On Tyre Width: Sensations and Social Representations
There is a branch of psychology, nearer to its border with philosophy than with science, which deals with a concept called Social Representations. It is an intriguing field of study, with the central premise that an individual’s perception of reality is shaped inasmuch by cultural narratives as it is by direct physiological perceptions. And further, that physical sensations are, in of themselves, shaped by cultural narratives to begin with.
In the cycling world, trends in tyre width offer an almost too perfect real-life scenario to see this phenomenon at play.
Over the past few years there has been a distinct shift in the popular narrative regarding what tyre width is optimal. I am sure I can’t be alone in remembering that as recently as 5 years ago, 23mm was considered the standard width for road use, and 21mm were not uncommon. When I moved to Ireland, some cyclists were even riding 19mm. The 25mm tyres on my roadbike were seen as exotically wide. And slow!
“You are making things harder on yourself with those big fat tyres,” I was told by People Who Knew, by People With Experience. This was followed by convincing technical explanations as to why narrow tyres roll faster.
Which is all well and good. People are entitled to their opinions. Except…
A couple of days ago, I bumped into one of those people again. I don’t think he remembered our earlier tyre debate; it had been a while. As bike people do, he examined my bike. When his gaze fell on the tyres he gave them a critical look: “You’d do better with 28s sure!” As I listened in stunned and not undelighted silence, he then proceeded to explain why wider tyres run at lower pressures roll faster, referencing road.cc, which in turn had referenced “that clever German fella in Seattle.”
“But sure you'll feel it yourself!” he added, encouraging me to give wider tyres a try as we waved good-bye.
So what exactly is it that we feel as we ride tyres of different widths and form impressions of speed and comfort? If the same people who were convinced they felt fastest on 21mm tyres a few years ago are now convinced they feel fastest on 25mm tyres, there must be some degree of external influence involved. To what extent are these physical sensations shaped by the current popular narratives - by the latest arguments in cycling magazines and forums, by the opinions of club-mates and bike shop staff, by what "the pros" ride?
I am no stranger to a 28mm tyre on a road bike. Or to a 32mm tyre. Or 42mm for that matter. And like everyone else, I sense - or think I sense - the so-called sweet spot. For road use, that sweet spot hovers at 25mm. Too wide by 2010 standards and too narrow by 2016 standards, it stubbornly persists in feeling “best,” to me. I cannot justify that feeling with a scientific explanation of rolling resistance. All I can say is 28mm+ feels clumsy and sub-23mm feels precarious, whereas 25mm feels like all is right with the world.
For mixed terrain, in the 650B size, I thought that I had settled on 42mm. Then recently I rode a pair of 38mms for a bit, when testing a batch of tyres a manufacturer had sent. When I switched back to my original tyres I was surprised to find that I missed the slightly narrower width. In what way the 38mm felt better, I cannot exactly say. But I am open to re-examining my preferences.
How do you know what tyre width feels optimal? And has this changed for you over the years?
A human's perception of what anything 'feels' like is created by the central nervous system. That creation, or output, of the brain is shaped not only by sensory signals coming from the body but by thoughts, emotions, memories, cultural expectations, cognitions, arousal level, personal expectations and any number of other factors. Frequently, what someone 'feels' and what is objective reality are two different things.
ReplyDeleteWith that said, what is it that matters to us most while we are riding? Objective reality or how we 'feel'? We ride because of how we feel. If something feels right, use it. If it stops feeling right and something else feels better, use that.
I've been riding on tires at least 35mm wide for too long so anything narrower just doesn't feel right to me. In fact, from a practical reason, anything narrower than 32mm is simply unusable as most of the time I end up on rougher, unpaved roads. I don't know yet what my optimal tire width is, but it must be somewhere between 35 and 60mm.
ReplyDeleteThe trend towards wider tires on road bikes is great as it's simply giving us more choice.
My most narrow tires are 28mm on my Surly Cross Check. I'm older and slower and fatter tires are more comfortable. I have 32s on my fastest bike. My time is about the same on all my longer distance bikes, give or take 5 minutes. I've seen a teenager on a steel frame hybrid go past me on fatter tires like I was still. The bike will only go as fast as you can go but for those wanting to count every bit of weight and get an edge, they'll choose what works best for them. [I rode on 25mm tires when I rode with other cyclists. They didn't have as many flats as the skinnier tires and felt better to me.]
