Jim’s Tech Talk
By Jim Langley
Thanks so much for the assist with Chuck’s question last week. He asked for your recommendations for inner tubes and puncture prevention. I’m sure your tips helped him and other readers with the same question.
Because flat tires are by far the most common breakdown, today I want to share a couple of your comments and answer a few related questions that were asked.
Latex versus Butyl Tubes
Let’s start off with Ray Bourne’s comment because he’s clearly done his homework!
“I cannot comment on the TPU tubes, but I’ve done a significant amount of testing over the years on butyl vs latex; specifically Continental “Race 700” butyl and Michelin “Air Comp” latex. I run Continental Grand Prix 4000s II tires (Haven’t “graduated” to the 5000’s because I have a good stash of the 4000’s!) I generally get about 2000 miles out of a rear tire before I send it to recycle and swap it with the front. Then I put a new tire on the front.
The Michelins have a greater resistance to puncture and will deform around a pointed object for some time before rupturing. Whereas the Conti’s will rupture almost immediately on contact with the entering point (be it glass or metal, it doesn’t matter).
The ride quality of the Michelins IS definitely superior to the Conti’s. I liberally talc all my tubes before use so I’m assuming the ride quality issue is due to the better flexibility of the latex. Although I ride with latex, I keep a butyl in my seat-bag for the unusual instance that I do puncture the latex.
When I get going after a flat repair with the butyl spare installed, the ride feels “Harder” (or stiffer) than with the latex. Then when I get home and repair and replace the latex, my ride quality returns to “Normal.”
And speaking of repairs, a REMA patch works on both butyl and latex although the latex cannot be buffed so I just use some IPA to clean the surface before applying the glue. It works for me and I’ve never had it fail. I usually stop after three patches just because the tube will then be about six years old!
Latex does leak down MUCH more rapidly than butyl. However, I don’t find that to be a problem because I check and pump my tires before EVERY ride to the pressures given by the Berto equations. And I’ve NEVER had a pinch flat with latex whereas, when I got lazy with butyl, I’ve had a few.
I realize this treatise is limited and totally subjective, but I wanted to share my experience from over the last 12 years as suggested by Jim.”
What a great tube comparison and review Ray. I appreciate you sharing this very much.
Patching TPU (thermoplastic urethane) tubes
Next up is “Bigborb” who asked
“Can you patch these TPU tubes – either with latex or butyl patches? That would be the deal-breaker for me. A $30 tube that cannot be repaired is just not worth the lump in my pocket if so.”
Yes you can patch some TPU tubes with Park Tool’s GP-2 Pre-Glued Super Patch Kit https://amzn.to/3D7Dv5o . Park says these patches are compatible with Butyl and Schwalbe Aerothan TPU tubes. However, they do not specifically say it’s compatible with other brands of TPU tubes. It’s also not compatible with latex tubes.
Park says that for Aerothan tubes you don’t need to sand the area with the puncture but you do need to clean it. They don’t say what to clean it with but I would use isopropyl alcohol (“rubbing alcohol”) since it should get off any oils from your hands and will evaporate quickly.
Sealants for bicycle tubes
Regarding the idea to put sealant inside inner tubes, “Charles” wrote,
“Muc-Off now makes an inner tube sealant: https://amzn.to/43mJXzY I didn’t see any information about using it with TPU tubes.”
And Brian Nystrom weighed in with,
“I’ve used sealant in clinchers with tubes since ~2010 and prior to that, in tubulars for a decade or so. I’ve had zero issues with either one and the only real caveat is that you need tubes (or tubulars) with removable valve cores (there’s actually a way to use sealant in tubes and tires without removable valve cores, but it’s way more hassle than most people will want to deal with).
I’ve primarily used Stan’s regular sealant https://amzn.to/3JRLuXM and it works so well that I’ve never had any reason to change.”
Thanks Charles and Bryan. As Bryan pointed out, not all Presta tubes have removable valve cores. Those that do have wrench flats on them, that’s the telltale sign. It’s helpful to have a valve core removal tool like this: https://amzn.to/44B9KWd If you don’t have the tool you can use a tiny adjustable wrench or pliers but be very careful not to damage the valve if you use those tools.
If you’d rather not mess with sealant, you can also buy inner tubes with sealant already in them from Slime and they’re available in quite a few sizes with Presta and Schrader valves. They’re called Slime Bike Inner Tubes with Slime Puncture Sealant: https://amzn.to/43cMFIk.
Using Nitrogen to Inflate Bicycle Tires
John Thomas asked,
“I’m wondering if anyone has ever inflated their latex tubed tires with nitrogen. The last 2 cars I bought came from the dealer with nitrogen filled tires, and I was amazed that I didn’t have to top them up for more than 3 months. From a cost/benefit perspective, probably not practical. Just asking out of curiosity.”
If you want to give it a try John, you’re in luck. Prestacycle sells the equipment to set yourself up to be able to inflate your bicycle tires with nitrogen. On this page they show their products and give reasons why you might like to use nitrogen as many car tire shops have:
If you go for it, please let us know what you think. But maybe you might want to see if your friendly local car tire place would be willing to fill up your bicycle tires with nitrogen first to see if it’s worth the expense.
Thanks again everyone!
Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.