same as is on the rear. Anyhow, the tire was only slightly easir to get on and off, it was still a pain in the butt compared to the bike shop bought rear tire. Tube seems to be fine after a few days, though it's a little low. For whatever reason, I coul dnot get the compressor to inflate the tire. It inflates the rear one just fine, but the front one, same tube from Walmart, it actually tended to deflate some while I tried to get the stupid nozzle on the stupid nipple :D I pumped it up by hand with an old bike pump as much as I could, but I am sure it was not 90 psi, it felt slightly softer than the rear one, and it's a simple plastic pump. Anyhow, a few minutes later, loud pop and the tube has exploded again.

1) Why is this tire such a pain in the butt to get on and off?!?
2) What keeps exploding my tubes?


Doohickie
12-25-08, 11:11 AM
Are you sure you have the correct tire size? If you have 27" rims and you're trying to put, say, a 700c tire on, it's not gonna work.

sch
12-25-08, 11:40 AM
I think it would be practically impossible to put 700c on a 27" rim
but maybe he did. Other possibility is that the original rim is
27" but not hook bead. Sheldon has a discussion of hook bead
versus smooth sided 27" rims and a hook bead tire would tend
to blow off a smooth sided rim. Rim should have an indentation
just inside the top of the brake surface which catches a
corresponding bump out on the edge of the tire bead. Smooth
rims will just have a tapered area there with no indent. The
change over in rim styles occurred in the late '70s for most bikes.
Inflating a smooth bead rim/tire was an adventure.


JahJahwarrior
12-25-08, 02:46 PM
It's not that the tire is coming off so much as it is the tube exploding.... 8 inch long split in the tube. the tube is a 27 inch tube, the tire is a 27 inch tire, just like the back tire and tube. First tube split overnight, second tube lasted a few days before splitting.

Could the Bell brand tire cause this? The tire is much harder to put on than the no name bike store tire. I'll probably take it to a bike store and hav ethem work onit...

I have a suspicion that it might be the rim tape is bad. It looks good, but it might shift when the tube is inflated possibly???

alpacalypse
12-25-08, 02:57 PM
sounds like you might be pinching the tube between the rim and the tire. Or, as you said, the rim tape is going.

Retro Grouch
12-25-08, 04:36 PM
I have a suspicion that it might be the rim tape is bad. It looks good, but it might shift when the tube is inflated possibly???

I doubt it's the rim strip. A migrated rim strip can cause a puncture in your inner tube but it won't blow out a long section of tube.

It sounds to me like you pinched a bit of the tube under the tire bead. That's pretty easy to do so, consequently, it's also pretty common. When it comes time to force the last few inches of tire bead onto the rim, go to the opposite side of the rim and pinch the tire beads into the inside of the rim. That'll give you a little more slack to work with.

z415
12-25-08, 08:17 PM
I agree with Retro. I have made this same mistake in a rush to get to a ride. 3 times in a row. Take your time.

Deanster04
12-25-08, 09:14 PM
If you are a newbie then use your LBS and pay the few dollars more. They are usually a good source of knowledge and are usually quite helpful. If you value your time you have spent far in excess in your time that is worth something trying to do this on your own. If you had brought your wheels to the store they probably would have recommended getting new tires, tubes, and rimstrips for the bike. There is a limited number of 27inch tires available today. Just the fact the LBS you first went to had the tires means they have been around for a while. They could have answered all your questions including the type of bead your rims have. Give them some business and get an education.

Big_e
12-25-08, 09:23 PM
That's all I use is Bell tubes and they work fine for me. Once I pinched a tube and it made a LOUD bang! The tube usually gets pinched right at the air nozzle of the tube as the tire and tube fight for space. After putting in a new tube and before completely airing up your tire. When you just have a little bit of air, push the tube's air nozzle inwards. This will cause the tube to be squeezed and allow the tire to squeeze into any available space inside the rim. Releaase the tube's nozzle and air up as normal and the tire should be seated inside the rim just fine.
Ernest

mike
12-25-08, 09:53 PM
There is more to changing a tire than it seems. If you just tried doing it raw without any instructions or experienced help, then don't be too disappointed in the results.

Go to your local library and get a book or video on bicycle maintanance. There should be a section on changing bicycle tires.

The other option is to go to your local bike shop or bicycle club, or friend who knows how to change a tire and ask them to teach you how to do it.

There are fine points too numerous to mention on a hand-typed bicycle forum. It is a good skill to learn, so learn from the best teachers you can find.

