invisiblehand

In brief, fast tires are wide supple tires that allow a rider to lower tire pressure.

The first article below confirms a finding by Jan Heine some time ago. The second article is Jan summarizing the findings.

Tire Pressure - Stop Guessing And Read The Science | TRS Triathlon

https://janheine.wordpress.com/2016/...ses-confirmed/

fietsbob

and expensive supple casing tires, not cheap ones ..

corrado33

Also, what causes the sudden jump in rolling resistance? Any theories? Jumps like that don't generally occur without good reason, and even then it's usually more gradual.

I'll hold my judgement until someone comes up with a model and can explain it using actual science. (Collecting a bunch of data under not-very-well controlled conditions does not register as "good science" to me.)

Show me the roller tests, but with a weighted tire and a textured surface, with an average "roughness" of X, Y, and Z. Give me slow motion video of what the tires do over those surfaces, or even a load sensor/movement sensor on the fork/hub.

Also, the "tests" were done at 15 MPH. That's... slow. Far too slow to be thinking about buying expensive "supple" tires. How does it change when you increase speed?

With all of that said, I run my tires at 70 and 75 PSI because I'm a light rider and I don't need anything more. I've never pinch flatted and anything higher makes the ride rougher.

ttakata73

This is pretty scientific proof of the idea; I think it makes sense.
Continental Grand Prix 4000S II 23 25 28 mm Comparison

Also, tubeless is more supple so faster.
Sadly no one makes tubeless small tires that folders need.
I wrote Schwalbe to make tubeless for the 45,000 Bromptons/year sold and they were not interested.
So I wrote Hutchinson but they never responded.

corrado33

And nowhere in that data is the sudden "jump" seen in the original links posted. Again, I will wait for a more broad, conclusive study.

fietsbob

Start on that Post graduate degree Program so you have access to the science to make real difference data, Otherwise its just another BF opinion hamster wheel.

VBQ does Roll down tests , Subscribe to the quarterly.

Though, Jan, Who Publishes It, Also sells Compass tires, none are folding bike size so He had no incentive to test any..

ttakata73

I agree more with the findings using the indoor fixtured wheel with consistent setup and smaller gains in performance.
Riding outdoors with a human has a lot of variables in weather, surfaces, etc.

I can say regarding the first article wider is not always better.
I have a fatbike on 4.5" tires at 20psi on pavement and it is quite slow compared to my other bikes.
I am sure the aero is slowing the bike more than rolling resistance but my perception is not reliable.
Maybe we will have 100mm wide carbon areo wheels for fatbikes for $10,000 from Zipp in a few years

1nterceptor

Not sure if these wider are better tests done simulate flat, uphill or downhill surfaces.
Don't really need help on level roads. I want more speed on my climbs; especially the
steep ones. On a personal level; skinniest/lightest with high PSI works for me. So I'll
keep using those for now:

https://www.youtube.com/watch?v=lmFU...IoDLA&index=18

https://www.youtube.com/watch?v=ROYH...6zPoymgKaIoDLA

sleepycactus

You can do "ghetto tubeless". That makes the tubeless specific rim you would need unnecessary. I used a split 16" tube on a 20" rim and it worked well. Had a tubeless fat Apple tire on it with stans sealant The post by the gypsy by trade describes the process well:
https://gypsybytrade.wordpress.com/2...bike-tubeless/

ttakata73

On a 20psi or lower fatbike I am not concerned with the ghetto method, but when running higher pressures on a road bike I worry the bead will fail or the carcass will leak air too much.
Many people say it's a bad idea to use a non tubeless tire for the above reasons.
I tried to go ghetto tubeless on my fatbike but the rims were too small or the tire bead was too loose, plus the carcass leaked too much.

Maybe it's just BS so tire manufacturers will make more money on tubeless tires, but I'd rather not risk it.