DirtRoadRunner

I'll be needing a new set of tires in the next month or so. After realizing my A23 rims are tubeless compatible, I'm thinking of giving it a shot. The question is, is the added complexity of tubeless worth it?

This will be on my Space Horse, which probably sees 49% pavement, 49% gravel, and 2% singletrack. The main areas I'd be looking for improvement in are :

- Fewer flats - I only have maybe 1 ever 1,000 miles or so, but it would be nice to have less. I did have to walk my bike about 8 miles this summer when I ran out of tubes - not fun.
- Less of a need to change tire pressure. Many of my rides are varied surface with lots of pavement, so I end up changing the pressure anywhere from 55 - 85 psi during the course of the ride. This takes a lot of effort for a 40c tire (going from from 55 to 85 psi), even with a frame pump. It would be nice to run a single, lower pressure and not have to mess with it.

Will a tubeless conversion be an improvement in any of these areas? Does the pavement rolling resistance suffer when running a tubeless tire at low pressure vs. a tubed tire at higher pressure? Some of my rides have significant pavement stretches in them, so minimizing rolling resistance is pretty important to me.

flargle

I say go for it.

The first setup will be a bit of a hassle & learning curve but after that it's really not that big a deal. I recently set up a pair of A23 with Specialized Terra 2Bliss and they inflated just fine with a floor pump. Here's my hot take:
- Get tires that are rated tubeless-compatible. Regular clinchers can work fine but you might as well stack the odds in your favor.
- Unless you have stuff lying around in your parts bin, just go ahead and order the velotape 21mm conversion kit. Different valve stems are shaped a bit differently so, again, stack the odds in your favor.
- Be semi-meticulous about having a clean, dry rim before you install the velotape.
- After you've installed the velotape, but before adding sealant, install and inflate the new tires WITH A TUBE. Make sure the beads are perfectly seated on the rim, and leave them in there for a little while (>10 minutes, say). IMO this is an underrated step in the process. It really helps the tape adhere to the rim, and also helps the tire conform to the rim.

chaadster

I haven't ridden much dirt tubeless, but I can say that with regard to the tire pressure swings, that'll remain the same. You're always going to need relatively higher pressure for fast rolling on pavement than the pressure you'll run for rough gravel. All tubeless really does in that regard is allow you to run lower pressure without risk of pinch flatting. For gravel roads, and trails, that's valuable, but decent roads will usually roll-off faster with more pressure.

I would certainly run tubeless on gravel if it were an option. I think most dirt flats are snakebite, so tubeless handles that easily. Add in the comfort factor, and it's looking pretty attractive.

chaadster

Absolutely and without question use tubeless tires to run tubeless.

pressed001

I think from what your goals are, that you are a perfect candidate for tubeless. Less flats and you can run less pressure.

flargle

According to this article, tubeless does have lower rolling resistance, and less of a penalty for low pressure vs high pressure on pavement:
TESTED: Rolling Resistance of Tubeless Mountain Bike Tires

Whether running tubes or tubeless, I've never even considered changing tire pressures during a single ride. I mean, it's completely counterproductive, innit? There's no way the higher pressure on pavement could make up for time wasted pumping and deflating. And even if it did...bleah.

A couple more thoughts:
- It looks like there are currently some very attractive options in the tubeless-ready mixed-surface ~40mm category.
- If you try tubeless and it just isn't working for you, hey, just plop a tube in there.

flargle

Man that WTB Nano 40c looks really good to me. Anyone here try it?

DirtRoadRunner

Thanks for the info - I think I'm going to give it a shot. The rims already have the blue Velocity tubeless tape in them, and I have an air compressor, so I'm already most of the way there.

Regarding the tire pressure issues, one of my favorite rides around here is ~35 miles of smooth pavement to a ~15 mile stretch of gravel road/rocky jeep trail that will beat you up when running 80 psi, and is frankly still rough at 50 psi (tubed of course). Then, there is another 35 miles of pavement back home. So I've found it worth it to stop for 5-10 minutes and air up to conserve energy on the long, paved spin back home. That being said, I'd love to skip that step and just keep riding. Ideally I could run 50-60 psi everywhere, and hopefully tubeless rolling resistance at 50-60 psi isn't that much different than tubed at 85 psi.

Think I'll try some of the tubeless Nano's once my MSO's bit the dust. Thanks for the advice.

justin1138

The Nano is an excellent off road tire as long as it's not too muddy or wet. I've had a pair of the Race version (not tubeless) for over a year and have put well over 1000 miles on them between two different bikes. Everything from commuting, dry races, 30 mile dirt loops and multi-day long rides over very mixed surfaces. I don't pay meticulous attention to the pressure, but I don't think I ever aired them up over 50psi. I was racing them in the 20's-30's at one point. Only two flats in this time. One pinch flat on a very bumpy race with pretty low pressure, and one very large piece of glass that would have flatted most tires. Two thumbs from this guy.

