Tube Cracks?

[garrett01]

This post may not be clear without pictures, but I'll continue...

Today I rode my bike and my valve stem on my rear tire was crooked. I went to a local gas station that has a free air compressor. I tried to move the tire back into position so the stem would be straight. No go.

I ended up taking the tire off and the tube out and putting the tube back in and re-mounting the tire. When I inflate the tube, I noticed little "cracks" in the tube that look like cracks caused by dried up rubber.

I've deflated the tire and just want to play it safe until I can get some advice on what to do. The tubes hold air good. They are the $4 "el-cheapo" Chinese tubes from Wal-Mart, "Bell" branded but had another manufacturer printed on the tube.

I'll try to get photos tomorrow. I'm not going to inflate it until I can get some advice - don't want to risk a blowout.

[undefined=undefined]Edit:[/undefined] This is on my mountain bike. The tire size is 26x1.95. The inner tube affected was inside a brand new "Bell" Kevlar tire from Wal-Mart. I installed the tubes in April. If it helps any, the tubes were bulging when new when inflated outside of the tire. (Attached is a photo of the bulge.) I'm just wondering if this is a bad tube. I also returned the same brand and type of inner tube to Wal-Mart as the two of the others I bought were also bulging and one blew up do to a faulty tire (not due to a defect in the inner tube) which is why the rear tire is new.

[DaveM]

The "bulging" is not an issue. This is normal with many tubes.
Cracks however, are a sign the rubber of the tube has degraded. Either old or exposed to too much air/light. I would replace any tube that is cracking.

[garrett01]

Here is a good picture of the cracks. I noticed that there was also some "poke marks" in the tube, even though there was no dirt in the tire when the tube was installed and first inflated, and there was no dirt in it yesterday also.

The file was too big to attach to this post and the forum won't let me use the "image" button so I've attached the link to the location where the photo resides on Flickr below.

https://flic.kr/p/nFnKcC

[DaveM]

Hmmm, not so sure those are cracks. Looks more like marks left over from the molding process or something. HArd to be sure from just that photo, but it looks ok to me.

[garrett01]

I'm probably just going to get rid of the tube and buy new ones just to be safe. There was also some poke marks/poke holes in the rubber that wasn't caused by dirt, etc.

Sad that these tubes are only 2 months old... I've learned my lesson to not buy $4 inner tubes from WalMart

EDIT: It may also be worth mentioning that these tubes did not have these marks before I installed it in the tire.

[DaveM]

Probably the right choice. You might want to inspect the inner surface of the tire. There may be hard/rough spots that are abrading the tube.

Always remember that Walmart's only criteria in sourcing stock is "what is the absolute cheapest thing available?" and that they buy in large enough quantity to slap whatever "brand name" they want on the box.

[garrett01]

(06-15-2014, 03:16 AM)DaveM Wrote:  Probably the right choice. You might want to inspect the inner surface of the tire. There may be hard/rough spots that are abrading the tube.

Always remember that Walmart's only criteria in sourcing stock is "what is the absolute cheapest thing available?" and that they buy in large enough quantity to slap whatever "brand name" they want on the box.

Okay. I don't know if I should check the front inner tube or not.

I bought both the front and rear inner tubes at almost the same time and the tires are the same (while the front tire is about a year older.)

[garrett01]

Just checked the front inner tube, and it looked okay. Must be the rear tire has a defect in it. But there certainly are "poke marks" in the rear tube when you inflate it just a little bit even.

[garrett01]

I threw out both tubes. The rear tire (the one giving me problems) is only three months old and is from Wal-Mart. The front tire, which is the same type and model of tire, also from Wal-Mart but is about a year old, was fine.