Some tire/tube questions

[garrett01]

Before I continue I must clear this topic up by saying that I'm only posting this for curiosity sake. I'll admit it... they're really dumb questions, but I had to ask them:

My first question is: would it be okay to temporarily run 26x1.95 inner tubes in a 27x1 1/4 tire at low pressures? My concern would be that the expanding tube would "force" the tire right off the rim, but am I right?

My second (and more "intelligent") question is: if you don't have a tire (but need to use your bike), could you inflate the tube (enough to give it shape), wrap the tube duct-tape to hold it to the rim (fully surrounding the tube so there is no more tube showing), and inflate it to 20 to 30 PSI? My theory is that the duct-tape would hold the tube, much like a normal tire. Obviously you couldn't run it at full pressure, and the tube would be much more easier to puncture while riding.

[cny-man]

Question 1: It would be difficult to fit a 26" tube onto a 27" tire/rim, but if you can do so with NONE of the tube showing under the tire bead it cannot push the tire off the rim at normal pressure.

I have heard of nobody crazy enough to try such a thing, so go ahead and let us know the result.

[garrett01]

(12-29-2014, 12:16 AM)cny-man Wrote:  Question 1: It would be difficult to fit a 26" tube onto a 27" tire/rim, but if you can do so with NONE of the tube showing under the tire bead it cannot push the tire off the rim at normal pressure.

I have heard of nobody crazy enough to try such a thing, so go ahead and let us know the result.

I knew question #1 was a very dumb question to ask... I was really more interested in question #2...

Thanks for your reply

[nfmisso]

Regarding #1 - I did successfully fit a 26 x 1 3/8 (37-590) tube into a 35-622 tire and on to the rim. It required some stretching, and I would avoid it. Based on that experience, there is NO way that you'd be successful with a 26x1.95 (47-559) tube in a 27x1¼ (32-630) tire and on to the rim.

Regarding #2 - do you have a good life insurance policy to take care of your dependents afterwards?

[cny-man]

(12-29-2014, 12:18 AM)garrett01 Wrote:  

(12-29-2014, 12:16 AM)cny-man Wrote:  Question 1: It would be difficult to fit a 26" tube onto a 27" tire/rim, but **IF** you can do so with NONE of the tube showing under the tire bead it cannot push the tire off the rim at normal pressure.

I have heard of nobody crazy enough to try such a thing, so go ahead and let us know the result.

I knew question #1 was a very dumb question to ask... I was really more interested in question #2...

Thanks for your reply

Not as dumb as.the second one. My try it comment was for that question. I'm sure Nigel is correct on the first one.

[garrett01]

(12-29-2014, 07:35 AM)cny-man Wrote:  

(12-29-2014, 12:18 AM)garrett01 Wrote:  

(12-29-2014, 12:16 AM)cny-man Wrote:  Question 1: It would be difficult to fit a 26" tube onto a 27" tire/rim, but **IF** you can do so with NONE of the tube showing under the tire bead it cannot push the tire off the rim at normal pressure.

I have heard of nobody crazy enough to try such a thing, so go ahead and let us know the result.

I knew question #1 was a very dumb question to ask... I was really more interested in question #2...

Thanks for your reply

Not as dumb as.the second one. My try it comment was for that question. I'm sure Nigel is correct on the first one.

I knew they were both dumb questions, but I thought the second one would be more "realistic." Wouldn't duct-tape be strong enough to hold 20PSI? Of course, you would have no puncture resistance.

I have some (realistic) questions I'm going to post in a new thread... they're not dumb questions that just came out of my imagination. ;-)

[cradom]

Re the second question: here's an image for you, even if it held air and didn't explode, think roller skating on an ice rink.
Very little friction. Even one little pebble and the wheel slides out from under you, leaving a streamer of tape.

[cny-man]

(12-29-2014, 05:12 PM)garrett01 Wrote:  I knew they were both dumb questions, but I thought the second one would be more "realistic." Wouldn't duct-tape be strong enough to hold 20PSI? Of course, you would have no puncture resistance.

I have some (realistic) questions I'm going to post in a new thread... they're not dumb questions that just came out of my imagination. ;-)

Again, just not sensible, but just for entertainment value:

Have you thought about how to deal with the spokes getting in the way of wrapping with plenty of overlap?

Do you have rim brakes - if so might get messy really fast.

Are you aware that a tube inflated outside the tire does not have anywhere near a consistent diameter?

When I had a very bad tire cut on my road bike in a remote area out west I did use duct tape to repair it, wrapping completely around the inside and outside of the tire, but NOT the rim - completely different issue.