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  • Anonymous

    Whilst I am all for bagging friction its also handy to make the bike move when we pedal.

    • Anonymous

       and corner.

    • and stopping us falling off when cornering

  • jules

    is there any info out there on optimal pressures for racing? i’m 85kg and currently running 100psi rear and 90 front, which i based on one of those diagrams i found on sheldonbrown.com. i suspect this is too low :)

    at what pressures do people find it becomes dangerous to run in crits (presumably at some point, handling/grip will suffer)?

    • Notso Swift

       Generally accepted that 12-15% drop is optimum in balance between drag and lateral grip, but you just need to try a few variables

    • Echidna_sg

       Depends how wide your wheel and tyre are. On zipp 404’s (pre-FC) I personally find about 110psi is best for me, but on Hed Jets, 90 psi is better…

  • VeloNomad.com

    Great article. The best Ctech one yet. By miles.

  • Unremarkableboy

    On getting a flat w/ butyl versus latex: the grain structure of the butyl creates a cascading reaction due to the tensile for from expansion and flaw induced by a foreign object, the latex on the other hand has a more random grain structure (which prohibits it expanding as much) but in the case of an induced flaw it cannot propagate and cause a puncture. So for puncture protection, latex is better and faster. Just pricier. 

    • Echidna_sg

       until it really goes and then latex often splits with instant deflation the result…. I’ve had it happen on a front wheel not long after a descent at around 35km/hr when the bunch slowed – possibly due to heat build up in the wheel (1200gm alu climbing clinchers). Net result I’d be dead if it happened during the descent at 70+km/hr but managed to keep it upright (just) at the lower speed – the tube had split for about 1/3 of its circumference. Vittoria super light latex, had done about 250km prior to the incident.

      • jules

        kindly desist from posting these incidents in future thanks, scares the bejaysus out of me :)

        • Echidna_sg

           you weren’t on the bike at the time!

          still, not a patch on when the face plate on my stem gave way and the bars just rotated out of my hands and I was watching the front tyre approach my nose at pace inside a group!
           

          • jules

            this guy needs to be banned now ;)

          • As Fyxo says “life’s to short to ride shit bikes” :-)

      • Info

        I second this concern about latex tubes.  I tried latex for about 3 months until I had a major blow out at 60km/hr. I came away unharmed but it scared the life of me. like Echidna_sg said the deflation has instant like and explosion. See picture attached of what the tube looked like. 
        Personally I don’t think they are worth the extra few watts you save.  

        • Comenarra_Dreamin’

          I had a tube that looked like that too – although mine went at about 45km/h on a gradual downhill. I put mine down to possibly mounting it with the tube under the bead of the tyre. Mine also had some black markings around the tear that I took as supporting this theory. As latex tubes are so supple, it is easier to get them caught under the bead when mounting a tyre.

          Should I revise my theory, or would this fit with your situation too? i.e. Had you changed tyres the night before?

          • Echidna_sg

             I’d ridden mine for over 250km since fitment on some pretty rough roads and when it went, everything was smooth, slight downhill curve. Given I’d been blasting along a descent only a few minutes prior and really leaning into the curves, I find it hard to believe that there was a pinch responsible…

        • Echidna_sg

           Very similar to the way mine looked…. except yours split over a shorter length….  net result is that I’m not convinced its worth the risk either and have gone back to lightweight conti tubes…

        • Richard

          Everytime my latex tubes looked like this, it was always a pinch flat, As mentioned before latex is so supple it can be pinched without giving way for a period of time!

          I now result to putting taccum powder on the tube and tyre before fitting(this is every install after the first time the tube is out of the box)

        • Richard

          Everytime my latex tubes looked like this, it was always a pinch flat, As mentioned before latex is so supple it can be pinched without giving way for a period of time!

