Noonievut

My gravel bike has 27.5x1.9 GKSK.  My tubeless version has had tubes since day 1 (over 1.5 years ago).  I'm 155# and will run the GKSK as low as 20-23psi.  At this psi the tires are a little sluggish on the paved part of my rides (some rides I'm on pavement for 50-70%), though are generally cushy enough for the gravel and occasional non-tech mtb trails.  My mtb mind says I can run even lower psi and make the gravel more cush, but am I going to be more sluggish on the pavement?

Put another way, if I were to run these tubeless and at the exact same psi, what (if any) would be the effect on pavement?

I'm not thinking of this from the flat protection (thorns, pinch flats)...I realize that benefit, but where I ride this is less of an issue.

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Spreader
Bicycle rolling resistance.com has an article on watts lost for tubes, latex and tubeless. I’d head that way and check it out. Lower psi = more watts lost to rolling resistance as well. Although IMO it’s negligible.
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Zurichman
I run 5 lbs. psi higher at my end if I know the ride is going to be more macadam. Never tested that though.

Zman
If it was easy it wouldn't be a memory. You just hope you don't have all your memories in the same ride. been there dun that Zman
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owly
I'd say you would be sluggish on paved at those pressures. 
I'm finding the more supple tyres can be run at higher pressures on paved and still be ok for the gravel etc.
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Koyote
20-23psi is pretty low even tubeless. Experience tell me that, unless you are on very smooth roads, your tires may burp out air and go flat at such low pressure.
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Noonievut
owly wrote:
I'd say you would be sluggish on paved at those pressures. 
I'm finding the more supple tyres can be run at higher pressures on paved and still be ok for the gravel etc.


That’s interesting, and makes sense.  My GKSK are not supple.  I do like them though, as for me they’ve been a good generalist mixed surface ride tire...that can do mtb trails good enough (with my lack of skills).  Maybe for my next tires I’ll look for something more supple
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AlanEsh
Koyote wrote:
20-23psi is pretty low even tubeless. Experience tell me that, unless you are on very smooth roads, your tires may burp out air and go flat at such low pressure.

Agreed, I mean how much more "Cush" will you get dropping from 23 down to 19? I can't imagine the improvement would be noticeable or worth the risk.

Just getting rid of the tubes will help make your wheels feel less sluggish.
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chas
Koyote wrote:
20-23psi is pretty low even tubeless. Experience tell me that, unless you are on very smooth roads, your tires may burp out air and go flat at such low pressure.


no burps is one reason I use skinny stripper latex strips for my tires.

Read a horrible article about someone who burped a high pressure road tire at speed and "woke up" on a life flight helicopter.   Probably not as catastrophic when not running 100+ psi, but still...
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chas
Noonievut wrote:

My gravel bike has 27.5x1.9 GKSK.  My tubeless version has had tubes since day 1 (over 1.5 years ago).  I'm 155# and will run the GKSK as low as 20-23psi. 



Personally, I would worry about steering response and having the tire roll on to the sidewall too much or just squirm at that PSI on pavement.  Things get a little squirrelly on pavement at low PSI 
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