In cycling, “contact points” are critical: bum on saddle, hands on handlebars, feet on pedals. But the most important one of all is “where the rubber meets the road”. Tires may be the most important component on your bike. The right tire at the right pressure makes a huge difference to your safety - your “grip” on the road - as well as to your comfort, and efficiency.
Diving into detail on tires, with a focus on tire width, tire pressure, and tire quality, we will discover:
Last spring, I took my new Niner RLT9 “adventure” gravel bike out for a spin off-road in Gatineau Park. My Niner is “built for comfort not for speed” - durable aluminum frame, long wheelbase, wide rimmed wheels, 40mm tires at a pressure of 40psi. After cycling some rough trails, I headed back on the pavement from Champlain Lookout. On the Parkway, for fun, I “opened it up” attacking the descent of Fortune Lake Parkway from the “T” intersection to Meech Lake Road. I found the descent fun and easy - the bike felt stable and sure-footed.
But here’s the thing - Strava recorded my fastest ever descent of Fortune Lake! Faster than on my carbon fibre race bike, with its race wheels and 25mm tires at 100psi. What gives?
Note: I’ve included a list of references and background reading at the end of this article.
There are two main components of tire rolling resistance:
When Crr and Suspension Losses are combined, a graph of total rolling resistance vs tire pressure (for a given tire type/width) for different road surfaces ends up looking like the chart below:
Notice:
That’s why we invented pneumatic tires - the air in the tire absorbs irregularities on the road and reduces the suspension losses, the “rattling” that steals energy. Let’s think about this intuitively - imagine rolling over a 5mm bump on the road as shown below:
The tire deforms to go over the bump, so you and the bike don’t “rattle” as much, reducing the suspension losses. The bigger the bumps, the more we would like the tire to be able to deform. So, we want lower pressure on rougher roads. And wider tires can be run at a lower pressure, giving us a speed advantage on typical paved road surfaces, and “win big” on rough roads. But there’s more!
Simply put, as the roads get rougher, your tires need to be wider for optimal performance, safety, and comfort. Yeah, but taken to extremes our arguments break down… wheels and tires do get too heavy, wide and “sloppy”. So for recreational riders like us, what’s the “sweet spot”?
Looking at the World Tour professional road racers use will give us a good handle on the minimum size of tire we should be using:
So that’s a minimum, if you are averaging 40kph and up and want to squeeze the last drop of performance at the cost of comfort and safety. What about us mere mortals?
By “experts”, I mean the high-end sportif enthusiasts, who are competing in events, riding hundreds of kilometres a week and keep current on cycling technology.
There’s a pretty strong consensus that for general purpose road riding on the sorts of roads we have in the National Capital Region, tires in the range of 32mm-35mm are ideal. For mixed-surface gravel riding, 38mm-40mm is the common wisdom. For rough, unmaintained roads, its the maximum you can fit on your bike (around 48-55mm for gravel bikes). But really, the best answer is: “The widest tires 32mm or larger that you can fit on your bike!”
If you want to be safe, comfortable and fast:
Tires smaller than 25mm are only suitable for the best velodromes, where the suspension/impedance losses are essentially zero. At the Pan Am Games velodrome in Milton, we use 21-23mm tires, pumped up as high as the tire will allow. (I use a 23mm tire pumped up to 130psi)
There are three main criteria that go into determining the correct tire pressure to use:
Use a tire pressure calculator to determine what pressure is right for you. Different calculators will give different results. Ones that I’m partial to are:
On road bikes, the front tire has less weight on it than the rear, so it uses a lower pressure than the rear. Below is my my calculated tire pressures for a wide range of tire widths and riding conditions. The smallest tire I use outdoors is 32mm, so the 25mm and 28mm rows are for example only. Each entry shows the front/rear pressure for a given tire width and road surface, given my total riding weight of 102kg. For example, I’d use a pressure of 60psi on the front and 65psi on the rear when on a typical paved road ride with my 32mm tires. But when I head into Marlborough Forest on my 42mm tires, I’d be down to 30psi on the front and 34psi on the rear.
OK, the last subject… what makes a good tire? Given we want a tire that deforms with a minimum of energy loss, “supple” is the name of the game. Supple tires have a very high quality tire casing, with a high thread count. (120 TPI and greater) And that makes them expensive. But it’s worth it, the ride feel of a high-quality, supple tire is quite noticeable.
Besides cost, the other tradeoff is durability. The most supple tires have a little less puncture resistance, especially in the sidewalls. But unless you are heading off on an epic bike packing adventure on rough roads, the tradeoff is well worth it. And even the sleekest, most supple quality tire will last a full riding season (say 5,000 KM)
What about the tread pattern? Modern tire compounds make significant tread patterns unnecessary for most riding. You will get the best ride using “slick” tires, or ones with a very subtle “file tread” pattern. Experienced gravel riders use wide (38mm and wider) file tread tires for most of their riding. A significant tread pattern is only necessary when riding in deep, soft materials like mud, sand, and snow, or when riding at very low speeds on rough ground where you make extreme steering actions (think mountain biking or bike packing on rough roads).