          I now result to putting taccum powder on the tube and tyre before fitting(this is every install after the first time the tube is out of the box)

        • GT

          I was talking to a guy at the coffee shop a few weeks ago – he mounted his bike to leave, dropped over the curb to the road, not even clipped in, and BANG. It was like a gunshot.  Turned out it was a latex tube as well, but at least it went when there was no chance of injury.

    • Anonymous

      Next reader survey should see how many of us have science or engineering backgrounds. Always good insights in the comments section!

      • jules

        i have an engineering degree, but unless you also have practical experience in a relevant field, it only enables you to speak with authority at the theoretical level. i’ve studied materials science at uni, but strangely enough we never covered the important topic of latex vs. butyl bike tubes. although years of fluid mechanics probably allows me to visualise the impact of varying tyre pressure on contact patch size etc. more easily than some. short answer – having a qualification doesn’t automatically mean your opinion is authoritative.

      • jules

        i have an engineering degree, but unless you also have practical experience in a relevant field, it only enables you to speak with authority at the theoretical level. i’ve studied materials science at uni, but strangely enough we never covered the important topic of latex vs. butyl bike tubes. although years of fluid mechanics probably allows me to visualise the impact of varying tyre pressure on contact patch size etc. more easily than some. short answer – having a qualification doesn’t automatically mean your opinion is authoritative.

        • Ed

          yeah but i like putting CP ENG on my emails and business cards

          • jules

            i did too but i found people just got confused about why i was working at Blockbuster

            • Anonymous

              Dr Jules – Principal Video Asset Manager MIEaust CPeng

        • Anonymous

          I was realistically more interested in the technical background of some of the people here and how it influences how they view cycling and their bike. How many other sport activities invite this type of indepth research that cyclists seem to do? I mean its not like we do this because we are shaving off a few seconds to win a time trial because its our livelihood? I too am a practicing structural engineer and it makes me think about my bike in ways I dont think about other elements of activities I perform.

          • jules

            i can appreciate that – i enjoy the mechanical side of the sport (i.e. maintenance) almost as much as riding

            • Rasmussen

              One of my many excuses for being slow. 

    • Anonymous

      Next reader survey should see how many of us have science or engineering backgrounds. Always good insights in the comments section!

    • Craig

      My experience has been very good with Michelin latex never having had blowouts with them at all. Less punctures than butyl too. I still have some that must close to 10 years old and are still going strong.
      I have been told though (by Zipp engineer)not to use them in all carbon clinchers because they do not handle as higher temps as what butyl tubes will.   

  • Nick

    For anyone interested in the S-Works Mondo’s, they have been replaced with S-Works Turbo which are meant to have even less rolling resistance.

    • Craig

      I actually found these tyres to be rubbish. Felt dead and not alot of grip.

  • D-Man

    Don’t forget the colour.  Has to match the paintwork.

    • Echidna_sg

       you mean black? as in there is no other colour tyre but black (with gum walls for the classic bikes)

    • Echidna_sg

       you mean black? as in there is no other colour tyre but black (with gum walls for the classic bikes)

  • Kiwicyclist

    On inflation pressure also remember there is quite a difference between what your pressure guage says on the floor pump vs what the pressure in the tire actually is.  Until I recently started using a valve guage I had probably being riding around on 95 -100 psi thinking it was 100-110 – the variance is about 5psi (for my pump anyway).

    • Andrew

      I have been having issues with accurate tyre pressure as well. What type of gauge do you use???

  • Thanks, a most interesting article. I’d encourage everyone to read the Bicycle Quarterly blog post you linked to (http://janheine.wordpress.com/2012/06/13/bicycle-quarterly-performance-of-tires/) because he talks about how the typical manufacturer tests don’t reflect real world conditions.

    Jan’s tests disagree with the roller data in a few places. He finds latex tubes to roll slower, and wider tyres always better in his tests (read the comments on the above post).

