Shimagnolo

I see "Measured Width 28 mm" in that review.

az_cyclist

I saw that too. I had another rider ask me if I was running 28's. At any rate they did feel like they had a softer ride than Conti 4000's. I may watch for Conti 4000s to go on sale in 700x28mm, and compare to the Michelin Pro4 Endurance 25mm

dbg

Fewer flats. Nobody mentioned fewer flats with lower tire pressure.
So: Much more comfort, similar resistance (w/supple casing at my low speeds), and fewer flats == big win for my riding preferences.

Camilo

I've read this before, but don't really understand what it means - and how would you measure it? Is there some way to measure it when you look at the contact patch on the road or, say, the part of the tire that is clean after wearing off the dirt from a dirty tire?

I can see a ~1+ mph increase in speed when going from chip to smooth pavement. I can feel it too.

Not a PR4 Endurance, but my 23 mm Michelin PR4 Service Course measure a little narrower than a comparable Continental Grand Prix 4000s. The PR4's measure about 23-24 on my Velocity A23 rims vs a healthy 25 for the GPs. For some reason i still like the PR4s better in general.

peterws

Now then. What do the racers use? Tour de France er al. Distance stuff, not all silky smooth roads.
Betcha they ride skinny, and the pressures will be bloody high. A tyre that absorbes bumps absorbs energy.
I had a mountain bike for years with road tyres, 1.5 X 26, was it? Was glad to get rid o` the 1.75 knobblies and put on slicks. It was a hard ride, but faster. Pumped up to about 60psi. Many punctures; many walks home.
Along came the road bike wi 700 X 25 fitted, and the requisite pressure (as much as I can comfortably put in with a hand pump) and they were more comfortable. No puncture in 6 years riding over some country roads until I got a Gator fitted (back) and hit a pothole . . . I rode it home.
Wouldn`t fancy underinflated road tyres, No siree . . . . They`d pick up everything!

Shimagnolo

A tire that is shaking the rider, is stealing energy from the crank to do the shaking.

Scroll down past the aero stuff, and begin reading at Part 4A: https://silca.cc/blogs/journal

wphamilton

Or to be specific, the 28C at 80 psi had the same resistance as the 25C at 100 psi or the 23C at 120 psi. (within 0.2 watts)

Miele Man

I remember when Avocet first came out with their narrow slick tires. Pete Penseyres did a test of them by riding his bicycle up a hill in the rain and staying on the painted fog line. Pete stated that he could NOT get the rear tire to break traction. I guess the rubber compound makes a difference as to whether a tire will slip on painted road markings or not.

Cheers

rm -rf

A quick google search, tour de france tire size pressure indicates that 25c tires are common, and pressures around 7 to 8 bar, 102 to 116, are typical. (For those lightweight riders, that's quite high pressure for a 25c. For local group type rides, a lightweight rider could easily have 85-90 front, and 100 rear.)

Examples:
From 2014
From 2016


It takes energy to flex the tire, but it also takes energy to jiggle and bounce the rider from the vibrations. That's the theory of letting the tire absorb the chip-seal rough roads. And the thin sidewalls on fast tires can flex without using much energy.

Carbonfiberboy 

Those are very interesting links to pro race equipment. One thing to point out there, from the standpoint of "are wider tires faster" is that wider rims are faster in typical race conditions with quartering winds. Fast carbon rims are now 25mm and wider so they can get a better wing section and reduce aero resistance. So they have to run wider tubulars to go with the wider rims. I doubt it has anything to do with tire width per se. Tires have to be perfectly fit to the rim to get the aero advantage from the rim. There's a good discussion of all this here:
THE RIGHT TYRE WIDTH ON THE RIGHT RIM WIDTH - Engineerstalk : Engineerstalk

The tire pressures in the first link do not refer to specific tire widths. For TTs, where comfort is not an issue, they run as much pressure as they dare in their tubbies - because it's faster. I mean 15 bar on a road stage? for a TDF rider? what could he have weighed, 180?

khutch

I hear that the pros have been going to wider tires lately, especially on the cobbles. That is interesting although they don't ride tires anywhere as wide as I do. I'm on my second set of 38 mm Vittoria Voyager Hypers (but they were called Randonneur Hypers when I bought the first set). At the speeds the pros ride they would be death by aerodynamic drag but they are fine under 20 mph and they roll very efficiently. Yes, the wider tire does absorb bumps very well if you drop the pressure a bit to keep your speed up on rough roads and you have a lot of control over that too because if you max out the pressure you can fly on smooth roads. RAGBRAI is the high point of my cycling year and with mile after mile of road cracks and other hazards to deal with there isn't a day that goes by that I am not glad that I was on 38's. There has been an optional gravel loop the last two years, need I say more? If you are racing then a 28 might be as wide as you could consider but for me those are the bare minimum!

Cyclist0084

I currently ride with 28mm but am definitely considering going to a 32mm with some kind of tread next spring. After a couple of wipe outs just within the last couple of weeks on wet surfaces, I definitely need something with a little more traction and comfort as well.

Mr IGH

I don't know if they're faster but I haven't found they're any slower. On long rides, I find the comfort of wider tyres saves energy and makes me faster at the end of the ride compared to tooth rattling skinny tyres....

