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23s come on almost all new road bikes, and tire selection is much better for 23s than other tire sizes at most shops.

The benefits of 25s and 28s are a better ride, more traction, and are more flat resistance than 23s. How noticeable is the difference in rolling resistance (in fact, some people claim that running slightly lower pressures allows for better rolling resistance on most 'real-world' surfaces)?

Are narrow tires only for time trials racers, or do they have advantages for the other 99% of riders?

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8 Answers 8

Weight. The less weight on the wheels the better. Same for rolling resistance.

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Yeah, the narrower tires weigh less and have very slightly less rolling resistance. They also create less air drag.

But you're right that there is a tendency to put the narrower tires on "road" bikes, even if they're clearly not "competition" class. I suspect that this is because, like several other aspects of a bike, the narrow tires are simply perceived (by most) as "better" and perhaps "sexier", and so they look better on the show room floor.

(And note that a cheap bike is apt to have 23mm tires rated at 85psi -- lower than optimal for many situations, while a better bike might have 27mm tires rated at 105psi. I run my 35mm tires at 100psi.)

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I just did a quick search and didn't see any 35mm tires rated above 85psi. Do you have special rims and special tires to let you ride such a wide tire at such high pressure? –  amcnabb Jul 26 '12 at 23:42
    
@amcnabb -- Well, I think mine (Performance) are technically rated at 90. My old Schwalbes, though, were rated at 105, IIRC. –  Daniel R Hicks Jul 27 '12 at 0:03

Because road bikes are meant for going fast. And a 23 mm tire is faster than a 28. Sure, it's not enough to make a noticeable difference for 99% of all the people who buy those bikes... but those people all think they're in the 1%.

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You mean I'm not? ;-) –  Wayne Johnston Dec 6 '11 at 2:38
    
Everyone thinks they're in the 1%. –  Daniel R Hicks Dec 16 '11 at 11:43

Narrower tyres support higher pressures for similar constructions and, basically, higher pressures equate to higher speeds. While a wider tyre, inflated to the same pressure would present a lower rolling resistance (thorough a smaller contact patch), as Sheldon Brown points out, this different effect of two similar tyres which differ only through width is entirely the point of why they differ.

For most conditions you get a more comfortable ride on wider tyres with slightly lower pressures, but to get to that point you trade-off speed.

Higher pressures also give you some inherent puncture protection - a well maintained tyre under higher pressure will repel potential sharps more effectively than a similarly constructed tyre under lower pressure.

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Actually, a wider tire, inflated to the same pressure, would have exactly the same contact spot size (if you ignore the softness of the rubber). –  Daniel R Hicks Dec 5 '11 at 12:14
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"higher pressures equate to higher speeds."This is a contentious issue. Some people claim that on real-world surfaces this is not true, as lower pressures allow the tire to better conform to cracks and bumps. –  limscoder Dec 8 '11 at 5:12
    
The puncture resistance of a tire is related to the total amount of air volume, not the pressure, which is why you can run lower pressures in a wider tire, and have the same puncture resistance as running high pressure in a narrow tire. –  limscoder Dec 8 '11 at 5:15

Because of a blown out tire, I put this question through a real world test over the last week. I typically commute on my mountain bike but switched to my road bike maybe 3 or 4 weeks ago just for fun. I hadn't ridden it for at least a year and therefore was paying very close attention to the speed; it was about 25% faster than on my mountain bike ... this of course has nothing yet to do with the question except to attempt to lend some credence to my questionable powers of observation concerning the very subjective information coming up.

The tires on my road bike were 700x25's and I kept them at just over 100psi. The back tire blew out last Friday. So I bought new 700x28's (Continental Gatorskins if that matters) over the weekend. I filled them at just over 100psi and re-calibrated my speedometer for the very slightly longer rolling distance.

And they are slower. This is of course the promised subjective information. But because I was paying such close attention to my speeds on a regular basis on my very flat commute, I think I have a good handle on the relative speeds. With the 700x25's I was regularly traveling at 15.5mph to 16mph. With these new tires my speeds are regularly 14.5 to 15mph.

The "test" is not entirely "apples-to-apples". While both old and new tires have equivalent rolling surfaces, the new tires are heavier than the old paper-thin 700x25's (even heavier I'm sure than would be the case between the same brand tire of different size).

