To Peak or not to Peak that is the question:

[opimax]

Honest question , have not read the links, why do dragsters have wide tires then?

 

[Shea N Encinitas]

At the same inflation pressure, a wide and a narrow tire have the same contact area...

I've never seen a wide tire rated anywhere near the pressure of a narrow tire. How is this a logical comparison? 45 vs 65 or even 120 PSI for example. The second reference even suggest lowering air pressure will reduce rolling resistance;

Because the internal friction and hysteresis within the tire’s materials will be lower, and because the surface imperfections in the road will be absorbed into the tire more easily...

Unfortunately this experiment also uses equal tire pressure (and materials) nullifying the results.

In my daily ride I'm often alongside road bikes on a big descent, I've learned to let them go first as my 2.2" tires will roll much slower, even while pedaling under power. A courageous roadie will reach 37 mph in a tuck (no pedaling) on this 400 foot slope, while I can barely keep up pedaling my arse off in unlocked turbo mode, also tucked. Of course I catch them on the flats and next climb.

While I don't doubt the science, I don't think the parameters reconcile with everyday real World experience. -S

 

[Shea N Encinitas]

Honest question , have not read the links, why do dragsters have wide tires then?

Because it is all about traction off the line!

 

[Ann M.]

Interesting line of thought; however, do not miss out on the very important stipulation that the wider tire rolls better only if it is at the same pressure as the skinnier tire. A narrower tire at a higher psi will outperform with lower air resistance and rolling resistance.

 

[stevenast]

Interesting line of thought; however, do not miss out on the very important stipulation that the wider tire rolls better only if it is at the same pressure as the skinnier tire. A narrower tire at a higher psi will outperform with lower air resistance and rolling resistance.

Exactly right. but don't forget the air pressure is relative, and you can bump the pressure up in your wider tire as well. I haven't done any research to see where pressure vs width equalizes.

A made-up example might be: 26mm @ 100 pounds compared to 57mm @ 50 pounds.

My original point was just that a wider tire is going to be better on an e-bike: stronger, more comfortable, and closer in rolling resistance than you might think, even if the narrow tire has been pumped up hard as a rock!

 

[Brambor]

There is a point of diminishing return when we move to fatbike tires. First it is extremely difficult to pump such tire to the same high pressure of a skinny tire. All in all the argument works as you said when all things are equal ... In fat tires making things like tire pressure equal is impractical. Last but not least all one needs to do is to try riding a fat bike and the realization will be obvious, making theoretical musings irrelevant.

 

[stevenast]

Not talking about fat tire, just 1 1/2 - 2" wide.

that isn't theoretical, that's actually an ideal size for an e-bike.

 

[Brambor]

umm, looks like I missed that part of the conversation. Never mind, carry along, nothing to see... sorry. I thought we were talking about Fat Bike tires.

 

[Shea N Encinitas]

Lycra riders beating you down the hill is due to aerodynamics... their body position.

I can tuck too, but the wide tires and knobs do push a lot of air.

Lost in all this, my original point was why change an ebike to narrower tires?

To go faster! Took my Dash from 45c to 38c, 40 PSI to 65 - definately faster, ride times, top and average speed all prove this for me.

The few ounces of weight saved is going to be irrelevant compared to the safety, comfort, and less rolling resistance from wider tires.

In my case 38c is still a pretty wide tire, heck I used to ride 22's. Perhaps those experiments were run in a vacuum. -S

 

[Shea N Encinitas]

I don't deny the science or the laboratory results, I just have my own experience and factual results to draw upon out of the road at higher PSI and narrow, lighter tires. The main discrepancy in this discussion is the higher air pressures of narrow tires. Run yours (whatever width) at 40 PSI for a few days then pump them up to the limit and get back to us. -S

 

[stevenast]

I just have my own experience

You're exactly right again! By pumping your new tires up 25 pounds higher than the old ones you get less rolling resistance in exchange for riding on tires that are hard as a rock. You've learned how to compensate and you feel the difference.

What you're feeling and the science are not in conflict.

 

[Ravi Kempaiah]

At the same inflation pressure, a wide and a narrow tire have the same contact area...

I've never seen a wide tire rated anywhere near the pressure of a narrow tire. How is this a logical comparison? 45 vs 65 or even 120 PSI for example. The second reference even suggest lowering air pressure will reduce rolling resistance;

Because the internal friction and hysteresis within the tire’s materials will be lower, and because the surface imperfections in the road will be absorbed into the tire more easily...

Unfortunately this experiment also uses equal tire pressure (and materials) nullifying the results.

In my daily ride I'm often alongside road bikes on a big descent, I've learned to let them go first as my 2.2" tires will roll much slower, even while pedaling under power. A courageous roadie will reach 37 mph in a tuck (no pedaling) on this 400 foot slope, while I can barely keep up pedaling my arse off in unlocked turbo mode, also tucked. Of course I catch them on the flats and next climb.

While I don't doubt the science, I don't think the parameters reconcile with everyday real World experience. -S

You're absolutely right.
In this link, they are only comparing 22, 23, 25 and 27mm and what they mean by "wider" is 27mm vs 22mm. Confusing it with 2.2inch MTB tires is a complete misunderstanding.
I have ridden with 2.2" tires on jumper and compare it with ST2's big ben with a slightly shorter contact patch. The difference is noticeable. I find it hilarious that people who have not put 1/10th of the miles you have, think your input needs to be corrected. You can google anything and become an expert in anything instantly.

I strongly suggest you stay and keep on riding with the cute doggie .... - R