choddo

I’ve had that on an IRC Formula Pro. I assumed it was because I had a flat which I rode on too far. Could see lots of tiny bubbles on the sidewall if I put water on it. Would be ok for a 4 hour ride but wouldn’t hold air overnight.

DaveSSS 

The sealant being used makes a difference when it comes to sealing sidewalls. Orange seal endurance works well for that, but I'm likely to try another brand of tire if sidewall leaks are common. I've seen that with Michelin tubeless.

tomato coupe

Same here. After a few years, I went back to tubes for my 25mm road setups. Now I use tubeless only on 32mm and larger tires.

3speedcliff

I'm asking myself the same question. I'm about 95% road and 5% mtb and a bit of a luddite with new technologies. So despite all the hoopla, both my mtb and road bikes still have tubes. I gather that the biggest advantage is on mtb but because I don't ride it that much, I've decided to keep tubes in the mtb. I'm setting up a new 650b road bike and have built wheels with Stan's crest rims. I figured this is the bike to make the shift to tubeless since it'll be ridden a lot and it will be 650x38 tires at 50-60 psi. But I don't get the claim that you can run lower pressures because you can't get pinch flats. To me if you're lowering the pressure to the point bottoming out the tire on the rim, you're running a big risk of rim damage. There's a very fine line between pinch plats and rim damage. So unless you can somehow predict exactly the right pressure that will result in only a light bottoming out of the tire on the rim on the biggest impacts you incur, I think the lower pressure capability is marketing BS. So that leaves flat protection, rolling resistance and ride quality. Perhaps I'm just lucky but I've been running Panaracer T-servs for several years with tubes and haven't had a single flat. These are not super chunky tires. As for rolling resistance and ride quality I imagine that it's possible that a tube might add a tiny bit of stiffness to the sidewall that might add a tiny bit of resistance at a certain degree of suppleness (or reduce the suppleness at a certain resistance). I'm still on the fence but I'd like to hear if anyone has any insight on the supposed lower pressure capability.

terrymorse 

That's not a bug, that's a feature of the modern "tubeless" road bike tire. Without regular application of sealant, it leaks.

To make a truly tubeless tire that doesn't leak, manufacturers would need to make them heavy, and a heavy road tire does not sell. So they trade off leak resistance against weight savings.

chaadster

Yes, if you rode on a really flat tire, that would almost certainly damage the tire. In your case, IRC uses a butyl liner on the inside of the casing precisely to enhance air pressure holding, so probably in riding on that tire flat, you distorted the casing enough to damage the liner, perhaps through abrasion of the bead against the sidewall and/or introduced enough heat that there was some chemical breakdown of the lining, too.

I had a pair of Formula RBCC some years ago and rode them without any sealant at all for a bit, because I could.

PeteHski

Some tubeless tyres are slightly porous and do require sealant, but many (probably most) are not. However they can still leak slightly around the bead without sealant, but it is a total non-issue unless you are trying to convince yourself that tubed tyres are better.

PeteHski

You can definitely run 38C tyres lower than 50-60 psi without any risk of rim damage unless you are extremely heavy. A quick check on the SRAM pressure calculator will give you a baseline pressure for tubed vs tubeless. Pinch flats are a much bigger risk than rim damage at low pressures.

terrymorse 

Requiring by design the regular application of liquid sealant is an issue, unless you are trying to convince yourself that tubeless road tires are better.

Or the equivalent:

Requiring by design the regular application of liquid sealant is a non-issue, once you have convinced yourself that tubeless road tires are better.

PeteHski

I top up sealant every 6 months and it takes about 5 mins. I ran tubed road tyres for about 50 years previously, so I'm well aware of their pros and cons thanks.

terrymorse 

Thank you for moving away from your general statement about tubeless tires, to a specific personal preference about tubeless tires.

My personal opinion is that a tire that requires the use of liquid goop to maintain pressure is dumb technology.

PeteHski

I'm just pointing out the practical reality for someone with no first hand experience of running tubeless tyres.

Branko D

GP5000 TL was designed to work without sealant and works without sealant (except it won't seal without sealant, obviously). It weighted about 80g more than the modern GP5000 S TR does and was a pain to mount. It weighted like a tube tire with a tube. Insane.

​​​​​​People prefer the lighter tires which are tubeless ready and require a bit of sealant for installation (could not add any later) over the fully tubeless but heavier tires as evidenced by the general preference for the new version.

Case in point, I still have like three on the shelf if anyone prefers tubeless which doesn't need sealant, because I prefer the new contis. There's a pair of them on what is now my son's bike which haven't seen sealant added in at least a year, running liners for the run flat capability.

Anyway, the rest of the bikes in house are all slowly being converted to tubeless with liners.