ReplyDeletei changed out from 25's to 28's for most of my riding and never went back. i've used 32's and loved them, but cannot fit mudguards around them on my most-used bike. i put 35's on my touring rig and they are very comfortable. The wider tyres are no "slower" than the 25's (i'm too heavy for anything narrower.)
ReplyDeletei've long ago stopped worrying about speed in favour of comfort and find i can ride longer without feeling beaten up by rough roads.
(As an aside, i've made a hobby of counting how many times Mr. Heine can fit "wide, supple tyres" into an article. ;-} )
My 'fast dry summer machine has 25s (approx 90psi) on it and alas theres no room for anything wider, but most of the time at the moment, I am riding an alluminuim road bike with 42s (approx 50psi). The 42s 'feel' more comfortable whilst riding- notably I spend more time actually sitting down on the saddle riding down rough potholey lanes, whilst on my other machine I would be standing all the way. The other thing I noticed was that when I get off the bike after an hour or two, I now feel fine straight away- whereas on my carbon road 25s, my lower back was sore and I needed to stretch and straighten up for a few minutes. Btw comment about JH made me laugh- I think he's great but I know what you mean
ReplyDeleteWhen I first got into daily commuting on an old cannondale racing bike I bought from a friend, I occasionally had pinch flats on the 23s. "I'll put fatter tires on it", I thought. They didn't fit, and I learned that tire width depended on frame restrictions (I know, you gotta start somewhere). In the 20 years since, I have ridden wider and wider tires, and found that as long as the tires are high quality (light and supple), I don't seem to pay any penalty for wider. In fact, some bikes seem to do better with wider.
ReplyDeleteRiding on 38s until they wear out, then headed wider,
Edwin
Doesn't it have much to do with road surface conditions? I ride only asphalt roads so 25/28mm tires seem just right to me. I ride 22mm tubulars that feel good on asphalt as well. I can't imagine those tires on dirt or gravel roads.
ReplyDeleteFirst step is measure your tires. Without a caliper and a measurement none of this discussion means much. In this household there are identical tires that measure 28mm on one wheel and 32mm on another wheel. Tire width changes with rim width, inflation pressure, and age. They stretch over time and some stretch a lot. One old Michelin started life at 39mm and was retired when it grew to 45mm. I thought my frame was shrinking. No, the tire was growing.
ReplyDeleteAbout perception. If you read bike history you will be told that singletube tires vanished in a puff of smoke in 1933, wiped off the map by the Schwinn balloon tire. There were good numbers of riders using singletube forty years after they were 'gone'. A few collectors still ride them. And they are currently in production. The historians will claim one of the main reasons for their demise was the extreme difficulty of patching them. Every singletube rider I knew kept them because they were flat resistant and so easy to patch. My personal opinion is they were not very good tires. They were loved.
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DeleteMy perspective is from forty years as riding as an adult and in my mind I've seen lot's of fads come and go but nothing changes. Well, except the dominance of social media and endless discussions about everything under the sun. Everything you've talked about over the years as major shifts, I've seen before, all the ebbs and flows. If one stays at it, thankfully, one eventually finds an equilibrium. It sounds like that's what you're going through.
ReplyDeleteI'll say that I'm unsure of who your audience is when talking about road riding and tire width. I'm not one of the lycra wearing, carbon riding, weight conscious, data collecting kind of riders but I do ride a road bike everyday and accumulate many thousand miles each year. Speed has never been a concern or a reason to make changes on my bike. The idea of optimal seems odd with regard to tire width. Optimal makes a lot of sense when talking about bike fit. Truthfully, I've not had the luxury of testing tire after tire in order to find a sweet spot. My bike came with a tire width, I'm satisfied, and it remains what it's always been.