UnsafeAlpine
12-26-08, 12:55 AM
I'd like to think of myself as a fairly competent mechanic. Aircraft mechanic by trade and I've been putzing around with bikes for quite some time. I have one bike with a wheel that takes me about 30 min to swap tires on. It's a 27 inch wheel. I'm not sure what causes this to occur, but it doesn't matter what brand of tire I use, it's just hard to work. If I come up with an easy way to install it, I'll let you know, but for know, just make sure you use the plastic tire levers and take your time.

Mondoman
12-26-08, 12:33 PM
2nding UA's point, different brands/models of tires seem to have slightly different diameters and will be tight or loose fits. I once got a Continental Traffic tire mounted on a Mavic Crossland UST wheel and it was such a tight fit that neither I nor the owner (not a mechanic) of a local bike shop couldn't get the tire off the rim. I felt much less sheepish after the mechanic at least had to use tools to get it off.

DannoXYZ
12-26-08, 04:32 PM
It's not that the tire is coming off so much as it is the tube exploding.... 8 inch long split in the tube. the tube is a 27 inch tube, the tire is a 27 inch tire, just like the back tire and tube. First tube split overnight, second tube lasted a few days before splitting. Here's the thing, a tyre is strong and unyielding. There's absolutely zero way a tube can pop due to pressure while it's inside the tyre. Think about it, a tube can expand to 6-7" wide without any problem and the tyre keeps it constricted to less than 1" diameter. That means that ALL for the force from the pressure is held by the tyre. The ONLY way for a tube to explode is if got outside of its enveloping tyre. This is typically the case where the tube is pinched between the rim-edge and tyre during the install. Immediately after you pump it up, or over time, the pinched tube will squeeze out and explode on the outside of the tyre. Telltale signs of this are long splits or star-shaped holes. The tyre will always check out fine in cases like this.

Here's a technique that'll work to ensure proper installation without pinched tubes and blowouts:

1. with tyre & tube off the wheel, give the tube a little pump so that it's round, but just barely.

2. insert tube into tyre and lay over rim.

3. push one bead completely over rim

4. stuff tube completely into tyre & rim so that remaining bead sits flush on rim-edge

5. start pushing over the remaining bead by hand

6. that last 6-8" will be tough, DO NOT try to push up on the tyre at the middle of the unseated section, no human is strong enough to stretch the bead on a tyre.

7. instead, push SIDEWAYS on the tyre at one of the two spots that wraps up and over the rim-edge; you don't need to stretch the bead this way, just push it sideways.

8. The last bit 3-4" may need tyre levers, to do this cleanly, the tyre lever must never leave contact with the rim.

9. place the tip of the tyre-lever on the rim-edge just under the unseated bead.

10. GENTLY push it up under the tyre, BUT don't push it further than the top edge of the rim, you can feel it drop down slightly. Again, don't lose contact with the rim, this ensures that you never open up a gap between the lever and rim into which the tube and squeeze into and get pinched.

11. next slide the tyre-lever sideways as far over as possible towards the area where the bead goes over the rim-edge; use your other hand to pinch the tyre onto the rim so that tyre doesn't slide off

12. then GENTLY lift up the lever and push the tyre over the rim-edge; typically you don't need to raise the lever more than 90-degrees perpendicular/sideways relative to the rim

13. pull lever out and repeat for other side. Remember, constant contact between the lever and the rim and don't poke the tip much further than the edge of the rim

14. After the entire bead's on, let out some air from the tube and pull the tyre sideways to inspect the gap between the rim-edge and tyre, no tube must show the entire way around on BOTH sides.

15. only after you've inspected the entire bead on both sides, then you can pump it up.

10 Wheels
12-26-08, 04:37 PM
sounds like you might be pinching the tube between the rim and the tire. Or, as you said, the rim tape is going.

You are Pinching The Tube inbetween the tire and the rim.
How do I know?

I blew up Two New Tubes last week.

JahJahwarrior
12-28-08, 02:06 PM
Thank you all for the advice and help!!

I will take it to a LBS this week and get them to help me :D The shop I had gone to before is 2.5 hours south, I'm back from college for the winter break and I don't know the bike shops here very well, since I didn't do much biking before college, so I decided to try to do it myself.

The brand of tire from the store down south was MUCH easier to work with than the Bell tire, and I won't buy tires from someplace other than a bike store again :D

wrk101
12-28-08, 02:53 PM
+1 Pinched tube.

Also, it makes no sense to put a new tire on a bike without a new tube. Tubes are cheap, and if you are paying someone to do the work, replace them both. It also eliminates the excuse: your tube was bad, yadda, yadda.