voz

As the title says, what is the big difference between more narrow and wider tires? I am thinking of picking up a Specialized Secteur Elite with 700x30c tires. Are wider tires used in racing today? I am by no means a fast rider as I am just getting into the sport, but is it worth picking up skinnier tires?

Thanks,
voz

DrIsotope

All other things being equal, wider tires are more comfortable. A narrow tire basically trades that comfort in for better aerodynamics, and (generally speaking) more speed.

Worth running skinnier tires? I run the widest tires that will fit in the frame. Trust me-- 100 miles on 700x32 is a whole different experience than 100 miles on 700x25.

So it's up to you to determine how much comfort you're willing to sacrifice for speed, and vice versa.

noodle soup

+1

I've used both 25mm tires and 30mm tires(tubeless) on a Trek Domane. There isn't much difference in speed, but the comfort difference is huge.

On rough pavement. 30mm tires are much faster.

63rickert

Yes, wider tires are raced. For smooth roads most are on 25mm tires. But remember most racers are near weightless. On rough roads it's no longer one-size-fits-all. Heavier pros use up to 32mm at Roubaix. A heavy pro looks thin to most of us. Unless roads are nearly perfect wide tires at lower pressures are faster.

daoswald

Acceleration on flat terrain is inhibited by various manifestations of inertia. One form of inertia to overcome is rotational inertia. A wheel at rest requires energy to be spun up to a given speed. The amount of energy required is affected by the rotational mass. A skinnier tire will be lighter weight, all other things being equal. A lighter weight tire will have lower rotational inertia, and therefore will require less energy to accelerate.

On an upward incline, part of your power output goes toward overcoming gravity. If you are on a 10% grade, you are lifting yourself and your bike 10 feet for every 100 of travel, or 1 foot for every ten of travel. A lighter weight tire will reduce by a few grams the weight you have to lift against gravity. Doesn't matter much for 100 feet of 10% grade. Matters a little more for 1000 feet of 10% grade, and possibly even more for 10000 feet of 10% grade. In the case of 100 feet, you're lifting yourself and your bike ten feet. In the case of 10000 feet on a 10% grade, you're lifting your bike 1000 feet. Weight starts to matter.

At 25mph, aerodynamics matter a lot more than at 10mph. So if you find yourself on flat terrain or on descents, a skinnier tire will have less aerodynamic drag than a fat one.

But all of these factors pale in comparison to the weight of the rider, the aerodynamic drag of the rider, and the total rotational mass of the tires, tubes, AND wheelset. A few watts savings can be had going skinny. Not a lot.

On the other hand, at 100 PSI you will have lower rolling resistance with a 30mm tire than with a 23mm tire at the same pressure. But people extol the ride-quality virtues of wider tires, and those come into effect if you drop the pressure a little, in which case rolling resistance might increase a little.

But wait, there's more; a wider tire at a sane pressure will be less sensitive to the bumps and vibrations of the road, and may maintain better ability to roll with the punches. That can improve performance a little.

What does it all mean out on the road?

I've ridden 23, 25, 28, and 32mm tires. I currently have 28mm GP5000 on my road bike and 32mm GP4Season on my hybrid. I'm slower on my hybrid, but it's not because of the tires. It's because my riding position on the hybrid is more like a sail catching the wind. And because the hybrid is ten pounds heavier with rack. But even then, I often loan my hybrid to my brother so he can ride along with me when I take my road bike on rides in the 16-28 mile range. He keeps up with me just fine except on descents where it's the aerodynamics that give me an edge. On flat terrain I'm just a little faster, and on 10% inclines he's right there with me.

Look more at the tire's performance characteristics, and less at its width. 30mm is fine. I'm perfectly happy riding 32mm tires on the hybrid. What I hate on-road is tires that are knobby or have a tread that is not slick where it contacts the road under normal riding. That sound of buzzing tires with tread make?.... that's the sound of watts being stolen from you.

Carbonfiberboy 

I ride 23mm tires on 24mm (outside) deep alu rims because they look and are fast. I don't ride Texas chipseal, but ordinary is fine. I have no problem with getting tired from vibration. I think the right carbon frame and fork takes case of that. I'm still riding the model frame and fork on which Lance won his first TdF. 18.5 lbs. Not far off what a new carbon endurance frame with disks weighs and because of the greater frame weight, probably better damping. Anyway, works fine at least up to 400k, which have been my longest day rides.

Wildwood 

Wider is potentially softer IS generally true, but not always. Sidewalls matter a lot.

I ride tubulars, my Veloflex 28s are noticibly smoother (even on chipseal) than my Schwalbe 30s. Even reducing pressures a bit makes little difference. The Schwalbe makes a more suitable off-roadie. On reasonable roads I would even prefer my Veloflex 25 over the Schwalbe 30mm. Also fatter tires are generally heavier which I find a poor characteristic on hills and in mts.

edit: I would much rather ride a paved road century on my 25/28s.

noodle soup

Have you tried an endurance bike like a Domane with disc brakes? Mine is way under 18.5# with Di2, Hydraulic discs, and 32mm actual width Schwalbe G-One Speed tires.

Its as as fast as any bike I’ve owned (that list is long), and is far smoother than any of them.

If I were you, I’d demo a 2020 Domane for a few days. Low end ones will be heavier than your bike, but I doubt you’ll notice the weight on the road.

Carbonfiberboy 

I'm sure those are lovely bikes. The huge advantage of mine is that, except for consumables, it's essentially free and is set up better for me than would be possible with any new bike I could buy. And as you say, I doubt I'd notice a little weight either way out on the road.

noodle soup

If you never try a new endurance bike, you’ll never know what you’re missing, and always think your bike is good enough.

