Peer Pressure
Eight point V bar. From the moment I bought my first set of high quality road clinchers, I’ve ridden at that pressure. I started with that number because that’s the pressure the sidewall told me to pump them up to; I didn’t yet understand much about balancing the benefits of high and low pressures to optimize comfort and friction; I just pumped them up as instructed and off I went merrily down the road.
I’m not as thin as I’d like to be, which is the same thing as saying I’m fatter than I should be, though I certainly hope I climb well for my weight, especially as my third (and hopefully charmed) ascent up Haleakala is looming large in Vajanuary. The point is, I’m not a whippet and even if I starved myself for the next five months and subsist exclusively on IPAs (I draw the line at cutting beer out of my theoretical diet; I might get desperate, but I’m no savage) I’d still be an Eros Poli at best. Being a big guy, the only factor that mattered to me when it came to tire pressure was avoiding the pinch flats that plagued me during my time riding cheaper tires and that meant maximum pressure, no questions asked.
We always dialed our pressure in for Mountain biking and would pull a few pounds out of our road tires when riding in the rain, but by and large, tire pressure was tire pressure, and as far as I was concerned, more was better. I even had a set of 20mm tires on a makeshift TT bike I had that I blew up to a whopping 10 bar. In the last few years, however, the Cycling world has become obsessed with doing the limbo and seeing how low they can go on tire pressure. It all began with an article in Bicycle Quarterly which conducted an extensive and flawed study on the effects of tire pressure and tire width, and concluded that lower pressure and wider tires are faster and more comfortable than high pressure, narrow tires; the idea is that lower pressure allows small bumps to be absorbed by the tire rather than bouncing the bicycle (and rider) in the air, and that wide tires flex more efficiently than narrow tires resulting in lower rolling resistance. Its important to remember that this gain in comfort and efficiency also comes with an increased risk of pinch flats.
This is all well and good, of course, though we always have to be careful to remember the basic principles of such a compromise; lower pressure and wider tires also mean an enlarged surface area which necessarily means more friction; a perfectly hard, narrow tire on a perfectly smooth surface would have almost zero friction, to the point that you’d be unable to gain enough traction to actually move the bicycle at all. What we’re after, in a practical sense, is a balance between the two extremes which optimizes comfort and tire efficiency against reduced surface area and the risk of pinch flats.
I became infected with Tire Pressure Fever myself as the Cycling world became increasingly obsessed with tire pressure. Down went the pressure in my tires and immediately I felt sluggish and lethargic on the bike. Climbing out of the saddle, I could feel the tires flex as I unleashed the Awesome Devastation of the Toothpicks of Navarone. Cornering was like steering in molasses; turn the bars, weight the pedals and then wait a few moments while the bike got round to responding.
These observations first had me reaching for the pump and then got me theorizing about what is really going on with tire pressure and what pressure is right for a given rider. I say “theorizing”, but most other people would use something closer to “guessing assertively”. But that doesn’t mean I’m wrong.
Basically, it comes down to finding the highest pressure and narrowest tire you can that gives a rider of your weight the right amount of tire flex such that your bike isn’t bouncing as it rolls over the tarmac and allows it to roll efficiently, all while minimizing surface area, risk of punctures, and sidewall deformation when accelerating (cornering and climbing are basically the same as accelerating; the acceleration vector is just in some other direction than forward.) This means that each rider at each weight with different preferences on the sliding scale between the above compromises will find a different optimal pressure. Impressed by Tom Boonen’s tire pressure at Roubaix? Tread carefully; that pressure was dialed in based on very specific criteria and unless you’re eating the same cobbles and weigh the same as he does, you’ll need a different pressure to find the same balance. Bicycle Quarterly has a chart that shows what they believe to be the ideal pressure by rider weight, though I don’t believe a word of it; I do however entertain the possibility that I could be missing something based on the fact that I didn’t actually read the article.
Me? I’m still happily riding at 8 point V. I’m comfortable, I’m not flatting, and I’ve got good control. Besides, it just has a nice ring to it.
@sthilzy
Those are precisely the tires I was describing in the article; Conti Super Sport Ultras. I think they came in a wire and kevlar bead at the time and I bought the wire back then. I was probably in 5th or 6th grade. Glad to see they still make them. Smooth tread in the middle and grippies on side.