I do, however, feel faster whenever I clean my bike which just happened yesterday ;)
I'm very happy with the 25c Grand Bois tires I'm running on my Axiom. I had considered installing 28's but wasn't confident they'd fit. On my heavier Salsa Vaya, which I ride here in Maine in the colder months, I have Schwalbe Marathon Racer in 700x38c. That bike is amazingly stable and plush over rough roads, but is definitely a truck compared to the Seven. I don't mind its extra weight because it such a comfortable bike and feels safe and relaxing to ride in all circumstances (except when there's black ice on the roads, even with studded Hakkapeliitta!).
ReplyDeleteI opted away from 23c width not so much because I felt 25 or 28c tires were faster, but because they were a bit plusher and had more road contact... in short, more comfortable and safer. Anyway, that's a funny story about the guy who changed his perspective. By the way, none of my riding friends would even consider using anything but 23c tires-- they think it's crazy to second-guess what the bike companies put on the bikes!
In Thailand I rode Panasonic RIBMO 28's on my hybrid, however, that was almost entirely on good pavements. They were great there. Now, living in Saskatchewan, I run Continental 35's on the same bicycle after finding the 28's rather squirrely on the constant road grime and loose sand of the Canadian prairies. The main "feel" different to me is the weight - it seems to take longer to get up to speed and slow down. The difference is likely measured in microseconds, but the feeling is in minutes, so it's obviously mostly in my head.
ReplyDeleteTo answer your question "To what extent are these physical sensations shaped by the current popular narratives?", I'd say they are totally shaped by "received wisdom".
ReplyDeleteHardly anyone will do their own objective tests of different types of tyres.
In the absence of data, then opinion rules. Narrower tyres must be faster because they are lighter and have less air resistance and drag, that is just common sense isn't it?
Until there is another more convincing explanation of why they aren't...
I transitioned to "adult" bikes in a time and place where 27" x 1 1/4" tires where pretty much what your bike had. It was odd for anybody old enough to have a driver's license to also be interested in bikes, so I was definitely not spoiled with choice.
ReplyDeleteThat said, I was interested in bikes. I inquired at the Schwinn dealer about "racing wheels" for my bike. Meaning, 700c with razor-thin tires on 'em. Because that's what I saw in the magazines. Politely stifling laughter, they would patiently advise that my pile of gas-pipe Schwinn would require much more in parts and labor than it would be worth. On offer, though, were 27" x 1" tires. For a paltry sum, I was going to get fast!
The limiting factor on my tire width at that time? My pump. I couldn't get it up to 190psi. It would barely do the 90-100psi I put into the 1 1/4" tires.
These days, I just put the fattest, good quality*, tires I can fit into the frame. *(Wide, supple tyres, yes!) I guess I've never made an effort to find "optimum" as I'm surely not pushing any sort of envelope with my riding.
Wolf.
All this talk about tire width, but no one has addressed your contention that psychology shares a border with science. They *may* be on the same continent ...
ReplyDelete!
DeleteOh, I think psychology definitely overlaps with both science and, for lack of a better expression, social science. At one end of psychology is simple neurology, physical responses in the brain to various stimuli, at the other end it's almost market research!
DeleteWhile I'm a big believer than tires have a big effect on ride quality, I have my doubts that very small changes in tire width alone could cause a noticeable effect. Is the behavior of a 23mm tire really that much different than a 25mm tire?
ReplyDeleteMore likely I expect is that it is the construction, materials, and condition of the tires that have the larger impact. I can easily feel the difference between tire brands of identical width, and I suspect that an old tire rides different than a new one due to hardening of the materials or other changes.
My takeaway from Jan Heine's writing about it is that the material of the tire itself has as big an impact as the width. People tend to focus on easily measurable and visible differences, so width is the focus. It's a lot harder to measure casing pliability, internal heat generation from friction, etc. etc.
But to the original point of the post. Yes, people's impressions are highly suggestible. Is there any aspect of bikes that don't feel better after a trusted source tells you that "X is best"?
Agreed, just too many other variables that affect ride, speed, comfort and handling - including road surface, inflation pressure, rider's weight, frame geometry and material, not to mention subjective impressions and personal preferences impossible to measure. I have seen how changing from one 28mm tire to another - same size, different tire - can make a big difference in a bike's feel even at the same PSI. I personally prefer riding a minimum width of 28mm if only to help prevent pinch flats or rim damage from such dastardly stuff as chuck holes, road debris, curbs, and such. Might as well throw that in as well.
