Just got a new bike, switching to tubeless. However, just to carry a spare tube in case I should need it, what is a recommended inner tube for 700 x 25-28?

What about the inner tubes the bike came with?

I'd recommend anything in 700x25-28.

If it's a 700C tire, then 700C or 622 would be the first choice. Tubes are generally made for one tube to accommodate a range of different width tires. So get a tube that your tire is within the width range specified on the tube or box.

You answered your own question OP.

I carry a Turbolito and it's special patch kit.
They are extremely light and better yet, roll up incredibly small.


I'd recommend you carry a regular tube, right up to the point you wonder why you are carrying one at all because you've never used it, then switch to a Turbolito.

Barry

Not the question you asked, but why are you switching to tubeless?

To run lower pressures and roll faster. Which covers about 95% of the people (Scientific WAG) who do it.

Lots of data showing that these are beliefs, not backed up by facts. Yes, that is the reason people switch to tubeless, but they got their reasons from the marketing department. Not saying there is something wrong with tubeless (though lots of anecdotes suggest they can be pretty fiddly) but don't expect a revelation in ride quality compared to a good set of standard clinchers with lightweight tubes.

.
...I have never transitioned to tubeless tires on a bike (although I've run tubeless tires on all the cars for a long time now).

For those of you who do set up your bikes with tubeless, isn't it kind of a sticky mess to find the offending object that flatted your tire, to the point where you need to run a tube to get home, then insert a tube, and pop the bead back on, so you can inflate your new tube ? Or am I just imagining this ? The tire has a lining of sticky sealant goop, right ? Isn't that difficult to deal with when your leak on a high pressure road tire doesn't seal on its own ? Or am I just imagining a problem that does not exist ?

I actually carry a 700x23-25 tube despite the 28mm tires on the bike. A little less room to take up, and it will get me home just fine.

I have been running tubeless road tires for 12 years now, so I was an early adopter. Guess what? It isn't obligatory to use sealant if your tires don't require it. If you do that, there is no sticky stuff inside the tire to make a mess and if you do flat, you can install an inner tube to get home. However, tubeless plus sealant will reduce the number of flats you have. In the 12 years since I stated using road tubeless tires I can count the number of on road flats I have had on the fingers of one hand even though I don't use sealant all the time. One time, I had a puncture caused by an industrial staple. I pulled it out and the air that was coming out pretty much stopped. I only had about 4 km to the end of the ride so I rode on but had to stop once half way and pump the tire back up. Guess what? That day I was riding without sealant in my tires. One of the flat tires I "suffered" happened while my bike was sitting in my living room. All of a sudden, I heard a hissing sound and my front tire deflated. Turned out to be somewhere along the tire bead. However, silver lining. I had a new set of tires ready to go and when I looked at the rear tire it turned out to be threadbare and would have soon failed. I might have saved the front tire by injecting sealant which I hadn't been using but I simply decided to install my new tires. It does help that the wheels I use do not have to be taped which seems to be one of the biggest problems people encounter

I don't ride tubeless but if you just want an emergency use spare that's lightweight and compact look at a TPU tube... They are pricey but since it's one tube and might not be used very often it could be worth the price.

I run TPU tubes in both my bikes tires and carry one as a spare.

a good idea/option. Given the spare tube is butyl, most regular - not superlight - tubes will stretch plenty enough to take up the small extra space in a 28 or even 32. But the difference in deflated 'size' & weight, compared to the next size up is quite a bit - allows more space for other stuff in small saddlebag.
Been running TPU tubes for about a month on 1 road bike, 23 & 25c. Had my 1st flat yesterday - it's now thorn season out here... TPU definitely needs a higher level of handling, when working with tube or tire swaps and patching... more on this later.
I have tubeless on my gravel and mtb, and do see a nice ride improvement, but not so sure about 23 & 25c for road. At this time the tire selection is limited, compared to tubed tires... I look for good performance tires, but $70+ per is not in my budget...
I have an extra Set of HED wheels lying around... I might make them 'Tubeless' and experiment in the future. 'Tubeless' on a wheelset with narrower than 21 internal, just doesn't make sense to me... A big part of the improved ride and lower psi is due to the advantages of wider internal rim widths (21, 23 and now even 25...).
Ride On
Yuri

Bench tests show that tubeless is marginally (1-2W) lower than a latex tube for RR which is marginally lower (1-2W) than a butyl tube. It's not marketing, it's scientific. It's not enough to matter for a ride to the grocery or a morning commute, but it starts to add up as the rides get longer, especially into the all and multi day epic sorts of things I do. I mentioned bench tests because they are reliably comparable to each other. As for fiddly? Yes, some tires can be, but most are not, especially if one knows how to mount them and set them up. It's not hard to learn how to do this.

