Poll: ENVE says 60psi, Continental says 80-109psi. What to do...
 

I know. "Test out the different PSIs and ride what feels best for you". That is exactly what I'm doing. Today's ride will be at 70psi. Rode it at 80 the other day. Later on will try 60. But I'm just curious what the rest of you err towards when the recommended psi by the wheel and tire manufacturers are so different.

For background, I've mounted 25c Continental GP5000 TLs on ENVE SES 5.6 wheels on my Cervelo S3. The Conti site for 25c GP5K TLs gives a range of 80-109psi. The ENVE website for the 5.6, with tubeless 25c tires, at my rider weight, gives a recommended pressure of 60psi with the caveat of:

65-70F. 70-75R. But tweak based on conditions and comfort needs.

Throwing more info to the mix, this chart at bottom, from mavic suggests a max of 6.35 bar for a 20c rim (Enve SES5.6), which is about 92psi.

I assume since you're quoting Enve as recommending 60psi, that you are about 150lbs.

It's a conundrum when a tire maker says minimum safe inflation is one thing (80psi), and the rim maker says the max for any weight rider (250lbs on Enve site) can only be 80psi.

https://cimg4.ibsrv.net/gimg/bikefor...c00e19c4f8.jpg

Conti's minimum pressure recommendations have never made sense to me, so I cheerfully ignore them.

Ride whatever pressure that floats your boat :) As long as your tire isn't underinflated to a point where it'll pinch the rim if you roll over a bump or something... Keep mind that there is an optimized pressure to reduce rolling resistance as well. You just need to find out which one!

No way I'd run 60. That's crazy low.

At 165 lbs, I run a minimum of 90psi for 25s, but I've also pinch flatted numerous times in important situations under 90 psi, so others may have differing experiences. But even with tubeless, I don't go below that as I hate the mushy feeling when standing.

I’m definitely trying to find that balance of low RR and comfort. On my TCR I run 28c 5K TL at 70 and find that to be my personal sweet spot. Yes if I went higher I’d decrease RR but then the comfort on badly paved roads (which is 95% of where I ride) starts to suffer. But that’s a 28c vs the 25c on my S3 which is the largest that frame will accept. I’m at the halfway point of my daily ride (aka Blue Bottle Coffee) and all far I’m really liking the 25c ENVE 70psi combo. Significantly more comfortable than the 80psi I ran the other day but still feels fast. I’ll experiment with maybe 65 in a day or two but 70 may be the sweet spot. Which would make it easy for me to remember so I can run either bike at the same pressure.

Well, at the point you'll either break a tube or crack a CF rim...

I try to avoid pinch flats whenever I can.

Speaking of manufacturer recommendations, it’s interesting how Conti’s lower psi recommendation for the 5K TL is 65psi for both 28c and 32c sizes but jumps up to 80psi for 25c.

The new 2020 Schwalbe Pro One TL Easy (the one with “souplesse” whatever that means :lol: but it is getting good early press) has a 70-110psi range for its 25c size. It drops down to 55-95 for 28c and 55-80 for 30c :eek:

I have greatly preferred the GP5K TL to any other tire I’ve ridden (Bontrager, Mavic Yksion UST, grand sport race). But I’m tempted to try out the new Pro Ones when they become more widely available and come down from their $81 per tire price. Seems they’re too new for anyone to mark them down just yet. I pay about $55 per tire for the 5K TL and that’s about right in my view for the price/performance ratio.

For those responding to the poll, keep in mind I’m asking about tubeless psi.

Keep in mind that the Schwalbes are now being spec'd with a 19mm internal rim width in mind, whereas the Conti are... well, I don't know. But that internal width changes the internal volume which is going to affect the recommended pressure ranges. The fact that your rims are even wider shifts the lower end even more.

See this thread from earlier this year.

https://www.bikeforums.net/road-cycl...a-dispute.html

I think an issue with at least some of the Enve rims is that they are wide rims, and are designed for use with wide, low pressure tires.