3speedcliff

Well the difference between hooked with tubes and hooked without is less than 1 psi for me. I'd bet money that no rider would be able to discern the difference, either in ride quality or average speed. Also this is beyond the accuracy of most gauges and the typical rider's dedication to pressure. I'm curious as to why the hookless calculate a 4 psi difference. Are the walls thicker and less prone to damage? Are they less likely to "burp"?. As far as the risks, I think you're comparing a risk that results in a 15 minute roadside repair that costs a $10 tube versus a risk that leaves you stranded and with $100+ repair. Personally, I'm going to run a few more psi to ensure that my rims never bottom out on an obstacle. It just seem quite foolish to do otherwise.

PeteHski

I can't say I've ever damaged a wheel rim, but I have had the occasional pinch flat. I think the pressure you would have to run to risk rim damage would be far lower than optimum anyway. Tubeless just takes away the risk of a pinch flat at the optimum pressure or slightly lower (for example I may run 5 psi lower in the wet). I don't have any experience with hookless rims, but I think they effectively increase the air volume and hence lower recommended pressures.

Eric F 

Agreed. I run 35mm-ish (they measure closer to 36-37 on my rims) tires on my gravel bike at 40psi, and have had zero issues with pinching/burping tires, even when banging them through some pretty chunky terrain, which I do on a pretty regular basis. Granted, I'm using tires built for gravel, not lightweight road race tires. FWIW, I weigh 180lbs-ish.

terrymorse 

The GP5000 TL is good for comparison, as it is similar to the standard GP5000, but with a heavier casing and a butyl liner to prevent air leakage. The liner is basically an "open" inner tube fused to the inside of the tire (which explains much of the weight increase). The TL is about 85 grams heavier than the standard GP5000, but only about 50 grams lighter than the TR ("tubeless ready"), which uses a lighter casing than the TR and no butyl liner (and it's actually smaller than the TL).

Comparing rolling resistance, the differences between the TL, TR, and standard GP5000 with latex tube are quite small, with the standard GP5000 + latex tube showing the lowest RR (per bicyclerollingresistance.com). If you're choosing tubeless for its lower rolling resistance, you're not getting it.

3speedcliff

I doubt there's been any accurate testing but my feeling is that the difference between a pinch flat with tubes and a damaged tubeless rim would only be a few psi. Of course there are tons of variables so even good scientific testing would only cover a few scenarios. Anyway, I have some gravelking slicks on the way so I may use tubes just to get started and then then try some sealant. I'm an amatuer framebuilder so this project is to cut the rear end off a CF road bike and widen the stays enough for 650bx38. So I need to have the tires mounted to check clearance but it will be a month or two before I have it ready to ride.

Chandne

The hookless tubeless rims are stronger and resist impacts better. Just look at them compared to hooked rims....the edge of the hookless rim is pretty thick while the hooked rims have a really thin hook. This year I mainly had the Specialized Turbo T2/T5s on my ZIPPS and I liked them. Next year, I'll put the ENVE SES 31s on since they measure 34 and ride beautifully.

PeteHski

If you are going to run 38C tyres at 50-60 psi then worrying about pinch flats or rim damage is academic. At what pressure have you found pinch flats to be an issue? I’ve run narrower 30C tubeless tyres at 50 psi on rough roads full of potholes with no hint of any rim damage.

eduskator

+1. Sealant creates a seal between the tire and the bead and this is important. My Schwalbe Pro One tires will always leak air (I'd say 5-10PSI/day) if seated on rims without sealant inside. In fact, it's written on the tire's box to go for a 25 minute ride immediately after adding sealant.

Paradox77

I also debated this recently tube/tubeless. I opted to just run tubes for now as it's less messy and easier to maintain/change at least in my opinion. However I do like the fact that you can run lower pressure on tubeless.

3speedcliff

I just threw the 50-60 psi figure out there. I may try lower once I get this bike built. I currently run 700x28 and I typically air them up to 70F/75R and ride them for 2-3 weeks at which point they're down to ~60/65. Personally I think I may have had maybe 2-3 pinch flats in 30+ years of riding. It's only been in the last few years that I've been lowering pressures, but not to the extent that many do. My point is not about my personal experiences but the overall claim we see that we can run tubeless at lower pressures because we no longer have to worry about pinch flats. My argument is that if you're lowering pressures to the point of bottoming out your rims, you're running a pretty high risk of being stranded with expensive rim damage. I don't believe any calculator or individual can determine the pressure at which a rim bottom out won't be severe enough to cause damage. If you do then fine, enjoy the ride. But for me I think I'll run a few psi higher and ride with the confidence that I won't get pinch flats or rim damage.

3speedcliff

That's what I thought but wasn't sure. So to me the lower pressure advantage for tubeless is only really valid with the hookless rims.

Chandne

I'm 175 lbs and with tubeless and my 25mm (inner width) rims, I run 55-60 PSI with 30/32 tires. I have hit potholes 2-3 times at 15ish MPH and have not hit the rim (yet) thankfully. I am sure my hookless rims will handle it better than any other hooked rim. Fortunately, we do not have many potholes where I ride, nor have I hit them at 25 MPH. This reminds me to get my winter bike setup though. While I keep my road bike handy, I often take out the "winter bike" with faster gravel tires just in case there is any slush under a bridge or something.