For example, my “go to” tire for road riding is the Continental GP5000 32mm tire. Other manufacturers have similar great tires… but you are in the $90 per tire range. A favourite tire of the gravel crowd are the Rene Herse Cycle Tires Their extra-light casing file treads are amazing and I love them. Their prices are hard to swallow, but I'm willing accept the pain in my wallet for the comfort and performance I get on the road.
But narrow tires and rims are more aero right? Less frontal area. Nope! Another misconception. If you take a simple narrow rim, with a narrow tire and place it in a straight headwind, all other things being equal, narrow wins. But we almost never ride directly into the wind! Most of the time the combination of our forward motion and wind direction means the wheel has bit of a “cross wind” on it. Also, modern materials and manufacturing techniques now allow us to create streamlined rim shapes. This ability to “shape” the rim, means the profile shape of the tire and rim combination matters a lot, and it turns out wider rim sections actually allow for better aerodynamics. But really, the aerodynamic losses from wheels is quite small compared to your position on the bike, your clothing, and your helmet. (If you care about aero, see Biggest Bang For Your Buck In Time Trial Equipment - CyclingTips, Buying Time: Which Aero Equipment Offers the Most Benefits? and Cycling Aerodynamics Time Savings: What Really Works, with Chart )
But lighter wheels/tires are better, because extra rotating mass slows you down, and is harder to accelerate. Nope! First, once the mass is moving or rotating, its effect on speed and effort is zero. Second, You can do the high-school physics math… the mass of rims and tires compared your your body weight and that of the bike is so small that the extra power needed to accelerate the wheel is so small as to make essentially no difference. (For more information see Will Lighter Wheels Make You Faster When Cycling | Pedal Chile | )
Going wider wins on comfort, safety, and speed. There is one downside… bike handling. The extra angular momentum of heavier rims and tires doesn’t affect your speed, but it does have a small effect on the steering. The steering will feel a little sluggish, especially at high speed. This matters to competitive cyclists who have to negotiate tight corners at 50kph and maneuver in a tight pack. But for us mere mortals, it won’t actually affect our riding.
The slight change in bike handling, and the more comfortable ride makes us “feel” that wider tires result in a slower bike, even though that’s not the case. We are misinterpreting the cues the bike is giving us. Besides, we “know” that lighter, skinnier wheels are better… “everyone” knows that!
Welcome to the complex world of misconceptions in cycling technology! We repeat erroneous ideas until they become “common knowledge”. We perform testing improperly, or not all. We make invalid assumptions. Jan Heine’s summary at Myths in Cycling (1): Wider Tires Are Slower – Rene Herse Cycles is a good read on why it took us so long to move back to wider tires on bikes.
Josh Poertner, the former head of R&D at Zipp Wheels, and the current owner of Silca, who has spent years studying cycling wheels and tires, and working with many pro teams to optimize their equipment states:
"I have often seen in testing that if a rider believes something to be true, he/she will very often ‘feel’ that in the test ride, particularly if the effect in question is relatively small. - The placebo effect is very strong in cycling…"
Cargo Cults are when we imitate behaviours without understanding how they work in the hope of achieving the same results. It’s common in cycling. Placebo Effects occur when our belief in something creates a real, positive, physical response.
Josh and his colleagues have produced a couple of podcasts on the topic. If you are interested in cycling technology, these are “must listen” shows - informative, and very entertaining.
Podcasts – Marginal Gains Podcast
These two sources provide a comprehensive discussion of the topic, written by acknowledged experts:
Jan Heine at Compass/Rene Herse Cycles:
Josh Poertner’s series in the Silca Blog:
In the previous article, we mentioned that many serious cycling injuries happen when cyclists are slowing and preparing to stop. So let’s discuss some techniques to prevent low speed falls.
Now all this may seem like a lot of effort. But it’s much preferable to broken bones! (As the old saying goes - you can pay me now or pay me later!)
How many times have you heard:
There are several things you can do to pretty much eliminate these two reasons for falling!
The market is dominated by two types of cleats:
The SPD cleats look like this:
The SPD-SL cleats look like this. Look Keo cleats are very similar. (Note the shoe cover!)
Here are some hints for preventing the dreaded “can’t unclip because the cleat is stuck” issue:
It’s a simple thing… when you get back on the bike after walking in your cycling shoes, test that you can unclip both feet. And test each foot twice! Better you know you have an issue when you are prepared for it, instead of when you have to make a quick stop! If things seem a little “off” try banging the bottom of your shoe against the pedal to dislodge any accumulated gunk, and test again. Often the act of clipping and unclipping a couple of times will help get rid of any issues.
Most people always put the same foot down, (usually the right foot). We get so we favour that foot in an emergency, even if we are leaning the other way. We get so used to having the same foot down, and starting with that foot down, that using the other foot is very awkward and unnatural.
You have to train yourself to be equally comfortable with unclipping either foot. Otherwise, if you go to fall “the wrong way” you won’t be able to unclip in time to save yourself!
