Loving 80 psi

[sjbraun]

I was able squeeze in a ride before work this morning. Usually I inflate my tires to 90-100 psi, but this morning, I just gave 'em a pinch, pronounced them adequately inflated and took off. My Hampstem seemed to ride especially smoothly over Tucson's rutted and cracked roadways. So out of curiousity, I checked the tire pressure when I returned from my ride, 80 psi, front and back. I'm running 25mm Michelin Pro4 Endurance tires, which actually measure closer to 28mm on Velocity A23 rims. At 175#, the ride was plush and I never worried about pinch flats.

If you haven't tried running wider tires and lower pressure yet, my experience today suggests you might want to give it a try.

Steve

[notoriousdjw]

I started checking my tires before each ride with a digital tire gauge and brass presta-to-schrader adapter and I found something similar. It only takes 10 psi to go from a springy pneumatic ride to one that rattles the shifters over every bump. For me the magic numbers are about 90r/80f on 23c tires Schwalbe Ones and 70r/65f on 28c Hutch sectors. I'm 175lbs riding on the carpet-bombed streets of Seattle.

[farmersam]

Thanks for confirming. I posted sometime ago about the bumpy roads in my area jarring me on my cross. It was recommended to deflate from 60/65 to 35/40 on a cross.

[eddief]

but great you discovered lower pressure. People I ride with are religious about inflating to a 100; even women at less than 150 lbs. You can tell em and tell em and tell em, but religion gets in their way. Me 190ish, Michelin Lithion x 25mm, at 80 psi. Just works.

[marciero]

I was bombing down long dirt descents in the Green Mts last week comfortably with 28 tires at 70/75. For me that seems to be enough to avoid pinch flats, and they still handle fairly responsively on the pavement.

[notoriousdjw]

I would share this chart and show them that most tires have <1w difference between 80 and 100 and ~2w difference between 80 and 120. That's a lot of pain to endure for 2 watts!

[MattTuck]

That chart is great. thanks for posting.

[guido]

Originally Posted by notoriousdjw

I would share this chart and show them that most tires have <1w difference between 80 and 100 and ~2w difference between 80 and 120. That's a lot of pain to endure for 2 watts!

Wow they actually found a tire with more rolling resistance than a Gatorskin. I thought it could never be done...

[marciero]

Yes, great chart, especially for comparison of various tires. Should keep in mind though that rolling resistance does not tell the whole story - on rough surfaces a high pressure tire will ride more slowly, or so the evidence seems to suggest. I am assuming the data in the chart was generated using some type of smooth drum/dynamometer setup.

[brownhound]

Jeez, maybe I have bad luck but I've gotten three pinch flats this year trying low PSI. Two on 23mm (Michelin Pro4) running around 80-90 and one on a 35mm (Clement USH) running around 50-60.

I keep my tires pumped high now, and consider the low PSI experiment over. For the record, I'm 155lbs. The flats seemed mostly to be from gravel.

[notoriousdjw]

Originally Posted by marciero

Yes, great chart, especially for comparison of various tires. Should keep in mind though that rolling resistance does not tell the whole story - on rough surfaces a high pressure tire will ride more slowly, or so the evidence seems to suggest. I am assuming the data in the chart was generated using some type of smooth drum/dynamometer setup.

If you read the section of that site called "the test" it expains:

the drum is covered with diamond plate to simulate an average road surface. This comes a lot closer to a real road surface than the usual very smooth steel drum.

[tumbler]

Nice charts. According to this, I can blame all of my slowness on my Conti 4Seasons. Apparently I need some Grand Prix 4000S II's from 2014 with latex tubes.

[Steve in SLO]

Latex versus non-latex tubes is a real eye-opener, IMHO.

[Llewellyn]

I've been riding 75-80F/70-65R for a while now. What a difference - I can't believe it took me so long

[etu]

Below 60 - feels sluggish, except for off road, mixed terrain
60-80 nice balance for fast commutes and long weekend social rides
80-100 aggressive weekend rides with friends