It’s a topic of hot debate among those that consider themselves hard core cyclists. To many tyre pressure is all about marginal gains; the speed improvements between 100psi and 110psi or what suits the specific gravel surface being ridden. Couple this with detailed analysis of tread patterns and things can get picky really quickly and way out of the range that most regular commuters need to worry about. Unless you commute on a aerodynamic time trial bike in a skin suit….in which case, as you were.
However, there are some aspects of tyre pressure that are of great importance to regular cycle commuters, here’s what you need to know.
What is Tyre Pressure?
Tyre pressure is a measure of how much air is inside the inner tube on you bike. This is direct corollary of how inflated, or hard or soft, your outer tyre will be.
Every tyre has a range that it should be inflated within. This will be printed on the sidewall of the tyre. It will say something like ‘100 psi MAX’ or ‘inflate to 50-85 psi’.
Tyres meant to be run at very high pressures are designed to minimise contact with the road and therefore be as fast as possible. They often have a very smooth surface as there is no need to for nobbles. Low volume, skinny road tyres are a good example of this.
Wider, nobblier tyres tend to be designed to have more contact with with ground and therefore be softer. However, this increases drag on the road and means you have to put more effort into riding on tarmac.
Why is correct pressure important?
Not only will having the correct tyre pressure make riding easier, it will also help prevent punctures.
For riding on roads, it is generally best to have your tyres at their maximum pressure, regardless of tyre type. This will make it harder for bits of glass and stone to penetrate and puncture them. It will also limit pinch flats. These are punctures that occur when the inner tube gets trapped by the rim of the wheel when going over bumps or rough ground. For example, going over a curb or average lovely London road pothole.
What can you do?
The easiest thing to do to keep your tyre pressure good is by regularly pumping up your tyres. It seems obvious to some, but in the last few years I have been surprised by the number of people who buy a bike and don’t really realise that they require any kind of attention.
When I used to work at Brompton, we used to get people coming back for their post sale checkup 2 months after taking it home and they hadn’t pumped their tyres once. The worst one was someone riding around with 36psi in both tyres. Brompton tyres have to be between 100-120psi.
A track pump with a pressure gage is one of the best accessory purchases you can make, after a lock and lights. If you don’t want to buy one, every bike shop has one you can use and there are some other public ones dotted around.
Generally tyres need toping up once a week if you ride regularly. If your bike has been sitting for two weeks or more then you will probably want to put some air in them before you ride. Having your own pump makes this possible.
What else?
If all of this seems like far too much hassle for you, then you could look into getting a set of Tannus solid tyres. We reviewed them a few months ago and they have proven to be pretty good on London roads for lighter weight riders such as myself. They remove the need to worry about pumping your tyres, or getting a puncture on the way to work.
Some tyres hold their pressure better others. I have noticed that the more puncture resistant the tyre, the slower it loses air. I assume this is something to do with them being stiffer?
Avoiding large bumps, holes and curbs will keep your tyres happier for longer as well. Just today I witnessed someone speed up a curb and blow out two tyres (they were riding a trike). Even if the tyres don’t blow, repeated jarring will reduce their pressure quicker, meaning you might be at risk of flats sooner.
What are your tips and / or experiences with tyre pressures?
My tyres say maximum 80 psi (Marathon Plus more-or-less puncture proof). I try and keep them at that, check them once a week or thereabouts. Lowest I’ve ever let them get was about 65 – or, 0, if you count the time I had a flat 🙂
Seconded, except that *touches wood* I’ve not yet had a flat in four years
Having recently tried the Tannus tyres on my Brompton, I have to say that they are not “pretty good” on London roads. They add constant and very noticeable drag, and their lateral grip is horrible on surfaces other than plain dry tarmac (e.g. white lines or cobbles).
Perhaps they are ok on full-size wheels — I don’t know — but for a Brompton I would definitely advise sticking with well-armoured non-solid tyres such as Marathon Plus.
Useful feedback – thank you!
Having gone through a lot of tyres on my Brompton I would say that Brompton own give by far the best grip, moving to marathon I had a few worrying moments in the first couple of weeks before I got used to them, they just seemed to want to slide in the wet. Further if the tyres were not bullets 100psi + on either type the handling became inconsistent and cornering at speed was really scary (as Emily said)
have a read / listen of this http://cyclingtips.com/2016/08/cyclingtips-podcast-episode-9-rethinking-road-bike-tire-sizes-and-pressures/
I was surprised to here it’s not as simple as higher pressure = faster! The pro’s will now often ride on wider and lower pressure tyres – and that has been proven to be faster in many cases.
Slightly off topic, but I actually do see a chap commuting on an aerodynamic time trial bike with in a skin suit most days. He’s got an impressive goatee and I see him at various points between Bethnal Green and Bermondsey, via Tower Bridge. He’s fast, but looks a bit silly.
ps. I use Continental Sport Contact 2 700×35 on my Genesis Croix de fer and at 80psi they are great, really grippy and fast. Not as puncture proof as Marathon plus, but still pretty resiliant, probably get 6 months of Leyton to Bermondsey without punctures on average.
I use Continental 4 seasons tyres. They are puncture resistant. I have had a few punctures in them but it has always been due to side wall damage. On one occasion I had allowed my rear tyre pressure to fall too much and the area outside the puncture resistance came into contact with the ground.
Rolling resistance is all about the non elastic nature of the tyre. A perfectly elastic tyre would not dissipate any energy when it is flexed. Real tyres do. The less flexing, the less energy that comes out of the bike and into tyre heat and noise. The area of tyre in contact with the ground (on a slick tyre) is easily calculated from the weight loading (per tyre) and the tyre press. So 200 pounds of rider plus bike = 100 pounds per tyre (approx); so a tyre at 100 pounds per square inch will have 1 square inch in contact with the ground. A skinny tyre has to deform more to put a square inch into ground contact than a wider tyre (or a smaller wheel tyre). However, the skinny tyre will often take a higher pressure, reducing the deformation necessary, will have a smaller aero dynamic drag due to the lower profile and lower weight.