There is a simple drill to address this: Alternate which foot you use every time you stop. First time unclip and put your left foot down, next time use your right. Then your left. When I taught myself this, it took me 2 full weeks to get comfortable using either foot. So it will take time… keep at it. This is also a great attention and memory drill - you need to consciously control which foot you are putting down, and remember it so you can use the other foot next time!
If you think you are going to be stopping, you can always unclip early. Better to discover you can’t unclip when you have a few seconds to try the other foot, try a few times, and have time plan your “escape” (see below)
When I’m off road riding, I will sometimes unclip when I see a very rough or problematic surface ahead… deep sand, mud, or large loose rocks. You will sometimes see pro road riders unclipping on slippery corners, anticipating they will need to put a foot down to keep themselves up.
Balancing a bike at slow speed (or when stopped) is very different from balance when riding, and requires significant practice. Given that falling at low speed is so common, it’s really worth practicing! The best, and easiest, thing is to “play like a child” at slow speed riding. Just try stuff, practice riding slower and slower, practice making sharp turns while riding slowly. Ride slow standing and sitting. Can you stop for a second then continue to ride forward? Here are some specific drills:
The tendency when we lose our balance on our bike is to try to put a foot down. But it’s often better and safer to recover from an “incipient fall” by riding forward. Sometimes this is not an option… you obviously don’t want to ride out into traffic at a busy intersection! But often that’s not an issue. When it doubt, if it’s possible, just move forward. This requires some significant mental training, which we will talk about in a future article. And the slow speed riding drills above will really train you to avoid falls by moving forward to recover your balance
Another common way to lose your balance is encountering a significant surface problem at low speed… a pothole, large crack, hitting a rock, a curb, etc. So practice! At a walking pace, ride off a curb. Find some big bumps in a parking lot and ride over them You will find that when you do this consciously, and at a walking pace, it will be easy to keep your balance. The trick is to practice enough so that when you have the issue unexpectedly when stopping or starting you will have the confidence to handle it.
So what if you really can’t unclip? This just happened to me. I was fitting cleats onto a new pair of shoes, and I went for a ride to test my cleat position without tightening the cleats on the shoes! So twisting my foot just twisted the cleat against the shoe… it was impossible to unclip either foot! (OK, that really was dumb!)
In my case, there were cars coming that prevented me from turning into my driveway, so I kept riding slowly until the road was clear. Then I turned around and rode back to my driveway. Next, I found a wall to lean against so I could stop. Then I leaned over and undid a shoe, so I could get my foot out and put it down. Phew! Then undo the other shoe so I could get off the bike. Now I could take my time to figure out how to get my shoes out of my pedals!
I’ll be blunt: “Given the amount of time I spend on a bike, I recognize there is a significant probability that my cycling career, or even my life, could end as a result of a serious cycling accident” As a cyclist, the risk of injury requiring hospital treatment (per km travelled) is significantly greater than when in a motor vehicle. The more you cycle, the greater the risk. You will crash!
There’s three options:
Blunt again: “The majority of cyclists choose the first two options!”. I’ve chosen to manipulate the odds, which is why I’m a CanBike instructor, a trained cycling coach under the National Coaching Certification Program (NCCP), why I spend so much time off the bike learning about cycling safety, and why I’m always practicing my bike skills, and teaching them to others.
There’s good news here… Cyclists have the ability to significantly reduce the probability of over 80% of the cycling accidents causing injury!
Cyclists I know have fallen at a walking pace and:
Slowing down won’t significantly reduce your risk, and many common, benign cycling situations are the most risky!
Before we get into specific tips and techniques, I’ve learned there are 3 things that are critical to cyclists improving their chances on the road:
The bottom line is “As a cyclist, using your brain can save your body a lot of pain”
In future articles, we’ll add the fourth A Action and talk about specific things we can do to minimize the odds of a serious injury on the road.
BANG! Hisss…! A Puncture! But who? Where? I’m riding in a peloton of 24 tightly packed riders in the middle of the steep banking on the Pan-Am Games Velodrome in Milton Ontario. It’s impossible to stay up on the banking after a puncture. Everyone knows someone is going down, and is going to take other riders with them. I’m a loser of this lottery. The rider with the puncture slides down in front of me and I flip over their bike at 34KPH, as four of us go down.
We untangle ourselves. No damage done I think … I get back on my bike to ride off the adrenaline and avoid stiffening up. WITHOUT CHECKING MYSELF OR MY EQUIPMENT! As I calm down I realize I need to carefully assess my bike and myself… I get off the track and check. Me, well I have a contusion the size of a tennis ball on my shin, must be from hitting a bike, but not really a medical issue. And my bike is OK.
BUT MY HELMET IS DESTROYED! (See the photo). I didn’t even realize I’d hit my head! Obviously I hit it hard, and the helmet did its job. Now I had to assume head trauma could be a possibility. I removed myself from the training, borrowed another helmet, fitted it to me, made sure I was always where someone could monitor me, and I rode slowly on my own, off the track.
The adrenaline will be pumping… an injured rider will not necessarily feel pain, and often will say “I’m OK” and want to get back on their bike. NO! Take it slow and do a thorough check: