How important is the right tire pressure? Very important!
https://www.sram.com/en/zipp/campaigns/total-system-efficiency?fbclid=IwAR3vihMRgksPP2BJ7VnlI92JBRlRqsnFqEkr9UAcr3KIq6xsLc7iQAKZfHg
Data from our RollingRoadâ„¢ tests show the difference between ultra-low pressure and high pressure can account for 50 watts in efficiency gains on a rough road. These tests, which measures power required to ride 32kph (20mph) over various surfaces, capture power lost to tire deformation, drivetrain, and whole body vibration.
https://youtu.be/-mw4fmOJ5GE
That took longer to show up here than I thought it would. Also, not sure why anyone would think 55psi is “super low” on a 28mm measured tire.
For this to work out, based on the bumpy in the video, you’d really have to do the math on time spent in each CRR scenario.
This has been covered a thousand times over. There’s been lots of videos that are more anecdotal showing riders “thinking” the higher pressure tire doing a roll down test on a gravel road to “feel” faster. Just to be proven wrong.
As for tarmac, I tend to agree you shouldn’t pump it up to max…but…what % of your route will you really benefit form the lower pressure?
My last TT bike ride outdoors was 30ish mi. I pumped up to a pretty solid 80/75 psi on 23/25 combo. I think there was a total of a minute to two minutes total accrued “rough road” that entire ride. The rest was smooth other than minute changes in texture.
It takes a pretty solid screwup in pressure choice to suffer 50w of damage for an entire ride.
Lastly, we’re not pro cyclists (I’m not), but the pros on pave’ run such high speeds that the spring/mass system isn’t in the same ballpark as some bloke doing Paris Roubaix on vacation. Speed matters a lot to spring/mass systems being modeled like a bike tire and rider.
As for tarmac, I tend to agree you shouldn’t pump it up to max…but…what % of your route will you really benefit form the lower pressure?
My last TT bike ride outdoors was 30ish mi. I pumped up to a pretty solid 80/75 psi on 23/25 combo. I think there was a total of a minute to two minutes total accrued “rough road” that entire ride. The rest was smooth other than minute changes in texture.
It takes a pretty solid screwup in pressure choice to suffer 50w of damage for an entire ride.
Yeah, agreed on the 50 watt scenario. I base my pressures more off comfort and no loss of speed, i.e. balance. Being that I am on the lighter end of the spectrum for total system weight and I don’t run 22s anymore that ends up being 55/55psi front and rear, respectively, on my road bike. I’m running 23/25 schwalbe pro ones (old version) that measure out to 25 and 28 on my 19mm internal Easton wheels. They are setup tubeless. I likely ride some of the nicest pavement in the nation outside of the random broken stuff. But when I do hit that broken stuff it’s not a question of am I losing 5 watts or not but how that impact impacts my ride.
Time Trial bike is a whole other animal and I will keep those trade secrets to myself. 😆
ETA: https://www.strava.com/activities/3718362217 This was this past Sunday’s ride. If I am losing watts due to "low"pressure(s) then I am likely more aero on my AR than my DA. 😉
As surface roughness increases, you want to run larger tires at lower pressures. We advocate using a tubeless setup to capture full benefits. Pinch flats are much less likely at low pressure when running tubeless
And therein lies the rub.
Tubeless sucks, and the pressures they suggest with tubes = boatloads of pinch flats for me.
Ah well. Always a compromise somewhere.
Tubeless sucks
Yeah, I think tubeless is the key here.
fwiw, I have ~5500 miles on my Pro Ones and only flatted once and really surprised it didn’t destroy my wheel on impact. another time I picked up a nail and rode ~40 miles (finishing my ride) thinking I was having a bad day, but when I got home I realized pressure had dropped to ~35psi. those tires are still going after I got them sealed back up.
I know many others have not had that experience and I do ride some choice roads.
Tubeless IS AWESOME!
FIFY
It sounds like you had a bad experience or something. I think you should give it another go. It’s been just brilliant for me.
I honestly can’t remember the last time I had to pull over on a ride for a flat. Riding is way more comfortable. I’m (apparently) faster.
Get real
FIFY
It sounds like you had a bad experience or something. I think you should give it another go. It’s been just brilliant for me.
I honestly can’t remember the last time I had to pull over on a ride for a flat. Riding is way more comfortable. I’m (apparently) faster.
Okay.
No.
You can just respond in the future. No point in changing my posts.
Yeah, agreed on the 50 watt scenario.
On a really rough surface and pressure way too high vs just right… I could believe it. Maybe.
I’d like to see some data on torque losses, particularly on a steep climb, with that fat squishy tire on the back.
I just looked at this and am looking for some advice.
I have ZIPP 858 wheels. It seems to be suggest for 303s you want to have your tubes significantly lower in pressure than I do - I perhaps feel like a moron.
What should my pressure be for relatively rough tarmac? I assume not the 100 I set them at.
https://axs.sram.com/tirepressureguide
I would use road and gravel for your surfaces and split the differences.
Lowering the psi on my 25mm TL tires on Zipp 303 NSWs was a revealing experience. I am at about 5.5-6 bar / approx. 85 psi or less.
Lowering the psi on my 25mm TL tires on Zipp 303 NSWs was a revealing experience. I am at about 5.5-6 bar / approx. 85 psi or less.
What size are you running? What’s your weight? I kept dropping until I was at 60psi and thought it was the greatest thing. Then I went down to 55psi and found the sweet spot. Such a difference.
I just looked at this and am looking for some advice.
I have ZIPP 858 wheels. It seems to be suggest for 303s you want to have your tubes significantly lower in pressure than I do - I perhaps feel like a moron.
What should my pressure be for relatively rough tarmac? I assume not the 100 I set them at.
What’s your weight? Can I assume you’re running tubes?
80kg. Yes latex tubes. Thanks in advance
https://axs.sram.com/tirepressureguide
I would use road and gravel for your surfaces and split the differences.
Thank you. Wow I’m way too high
Yeah, agreed on the 50 watt scenario.
On a really rough surface and pressure way too high vs just right… I could believe it. Maybe.
I’d like to see some data on torque losses, particularly on a steep climb, with that fat squishy tire on the back.
This entire claim should be pretty easy to validate on a real road; the white paper is based on their proprietary testing system, and they didn’t actually provide much data from their third party consultant. And there’s a gem on page 7.
80kg. Yes latex tubes. Thanks in advance
Forgot to ask the tire width. It’s kind of important. if you have a measured width that would be better than what the label says.
Also, good tool to start off is:
https://info.silca.cc/silca-professional-pressure-calculator
80kg. Yes latex tubes. Thanks in advance
Forgot to ask the tire width. It’s kind of important. if you have a measured width that would be better than what the label says.
Also, good tool to start off is:
https://info.silca.cc/silca-professional-pressure-calculator
Is there a better one to start (or finish) off?