dmanthree

The rolling resistance site has tested the same tire, a GP 5000, at a variety of pressures. As usual, larger tires roll easier at higher pressures, but not by much. What was interesting to me was the result at the so-called "recommended" pressure, where the results were nearly equal. Take it with a grain of salt, of course, but still worth a look.

https://www.bicyclerollingresistance...000-comparison

Psimet2001 

Derp.

Hopefully this starts the new trend back to where we came from - which is where we got to after coming back from going wide way back when.

As a whole cyclists really are a collection of over-educated idiots (myself included).

A lot of this is why I stopped buying into the specifics surrounding trends a long time ago. I've lost track of the number of times someone has asked, "Deeper is more aero, right?" "Many times, yes but not necessarily." "Wider has lower rolling resistance right?" "Then why aren't you out riding on fatbike tires? Wider isn't always better. Get what's right for the way you ride."

dmanthree

I've found that 700x25 works best for me. Go figure.

TimothyH

Rolling resistance is way down on the list of important attributes for a tire but seems to be all anyone talks or cares about.

asgelle

Don’t assume everyone has the same priorities you do. Riding tires with 0.005 higher Crr is like always riding a 0.5% steeper road than the one you’re on. For me that’s important. I don’t expect everyone to feel that way.

Anyway there are are plenty of threads on wear and flat resistance if that’s what you care about.

dmanthree

When I choose tires, I take all things into consideration and find a balance between RR, durability, handling, and ride quality. Also, the time of the year plays a part in my decision. For example, in the fall the early spring I choose a tire, the GP 4 Season, that's a lot more durable because I don't want to change tubes when it's cold, dark, etc. But RR *is* a factor.

Marcus_Ti

In case you're curious, I know I was....per BRR's own data, in order to find a difference of 0.005 higher Crr to compare; you'd be looking at the 1st place infamous graphene'd Vittoria Corsa (that lost a certain famous Kristoff his Paris-Roubaix chances due to flats) that retails for $80-100 each online....with the 66th place Schwalbe Lugano, a tire that is a cheapo $20USD tire ....and even that comparison doesn't have 0.005Crr delta across all pressures, only at 60PSI.


IOW.....Crr differences are mountains out of molehills.

DrIsotope

In my experience, there are tires like the Conti Gator Hardshell, and there's everything else. Spend some time on a Gator anything, and you will be happy with any tire in the future.

My considerations in order of importance: puncture resistance -> longevity -> rolling resistance

I used to think cost was one of my main sticking points, but I've been on tires of ~50 bucks each for several years now.

I also 100% agree that people put waaaaaayyyy too much emphasis on Crr... or not enough. I still routinely see $10k superbikes on Hardshells.

RChung

That was just an example to convert Crr into something recognizable. Differences in Crr between two tires scale exactly like differences in slope: it doesn't just apply at .005. The difference between a Conti 5000 and a Conti Gatorskin at 100psi is about .003, so riding the Gatorskin is like climbing a slope steeper by .003 (or 0.3%). That's always and everywhere, so when you're coasting downhill, the road appears "less steep" to the Gatorskin by 0.3%. I've known guys who used Gatorskins on the bike leg of triathlons.

Over a 25 mile ride, riding the Gatorskin is like climbing an additional 400 foot hill compared to the Conti 5000. Over a 60 mile ride, that's a 1000 foot hill. The bike leg of an Ironman is 112 miles. That's an 1800 foot hill. Maybe that's a molehill to you.

In Paris-Roubaix, Kristoff wanted to ride the same tires that got him such good results the previous week in the Ronde. Kristoff used them *against advice*. Paris-Roubaix cobbles are *not* like the cobbles in the Ronde, and the lesson is that you should not ignore good advice. The tire *width* he used successfully for the Ronde was the wrong tire width for P-R.

Sy Reene

If I had a wish, it would be that BRR somehow could figure out how to test 'grip' (wet vs dry at least). I would imagine that this somehow measurable dimension could have some correlative relationship to your more subjective 'handling' and/or 'ride quality'. Puncture resistance and rolling resistance of course aren't everything.

dmanthree

BRR is only a single data point, so I try to gather more info from user reviews on Youtube, etc. Honestly, most modern high-quality bike tires are very good, so the differences are pretty minimal. And I have brands I trust. For example, I bought the new GP 5000 without reading much about it. They're excellent. Not sure about durability yet, but so far so good.

Sy Reene

My concern, though currently unsupported, is that since BRR has become a well-known go-to review site, that the bike tire makers' marketing depts are aware of this, and will start getting their engineers to focus on designing tires to ace BRR's tests. I don't know what sacrifices to the currently non-tested qualities that this approach could lead to.

jackb

How many watts difference are necessary before a cyclist can actually feel the difference in rolling resistance? I can't even feel the difference between the rolling resistance between the 42mm tires on my touring bike and my 32mm tires on my endurance.