Like the OP though, I'm ready to give tubeless a shot. I'm at the end of cross season, my Nano's are just about toast, time to set the cross bike up for the off season and experiment...

chaadster

It's probably better to think of what you're talking about in terms of drag, rather than Crr (rolling resistance) because unless you're comparing tires of the same size and construction, Crr gets washed away by all the other variables.

If you think of it as drag (friction), you might imagine the extra contact area afforded by lower pressure isn't doing you any favors.

Lower pressure is great if you need to roll over irregularities, but on a smooth (relatively) surface, where bump forces don't really factor significantly, higher pressures roll faster.

In other words, there is no way 50-60psi tubeless is going to roll as efficiently on smooth pavement as an equivalent quality, same sized, tubed tire at 85psi.

Tubeless is great, but it doesn't obviate the need for different pressures on different surfaces.

flargle

Look at the graph in this article, which shows that tubeless at 25psi had less rolling resistance than a butyl tube at 55psi:
TESTED: Rolling Resistance of Tubeless Mountain Bike Tires

Also look at the shape of the tubeless curve, which shows negligible difference in rolling resistance for tubeless between 35psi and 55psi. The curve levels off, and more air above 50psi won't save you hardly any watts on pavement. A latex tube does almost as well. Butyl, the worst of the bunch, only adds 4 watts for between 25psi and 55psi. The difference between 55psi and 85psi looks like it'd be around 2 watts (or less).

The take-home is that any speed gains from higher tire pressure start diminishing at low pressures, even for butyl tubes, but especially for tubeless or latex tubes. These tiny speed gains aren't worth the time and effort to air up mid-ride when mixed surfaces are involved.

DirtRoadRunner

Yesterday I received a bottle of Stan's sealant in the mail, along with some tubeless valve stems. A pair of WTB Nano 40 TCS's will be here next week, so I'll be giving it a shot!

After reading the replies above, hopefully I don't suffer too much of a drop in performance on the pavement. It would definitely be nice to run a low pressure (like sub-40 psi) on some of the really rough roads around here - and I can live with still changing tire pressures once or twice a ride if the comfort/handling factor improves. I do notice a pretty stark difference with my current tubed MSO setup at ~50 psi vs. 85 psi. It probably has to do with the tread of the tire - at 85 psi on pavement, it only really rolls on the mostly-solid center strip, while when it gets near 50 it starts to also roll on the center strip and the lugs. I doubt the difference would be as much on a tire with a more consistent tread, or on a slick.

chaadster

Thanks for linking that again, as I did not read it the first time; I usually am only concerned with roadie stuff, and defaulted to that mode, but I recall now where I am!

It does appear that the variance is closer than I'd thought, so I will concede it may be possible a TL setup could roll better in the situation were discussing.

However, the test here raises a few questions, especially about the impact of width, and also which type of tire (tubed or TL) benefits more (i.e reduces Crr) with higher pressures.

Looking at the results, the tire rolled better at higher pressure, and the advantage was to tubeless across the range (ignoring latex). However, the tubed (butyl) setup saw the greatest reduction (in terms of watts) as pressure increased, saving about 2x the watts at 55psi vs. 25psi, a spread of about 10w. The TL saved about half as much, or 5-point-something watts.

I don't know exactly what it means, but it does call in question the presumption that a 40c TL tire at 55psi would certainly roll better than a tubed 40c tire at 85psi. It may-- I was perhaps wrong to say "no way"-- but I'm not convinced it's a given.

This VeloNews article discusses some of the issues I'm thinking about: Resistance is futile: How tire pressure and width affect rolling resistance - VeloNews.com

Also, factors like feel and handling should be considered, and a too soft tire, even if it rolls with little effort, could induce bouncing under hard efforts, feel vague, transition abruptly, and erode handling precision and confidence.

Ultimately, we all agree that tubeless is the way to go, and what the final setup pressures look like and the results are all depend on factors only the OP knows, such as their weight, riding style, and road conditions. I run 23c TL on the road (at about 15psi below tubed pressures, or 90/95 f/r) and love the feel and performance. #nevergoback

chaadster

Congrats; I hope you love 'em!

Yes, I agree the Crr differences we're talking about here are really quite small, and likely to be only really noticeable at the margins, you know, like if you're really doing a time trial type effort. I switch between a wide/mid-deep rim TL wheelset and a standard width/height tubed wheelset, and while the TL is undoubtedly faster-- it holds all my Strava PRs-- the tubed set do not degrade my experience or enjoyment.