@Russ M
Welcome, and sorry that your photo wouldn’t load. Not sure what wizardry you were trying to pull off, but if you log in you can just upload a photo or embed one using the little photo button.
@Gianni
It doesn’t surprise me because BQ gets it wrong every time, in my esteemed opinion. In the article that started the whole revolution, the author started off saying that rumble strips and cobblestones feel about the same so any test done on rumble strips therefor apply to cobbles. What a fucking load of shit. I could barely keep the vomit down until I finished the article, at which point I chucked the mag in the rubbish bin and puked on it.
@VeloVita
I’m running 25’s on my Rain Bike and I run them at 8.V bar just like everything else. They seem more comfortable and seem to have better cornering traction in the wet, though I suppose I’d have to think carefully about if that is actually true given I’m still riding them as hard.
There. Done thinking hard about that and yes I think wider tires have more traction even at the same pressure.
@mauibike
Looking forward to it.
@the Engine
Surely I don’t have to tell you that unless a Keeper writes about it, its not recognized as an official discussion.
The Schlecks must head up the mountains at 2 bar in order to avoid blowing their tires this way on the way down.
@Marko
You need a set of tubbies; talk about cornering comfort. You can also go lower without the downside of having things getting sloppy; the round tire just holds it shape better both cornering and accelerating.
I hardly felt a loss in performance on my FMB Paris-Roubaixs when I was all the way down to 6 bar for our rough rides at Keepers Tour 2012. I’ll try something in the 5 range this year.
@frank
Less pressure up front, because less weight means you can get away with it. Less pressure allows the tire to deform more, more surface area, more friction,more grip for cornering. The tire can also deform around uneven surfaces more easily, keeping better contact. Not to mention increased suspension. Rolling resistance is so negligible I don’t even care, just like hollow/carbon/aluminum/titanium bolts, whoopdy-do!
@frank
Yeah, wider tires still deform more if pressure is held constant between the two.
@frank
I had not read that article so I was living in vomit free heaven until you just relayed it to me….thanks Frank I am now brushing chunks off the keyboard!
Here is something to assist ( http://www.vittoria.com/en/app/ ) from our good friends over in Madone Italy.
@frank
Then what do the collective Velominati think of Jan Heine’s Grand Bois (Panaracer) tires? I was considering picking up a set of the 23 or 26mm versions as I’m looking for a gumwall clincher that’s relatively light and supple but more durable than the Veloflex, Vittoria or Challenge offerings. I’ve read good things about the Col de Madelines and Cerfs, but not necessarily from anyone I particularly trust.
@Russ M
I knew this lower tyre pressure thing was an April fools joke…it is telling me I need to set mine at Zero Bar. I think it is saying to me “Fuck off fat boy, you need to go solid rubber, get a Penny Farthing!”
@Deakus
Mmm read the small print…mobile app only does not look like you can use it on your PC! I am afraid I don’t have a smart phone……because I am already SMART….so I guess I will have to live with pinching the tyres and go “yeah seems ok let’s just ride!”
@Nate
I agree wholeheartedly, and this is more or less the point I was getting at. The FMB’s construction is so sublime that they perform amazingly at high and low pressures; even at 9 bar, they feel like pillows. The all weathers I’m riding on the rain are probably better to ride lower because their casing is so unforgiving that there’s likely too much loss in the rolling efficiency.
This is, of course, a nonsense expression; less is less and more is more. Less might be better, but its not more.
I don’t think it doesn’t matter, I’m saying it has different forces on it than the back and therefor requires different thinking. Case of extreme is CX; I lost my front wheel in a fast corner because I was running it too low – the back tire needs traction to give grip for acceleration but the front only needs it for steering – they’re very different requirements. You can run – and I have been doing this quite happily since my crash – the front much higher than the back and have great steering control while the back is run really low to keep good grip on the mud. This also keeps the front from flatting when you hit something hard; normally you hit something and bang the front rim and then instinctively unweight the back a bit – if you have the front high enough not to bang there is a good chance you’ll be off the wheel by the time it hits the same thing.