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Yes, a big part of "rolling resistance" is the energy lost to heat in the tire rubber as it flexes. For this reason tire with a thinner wall will generally be more efficient. The type of rubber also makes a difference. I know from my days of testing rubbers for the Air Force that there's about a 4x difference in "lossiness" between different types of common rubbers, varying with other properties of the rubber such as traction and wear resistance. –  Daniel R Hicks Dec 16 '11 at 16:08
    
@DanielRHicks: That makes sense and had not thought about that aspect. And it would definitely apply in this case. Those old tires were seriously thin. The new ones I suspect will stand up well to goatheads, which are a serious menace here. –  Mark Wilkins Dec 16 '11 at 16:15

WIDER TYRES ARE FASTER

Every study on rolling resistance (including ones carried out by the leading tyre manufacturers) demonstrates clearly that wider tyres have LOWER rolling resistance and not just at the same pressure. This is also verified by many people (including myself) who use 25mm-28mm and much wider tyres on a regular basis and will never go back to anything narrower.

For vast majority of road cyclists there isn't a single rational reason (other than time trailing) for using 23mm tyres if the same model is available in 25 or 28 or wider width. On some bad roads (e.g. UK) it's actually unwise and dangerous to bounce around on such narrow piece of rubber.

There are several reasons why the myth of "fast" narrow tyres is still alive and kicking.

  1. 23mm is everywhere from the adverts, your local bike shop, cycling club to the TdF. It's inconceivable for most of people to think that so many people around them could get it so wrong. Most of folks just go with the flow and don't ask questions.

  2. People believe that they can "feel" rolling resistance and if narrow tyres are pumped up to its usual 100-120PSI it feels fast. You can't feel rolling resistance but you have to methodologically measure it with a power meter of some sort. Firmness and discomfort doesn't translate to speed, quite the opposite.

  3. It's a common belief that rolling resistance is just a function of a contact patch and the lower the contact area the faster the tyre is. The facts are that the shape of a contact patch and volume are more important than the total area.

  4. People assume that rolling resistance is just about hysteresis (friction/resistance with the tyre itself) and nothing else. They are unaware of (or ignore) "suspension losses" which occur on some less than perfectly smooth roads (most) and are about energy lost on lifting the rider/bike on imperfections of the surface. For the same reason but on a much larger scale most of experienced mountain bikers with half brain run their tyres at a low pressure to go faster as even small obstacles (even bumpy field or gravel) are absorbed more effectively with less energy lost.

  5. People confuse assumptions and beliefs with hard evidence. How many times you've read/heard: "Surely there is a reason why 23mm tyres are so popular..." "Surely if the pros use 23mm tyres..." Assumptions don't prove anything.

  6. Some people (like one of the posters) have tried wider tyres and they found them slower. Only comparing identical tyres in different sizes make sense and it's pretty obvious that a 23mm Michelin Pro3 is going to be faster than a 28mm Gatorskin due to a different design. Also the difference in speed that 2-3mm difference offers is most likely very small and can be only measured during repeated tests with a power meter at various pressure levels to find each tyre's sweat spot.

  7. Many people have never tried anything wider as their frames/forks don't have enough clearance and more sensible and practical bikes taking wider tyres aren't "good/fast" enough for them or don't look right. They've never tried any fast wider tyres like Rivendell Jack Browns 33.3333mm or Schwalbe Kojaks 35mm or some fast 650B tyres. They have never run a pair of custom shaven completely bold 26x2.00 Schwalbe Furious Fred 120TPI 3oog mountain bike tyres on the road. It could be an eye opener.

  8. Narrow tyres can be pumped up to higher pressures and higher pressure equals more speed. That's incorrect. As you increase the pressure, rolling resistance is going down but then at a certain point starts climbing sharply due to reduced ability of the tyre to conform to the non-perfect road surface (suspension losses). Even on a track/velodrome you won't benefit from 200PSI.
    For every tyre width/volume, road surface and the rider's weight combination there is always an optimal (fastest) pressure. High pressure on its own means absolutely nothing.

  9. The pros use it! This the favourite argument of the defenders of status quo. You can't argue with it, can you?

Well... the pros ride at completely different speeds and therefore the aero benefits are probably more significant than rolling resistance. An average amateur rider would be naive to worry about the air flow differences between 23-28mm tyres. Weight is also crucial as winning the stage / future career can be decided on a single climb. Again people worrying about the weight difference of several grams (rotating or not) may be slightly over-anxious.

The pros used to use 19mm tyres too in the past and now they are very slowly migrating to 25mm tyres. Were they wrong at the time, or are they wrong now or they will be wrong in the future? What if they discover that 28mm is even better? Will everyone be blindly following them? The truth is that they are as guilty as you and me of being humans and use stuff that feels right and also aren't immune to peer pressure.