DeleteYou're citing J. Heine who explains somewhere that going from 23mm to 25 mm means about 20% more volume. That is an important change.
DeleteHmmm, J. Heine cites 18% more volume from 23 -> 25. Though he's using idealized circles to calculate that change rather than real world volume of two mounted tires. I would suspect the actual change would be less. Regardless, I'm sure tire width (volume) is a factor (maybe even "noticeable"), but I think it gets a bit too much attention because it is easily measured and is visible. I've ridden wide tires that are massively slower than narrower tires and vice versa. There's a lot of factors involved.
Deletehttps://janheine.wordpress.com/2013/05/23/tire-width-how-much-difference-do-a-few-millimeters-make/
Of course all other things being equal.
DeleteGoing from a racing tubular in 23 to a utility tire with reinforcements in 25 (probably doesn't exist, but it could even be 28 or more) will certainly make you slower.
Frame material and design has a big impact on how tires feel, so I wonder how far the wider-tire trend is a delayed reaction to the displacement of steel as the universal frame material (and not-so-damn tight as the common design) for riders wanting to go fast. For a long time tires around an inch (25 mm) were what you saw on all road racing bikes. The bikes were steel. Now racing bikes are both more tightly designed made of more rigid materials. So wider tires both feel better and (for Heinean reasons) work better. If correct, this theory would indicate there is some objective basis for the belief that wider tires are better now even though narrower ones used to be better for fast road riding. Even someone who changed his or her mind just in the last five years would have some justification: He or she, riding steel, grew up in the (objectively reasonable) belief that an inch was a good width, adhered to that belief through inertia through the advent of the aluminum/carbon era, and then corrected when exposed to wider tires as they became popular recently.
ReplyDeleteWalter
While going to wider tires is often done for comfort, I have taken a bit of a different approach to achieve the same comfort. I bought an older hardtail Litespeed mountain bike, (26" wheels,) to ride on the road. I do a lot of riding on bike trails that are paved, but quite bumpy. I was getting too beat up riding my nice old Colnago. I equipped the mountain bike with 25c tires, and it goes like a road bike, but I have the cushioning of a modern air/oil suspension fork, and a shock absorbing seatpost. It's a very comfortable ride; friends who have ridden it absolutely love the ride. The 25c tires take almost a pound off the weight of the bike compared to the wider tires I have, and that makes a huge difference when you're dealing with unsprung and rotational weight. BTW, if you look at what most NYC bike messengers are riding, it's similar to what I have done, (but usually not such a high end bike). It took a little bit of doing to get the gearing right for high speed road riding; I needed larger front chainrings, and a smaller cassette, but it's still easy enough to obtain. I don't think this can be done with a newer mountain bike; you can't get the gearing you need for the road. But the older MTB bikes with 8sp XTR gruppos can be made to work well on the road. Mine now has 26/36/48 and a 12-32; but I could go 12-28 maintaining an XTR cassette if I wanted to, perhaps even smaller with a DuraAce cassette. This set up will keep me very happy until I can afford a road bike with suspension like a Specialized Roubaix.
ReplyDeleteThe added benefit of this type setup, is that I can easily choose much wider tires if I want to ride on gravel or dirt. I have a wide knobby set and a wide all-terrain set sitting in my garage if I get motivated to switch. But switching tires is about traction, not comfort.
I have always felt that gravity was the most pernicious of social constructs.
ReplyDeleteBack on topic, a lightly built fat tire beats an armoured up skinny tire.
Dipl-Ing Jobst Brandt designed some pretty good 27mm and 30mm road tires for Avocet in the late '90s, they never became very popular, except at Rivendell. Where they led to the
Rolly Poly 27mm. I had a road bike built in '04 for the Avocet 30s, the tires went out
production soon afterward. Nice to be able to get tires again. SG8357
The Avocet tires were by IRC and there were quite a few that had the very soft, almost gooey feel. And they were fast regardless of how smooth they felt. Gone. Missed.