If your front wheel needed zero traction, we’d all be on unicycles and, as @Chris says, then we’d be on a different site…
@Deakus
If that didn’t work go to the sites Vittoria home page and check the TECH tab under that pick FAQ and then scroll down to what they refer to as the ideal tire pressure chart. While im sure someone put alot of time into creating it , there is no substitute for works well in our own neck of the woods. 8+bar “V” for me. 90kg fighting weight and happy. You said it best , lets just ride and look forword to the IPA at the end .
Unrelated: Wiggo jams out? He looks mighty uncomfortable.
I’ve found myself in a position where my only pump is a €14 handpump from Decathlon (a sports megastore here in France). I lack the necessary Velominatus Budgetatus savvy to acquire an actual pump, so I’m running my tyres at whatever pressure my forearms tyre out at.
My (cheap) track pump broke a while back, so I have been riding at about “I’m sick of this hand pump”bar for a couple months. Lots of flats, but a Lezyne is on the wish list. My rear has had a slow leak for 2 or 3 weeks and I was too lazy to patch it so I just inflated it everytime, it would be flat by the next day. I just patched it though as part of my Christmas break great bike strip-down and clean.
@VeloVita
Panaracer Pasela TG K 25c. No trust in me.
@frank
Was looking for a site containing monkeys on unicycles but found this excellent example of peer pressure going wrong:
@itburns
That is just awesome! Shame the monkey did not remove some of the daft idiots from the gene pool!
@unversio
I’m not sure what you’re saying, but that tire at 320 grams probably rides a lot differently than the 220g Grand Bois Col de Madeline or Cerf I was referring to. I’m guessing the difference would be akin to sleeping on a rubber ‘piss protector’ sheet vs some 900 thread ct Egyptian cotton. That said, each serves its own purpose.
Not sure what I am saying either. You gave a wonderful analogy though. I’ll go back to my silence.
@frank
http://www.youtube.com/watch?v=0A5t5_O8hdA
@VeloVita
What does it mean when listed 260|320g ? 260 or 320 ??
@frank
This is the image I have in my head on the way down:
http://www.youtube.com/watch?v=RxXqQqAc2pA
@unversio
The lower weight is for the folding version with the aramid bead, the higher for the steel bead. I stand by my original assessment though as both have a 66tpi casing which isn’t terribly supple. I still don’t understand what you were saying though – were you saying they were good or bad?
@xced
Brilliant, at 85kg, that means always 8 point V bar.
This is always a topic of converse on the club run, particularly if someone gets a puncture. One particular club member being obsessed with which tyres, size and tubes the puncturee was riding.
these things can go too far sometimes…..
@simonsaunders
As bad as roadies are, go on a ride with a few CXers and you’ll go insane. Pressures are measured down to fractions of pounds. Its not uncommon to be on the start line and overhear the nervous chatter of what pressure they are running and should it be this or that. It never fails: right before the gun goes off, you’ll hear someone letting a bit more air out of their tire. Pfft.
Seems about as productive as letting out a fart before a climb to try to reach a better power-to-weight ratio.
@frank
I prefer to let air out of my neighbor’s tire right before the starting gun. As much air as possible.
@frank Wasn’t it Museuw who was famous for nervously letting even more air out of his tires at the start of Paris-Roubaix? I think I read an anecdote somewhere that finally the wrenches would fill the tires to the requisite (low) pressure and superglue the valve stems shut, against him letting the air out.
@frank
Well, that would obviously be counterproductive as everyone knows that hot air provides lift.
@VeloVita
I’ll now say, “they are not so good (for road).” But will keep plans to use them on the off-road (semi-dirt road) ride that I am planning in January.
@Gianni
I have a Fuji SST which is quite stiff, so Ive kinda killed two birds with one stone by doing it this way …. very responsive and fast up front but quite compliant up the back and not so hard on the old “behind”.
Works well and no noticeable effect on performance.
Maybe a bit of placebo effect going on here also.
This is how you feel when trying to inflate a tire (tyre, whatevers) with a shitty pump:
Hmmm:
Never mind………..
