Posted: 6/5/2026 8:41:28 PM EDT
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I started road biking last year and understand that tubeless allows you to run lower pressure. I got a flat last year and had the LBS do it tubeless. Since then I only get a few miles before it sinks down almost to the rim. I've done the soapy water check and also had the shop test it and nobody can find a leak. Both tires are original to the bike. The front still has a tube and never has problems. Am I doing this wrong or what? Attached File Attached File |
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There's gotta be a leak, somewhere. The air could be escapoing into the wall of the rim, I had that happen on a set of Mercury carbon wheels. I'd try a different tire, and see if that helps? MAybe swap the front to the back? They are tubeless ready tires, right? |
Looking back I realize, nothing have I done
Left to die with only friend,
Alone I clench my gun
Left to die with only friend,
Alone I clench my gun
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Originally Posted By kevhogAZ: There's gotta be a leak, somewhere. The air could be escapoing into the wall of the rim, I had that happen on a set of Mercury carbon wheels. I'd try a different tire, and see if that helps? MAybe swap the front to the back? They are tubeless ready tires, right? |
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Get a spray bottle, fill it with soapy water and literally soak every part of the rim with it. The air is escaping somewhere, you've gotta find where. I usually find hard to locate leaks around the spoke holes. Air going under the rim tape is pretty common. |
Looking back I realize, nothing have I done
Left to die with only friend,
Alone I clench my gun
Left to die with only friend,
Alone I clench my gun
| I'm not sold on road tubeless. I tried it and I really loved the grip and the feel of 65psi pressure right up until I got a flat. I could not get the tire off the rim with my jumbo tire levers and my buddy's tire-jack. It was the only time in tens of thousands of miles that I had to get a ride home. I sold the wheel set and I went back to tubes on the road. |
"One day, your body will become your priority whether by choice or by consequence" - PK
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Originally Posted By -Obsessed-: What's the tire width, pressure, and system weight? What sealant? How often do you top off the sealant? I've never topped it off because this has been an issue since going tubeless in the first place. You can even hear some still swishing around in there so it shouldn't be a top off issue. |
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Have you put any more sealant in it? If not I’d try that. Could be an easy fix. Edit. Saw that you hear stuff inside. Make sure it’s not dry sealant making the noise and that it’s actually liquid. Dried sealant in one of my MTB tires. Attached File |
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Originally Posted By Gigity: I think it's 700x28. Stock Specialized Roubaix tires. I weigh about 210 and thought maybe it's too much for the sidewall of the tire. I've never topped it off because this has been an issue since going tubeless in the first place. You can even hear some still swishing around in there so it shouldn't be a top off issue. What pressure are you running? And what is the rim max for pressure on tubeless? You're on the heavy side for tubeless that narrow. Your ideal pressure nodes for that weight and width is 77 and 95 PSI. 95 is likely beyond the max pressure of the rim tubeless, and frankly 77 may be as well. I'd be running 35s minimum if I were you. |
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Originally Posted By -Obsessed-: What pressure are you running? And what is the rim max for pressure on tubeless? You're on the heavy side for tubeless that narrow. Your ideal pressure nodes for that weight and width is 77 and 95 PSI. 95 is likely beyond the max pressure of the rim tubeless, and frankly 77 may be as well. I'd be running 35s minimum if I were you. it sounds like I should scrap the tubeless and go back to a tube. |
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Originally Posted By Gigity: Based on the gauge on my cheap pump it looks like 30 psi is as much as I can jam in there. it sounds like I should scrap the tubeless and go back to a tube. My dude, that's your problem. What kind of pump do you have? You need way the hell more than that.  go get yourself a nice pump.
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Originally Posted By -Obsessed-: My dude, that's your problem. What kind of pump do you have? You need way the hell more than that. go get yourself a nice pump.https://media2.giphy.com/media/YmQLj2KxaNz58g7Ofg/200.webp?cid=8dc8958ci3qa9jk348vj5db7q042s2ajn7fbqjs5d9en339e&ep=v1_gifs_search&rid=200.webp&ct=g |
This showed up in my Active Topics, I'm not a cyclist but I have a few decades dealing with tires. Soapy water and a spray bottle will find most leaks but sometimes like what you're finding out with they can be hard to find at times using that method. It may take completely submerging the wheel in water or partially submerging it in a trough,or bath tub (when the wife isn't around  ) if you don't have something big enough to fit the whole wheel in to find the leak.