DeleteSince I rarely go on longer rides that will stay on good quality pavement wider tires 32-35mm are the norm for me. Anything less and you get beat up and you start to slip and slide too much. Tires wider than about 35mm generally don't improve riding on the rougher stuff enough to justify the drag created on the smoother stuff. However, when it comes to my fixed-gear that use for getting around the neighborhood, the skinnies I keep on it are just straight up fun. But, they're on there not because they're faster or more effiecent, but because I find them fun to ride on.
ReplyDeleteThe optimal tyre for speed or grip should be measurable. For comfort it's purely perception, obviously. But in either case, are there any constants? A wider tyre should usually be run at lower pressure. The ratio of rim width to tyre width will be different; or if you keep it constant, you are dealing with a different rim and its effects on speed, comfort, etc. Then we are talking about changes over the course of five years or so. It's possible there have been developments in tyre technology over this time. And even if there haven't, manufactured items vary from batch to batch as machinery wears, workforce changes affecting working practices and QC, etc; and that's before we consider variations in the natural component, ie latex from the rubber tree. And the environment in which we use the product has changed. At least in the UK (with the exception of Wales), road surfaces have deteriorated over the past several years due to budget cuts, especially on minor roads and urban non-primary routes where cyclists are most likely to ride.
ReplyDeleteNevertheless, social representation has to be a large part of the reason for the change in thinking around tyre width. One of the great things about this blog is that most people would just call this "fashion" but you have an explanation for fashion!
There's so many factors that effect tire performance especially with tires below 28mm, Normally tire pressure would be the most important variable, but below 28mm tire pressure is probably pretty close to the same between widths so then it comes down to the environment and tire construction.
ReplyDeleteJan Heine's article on this basically says that the wider tires at the proper pressure ride better by dispersing vibration, the way that makes them faster is because the reduced vibration also means the rider is more comfortable and get less "beat up" THAT is a direct reflection of how you feel! If you feel faster then you most likely will be. In a ideal environment rolling I a straight line on a piece of Glass, a super skinny, high pressure tires will be faster (or at least more efficient which is kind of a double answer, but not exactly), but how many of us ride in ideal circumstances? None I am sure, for your environment 25's may suit you, in a different environment? maybe not! the important thing is to decide for yourself. For me? I am really too heavy to ride a super narrow tire, I have to pump it up so much that every little road imperfection is transmitted to the rider, additionally I ride mostly in the city and skinny tires just give me too much to think about with cracks and expansion joints in the road. Ideal for me is about 35MM but I could go down to 32MM without any problem depending on the bike. On my Clementine I like 2" wide tires! - masmojo
I've read a few comparisons, and even recent technical articles on the subject, and it seems to point to some deformation and compliance at the contact patch being faster than super-high pressures required to run a skinnier tire for a rider of the same weight. In other words, for each rider/wheel/bike combo, there is going to be a sweet spot for tire width and pressure that allows the tread of the tire to conform enough to the road without resulting in too much sidewall deflection when cornering or putting other lateral stresses on the tire.
ReplyDeleteIn order for a 200+ pound fellow like myself to ride 21mm tires without excessive (and dangerous)sidewall deflection, I have to run them at their maximum pressure so that they are so hard that the tread no longer flexes when it touches the ground. This adversely affects not only comfort and traction, but has recently been found to also increase rolling resistance. Conversely, a svelte rider on 28mm tires has more rubber than they need. 23mm or 25mm tires, depending on construction, rubber compound, etc. will get a smaller rider right into the sweet spot.
"So what exactly is it that we feel as we ride tyres of different width and form impressions of speed and comfort? "
ReplyDeleteWe feel the power of marketing! 25 or more years ago, I recall suffering 120 psi 19 mm tires because that's what Colorado Cyclist or Bicycling or somesuch praised. Now I think 28 mm is a sweet spot for road and firm dirt, because Jan told me so!
Seriously, the acquaintance who so blithely switched from 23 mm to 28 mm could be assiduously following the latest trends; or he may really have learned something over the past year or two. I know that my own opinions have, at least in the past, been shaped by the marketers and the reviewers in the big bike mags, but I do like to think that, now, they are at least a bit more independent and based on experience, though I value highly the opinions of others whose experience I have learned to trust. At least, I am not buying any wider rims -- I hear that's the new "wider is better" component.
