jur

Actually, Schwalbe make a big song and dance about these having low rolling resistance. Big fat does not necessarily equal slow roller.

EvilV

I wonder how that works.

I read some reviews of the Dahon Curve whoch said how fast the tyres were even though they soaked up bumps as well as a suspension system (so it was said).

awetmore

There is no reason to significantly overinflate most tires. It doesn't help the rolling resistance, and can increase it if the bike is constantly bouncing. It also reduces traction.

I run the Greenspeed Scorcher tires on my Tikit (the tires are 40-349 sized) at around 50-60psi. I re-inflate them when the pressure gets down below 40psi.

I hated the Schwable Marathons, especially in 349mm. They are a very harsh riding tire.

alex

awetmore

Roll down tests can be done with lab conditions. The problem with rolling resistance tests done in labs is that they rarely reflect the rear world. The tires are usually tested on smooth drums that are around 6" in diameter. These bear no reality to road surfaces. The bicycle and rider are removed from the equation, even though those provide dampening and suspension.

I've been involved in the rolling resistance testing for Bicycle Quarterly. We use the same bicycle and rider for all tests. We use the same test track and time the center of the rolldown (ignoring timing from the start and end when the rider may wobble). The rider does the route 3 or 4 times and is timed by two people independently. We always use reference tires for the first and last rolldown to make sure that our times are consistent in a day. The timing is done at 5am when there is no detectable wind (using a very accurate wind meter) and in a certain temp range. The exact procedure and results are listed in BQ issue Vol 5 No 1. https://www.vintagebicyclepress.com

I think that this gives much more accurate results than a drum test. It also takes a significant amount of time.

invisiblehand

EvilV ... the best explanation is on the Schwalbe website under the Tech tab.

Oh ... why am I making this difficult?

https://www.schwalbetires.com/tech_in...ing_resistance

EvilV

Interesting link there.

werewolf

I hated the Schwable Marathons, especially in 349mm. They are a very harsh riding tire.

__________________________

Could you recommend a tire that rolls better with equal flat-resistance?

Tire pressure. I easily weight over 100 pounds more than many riders on the same (20X1.5) tire - 150 pounds in the case of a small woman, so I would think that's another reason for me to keep the tire pressure all the way up at max - keep from bottoming out the tire.

On motor vehicles, anyway, I believe the #1 cause of tire failure is low air pressure in the tires, even more so in hot weather, like you get here. And it's pretty much accepted that high air pressure in motor vehicle tires = better gas mileage.

werewolf

I've always run my bike tires at the recommended pressure, namely the max. pressure. I've never encountered bike tires before that recommend such a wide range of pressures as these Marathons, but then I've been away from bicycling for a long time. Maybe tire pressure recommendations have changed whiel I was away, or maybe it's because I never rode on small tires before.

jur

Tyre pressure is an area of myth and hype.

myths:

the sidewall value is the recommended pressure. Not so, that is the max beyond which the tyre cannot be guaranteed to resist failure. This value is dependant on the carcass strength, the density of weave. The correct pressure depends on a the mass the tyre has to bear - must be high enough not to bottom out. Connected with this there is sometimes quoted a maximum mass. For a very light rider, optimum pressure is lower, as the tyre still has to 'give' a bit to absorb road irregularities.

The higher, the better. Not so, Alex already mentioned this. Beyond a certain pressure (110psi for typical roads) rolling resistance actually goes up again, since the wheel is almost as hard as the rim itself which would have appalling rolling resistance (unless on steel tracks).

The amount of drag caused by the tyres is proportional to speed. So if you're exerting 80W, it is not 20W you lose, rather it is a percentage of your power, perhaps only a few, less than what you lose through the drive train, and certainly much less due to wind drag.

Raxel

Tire pressure seems to be a personal choice. I always pump up to the max. pressure because I am kinda heavy and want to go as fast as I can. My GF prefers 1.5 marathon @ 60psi as it is much more comfortable than stelvio @ 100psi. But marathon did not suit my taste, even @ 100psi. Now she rides a full suspensioned moulton with conti GP @ 120psi and is happy with it.

kraftwerk 

100 psi on my 451's Stelvio's. 80 psi, sometimes, when I am traveling in areas with broken glass.
I go as high as 110 psi for fast cruising

14R 

100psi front wheel, 90 on rear.

awetmore

Flats aren't a big problem for me, so I don't prioritize that when selecting my tires. That is a long way of saying "no" I guess. I haven't had a flat yet with my Greenspeed Scorcher tires and they have a much nicer ride than the Marathons.

There is very little in common between bicycle tires and car tires. On most bicycles the tire is being used for suspension, while all common road cars have suspension.

Fear&Trembling

My weight 89kgs.

Bike: Trek F600 (unsuspended) ISO 406 wheels

Stelvios: R: 105psi F: 95psi
Kojaks: R: 90psi F: 80psi
Scorchers: R: 85psi : F 80psi
Marathon Racers: As for Scorchers.

werewolf

I'd like to try those slick Scorcher tires, Awetmore. The Marathons are kind of noisy. I'd been away from bicycling for along time. I can hardly believe the prices they are getting for bike tires now, more than car tires used to cost - and car tires have, what, about 1,000 times the material in them! The Scorchers are near $40 a piece.

werewolf

What ever happened to those bicycle tire scrapers we used to mount to brush off debris from the tire? Have they gone extinct? They're particularly effective with slicks.

jur

They have been called of dubious value. I haven't seen those for sale anywhere.

mrbrown

65-75 psi on 20 x 1.5" Marathon Racers on my Dahon MU P24 (max 85 psi)

55-60 psi on 16 x 2.0" Big Apples on my Dahon Curve (max 75 psi). Too much and you lose the benefits of comfort from these tires.

90 psi on 26 x 1.25" Panaracer T-serv Messengers on my Hardrock (max 100 psi)

My LBS tells me not to hit the max, just keep it about 10% to 15% under.