DirtRoadRunner

On Saturday I took my semi-tubeless setup on its maiden voyage. I say "semi" because the night before the ride, I noticed the front tire was flat. After messing with it for 15 minutes and getting continued air leaks, I realized I had damaged the Gorilla rim tape when putting the tire on, and it was leaking through the nipple hole. The back was holding air just fine, so I threw a tube in the front and did a nice 27 mile ride with smooth to rough gravel, pavement, and some rocky to muddy jeep trail. I put 55 psi in both the tubeless rear and tubed front tire.

Tubeless is definitely an improvement over my tubed setup.

- Comfort on gravel was significantly improved. The bike just floated over stuff that used to jar me around. Even with both tires at the same PSI, the rear was much cushier going over rough stuff than the front.

- Rolling resistance on pavement and gravel was about the same as my previous tubed X'Plor MSO tires, despite running lower pressure in the Nanos. I'm not sure how much of this is due to the lack of tubes vs. the differences in the tire.

- Traction on singletrack was a lot better as well, though some of this could be due to the more aggressive tread on the Nanos.

- I hit ~39 mph on pavement, and noticed a bit more squirm from the rear tire than I would like - so I'll pump these all the way up to 65 psi for significant pavement riding.

FWIW, the Nano actually had a little worse traction on dry hardpack than the old MSO's, or the Conti Speed Rides I used to run. This probably because the large lugs on the Nano grip worse on a hard surface than smaller lugs or a file tread tire.

Definitely and improvement, and I think I'll be able to ride longer with less fatigue, and hopefully less flats.

Planemaker

Around here we run tubeless at 40 psi or less on gravel. When on pavement, I don't see a noticeable drag.

DirtRoadRunner

I'll try 40-45 psi for my next ride, after re-taping my front rim. The only reason I ran 55 was because I don't like going below 55 on tubed tires and wanted the same pressure in both. I couldn't believe how much smoother 55 psi tubeless was vs. 55 psi tubed - and how the drag/rolling resistance on pavement didn't feel any different than tubed tires at 65+ psi.

FlashBazbo

I have a question I rarely see discussed. With tubeless, how often do you change the sealant/goop? I've heard and read that the sealant tends to congeal or harden within 30 days and won't seal punctures anymore. Do you remove the tire and give everything a good cleaning before remounting and refilling everything? How do you get the hardened goop out of the tire? Do you just add more goop (rotating weight)? How do you handle this?

Henry III

At the shop we normally said 6 months tops before it turned to dust. You'll still have a decent seal but any punctures you'll be SOL. We would also tell people to carry a tube also for those just incase situations when the sealant isn't able to fully seal a puncture.

Though changing pressure multiple times during a rude would get boring fast. I just pump it up to a happy medium pressure and forget about it and enjoy the scenery.

BluesDawg

Depending on season, usage, the particular sealant used and other mysterious factors, tubeless sealant will need to be added every 1 to 3 months. The "goop" is mostly liquid and it dries up leaving a powdery film with some strands or thin globs that can be washed out or simply left in the tire as more sealant is added. I leave it. I've never weighed the residual matter, but I'd estimate it as weighing about point poop per tire.

flargle

RTFM: Sealant

"Stan's Tire Sealant will stay liquid in a mountain bike tire with a thin casing for 2-7 months on average. Riding in arid climates or storing the bike in a hot area will requires more frequent monitoring of sealant levels."

I think 6 months is a good benchmark and coincides with most people's seasonal maintenance. It's not much effort to pop off one tire bead and take a peek.

FlashBazbo

Yeah, I've read Stan's publicity release. Around here (not a hot, dry area, most of the time), I'm hearing that it lasts more like 30 to 60 days if you ride every week. If you don't ride every week, it seems to set up a lot quicker than 30 days. (That's something else Stan's publicity materials talk about -- spin the tires at least weekly whether you ride them or not to keep the sealant from affixing itself to just one spot in the tire.)

FlashBazbo

Here's a test with info from a couple manufacturers -- also about the weight of the residual in the tire:

Tubeless Tire Sealant Tech, Part 1 ? How Often Should It Be Checked & Replaced?

UnfilteredDregs

If you don't ride the bike enough it potentially can settle at the bottom of the tire and solidify. I ride 4 times a week and I've never had this issue with my operating wheelset. I left the sealant in my spare set and it did solidify. I gently pried it out of the tires in question.

I wouldn't go more than 2 moths without adding some sealant. I keep 1oz in each tire...and Orange Seal is better than Stan's.

flargle

Scanning through this whole discussion, my takeaway remains what it's always been: the frequency of checking sealant really depends on context.

If I'm riding local trails for fun, I don't bother worrying about it. I still carry a tube, a bit of duck tape wrapped around a tire lever, a CO2, and a pump, because even tons of fresh sealant can't fix all punctures.

If I'm doing an important race, or going on vacation, or going on some epic ride far from civilization, then of course I'm going to be extra-careful about every aspect of the bike.