As to "feel" in the physical sense: 28 mm Compass Elk Pass tires "feel" fast in the sense that it seems easier to maintain a given cadence with a given gear in given conditions, comparing these tires to others -- high end ones, Conti GPs, Michelin Pro Races. They also feel very smooth, which I associate with the feeling of speed (I *do not* buy the hypothesis that people consider skinny, hard tires fast because they "buzz"; to me, plush or smooth feels faster.) I can say the same about Schwalbe Furious Freds compared to Big Apples: it feels easier to pedal them.
It's important to note that not all "wide" tires are created equal. Bicycle Quarterly's research has shown that, in addition to tire width, a tire with a supple casing is faster. This link to Jan Heine's blog shows some of his extensive research: https://janheine.wordpress.com/2012/06/13/bicycle-quarterly-performance-of-tires/
ReplyDeleteBollocks to new tyres. I'm getting new roads.
ReplyDeleteHa! I've got those exact 650b tires on my bike right now. Love them!
ReplyDelete35mm on both my Novara Randonee and Surly CC, 28mm on my '86 Elance and 23mm on an '89 Allez. These tires suit me and perform well for the varied and different tasks each of these bikes provide for me.
ReplyDeleteReality rules, which is more scary than comforting, so I just try to make the best I can with what I've got and am grateful for that! If I've got tires/tubes which hold air I'm in optimal heaven.
ReplyDeleteA very interesting article.
ReplyDeleteI have quite a few 1950s and 1960s bikes. Some I like to keep "original", but this means woods valves and raleigh record tyres or similar. Low pressure, leaky and high rolling resistance. If you put modern Schwalbes on (26x 1 3/8), and presta valved tubes, things are noticably better, even on heavy steel monsters with full steel chain cases.
The early bromptons had 16" Raleigh records (a tyre for 1970s children's bikes) and were (comparitively) awful to ride. When Schwalbe started doing a 16" tyre it made a huge difference. My brompton is old enough to have a four digit serial number and is not as nice to ride as one you might buy now, but the single biggest upgrade was the tyres.
In terms of modern tyres, they are all so much better. I have Marathons on most of my practical/utility/commuter bikes now, and they range from 28 to 38. It's all personal, but my own preference is 35 for touring, 38 for leisure/commute.
I have found as I have got older and slower and heavier, my preferred tyre size has grown in sympathy with, and proportionally to my waistline.
I don't have much to chip in, except that I find it intuitive that you'd find your sweet spot for tires to be a bit narrower than the current "objective" wisdom prescribes. The Bicycle Quarterly crew did some serious research on the subject that a lot of people are now recognizing as correct, but they found their optimum using primarily men probably weighing an average of 165 lbs or thereabouts. It makes intuitive sense that as a smaller rider on a smaller bike would end up finding that smaller tires work better.
ReplyDeleteOver time I've come to believe that empirical, objective (although that term is loaded) research is indispensable for getting close to a solution, but that once you're in the right neighborhood, you have to close that last mile to "just right" with personal experience. You could chalk that up to error or bias in the research (e.g. doing most of your tire testing with riders of a certain body type) or to social and cultural phenomena like the ones you describe in your post. It's probably a bit of both in most cases, and often they seem to overlap.
And their weight and riding style. Personally, I've been slowly expanding my tire size since about 2012 as a way of avoiding pinch flats. I went from 22 to 25 to 28, and when I crossed the 30mm barrier I discovered that I could now ride on roads that were previously impassible... persuing these roads led to more flats and, well, long story short, now I ride 2" tubeless.
ReplyDeleteIf I weighed less than I do (200 pounds) I probably never would have gone beyond 28. I wasn't seeking any optimum. I was fleeing a problem.
I marvel that the general market shift to wider tires appears to have been predicated on the writing of a single person, who determined his conclusions via limited research and who happens to sell wide tires. I've always liked Jan and appreciated his work, but to say that wider tires are faster almost without exception over-generalizes. Velouria, for riding at full gas with constant accelerations, 25c high performance tires appear faster to me also.