I think you're imagining differently than it really is. I've had 4 punctures/cuts over the last 5 years. 2 were immediately obvious as requiring a tube (and a boot) due to the sidewall cut*. Sort of messy to deal with because I was on a club ride and I wanted to get it fixed as fast as possible, but honestly, it was no messier than the dude who dropped his dirty chain and then struggled to get it pulled out from between the little chain ring and seat tube. Plus, latex based sealant rinses off pretty quickly with just some water. The other 2 were pieces of something that went through the tread, in both cases I could hear the air slowly releasing and see small spurts of sealant coming out of the tire. I stopped, turned the wheel so the hole was at the bottom, waited about 5 minutes, and then continue on my way. In those instances, I didn't need to hunt for the offending debris hole, it was obvious where it was, but it also sealed on its own after losing 2-3 psi.

*sidewall cuts are particularly annoying and shouldn't happen. But, that particular brand of tire due to it's carcass construction seemed vulnerable enough to it, that after the second cut (going off a curb both times) I decided to stop running them, and I haven't had any issues since.

Those numbers seem high, at least when comparing tubeless + sealant with latex.

Tests at bicyclerollingresistance.com, at 80 psi:

Not sure where you got your TPU tubes from but I have the Tubolito X-CX TPU's and they come with a 1-year warranty. Get a flat, notify them via online warranty claim and they send you a code to use in their store to order a replacement with free shipping. It's not a scam and it's legit. Just make sure you register the tubes on their website within 30-days of purchase.

I believe the 1-year warranty is only good with their X series tubes and I think they only make the X series for their City and Gravel TPU's but it's still a killer bonus. Sure the tubes are expensive but with a 1-year replacement warranty, it's worth it to me.

Edit to add warranty information for anyone interested.

https://www.tubolito.com/wp-content/...G_20211022.pdf

From what I assume was the same chart at bicyclerollingresistance.com at some point in the past, since I was going off memory. I doubt I spent much time studying it, since I don’t fret over grams or single watts anymore.

Thanks for the info! but... the TPU tubes I have on my roadie are the chinese RideNow. I have Schwalbe Aerothan on my gravel... but on Tubolito...
I bought the RideNow tubes via AliExpress, wanting to experiment... They've been working great for a while, but I did get that bit of thorn 2 days ago...
I wrote more about this whole adventure, in another thread which focused on the Chinese TPU tubes - specifically RideNow. (linked) if anyone is interest in them or the general conversation.
my 2nd attempt at patching the tube has proved to be successful. I think, working with TPU requires a slightly higher level of awareness and detail, because of the very light nature of TPU.
Not unreasonable, and the chinese TPU tubes, only a slight higher cost than regular butyl, hold air well and ride well. May not be a fit for some, but they'll work for me on my roadies.
Ride On
Yuri

I'm not sure 'Tubeless' can be directly compared to 'Latex' or even 'Butyl'.
A 'Tubeless' tire will have a different construction, than a tire built for tubes (Latex & Butyl), Even if a manufacturer gives it the same model name, the tires will be different.
Then considering that 'Tubeless' CRR curve (at varying psi) will be different and be optimized different from Tires with Tubes.
I don;t think that you can compare at any 'same' psi... One might be able to make a comparison, by using whatever is the lowest CRR found (at whatever psi and applied 'weight') and then compare to the lowest CRR for the other mode....
for example:

note the sharp increase in CRR at 115 psi, here from a Tom Anhalt study, referenced in a SILCA article on impedance... there would be a substantial increase in CRR with the tire/tube inflated to 80 psi... and this would all be different for a Tubeless.
It doesn't seem there's an easy 'This is better than That', when it comes to actual wheel/tire usage.
also, it would be good, when posting some tech 'image' or 'data' to also include a link to where that data can be found... gives readers an opportunity to do their own review and their own conclusions.
Ride On
Yuri

What leads you conclude there would be an increase in CRR at 80 psi, and why there would be a difference between tire/tube and tubeless?

The divergent Tom Anhalt "jump" in resistance curve is basically due to the inflated tire not deflecting enough to conform to the road's roughness.

What 'leads me' is right there, in the chart for a tire with latex. The 'jump' is inconsequential, in this conversation.
The difference between 80 and 115 psi for this tire and latex is sizeable, in the favor of 115. given the test conditions. CRR will also vary, depending on the force/pressure put to the wheel assembly on the roller - so there's likely a broad range of what is 'optimized' between a 130 lb and 230 lb rider. Would be true for any/all tires or tire/tube combos...
Difference between Tubeless and Tire/tube ? As I noted, tubeless tires will be constructed differently and will react differently...
I don' think there's a direct/equivalency between a Conti GP 5000s and 5000s TR. Basic contruction might be similar, but add some more/different interior wall sealing, different construction at the bead, there'll likely be difference performance curves.
Ride On
Yuri

So you are referring to the rolling resistance increase at 80 psi versus some higher pressure. Okay then.

When it comes to rolling resistance, tire/tube combinations have been compared.

Here is an "apples to apples" comparison of the Continental Grand Prix 5000, both tubeless ready with sealant and tubed versions. The differences are miniscule.

So, just to get back to the original question. All that the OP was asking was about the sort of inner tube they should carry in the event of a puncture. This thread has devolved into a debate about whether inner tubes are as efficient as tubeless setups. Why not get back to answering the original question? If the OP's bike came equipped with tubeless ready tires with inner tubes installed, all they have to do is keep the inner tubes as backup if needed on the road