chaadster

I’m not sure I follow the reasoning going on here, but going back to the OP, the question was simply which light tube to use in Marthon/Marathon+ combo.

The answer was simple, too: use TPU tubes. There is simply no downside to using TPU, and they give up nothing compared to any other tube type.

Now, if you’re considering running a Marathon in back rather than M+, sticking with TPU for the tire switch is the win/win. TPU offers better puncture protection than any other type of material, and offers the best puncture resistance when compared across similar tube types, meaning that a heavyweight butyl could resist a staple better than a lightweight TPU, but you lose the weight savings you’re after.

Whether any of this translates into energy savings, I don’t know. We don’t know the wheel size, tire size, or type of bike, but I know Marathons and they’re heavy as heck. Marathon Plus in 700x35 weigh a shocking 900g apiece…that’s 4lbs of rubber for a set! If I had to push that around, I’d look to cut weight anywhere I could, regardless of concerns about energy efficiency, or even more likely, I’d simply not worry about it, and just ride my battle tank.

But, if I could get my 34lbs tank down to 32lbs for little money and without sacrificing durability, I’d do it.

momoman

My friends and I have put about 2,000 miles collectively on Ridenow TPU tubes. Here are my observations:

• I've only tried the 36g version and not the newer 24g version.
• There are QC issues. Some are bad right out of the box and leak. I've had to toss 2 new tubes because they leaked within hours.
• The ones that don't leak are great! I've had some on wheels for more than a year and they haven't leaked unexpectedly. They gradually lose air at about the same rate as butyl tubes.
• I carry 3 spare Ridenow tubes and adhesive patches and they weights about the same as a single butyl tube and take up less space.
• The Ridenow stick on patches didn't work for me, but worked for my friends. My 2 patched tube eventually leaked. I've tried re-patching and they leaked so I tossed the tubes.
• I've gotten 2 flats over 1,000 miles. The tubes get a pinhole cut but do not burst suddenly. I gashed a new Conti GP5000 tire on road debris and the TPU tube had a small hole from the cut. There was no pop or sudden gush of air from the flat - the tire/tube hissed air out over a few seconds and I heard the hissing air.
• Despite the QC issues I really like the tubes.
• I paid under $7/tube buying in quantity but lately I've seen them for $5.xx if buying in quantity. This is for the 36g version.

I'm glad I gave the Ridenow tubes a try. I'm convinced they are better for me for my rides (brisk group rides with 100 riders, occasional climbs and long descents). Using lighter TPU tubes on my rim brake carbon wheels give me more confidence than my latex tubes on long descents. Supposedly, the TPU tubes handle heat better than latex. More of my friends are switching over to Ridenow tubes since they are under $6/tube now and they also carry 2-3 spare tubes.

The tubes are very popular in Asia and outstide of the US. There are numerous Youtube reviews for the Ridenow TPU tubes. Here's one review:

ThermionicScott 

I do feel that it's the tire's job to resist punctures and the tube's job is merely to hold air, so thin/lightweight tubes strike me as the way to go. I've been really impressed with Schwalbe's "Extralight" and "XXLight" models -- they hold air a lot longer than I expected from how thin they are.

(TPU tubes sound even better, but I haven't given them a try yet.)

chaadster

This underscores one of the benefits-- a safety feature, even-- of TPU. Schwalbe have pointed out their particular TPU does not tear and blow out suddenly like latex and butyl are prone to do, so it's much less likely to have a catastrophic flat that could result in loss of control.

That's a extra measure of confidence, especially when descending, but it also means, as I have experienced, that a puncture doesn't necessarily mean the ride stops. I had it happen once that a slowly leaking puncture in an Aerothan allowed me to finish the ride home with occasional pump-ups along the way. I could only go a couple of blocks before needing to pump, but it was a lot better than walking, and TPU's superior dimensional stability meant the ride wasn't squirrely or sketchy as the pressure got really low.

I've had perfect results patching Aerothan with Lezyne self-adhesive patches, but I did prep the patch area with an alcohol wipe.

icemilkcoffee 

The self adhesive stick-on patches do NOT work on these TPU tubes. I just had two of them start leaking the day after I put them on. One was an expensive Revloloop patch and the other was a RideNow cheap patch. Neither worked on this Revoloop TPU tube. Although I have to say that an earlier Revoloop patch did work fiine on another bike. It's not working reliably enough to give me any confidence.
Anyways, I am ordering some Ridenow glue-on patches to see how they fare.

momoman

I used the Ridenow self-adhesive patches I got a year ago and they didn’t work for me and I used the included alcohol wipes and even tried my rubbing alcohol I had. My friends ordered their Ridenow tubes and patch kits much more recently than I did. Maybe their newer patches work better than what I got a year ago.

icemilkcoffee 

Right. The self adhesive stick-on kind doesn't work well. Just like with butyl tubes- the stick-on patches are very unreliable.
But RideNow also makes glue-on patch kits as well with a separate tube of glue. Hopefully that works as well as glue-on patches do on butyl tubes. I was just going to buy the RideNow glue-on patches when I found the Pirelli Smartube patch kit:

I bought this kit instead. $7.19 for 10 on Modernbike.

chaadster

Sounds like you guys should be using Aerothan TPU tubes and repair when needed with Lezyne self-adhesive patches and 91% isopropyl alcohol... If you really want to do it right sub in Gyeon Q2M Prep instead of 91% isopropyl. I had some at hand from ceramic coating my car; works a treat.

santa fe 2926 

Is the psi in the TPU tubes the same as butyl tubes?

terrymorse 

There should be no difference in max. pressure rating, as it's the tire that limits the pressure.

But since a TPU tube is thinner (and therefore the air volume is greater), you may be able to use a slightly lower pressure with a TPU tube.

chaadster

Yes. The tire pressure you use is virtually nothing to do with how air is retained in the tire-- i.e. type of tube material, tubular or tubeless-- and rather determined by tire size, rim internal width, surface conditions, and rider/bike system weight. Assuming all else is the same and you're just swapping butyl tubes for TPU, there is absolutely no need to change your preferred pressure.

tFUnK

Threw some Marathons on the commuter. Dang those tires are heavy and stiff. TPU tubes aren't going to make them ride any better.

TPUs aren't more popular now because they came out around the time a lot of folks went to tubeless. If TPU tubes were available in the early 2010s that would have been a game changer.

nick_a

I'm not super experienced, but I've had good luck with the Schwalbe Extra Light line.

daviddavieboy

As an old fart at heart I still use tubular tires an many bikes as well as latex tubes when riding clincher tires MOSTLY (my tubs have latex as well). My tube of choice are the Challenge brand as they are seamless and I have had great success with them and when I have flatted the repair was perfect as long as a latex patch kit was used. With other brands of latex tubes I have had them leak at the seam of valve stem. The reason I say mostly is because on one bike I am experimenting with road tubeless in a rear tire with great results so far nearing 2000mi without incident. -I have don't have the fortitude to try in the front tire yet.