I find it’s worth experimenting to see what the best pressures are for you.
My commute is 15 miles each way, 99.9% on tarmac, with one short stretch of stony path. I ride it on a CX bike (as disc brakes weren’t available on road bikes when I got it), and find that if I put the tyres (700x38c Conti Cyclocross Race iirc) up to full pressure, the ride is pretty uncomfortable.
Dropping it down by around 20 PSI results in a lovely, comfortable ride with no noticeable increase in drag – certainly no drop in average speed on my commute – and also no increase in punctures.
I am, of course, now going to get double punctures on my next dozen commutes!!
Anything below 80 psi runs the risk of impact punctures, so comfort can come at a price
I disagree. At 38mm width, a lightish rider and bike combo could run the front tyre down to 45psi without impact punctures, the rear to maybe 65.
20 psi will result in significantly reduced grip, a lot of drag and an increase in puncture risk. I strongly recommend you give it up.
Have a listen / read of this http://cyclingtips.com/2016/08/cyclingtips-podcast-episode-9-rethinking-road-bike-tire-sizes-and-pressures/
I was surprised to find it is not so simple as higher pressure = faster. It is really interesting and was all news to me!
What exactly was the trike doing? As I have a Christiania I do not want to do it, especially a tyre change is a major job 🙂
I have found exactly the same as Chris. I run 28mm continental Gatorskins and haven’t had a puncture for ages (touch wood).
I used to run them at the recommended max psi as per the article but I found the ride pretty jarring on my boardman team cx. Backing off the pressure about 10 to 15 psi to the middle / lower part of the recommended range resulted in a much more comfortable ride with no noticeable loss of speed and no pinch flats yet.
Emily said she’d noticed that the more puncture resistant the tyre, the slower it loses air. Unless you’re running tubeless, the tubes hold the air in, not the tyre. Tubes seem to come in varying thicknesses, and my unscientific conclusion based on how often I have to pump up the tyres (or should that be tubes?) on my own bikes is that the thicker (and heavier) the tube, the less frequent top-ups are needed. My hybrid with heavy tubes, and only pumped up to 85.psi – every three weeks at most. My ‘Sunday best’ road bike with lightweight everything and pumped up to 110 psi – at least every week.
And then there’s the pressure thing. I’d had my Sunday best bike a week and ran over a wood tiling batten or somesuch lying in the road in the West End. The result: two snakebite punctures in each wheel. I didn’t have eight patches or two tubes to hand so ended up pushing it home to Shepherd’s Bush. My own fault – I hadn’t checked the pressures before leaving home. Since then I take it to the max with pressures and accept the suffering on rough roads.
And donning my Pedants-R-Us hat for a moment: Emily, get your nobble (what people do to race horses) and your knobble (the lumpy bit on a tyre) sorted out!
I run marathon plus on my Brompton at around 90 psi. I found that as I am over 17 stone I bust spokes regularly when they were over 100 psi, I’m assuming there was less damping and more force was being transferred to the spokes. I don’t suffer regular punctures at thus pressure.
of course you can add tire liners to lessen the number of punctures.
As an experiment once, I got a no-longer-usable tube and cut the valve stem out of it , then placed into the tire as a cushion BEFORE placing the real tube in and then mounted to the rim. An object now would have to go through the tire, then 2 layers of old tube in order to hurt the inflated tube.
Inflated to correct pressure and it worked great. I could notice the extra weight, but the resistance did not seem to increase and the ride was much more comfortable.
have never read of this procedure or met anyone else who has tried this.
You can get anti puncture tape does the job no weight
A track pump was one of my best purchases shortly after I got my first proper adult bike. As Emily says, one of the best accessories you can buy.
Run schwalbe One tyres, 100psi front and 110psi rear. Ride comfort is not to bad, covered just over 3000 miles so far on these tyres and no punctures (runs off and touches wood quickly) ☺
The Schwalbe US site used to have a good section of articles based on bike balance(weight distribution 55% rear45% front) rider weight ,tyre type and width. I now have 25mm Schwalbe one for me 95psi front 105psi rear very comfy
I disagree about running tyres at maximum pressures. Use a calculator which takes in your weight, riding style and tyre width to give the 15% drop pressures for each tyre, then vary slightly to taste.
I’ve been running some Schwalbe G-One Speed in 30mm, tubeless for 4 months now. they are super comfortable and corner really well.
Currently, put 60psi front and 65 rear. I’ve not noticed any speed decrease if anything they seem to be faster than my only 25mm Conti gp4000s ii’s.
Hi, We do quite a lot of touring. Went from the UK to the Black Sea a few years back on a couple of Trek hybrids set up for touring. Carried the camping gear as well using Ortlieb rear paniers and a rack pack. No front paniers required. Tyres were Schwalbe Marathon Plus 700 x 35C and we broke a few spokes, but had no punctures at all on either bike for the 3000 miles. The bikes weighed about 15kg, rear loads approx 22kg, front 4-5kg. For a rider weighing 60kg, tyres were set to 40 psi front and 60 psi rear. For a rider of 74kg tyres were set to 50 psi front and 70 psi rear. We do not hammer the bikes and slow down when the roads/tracks are rough to let the tyres do their thing. At home without the loads we tend to use the same pressures, but can back the rear pressures off 5 or so psi to maintain some comfort on the local bumpy roads if need be. As for rolling resistance, never a problem, these tyres roll well. I hope this helps. Certainly works for us. Brian