Bicycle Mechanics - Anyone have experience patching tubes w/ cut up tubes?

I've tried it out as per someone's post on the forum using rubber cement (~$1+) and it seems to work well for mtb tubes using mtb tube scraps, but the mtb tube scraps don't seem to work very well on road bike tubes. Are the mtb tube scraps just too thick for the road bike tubes or can I only use scraps/rubber cement on lower pressure tubes/tires?

It's both a problem with the pressure (and probably you're making the patches smaller) and the material. Good quality patches (any that actually work) are made of a sandwich of different rubbers. the surface that touches the tube is unvulncanized rubber that's got fast-acting vulcanizing accelerators in it. The cement has a vulcanizing activator in it which activates the the accelerators. Combined with the free sulphur in the tubes rubber, this vulcanizes the patch to the tube, forming a permanent bond. With just a piece of tube, you're only getting the mechanical bond of the cement, which isn't very strong, particularly compared to the deformation of the tube in use.

To what end are you doing this? I take care of our personal fleet of 7 bikes and have patched no more than three tires in the last 5 years and 10000 cumulative miles. At even twice that rate, it would take 5 more years to use up a couple of inexpensive patch kits. Have one less Starbucks drink per year and you can afford more real patches than you will ever use.

No starbucks here and I've gone through a lot more in the way of tubes that I would like to patch thanks for the most part to goatheads. I also have a few splits I'd like to repair that don't come in patch size, so if possible I'd like to be able to use tube scraps. Based on your responses I did a bit of research and it looks like I should be OK w/ something that actually vulcanizes the patches (like from an auto parts store) as opposed to rubber cement. I'll just need to let it set longer if I'm using two pieces of tube as opposed to a patch designed to be used with it.

Thanks everyone!

Proper repair units are cheap, available in a range of sizes and shapes, and will actually work. 100 rema tip-top patches cost 15 or 20 bucks, 15 or 20 cents a piece. I don't know what your time is worth to you, but even if you value it at a buck an hour, it doesn't take many failed patches -- and at road bike pressures, and deflections, you'll have lots -- to make that cheap.

Where do you people come up with these ideas? I never said I needed patches. I bought 100+ in varying sizes about five years ago and I have most of them left. The wax paper on top doesn't come off any more due to the heat but they work pretty well. What I'd like to use the tire scraps for are 4"+ long splits that I can't use the patches on. I just picked up some auto rubber cement so I'll see how that works with the tube patches in a bit.

Do people really patch tubes with 4"+ splits? Yikes

Where do you people come up with these ideas? I never said I needed patches. I bought 100+ in varying sizes about five years ago and I have most of them left. The wax paper on top doesn't come off any more due to the heat but they work pretty well. What I'd like to use the tire scraps for are 4"+ long splits that I can't use the patches on. I just picked up some auto rubber cement so I'll see how that works with the tube patches in a bit.

They are trying to tell you that you're doing it the hard way.

new tubes are cheap..

new tubes are cheap..
And stimulate the economy, citizen!

Easy for you two to say! if you ain't all talk then send me a few hundred bucks and I'm sure I'll change my tune. :D

Comrade, a tube is just $5, thorn resistant, $15. or thereabouts..
tire patches have a non butyl layer that the glued surface adheres to,

vulcanized rubber can be glued together, it's all surface prep and getting the glue right.

a couple hours of labor, to limp into a bike shop then buy a new tube..

Or, you could adopt the mid war austerity, and stuff your tires with straw and rags.

Patching a 4" long hole is false economy. Have you tried Armadillo tires from Specialized? What do other riders in your area use?

And stimulate the economy, citizen!
My guess would be saving money for the therapy sessions.

The only therapeutic advice I need is to check out Sheldon's site (http://www.sheldonbrown.com/brandt/patching.html) before I get the advice of the BF peanut gallery. :twitchy:


Patches can be made from tube material but this must be done carefully following the same procedure as preparing the tube. However, butyl tube material, unlike commercial patches, is impervious to rubber cement solvents and will not cure if the glue on the tube and patch is not completely dry. This presents a substantial problem.

There's no magic vulcanization or a need to buy $50 in tubes for an $80 bike. The lighter colored rubber material on most patches is permeable to the solvents used with rubber cement, so even if the cement isn't completely dry when the patch is applied it can still cure. Butyl on butyl otoh can't do this, so the cement needs to be completely dry to use rubber scraps as patches. Thank you Sheldon and Jobst! Screw you BF nutjobs! :p

Like I said, you are doing it the hard way. And you think other people are nut jobs?

Some nuts you just have to let learn the hard way. It does no good to tell them that 4" rip in a tube isn't practically patchable with another tube in a reliable fashion. Or to help them to determine why they are getting a 4" rip to begin with (In 30 years I have never seen this)

Just place your seats in the reclined position and enjoy the show...

The only therapeutic advice I need is to check out Sheldon's site (http://www.sheldonbrown.com/brandt/patching.html) before I get the advice of the BF peanut gallery. :twitchy:
So why did you ask for it?

Thank you Sheldon and Jobst! Screw you BF nutjobs! :p

WOW! is all I can say.

new tubes are cheap..

Send me 5 tubes.. Thanks.

Like I said, you are doing it the hard way. And you think other people are nut jobs?What way am I doing it again?


Some nuts you just have to let learn the hard way. It does no good to tell them that 4" rip in a tube isn't practically patchable with another tube in a reliable fashion. Or to help them to determine why they are getting a 4" rip to begin with (In 30 years I have never seen this)So far so good but time will tell. Of course in 30 years you hadn't seen the information on Sheldon's page that could have answered my question, so that doesn't bode well for any experience you may have.


So why did you ask for it?I hadn't seen the page yet and I figured I could get some helpful advice on the forum. Obviously I was wrong about the helpful part, but live and learn.


WOW! is all I can say.You're telling me! 15+ posts and not one of them helpful... You would think at least one person here would have seen the information on Sheldon's website and posted it here, but all I get is incorrect or off-topic posts.

You would think at least one person here would have seen the information on Sheldon's website and posted it here, but all I get is incorrect or off-topic posts.

You are way out of line. Just because you did not like the answers you received does not mean that they were not intended to help. Mr, if you are patching tubes with holes that large you are pissing into the wind in the opinion of most here. You will of course, "live and learn" but the posters here have lived and learned so how about a little respect for the time they have put in. We all appreciate Sheldon's site and Have Read Jobst' book as well. Just because you CAN patch doesn't make it wise to do so in the larger picture. I'm glad you found what you were looking for but don't get on us here because you had to dig a little deeper to find someone who agrees with you. We are not you mothers here.

There are plenty of great resources on the web to search with a wealth of info. Man up and do a little digging before you come here and criticize. And remember low price and low cost are not necessarily the same thing. Sometimes, the cheap route costs quite a bit more. In the spirit of goodwill but only God knows why after that last post:

http://www.sheldonbrown.com/ You are aware of this one.
http://bicycletutor.com/
http://www.parktool.com/blog/repair-help
http://www.utahmountainbiking.com/fix/

this vulcanizes the patch to the tube, forming a permanent bond

This is what everyone says when they want to look smart, but unfortunately it just isn't so.

Patches can be removed by heating them up. I didn't believe it till I tried it myself.

It's a very good bond, but it isn't permanent... it isn't a melting or welding or fusing together of the patch and the tube.

What way am I doing it again?

Like a hard headed, arrogant, dim wit from what I can tell.

The only therapeutic advice I need is to check out Sheldon's site (http://www.sheldonbrown.com/brandt/patching.html) before I get the advice of the BF peanut gallery. :twitchy:



There's no magic vulcanization or a need to buy $50 in tubes for an $80 bike. The lighter colored rubber material on most patches is permeable to the solvents used with rubber cement, so even if the cement isn't completely dry when the patch is applied it can still cure. Butyl on butyl otoh can't do this, so the cement needs to be completely dry to use rubber scraps as patches. Thank you Sheldon and Jobst! Screw you BF nutjobs! :pI've had several discussions with Jobst in RBT regarding tube patching techniques. I disagree with his technique and his explanations. Based on the criterion that a patched tube is immediately ready to ride, I claim a 90% success rate for my technique. Jobst admits that his technique requires 24 hours to cure before riding.

Regarding your specific problems. The easiest repair method is to avoid flats. A 4 inch slit is usually caused by the tire bead pressing on the tube and pinching it. That cause is 100% avoidable by taking extra care in mounting the tire. There have been several excellent detailed descriptions posted here on how to avoid this problem.

I bought 100+ in varying sizes about five years ago and I have most of them left. The wax paper on top doesn't come off any more due to the heat but they work pretty well. A five year old patch is probably toast. The foil side of patches is treated to react with the cold vulcanizing solution applied to the tube. This treatment will evaporate with time and heat. Most patches use a clear cellophane or plastic as the carrier on the butyl side. The only patches I've run across that used wax paper were made by a British firm: Bikit. If your patches were indeed made by Bikit, they are a lot more than 5 years old.

You can still use patches, even if you do not have a 4 inch long patch. The you can apply a patch to the outer butyl side of a patch. The butyl side requires the same preparation as a tube surface: cleaning (sanding) and applying cold vulcanizing solution. It also means you must learn how to remove the cellophane without pulling up the patch. Therefore, you may use 5 or more 1 inch round patches to completely cover a 4 inch slit.

I just picked up some auto rubber cementI purposely used the term "cold vulcanizing solution" rather than cement because rubber cement is not used for applying patches. The solution is designed to work with the patch. Mix brands at your own peril.

If you insist on still trying to use an old tube, here are some hints. First, you must apply vulcanizing solution to both surfaces and let them dry completely. You should apply pressure after you apply the "patch" to the tube. This pressure should go from the inside to the outside. The purpose of this burnishing is to remove any air pockets. Rubber vulcanizes to rubber - not air.


I've tried it out as per someone's post on the forum using rubber cement (~$1+) and it seems to work well for mtb tubes using mtb tube scraps, but the mtb tube scraps don't seem to work very well on road bike tubes.
You did not mention the size of the road tubes that don't work. I've always wrapped the tube around a flat surface (a patch kit box). I've used the box as backing when I burnish the newly applied patch. Road tubes can be extremely narrow. The patch must fit within the tube. Standard 25 mm patches are too big for many road tubes. I use 16 mm for most road tubes.

I can see a lot of problems trying to cut a 5 inch long patch that will completely cover a 4 inch slit and still fit within a flattened road tube. One suggestion would be to get a patching tube of equal size and cut out a length of the tube. I'd then cut out the section with the 4 inch slit and splice it with the patching tube section I created. This would limit the vulcanizing two areas to where the splice met the original tube. I'd think these two areas would be easier to vulcanize.

The only practical use for this solution would be, if I had a with a broken valve and another of the same size with a perfect valve but otherwise unusable e.g. a tube with a 4 inch long slit somewhere else on the tube.

I hadn't seen the page yet and I figured I could get some helpful advice on the forum. Obviously I was wrong about the helpful part, but live and learn.

This is the fix
(http://www.notubes.com/Default.aspx)

This is what everyone says when they want to look smart, but unfortunately it just isn't so.

Patches can be removed by heating them up. I didn't believe it till I tried it myself.

It's a very good bond, but it isn't permanent... it isn't a melting or welding or fusing together of the patch and the tube.

It is, in fact, vulcanized together, if it's done properly. It's not nearly as well cross-linked as the main part of the tube is, because there isn't enough unbound sulphur in that rubber for the patch's rubber to react with. But a properly patched tube can not be peeled off, without causing mechanical damage -- you're tearing the rubber, not peeling the two layers apart at the glue line.

I've had several discussions with Jobst in RBT regarding tube patching techniques. I disagree with his technique and his explanations. Based on the criterion that a patched tube is immediately ready to ride, I claim a 90% success rate for my technique. Jobst admits that his technique requires 24 hours to cure before riding.

Jobst suffered from a problem that many engineers do, which is that they won't believe that their knowledge doesn't apply to something where it doesn't. Rubber patching is a big big issue for chemists and chemical engineers employed by rubber products companies; it has almost nothing to do with mechanical engineering, and you need to understand the chemistry to understand why the instructions are what they are. (You don't need to understand the chemistry to use the stuff; you just need to follow the manufacturer's instructions.) Lots of effort goes into making systems that work well together.

If the original poster is going to insist on using unsuitable material, he's not going to have good results, particularly at high pressure and small diameter tubes. A heated clamp (or maybe even a household iron, no steam) would help loads. There's not really much sulphur available in the surface of the tube, and without a thiocarbamate (which is typically what's in the unvulcanized surface of the patch) to do its cross-link accelerating magic, it's not likely you'll get much in the way of tube-glue-tube bonds. Heat and pressure help that.

So far so good but time will tell. Of course in 30 years you hadn't seen the information on Sheldon's page that could have answered my question, so that doesn't bode well for any experience you may have.

I have enough experience that I have tried this. I have enough experience to to not waste hours of time researching, a couple of trips to the store to purchase various rubber cements and hours waiting for it to dry for a $3.00 tube. Some of us have enough experience that we don't need to peruse everything Sheldon or Jobst have on the internet, some of which I disagree with based on experience. Some of us have enough experience that we don't get 4" rips in our tubes (which curiously you never do state how you get these). Also many of us look at it from the point of a customer bike and that kind of patching would never make it onto, or back onto, a customer bike if it was found. Maybe when you have more you can question mine.

I used to sew up the sidewalls on my Snakebelly tires when they ripped also but i don't anymore, based on experience.

when i pick up scrap bikes, i always keep the good inner tubes, and that dont cost me a penny !

If you are an ex-smoker still addicted to nicotine, a piece of well-chewed nicorette gum is a great get-you-home fix.

Ive always wondered if a piece of velcro adhesive strip would work, as the adhesive on that stuff is amazing.

It is, in fact, vulcanized together, if it's done properly. It's not nearly as well cross-linked as the main part of the tube is, because there isn't enough unbound sulphur in that rubber for the patch's rubber to react with. But a properly patched tube can not be peeled off, without causing mechanical damage -- you're tearing the rubber, not peeling the two layers apart at the glue line.

If your descriptions in this thread about how cold patching works are true - I have no way to know if it is, I'm not a chemist or a chemical engineer or a specialist in rubber - please consider putting an article online somewhere.

I still have my doubts, because I really have been able to easily pull "properly patched" patches off, after heating them with a hair dryer. Which is obviously much more heat than the patch would ever see inside the tire, but from that point on I stopped using terms like "vulcanization" or "permanent bond".

Maybe the chemistry is designed to fully bond the patch and the tube under ideal conditions, but in practice it rarely works out that way? Instead giving a result that is "good enough" but not really vulcanized, cross-linked, etc?

I really would like to understand this. If only so we have a reliable answer for the periodic bickerfests on this topic. I just don't get why this is so shrouded in mystery. Enough cyclists are at least curious about how patching works, that someone like Rema tip-top should have a quick-and-dirty explanation available. They don't have to give away trade secrets and they don't have to include molecular diagrams. Just a semi-technical overview of the process, and what the steps in the process really are doing, and why deviating from the recommended steps will compromise the quality of the result. This could easily be done in less than a page. Put it online and be done with it.

You are way out of line. Just because you did not like the answers you received does not mean that they were not intended to help. Mr, if you are patching tubes with holes that large you are pissing into the wind in the opinion of most here. You will of course, "live and learn" but the posters here have lived and learned so how about a little respect for the time they have put in. We all appreciate Sheldon's site and Have Read Jobst' book as well. Just because you CAN patch doesn't make it wise to do so in the larger picture. I'm glad you found what you were looking for but don't get on us here because you had to dig a little deeper to find someone who agrees with you. We are not you mothers here.Well sure, shoot, someone with no experience patching long tears in mtb tubes must give the best advice, after all they've tried to do it so many (0) times? Or how about patching tubes by not patching them! Brilliant! Or better yet, I can go out and buy a bunch of 25mm circular patches I already have. That's so on topic!

You and dscheidt at least offered well meaning and somewhat useful, if not explicitly on topic advice initially, and I thanked you both for it. After that the thread just went to crap. Almost everything (including both of our posts) after is either asinine, off-topic, or in a few cases both, with the exception of SBinNYC's post.


Like a hard headed, arrogant, dim wit from what I can tell.For real? I guess people shouldn't be patching flats. I mean, everything makes, like $50+/hour, so it's just not worth their time.


This is the fix
(http://www.notubes.com/Default.aspx)How could I have missed that! The best way to patch tubes is to not patch tubes! Brilliant! Lemme guess, you ride your bike by going for an hour long drive in your car. Your average speeds must be amazing!


I have enough experience that I have tried this. I have enough experience to to not waste hours of time researching, a couple of trips to the store to purchase various rubber cements and hours waiting for it to dry for a $3.00 tube. Some of us have enough experience that we don't need to peruse everything Sheldon or Jobst have on the internet, some of which I disagree with based on experience. Some of us have enough experience that we don't get 4" rips in our tubes (which curiously you never do state how you get these). Also many of us look at it from the point of a customer bike and that kind of patching would never make it onto, or back onto, a customer bike if it was found. Maybe when you have more you can question mine.

I used to sew up the sidewalls on my Snakebelly tires when they ripped also but i don't anymore, based on experience.I doubt I've spent an hour of time replying to this thread, much less an hour patching tubes. Still, if you make upwards of ~$50/hour then it's not worth your time patching anything unless you happen to like patching tubes more than you like working and can also get $3 tubes (Where?). I also love your approach on experience. You've never patched a 4" long tear, or even seen one, but your vast experience on the subject, which amounts to no experience, leads to you believe it won't work. Brilliant! It's almost as good as patching tubes by not patching them!

I've had several discussions with Jobst in RBT regarding tube patching techniques. I disagree with his technique and his explanations. Based on the criterion that a patched tube is immediately ready to ride, I claim a 90% success rate for my technique. Jobst admits that his technique requires 24 hours to cure before riding.

Regarding your specific problems. The easiest repair method is to avoid flats. A 4 inch slit is usually caused by the tire bead pressing on the tube and pinching it. That cause is 100% avoidable by taking extra care in mounting the tire. There have been several excellent detailed descriptions posted here on how to avoid this problem.
A five year old patch is probably toast. The foil side of patches is treated to react with the cold vulcanizing solution applied to the tube. This treatment will evaporate with time and heat. Most patches use a clear cellophane or plastic as the carrier on the butyl side. The only patches I've run across that used wax paper were made by a British firm: Bikit. If your patches were indeed made by Bikit, they are a lot more than 5 years old.

You can still use patches, even if you do not have a 4 inch long patch. The you can apply a patch to the outer butyl side of a patch. The butyl side requires the same preparation as a tube surface: cleaning (sanding) and applying cold vulcanizing solution. It also means you must learn how to remove the cellophane without pulling up the patch. Therefore, you may use 5 or more 1 inch round patches to completely cover a 4 inch slit.
I purposely used the term "cold vulcanizing solution" rather than cement because rubber cement is not used for applying patches. The solution is designed to work with the patch. Mix brands at your own peril.

If you insist on still trying to use an old tube, here are some hints. First, you must apply vulcanizing solution to both surfaces and let them dry completely. You should apply pressure after you apply the "patch" to the tube. This pressure should go from the inside to the outside. The purpose of this burnishing is to remove any air pockets. Rubber vulcanizes to rubber - not air.


You did not mention the size of the road tubes that don't work. I've always wrapped the tube around a flat surface (a patch kit box). I've used the box as backing when I burnish the newly applied patch. Road tubes can be extremely narrow. The patch must fit within the tube. Standard 25 mm patches are too big for many road tubes. I use 16 mm for most road tubes.

I can see a lot of problems trying to cut a 5 inch long patch that will completely cover a 4 inch slit and still fit within a flattened road tube. One suggestion would be to get a patching tube of equal size and cut out a length of the tube. I'd then cut out the section with the 4 inch slit and splice it with the patching tube section I created. This would limit the vulcanizing two areas to where the splice met the original tube. I'd think these two areas would be easier to vulcanize.

The only practical use for this solution would be, if I had a with a broken valve and another of the same size with a perfect valve but otherwise unusable e.g. a tube with a 4 inch long slit somewhere else on the tube.

Ideally I'd like to avoid splits, but I've had a couple due to crumby (new and old) tires, and a couple due to inexperience/haste. Fortunately the road bike tears aren't too long, and they seem to be holding up well with a 50mmx25mm patch I cut in half and used (All my old patches seem fine, which could be because I store them in a thick envelope or because of dumb luck). In terms of the method used, I don't think it matters that much for patches and rubber cement. If you just slap it on and go it should be fine most of the time. For instance the rectangular patch I cut in half and used on the road tube had the "inner/cut" sides shifted after I removed the tube (With cats there are always going to be slow leaks that are a pain to find), but the patches were still 100% functional.

Surprisingly the long mtb tear is still holding up, so with good prep (what you and everyone else mentioned) it appears someone can patch some really big tears, at least temporarily. The only trouble I've had on the long tears was using the patched tube immediately, so I'm thinking the prep you mentioned is crucial for butyl on butyl, but not so much for patches, which is why the instructions with my patches had poor results for butyl on butyl.

Some of the road tubes I have are a bit too big for the 25mm patches, so what I usually do is apply the patch, fold the middle of the patch and clamp it. As long as there isn't any excess material under the patch it seats fine IME. I've also cut up patches, but without the lighter colored edge along the cur they're more likely to shift once I inflate the tire, so I tend to clamp those and let them dry before I use them. A couple other posters seem to be really intent on the whole vulcanization versus adhesive thing, so I should probably apply some patches to an old tube and see if using a heat gun makes them easier to remove a few months later. :thumb:

"new tubes are cheap.."

No, I think it's a lot of bicyclists that are cheap. Way too cheap for their own good. bk

Some riders do not have the talent for tube patching.