Road cycling community tends to be very traditional, conservative and protective of the status quo as I've experienced on other forums and in real life but for being open-minded and embracing "new" things can greatly benefit one's cycling.

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You have some very interesting thoughts here, but unfortunately the tone seems unnecessarily confrontational. It would also be helpful to have references for any specific studies that show that wider tires have lower rolling resistance, so it's not just one person's word against another's. –  amcnabb Jul 26 '12 at 22:00
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I tend to agree on the point of suspension loss affecting rolling resistance, leading to slower speeds. It does depend on the type of riding you do. Skinny 23mm tires are ideal on smooth pavement. If you hit rough pavement, cobbles, tar and chip, all of which I ride over every day, then you may be better served with 25mm-28mm tires. If you hit trails, gravel, or dirt, you'll want to go bigger yet, maybe 28mm - 35mm. It's partially to use the extra air volume to absorb shock, increase traction, prevent sinking in loose terrain, and avoid slowdown due to impact of small road imperfections. –  Benzo Jul 26 '12 at 23:27
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You might find the Rivendell Reader review of Surley's Pugsley interesting. After Grant made it up his benchmark climb in under 8 minutes on the Pugsley he says "I don't get it - The 15.9lb wheels alone weigh more than some whole bikes." and notes that he "feels slower" on it but is as fast climbing on the heavy fat-tired Pugsley as on his lighter narrower-tired bikes. –  Mike Samuel Jul 30 '12 at 19:01
    
On my bike, the advantage is that 23mm tires fit between the brake pads (even with the brake quick release opened all the way), while when I tried 25's, I had to let the air out of the tires get the wheels on and off. Not a big deal if you only take your wheels off to fix a flat, but when you have to take the front wheel off to put it on the bike rack, it quickly gets annoying. Granted, I only tried one brand (Michelin) of 25mm tires, so maybe another brand would be less wide and would fit better. –  Johnny Oct 25 '13 at 21:39
    
I miss my old racer. 11mm front tire and 17mm rear tire on Mg alloy rims. Admittedly they weren't very strong - I shattered two wheels in 18 months, but it was a fast bike, and still the lightest I have ever owned. –  Rory Alsop Oct 28 '13 at 16:16

Tire width (and tire pressure) are controversial because it is extremely difficult to find meaningful data and because there are so many variables involved. Variables include both rider preferences, such as speed, comfort, price, and durability, as well as physical factors, such as tire width, weight, types of rubber, casings, road surfaces, etc.

The issues that everyone agrees on are that narrower tires have less weight, less aerodynamic drag, and less comfort than wider tires. Weight includes both the tire itself (about 100 g per tire to switch from 23mm to 28mm) and the larger tube to go with it (about 25 g per tube). That gives a total of about 250 g, which for acceleration is equivalent to about 500 g on the frame. Drag is harder to quantify, but a thinner tire is more aerodynamic than a wider tire. Comfort is also hard to quantify, but a wider tire and lower pressure are generally more comfortable.

Rolling resistance is a contentious issue. Lennard Zinn wrote two columns about rolling resistance: Seriously, wider tires have lower rolling resistance than their narrower brethren and Again, bigger tires roll faster, citing data and comments from Schwalbe, Wheel Energy, and Zipp. Critics such as Lloyd Chambers (in Are Wider Road Bike Tires Faster) have noted that such comparisons assume that tires assume equal tire pressure for tires of different widths, ignore aerodynamics and handling, and assume unrealistically low loads (50 kg). It seems that wider tires probably have lower rolling resistance, but this position does not seem to have been thoroughly proven yet.

Whatever the theoretical ideal, there are a few critical issues that make wide tires less practical for many cyclists. First, most road bikes are designed for 23mm tires and may not have clearance for 27mm or wider tires. Second, most road tires sold are 23mm, and wider tires may be hard to find and more expensive. Third, most wide tires are designed for utility bike use and are heavier and less supple than racing tires. Fourth, wide tires may be less stable on rims designed for narrow tires (according to Zipp).

There are some indications that wider tires that are specifically designed for speed may have lower rolling resistance than thinner tires, but this is just one of many important factors that cyclists must consider.

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+1 for the links. Good reads. –  Chef Flambe Jul 27 '12 at 22:33

I think because 23mm tires typically have higher pressures and a larger contact area with the pavement, reaching high speed is easy but maintaining speed is hard.

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