Sy Reene

I don't know you'd 'feel' a difference.. you'd just go slower for the same effort. So, maybe a bit less wind in your hair would be felt.

colnago62

I ride Gatorskins during the winter. They sand the crap out of the roads around here and it mixes with other debris. Flat city.

Marcus_Ti

...and the difference would probably be within the margin of error of an average and really good wheel-rollout calibration on your speedometer.

Sy Reene

maybe.. I left out all sorts of qualifiers for the OP.. I imagine he has weight differences between the 2 bikes he referenced, and I imagine the 2 tire sets he runs are probably not the same make and/or model. So unclear what he means by 'feeling' a difference in rolling resistance. Those 2 bikes being ridden should feel a good amount different otherwise.

TimothyH

I care little about wear and while flat resistance is important it isn't a huge concern where I ride.

Grip, forgivness, nervousness near the limit, suppleness - these are all subjective, impossible to measure but arguably more important than rolling resistance. Weight, for some of us who are not powerful riders, is just as important as rolling resistance.

As an example, Vittoria Rubino G+ Speed are extremely supple, have huge amounts of grip and are very forgiving when mistakes are made while cornering hard. They also weigh only 206 grams each and wear out in 1200 miles. I think they are a better tire than the much lauded Corsa G+ which is 20% heavier and quite nervous near the limit.

Anyone can make a tire with very little rolling resistance but no one wants to ride a tire with little grip, is unpredictable in turns and accelerates like like a piece of granite. It is difficult to make tire with low rolling resitance which is also forgiving, grippy and light. They exist but are expensive.


-Tim-

Marcus_Ti

As it turns out there's much scientific writing on this topic...in part because of activities like drag-racing, where tire-slip and tractional friction are real problems with massive implications for acceleration and therefore winning.

https://www.mathworks.com/help/physm...meterized.html

https://www.quora.com/Vehicle-Dynami...w-does-it-work

The problem for bicycles in modeling/comparing....I'd wager...is that road surfaces vary tremendously in friction even in bone-dry contexts, probably so much so that the road-variance overcomes any difference in what a slick bicycle-tire does. For example, smooth UCI-ProTour fresh laid black-top, versus Ye Olde rocky pavement in a parking lot. You can especially see this on ProTour racing where people crash from simply riding over painted-lines on the pavement--the variances in traction supplied from the road is enough to cause the tires to slip and the rider crash.

Which raises the other problem. There's what tires-on-drums in a lab tell you (great for controlling/isolating a million variables), then there's what people actually being subjected to forces IRL tell you....then there's placebo/nocebo effect.

Sure a 23mm slick may have a similar or lower rolling resistance (and lets not forget aerodynamic properties) than a 30mm or 40mm at any given similar/different pressure on any given control-wheel....but after a 60mi day on "normal" roads (read IRL roads that are cracked and pothole-ridden and rough), while the 30mm or 40mm may score lower in any given metric on the rollers in a lab when inflated to proper pressure the rider will probably be less fatigued/sore. The same can probably be said for tire TPI and construction.


Which all leads to lots of words words words:

https://janheine.wordpress.com/2018/...es-are-slower/

Seattle Forrest

My guess is the number of cyclists who know what rolling resistance is, is too small to justify the expenses of engineering tires to their test. But who knows?

79pmooney

I like that Vittoria seems to not have paid much attention to the site. The wonderful G+ tires are well down the BRR list but in my book rate very high as a tire overall. Best ride (cornering, ability to climb out of cracks and ruts, good on flats and wear well; in other worlds the big picture for a road tire) of any tire I've ridden. (Well except for the properly aged handmade silk tires I got to race decades ago. But those tires didn't like water.)

And to Psimet2001's comments on tire "knowledge" - I get a kick out of the idea that tire inflation should be so tire deflections are equal; in other words reflecting the say 40%-60% weight balance on the wheels. The "rule" 40 years ago was front tire had 5-8 psi less than the rear; far closer to equal than any weight balance or deflection scheme. I still go with the old rule. It works. (So does the thumb and finger pinch when no gauge is around.)

Ben

Seattle Forrest

It's definitely something to be aware of. But for context a 0.3% grade is a false flat.

RChung

There's a lot of variation across individuals but, mostly, human beings are pretty much perceptual dullards. Whether something is perceptible to human senses isn't always a good standard. It depends on what your goals are.

That said, most riders I know can easily "feel" the difference between a Conti 4000 and a Conti Gatorskin on the same bike.

RChung

That's kinda appropriate. The one time I used Gatorskins I kept looking down to see if I had a flat. It was a false flat.

noodle soup