IKR

Say what you will about the downsides of tubeless, but give the devil his due. Pinch flats don’t happen with them.

The end of my experiment with Schwalbe One tires was when I hit a rock on the road which tore a chunk of the tread/sidewall out, and didn't seal.

Not that big of a rock either, but probably rather sharp.

I have wondered if I had let the pressure get too low, and it did, in fact bottom out when I hit the rock causing damage that would not have occurred if I had the pressure higher.

Not sure in this context a wide tire is, but per Enve, these 20mm internal-width rims are "optimized for 25mm tires"

https://cimg2.ibsrv.net/gimg/bikefor...6f5ffb29a8.jpg

The ENVEs are optimized for 25c and that's the largest I will mount on them for the foreseeable future for one simple reason: 25c is the widest the S3 will safely accommodate per ISO safety rule of 4mm clearance on each side. And the 25c need to measure pretty close to it to maintain that clearance. Currently my 25c 5K TL measure 25.93 and that leaves about 4mm clearance on one side of the chainstay and about 3.8mm clearance on the other side. If I buy and mount the 25c Pro Ones and they measure large, like 27mm, I'll really be cutting it too close for comfort. However if the new Schwalbes are spec'd for 19mm rims, then hopefully they won't expand too much on a 20mm internal rim width wheel.

Just returned from 20+ miles with the 5K TLs at 70psi...I think I'll keep them there. They're comfortable enough when I roll on bad roads, so I don't feel the need to dip down into the 60s. Might experiment going slightly higher next ride, maybe 75, to see if I gain a little bit in reduced RR without giving up too much comfort.

Wait... how heavy are you, OP? 150lbs?
If you have the cojones for it, you can run your tires very, very low. I weigh between 135 and 145 (read: I am fat for now). I use 25mm tires on an ultra wide 23mm rim. With a super supple tires, I run less than 50psi front and 55 psi rear. If I don’t care too much about responsiveness, I’ll go 45psi F and 50R. It’s spooky when I hit potholes or whatever, so I wouldn’t recommend this to anyone in a truly crappy area... but you definitely have room to experiment with. Personally, I think 60F/70R is practically rock hard. I’ve gone as low as 35 psi front (rainy super technical crit. 9 people crashed in a field of ~25. I did not) with no adverse effects.

Jan Heine wrote an article at some point that the “goldilocks” zone that everyone really likes for their tires is actually the slowest because it doesn’t let you float over rough tarmac as with ultra-low pressures, nor do the tires absorb little energy like with rock hard pressures. Try to think to yourself “smoother is faster” and see how low you can go. Bonus if you have a power meter and a calm, flat section of road.

Why does it seem a bit funny to me to invest in $2500 wheelsets, and then to need to run your nice tires at inflation pressures resembling molasses?

Has there been an updated "15% deflection" or whatnot study using tubeless. Enve says 63psi is optimal for a 150lb rider and 23mm tire running tubeless on asphalt. That just seems kinda weird to me.

Didn't appreciate the discussion was about tubeless--duh.

Acktchooally, running your tires “like molasses” exploits your high end tires more than running them super high. If you were to try out a 25mm vittoria corsa and Gatorskin at 130psi, you’d be a bit hard pressed to tell the difference. Try it again at 45 psi and you’ll notice immediately which one is better.

Nicer tires are nicer regardless of what pressure you run them at, but they broaden the gap when run low.

Even though you can't pinch flat a tubeless tyre when you bottom it out, you are still increasing the risk of damaging your expensive rims.

Correct...instead of ruining a $5 inner tube...you bottom out and bend or break a rim that costs $100-1,000USD retail plus cost of rebuilding the wheel. Great economy.

since Enve was part of the discussion.. I presume running too low in your road tires, the same could happen?

https://www.enve.com/en/journal/pinc...mate-buzzkill/

I've pinch flatted two tubeless road tires. It sucks more than tubed tires because pinch flatting a tubeless tire is a terminal event for that tire. Lower pressures + wider rims = much higher propensity to pinch flat regardless of what's inside the tire.