Carbonfiberboy 

Ah, you see my point! When I first rode this bike, I noticed that all I had to do was push on the pedals and keep shifting up and the bike just went faster and faster seemingly with no limit. I'll admit, I've never ridden anything like it. It's not endurance, it's full race. I descend faster than anyone, sorta my point in this thread. I know because no one ever passes me (70 kg).. It climbs well. As a geezer, my lowest gears (g.i.) go 23, 27, 31, 35. How 'bout that, 4 g.i. apart with a 128 g.i. top gear. See what I'm sayin'?

noodle soup

I totally see your point. If you remain ignorant to some changes/improvements that have been made, you might not ever feel the need to change.

BTW, please don't be offended by the use of the word "ignorant". It's the appropriate word for this particular situation, not a comment on you, or your character.

Rides4Beer

I'm still fairly new to cycling, but I'm finding that bigger tires are in fact faster for me. I'm 185lbs, and on average to crappy roads, comfort = speed. I can def go faster if the tires are soaking up the road instead of bouncing me all over the place. That's why I'm replacing my 23mm tires with 28mm (they'll measure out around 30mm).



I'm really liking the '20 Domane SL5 in Rage Red. I have no problems with my 22lb gravel bike on the road, so I'm sure a 20lb Domane would be fine.

noodle soup

On the Fuji? Let me know how this works out. A friend is thinking about using the same setup on his Transonic.

Rides4Beer

Yup! The 23's are aero optimized per the 105% rule, but after riding 28mm GP5Ks on my gravel bike (measure at 30mm on 20c rims) and realizing that I'd rather give up a touch of aero for comfort, I'm making the switch. Timing was good, my 23's are just about toast. I'll let you know how it goes, they should be here this week ($85/pair from Merlin w/race tubes).

Seattle Forrest

Mine is almost exactly 18, with hydraulic discs, Di2, and a power meter. In 58.

WhyFi

This is where I'm at, too. About the same size, about the same ****ty roads.

For me, it's not so much tire size that I'm after as it's a tire pressure target and the tire width is what gets me there. I can run my 30mm tires at 65-70psi - soaks up road imperfections and I feel *so* much better at the end of long rides.

At the same time, if I were light enough to run 25s in that region, without a greatly increased risk of bottoming out/pinch-flatting, I'd totally do it and not think twice. Along those lines, there's a lighter guy in my club (prolly sub-150) that's running 32s at 50psi or under. I think it's kinda silly. I can't imagine that much of a comfort gain at that weight and I don't think that I'd want the extra mass (rotating, even!) and frontal area for those (questionable) comfort gains.

Rides4Beer

I love riding my gravel bike on the 40mm tubeless gravel tires, there's more rolling resistance of course, but at 40/50psi, they just soak up every bump and crack. The 28mm GP5Ks strike a good balance for when I want to go faster. I'm betting the 32mm GP5Ks would prob still be just as fast and even more comfortable. I might try those on the road wheelset I have for the gravel bike, not sure my Fuji could clear those, I'll see how much room is left when I get the 28's on there.

WhyFi

Eeeeeh. I've got a gravel bike with tubeless 38mm tires at <40psi. For putzing around solo it's fine, but I've taken it on spirited group rides and it's undoubtedly more work. On the flats, they actually roll really well, but any climbing and/or acceleration? Ick.

Tying in to another thread, and telling you something that you probably won't like to hear - my Domane with 30mm tubeless is actually more comfy than my gravel bike with 38s. You should really go down to the shop and take a peek at one

diphthong

generally run 23's on the light bike because i'll ride up a big hill or two on occasion and every ounce seems to count.
i've run 25's on the same bike and haven't noticed a difference in ride smoothness/vibration dampening quality but
have noticed a difference in handling, acceleration from (complete or nearly so) stops and climbing longer (1+ miles) hills.
double wrapped the handlebars to deal with extra vibration and it works for me. if i know i'll definitely be doing
some serious dirt stretches, i'll rock 25's but my dirt adventures tend to be spur of the moment and i've done 23's where i shouldn't have.
rarely a flat in those conditions but my speed isn't the best.

Rides4Beer

LOL I'm trying to put it off, but I have a feeling my truck is going to drive itself to the Trek store.

shelbyfv

I believe I'm destined to win a new bike via the Trek Century Challenge on Strava. Probably pick the Domane, though my current bike is comfortable.

jfranci3

I'm using 30c Schwalbe G-One Speed tubeless (highly recommended) as my gravel bike -road tires. They are every bit as fast as my GP5k 25c/28c on my road bike. They probably give up 4-5w of aero to the 25c tires over 25mph, but not rolling resistance. I don't notice the difference on my group rides, and I've even set a PR on Strava on the 2 mile long segment I hit every ride. There's no difference in speed between a wide or narrow rear tire for the most part. As a counterpoint, my more road-oriented 35-42c gravel tires give up about 1mph generally and have a lot more aero drag. Any tire would be faster than the stock tires on that bike.

One problem with fat tires though, they do look silly on narrow rims. Those 30c tires look horrible on my 22mm wide road wheels and great on my 30mm wide wheels.

CliffordK

Whew, the last time I did 150 miles on 32mm tires, it just about killed me.

One thing that should be pointed out is that a quality low rolling resistance 32mm tire is probably close to the rolling resistance of the average 25mm tire.

However, take the commuter tires, touring tires, etc in the 32mm size, and they can be BEASTS.

DrIsotope

Oh-- for absolute clarity, I was indeed talking about like-for-like. My most recent "long ride" was 140 miles on 700x35s. But not Marathon Supremes, mind you, rather Pirelli Cinturato Velo tubeless-- running at a pillowy 60psi.

I looked through my history, and I have a grand total of three centuries on 700x25s. Everything else, 32 or wider. All but one tubeless, and all at least relatively fast-rolling.