ReplyDeleteMy Cervelo R2 feels great rolling the Grand Bois 26. Not sure how much of that is the power of Jan's persuasion but don't really care. Below 20 mph like on a cool weather solo ride the Grand Bois 26 on stock Shimano RS10 wheels feel best. Above 20 mph such as on a fast summer group ride a barely narrower Clement Strava LGG 25 on mid-aero carbon wheel feels best. My perception is that the carbon dampening kicks in at greater speeds but rubber dampening is more a function of pressure*volume.
ReplyDeleteI like the feel of slightly fatter tires, but I'm a bit confused by people who say that there is no difference in speed. Maybe so in terms of rolling resistance--that's a complex issue--but in terms of weight it would seem to be pretty straightforward. Most of my skinnier tires--say, my 23s--are much lighter than my wider ones--say, my 32s. No? Am I missing something?
ReplyDeleteEffects can offset each other. (And on some rides, weight is more or less irrelevant.)
DeleteWider tires are generally heavier than skinnier tires. Generally speaking, the difference isn't so great if you compare different sizes of the same tire. So for example, if you compare a Panaracer Pasela 700x23c (240g) to a Panaracer Pasela 700x32c (350g), that's a 110g difference. If you factor in the weight of a 700x23c tube (125g) and the weight of a 700x32c tube (140g), and the additional weight of an aluminum road rim (435g) and rim tape (16g), there's a total rotating weight of 816g for the 700x23c tire and 941g for the 700x32c tire, or a difference of 125g total rotating weight per wheel. You'll definitely notice the difference when you spin up the wheel, but the difference might not be as much as you think.
DeleteOn the other side, there's the issue of rolling resistance, of reduced fatigue from road buzz, of increased control when going over rough surfaces (because your thicker, softer tires are rolling over bumps that your thinner, harder tires would bounce over), and of fewer pinch flats and fewer flat tires overall.
On the third side, a wide tire on a narrow rim might create more aerodynamic drag than a narrow tire on a narrow rim and increase the rolling resistance of the tire. But a wide rim will weigh more than a narrow rim. So pick your poison.
There's a lot of variables to consider in your tire choice: wire vs. folding, thread count, tread compound, and so on. A lot of these choices influence rolling resistance and rotational momentum substantially, maybe not as much as tire size, but they must be considered as well. I think that a part of the issue is that most people start out on utility bicycles with tires that are made for cost and durability rather than speed. When they go out and buy a speedy road bike with upmarket skinny tires, they associate the zippiness with the measurable attributes (skinny tires) rather than the attributes that are harder to see (top-of-the-line tires that the tire maker provided for cheap so that you get hooked on that brand). Even if you were inclined to compare different sizes of the same tire, you aren't able to find a tire that is made in sizes that are very different from one another, particularly for racing bike sizes.
ReplyDeleteSpeaking personally, I put 25s on my racing bikes because they aren't able to take 28s. I don't find so much of a difference between 23s and 25s but definitely appreciate the slightly greater resistance to flats that larger tires provide. 32s and 37s are nice too for bikes that take them. 32s are great for bad pavement and gravel, though I might take a 37 if speed isn't so important.
You mean my 2.25 inch tyres are not optimal? Yikes.
ReplyDeleteI actually can tell the difference between two tyres of the same width and the same psi (ie, 35mm Schwalbe and Pasela). Riding the exact same route to work every single day makes it easier to pick up on even small differences, especially with 12% hill in the way. All I can say is that (shameless plug) the Compass tyres are a total game-changer, and completely blew my mind. And by speed I mean what gear I'm using for a given effort and terrain. Am I getting to work quicker? Yup. Really paying attention to pressure is critical though. 50/ 60psi f/r no more. I have found that as JH says that casing is more important than width--ie, that a 32mm Compass rolls smoother/ faster/ with better road feel than the 35mm Schwalbe, at any given pressure. That's on pavement. I've ridden gravel since I was I kid, and the science JH laid down made sense given 25 years of pushing any type of tyres over gravel and mangled tarmac. Asupple 28 is better than a tanky 42 that weights 800g. Cultural narratives are less important to an old farm boy like me. But it is true what you say! People get hung up on stuff. I miss my 23mm Michelin Hi-lite Pros, but at that width gravel starts to eat rims.... .
ReplyDelete