@scaler911 Please explain …. my brain hurts
I invest enough time ensuring my socks match my R1s that match my shorts that match my arm warmers that match my gloves that match my Jawbones that match my Mavic helmet that matches my S5 to worry about such inconsequentials like tyre pressure. Velominatus pedantry is a demanding beast.
I have been thinking about this stuff for a while now, so very fortuitous, Frank. I have run the Force/Attack combo with happy results. I have used lightweight Tufos, that lasted for over a Year. I still find myself attracted to some of the more Italian skinny tyres. Pumped to near max psi in the rear and only slightly lower in the front. Consider it very traditional. Like 3x spoke. But given the chance to need them, a set of FMB P-Rs would be sweet.
I think I need to get in touch with FMB. For professional reasons of course.
Checked my Joe Blow and been riding my Conti GP4000’s and Gator Skins at 110psi, which I check before each ride, this equals 7.V bar so obviously I need too loose 4 kilos!
I suspect much of the move to wider tires and lower pressures is a way to smooth out the harsher ride of deep section carbon rims. Modern alloy wheels often have a similar issue: overbuilt rims to compensate for low spoke counts. My old-school wheels, with ~300g rims, 32 DB spokes and 19mm tires feel far cushier and somehow “livelier” than my 24/20 spoke 50mm carbones with 22s. All are tubular, Conti Competition or Sprinter. Pressure is always 8 to 8.V bar. Decades ago I was warned that lower pressure would precipitate rolling a tire.
My numbers are always at the end of the scale… (eheheh).
What’s with the obsessing over 5 to 10 psi here or there? I have two floor pumps, one an SKS and one a Bontrager. They each give different readings. The Bontrager produces a much harder tyre for any given reading. Therefore I am firmly in the camp of ‘if it feels right, it is right’, but I can’t necessarily put a guaranteed number on it.
I’ve always been happiest at 120psi which is near as damn it 8.V Bar. I’ve found that with anything less I start to notice the tyre moving about and a little voice in the back of my mind starts telling me that I can only feel the movement because I’m losing air.
I suspect that this has come from spending too much time on the rollers where the bike tends to bob when I’m down below 110psi and working really hard in the middle of a 2 x 20 or full on ten when you really don’t need little voices questioning your ability to finish at your current pace – extra voices telling you your’re losing air really screw with you as do the ones that tell you that your failure to achieve the principle of silence is bleeding watts all over the place.
The combination of my Dura Ace hubs and tubs is also feels beautiful fast at 8.5V without allowing too much vibration through.
@the Engine It always amazes me just how much he moves his body around in that clip. Classic.
@Fronk,
it’s a v. inneresting piece. However, you don’t say how tall/weighty you are to get an idea. I used to run 20mm rubino pro’s at 130psi until they exploded-frightened the shit out of the girls at the lights-and I had to walk 7K home. I’m 1.88m and much heavier than I should be. I also run the same pressure as you 120psi on all my tyres; tubs and clinchers which gives a silky ride. I’ve been doing it for so long my cheeks can tell if the tyre pressure is low.
You boys are running some serious pressure……I sit around the 6 and V bar mark or 95 psi in old money. I’m about 81 kg so not that light.
@Nate
Hey, whatever gets you there in your head. Personally, I’m above such trickery like farting to lower my BMI before a climb.
I fart for propulsion and weight loss. Much more rational and a double-whammy to boot.
@unversio
Ah, yes the low TPI count casing and the kevlar belt most likely makes for a pretty stiff tire – surely durable though.
@Monty
I can certainly notice a difference of 5-10psi on chip seal roads. On my aluminum Ridley that can make the difference between finishing a long ride fairly fresh and praying that its close to being over halfway in. So much is made of the difference in ride quality between frame materials (e.g., aluminum is harsh, steel is like butter, carbon absorbs road buzz) but then people throw stiff tires on and pump them up until they feel like granite. Ride quality can be dramatically enhanced/altered by careful tire and tire pressure selection.
@Dan_R
FMB also has a pile of other tires which I assume are as supple. The only problem with FMB is that they realize they have a quality tire and they charge accordingly. When I say “They” I mean “Francois” as I don’t think there is anyone else working for him.
@piwakawaka
This is a beautiful viewpoint: use your ideal tire pressure to decide what your ideal riding weight is. It’s so backwards its forwards!