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Originally Posted By Gigity: I am a rookie, therefore rookie numbers. But even if I start at 30 it's still dropping to ~20 during the ride. Time to dunk it in the bathtub. My guess is you need more sealant or you need to redo the rim tape. I see that stuff get peeled off the rim a lot and it leaks through the spoke holes then. Hard to find those without dunking the tire. |
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| I had a presta valve core get jammed slightly open with sealant. It leaked air until I replaced the core. You can also wash the core in hot water after removal to unjam it. |
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Originally Posted By Anastasios: I had a presta valve core get jammed slightly open with sealant. It leaked air until I replaced the core. You can also wash the core in hot water after removal to unjam it. Either way, thanks, fellas. The tire is now holding at 62 psi. |
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Originally Posted By Gigity: Funny you say that. I took it to the trek shop today and went back with a tube. Shop guy handed me the old presta valve and said that was probably the culprit. Either way, thanks, fellas. The tire is now holding at 62 psi. Ah yeah, I hate valve cores. I ended up going coreless. Never going back. |
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Originally Posted By -Obsessed-: Ah yeah, I hate valve cores. I ended up going coreless. Never going back. Originally Posted By -Obsessed-: Originally Posted By Gigity: Funny you say that. I took it to the trek shop today and went back with a tube. Shop guy handed me the old presta valve and said that was probably the culprit. Either way, thanks, fellas. The tire is now holding at 62 psi. Ah yeah, I hate valve cores. I ended up going coreless. Never going back. |
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-St. Silouan the Athonite
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Originally Posted By Gigity: Based on the gauge on my cheap pump it looks like 30 psi is as much as I can jam in there. it sounds like I should scrap the tubeless and go back to a tube. Originally Posted By Gigity: Originally Posted By -Obsessed-: What pressure are you running? And what is the rim max for pressure on tubeless? You're on the heavy side for tubeless that narrow. Your ideal pressure nodes for that weight and width is 77 and 95 PSI. 95 is likely beyond the max pressure of the rim tubeless, and frankly 77 may be as well. I'd be running 35s minimum if I were you. it sounds like I should scrap the tubeless and go back to a tube. I had the same tires on my older Roubaix. They actually measured 30mm. Pull the valve core out of the wheels and make sure it’s clean of sealant. Use a piece of wire coat hanger and push through the stem and make sure it’s not clogged. Make sure valve stem is firmly tightened. Rotate the valve to BDC and use that same piece of wire to make sure you have enough liquid sealant in the tire. I use 2.5-3 oz. Get a good pump and gage. I use a presta inflator on my compressor and a good floor pump. |
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Originally Posted By Cooper1: Seems like so much work instead of just using tubes. What are the benefits over tubes? In the snow, my fat bike tires are 4 psi rear, 6 psi front. You can't do that with tubes. On my gravel bike and fat bike I wore the treads off several tires without ever getting a flat. On my road bike I was able to run as low as 65 psi. The low pressures give you amazing grip and a soft ride. (I used to ride old school tubular or sew-up tires and the ride feel is noticeably better than clinchers with tubes.) |
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I'm not sold on tubeless for skinny tires yet. I run it satisfactorily on 32c, but I've always wondered if you have enough volume for there to be enough sealant in a skinnier tire than 30 or even 32c for it to work properly. I'm 195# and run 65# rear and 62# front on tubeless 700 x 32c. For an over 55 rider it is world's more comfortable than 100psi tubes on 23c tires. Been tubeless on mountain bike tires for 8 years and I'm not going back to tubes there. |
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Originally Posted By -Obsessed-: It's also a lot less rolling resistance. My 44c Snoqualmie Pass tires tubeless at 37psi are less rolling resistance than a typical 25c road tire at 90psi. The physics behind it is pretty fascinating actually. |
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Originally Posted By Cooper1: Seems like so much work instead of just using tubes. What are the benefits over tubes? For me the biggest benefit of tubeless is preventing flats from road debris. Those little shards of glass and wire from steel belts that work their way through the tire and you can’t see them. You change the tube then get a flat 5 miles later. Tubeless just seals it and you go on. |
" Don't cry, nobody shoots Glocks anymore."
"But the new Admin. is a Master in IDPA"
"MASTER in IDPA..."
"is like C Class in IPSC!"
"But the new Admin. is a Master in IDPA"
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"is like C Class in IPSC!"