Shimagnolo

Traction on hard surfaced wet roads is more about rubber composition than anything else.
Tires intended to optimize long wear use a harder rubber, with the downside of poor wet traction.
Tires intended to optimize traction use a softer rubber, with the downside of shorter tire life.

On wet roads I've found Schwalbe One and Schwalbe Marathon Supremes to be excellent;
As opposed to Gatorskins that break loose w/o warning.

1989Pre 

Speed is not the only desireable factor in tire size selection. Handling is an important factor, to me, anyway. Anything over 24mm just feels bulky and unresponsive to me.

FamilyMan007

I can certainly appreciate that at some stage installing wider tires on narrow rims will worsen handling (especially if pressures are reduced).

Is it possible that that handling reflects more than tire width, as it is not clear to me why a wider tire on a wider rim should handle markedly worse than a narrower tire on a narrower rim

I find it a challenge to sort everything out - but my impression is that for any given bike/rider, there is an interplay between several factors, including;
~ rim width
~ tire width (actual on specific rim, not what manufacturer states)
~ tire pressure
~ tire construction

So much to learn - what tire widths should 'N+1' Road bike accommodate in 2017 ? (sounds like a 1st world problem, eh)

Cyclist0084

That's good information to know. Will look for something with softer rubber when the time comes.

Thanks, I appreciate it!!

OldsCOOL

We may be the only ones that understand and believe it. I wont have 25's because they are heavier and I can feel it. In a hillclimb or sprint (horizontal hills) you can tell right away.

rydabent

The simple laws of physics cannot be set aside. Narrow rock hard tires cause the bike to raise up. That vertical motions sops energy, and makes the bike slower period!!!!

That is why way back when pneumatic tires were invented and replaced the hard rubber strips on bike wheels, bikes suddenly became faster. Hard to argue against this. If narrow rock hard tires were faster, racers would be using hard rubber strips on their wheels instead of inflatable tires.

1989Pre 

The basic laws of physics, in this case, adhesion, provide us with the knowledge that when surface contact area is increased, adhesion increases. This means that 25's (and certainly anything above) are harder to propel or turn than 23's, unless the compound is harder. I do not want this on a long ride.
Many times, the nibility of the 23's have allowed me to surgically manouver past, there-by preventing me from hitting, small objects (or recesses or bumps) in the road. 25's (and above) provide added comfort. I can appreciate this.
I am not looking for "comfort" on a training ride, and anyway, my road bike is perfectly comfortable, even without padded bar tape.
There is a reason that we, as kids, eventually left our Sunbeam and Firestone cruisers in the garage and bought Raleigh Sprites or Schwinn Varsities.., and it wasn't just the number of gears.

John_V 

25c is my preference. I don't really care much about gaining a quarter of a second in speed with narrower tires. All I know is that they are more comfortable to ride than a 23c and my bike won't take a 28c. I do know that I am noticing more and more new bikes being shipped with 25c tires than 23c tires, including tri-bikes.

Cougrrcj

My 'Arizona bike' - the one I keep in AZ to ride when I visit - came to me with 22mm front and a (flat) 25mm rear. I had a problem with the little riding that I did out there last visit because the pavement is rough. The asphalt binder just 'goes away' in the desert summer heat, leaving an exposed aggregate pebble surface - at least on US60 from Apache Junction to Florence Juntion (AZ 79). That high pressure 22mm front tire beat the crap out of me. I had changed out the rear 25 for a heavy Vittoria Randonneur II 28mm, but am reconsidering. I'm going back out to AZ this next week, and bring two sets of new tires -- Vittoria Rubino Pro Tech III in both 25 and 28mm widths. We shall see...

FamilyMan007

I am impressed you are that sensitive. Wonder how much more cycling I need to do to reach such a level?

I am pretty sure I could not tell the difference (I understand about 20 grams each wheel - say 40 grams in total - for Continental 4000Sii).

Although I confess that when I switched from Grand Prix to the 4000Sii I am pretty convinced I liked riding on the latter more than the former - but never did conduct a 'blind test' to try to determine whether this was anything more than the 'placebo' effect!

Like I said - fascinating 1st world challenges.

DrIsotope

Too bad none of that is true in regards to our application. From the Velonews CRR tests a few years back:

"Tire rolling resistance on the road is caused by (1) internal friction and hysteresis (deformation over time) within the tire’s materials, and (2) on rough roads, small bumps lifting the bike and rider slightly (uphill) on each little impact.

By definition, wider tires will have shorter contact patches and, hence, less tire deflection; if the tire pressure is the same, the area of the contact patch must be the same to support the same load. The shorter the contact patch, the lower the vertical depth of tire deflection; the internal friction and hysteresis within the tire’s materials is lower.

If a wider tire is made of the same materials in the same thickness as a narrower one, it will roll faster, because (1) the internal friction and hysteresis within the tire’s materials will be lower, and (2) because the surface imperfections in the road will be absorbed into the tire more easily (since it has more deflection available), thus lifting the bike and rider slightly less with each little impact."

A wider, heavier (even much heavier) tire would be slower only for the amount of time between standing still and cruising speed. Then, the wider tire would maintain a higher speed for the same wattage output compared to a narrower tire.

My personal favorite from this whole thread is feeling the difference in weight between 23s and 25s. That is simply remarkable BF-ness. Almost unparalleled. The weight difference between a typical 23 and 25 tire... about 20 grams.

OldsCOOL

Nice sarcasm.