    My other concern is the focus on speed – rolling resistance and aerodynamics. If you are not racing – just social riding or sportives or Gran Fondos for example – then comfort is pretty important too. Wider tyres and lower pressures soak up the bumps and reduce fatigue. Also puncture resistance deserves consideration – for most amateur races, a puncture is almost guaranteed to cost you the win isn’t it?

  • Thanks, a most interesting article. I’d encourage everyone to read the Bicycle Quarterly blog post you linked to (http://janheine.wordpress.com/2012/06/13/bicycle-quarterly-performance-of-tires/) because he talks about how the typical manufacturer tests don’t reflect real world conditions.

    Jan’s tests disagree with the roller data in a few places. He finds latex tubes to roll slower, and wider tyres always better in his tests (read the comments on the above post).

    My other concern is the focus on speed – rolling resistance and aerodynamics. If you are not racing – just social riding or sportives or Gran Fondos for example – then comfort is pretty important too. Wider tyres and lower pressures soak up the bumps and reduce fatigue. Also puncture resistance deserves consideration – for most amateur races, a puncture is almost guaranteed to cost you the win isn’t it?

    • For what it’s worth, good quality modern tyres are pretty puncture resistant.  I think I’ve had two during a race over the last three seasons.  Tubulars, particularly, seem to be very hard to puncture.  El-cheapo OEM tyres, not so much.  IMO the first thing anybody who buys a road bike should do is bin the cheapie tyres and fit something better – or, alternatively, negotiate with the dealer to fit something decent as part of the deal.

      If you want extra puncture resistance for not-racing, Continental Gatorskins seem to be all but bulletproof.

  • Thanks, a most interesting article. I’d encourage everyone to read the Bicycle Quarterly blog post you linked to (http://janheine.wordpress.com/2012/06/13/bicycle-quarterly-performance-of-tires/) because he talks about how the typical manufacturer tests don’t reflect real world conditions.

    Jan’s tests disagree with the roller data in a few places. He finds latex tubes to roll slower, and wider tyres always better in his tests (read the comments on the above post).

    My other concern is the focus on speed – rolling resistance and aerodynamics. If you are not racing – just social riding or sportives or Gran Fondos for example – then comfort is pretty important too. Wider tyres and lower pressures soak up the bumps and reduce fatigue. Also puncture resistance deserves consideration – for most amateur races, a puncture is almost guaranteed to cost you the win isn’t it?

  • shinyandfree

    I once saw multiple latex blowouts just from sitting in the sun on a hot day. That was it for me

  • shinyandfree

    I once saw multiple latex blowouts just from sitting in the sun on a hot day. That was it for me

  • shinyandfree

    I once saw multiple latex blowouts just from sitting in the sun on a hot day. That was it for me

  • badaboy

    Would like to see some thoughts on tubeless.  Campagnolo seem to have committed significant development to this and offer options in their range of wheels.  Something must have ticked the box for them.

    Also, I use Michelin Pro-3 with their latex tubes.  The tyre cut up a bit but I found incredibly puncture proof todate.  It could be the tyre it could be where and how i ride.  But I use to ride Conti’s GPs now only the Pro-3s and soon Pro-4s.  The last time I had a puncture, was more of a slow leak.  I found that the latex tube had stuck to the inside of tyre casing this was on full carbon clincher rims (enves 45s) I wonder if it was due to heat build up (carbon).

    • Alpuncho

      I have run tubless for few years on Shamal ultra 2 ways fit,I got a love and hate relation with these tyres (hutchinson )when they are on the wheel this is great, I run 90 psi at the front and 95 psi at the back,they rolls and corner very well
      .Due to the low pressure this is a very confortable ride compared to the normal clincher ..But they are a pain to fit in..I ‘ve had bleeding tumbs to fit them on! do not use any lever as this will create micro dents and damage the carbon bead .”.the tubless” bit will be busted!(can still fit a tube,but..)Futhermore when you get a flat  they are tricky to fix,again I use them with a tube .So I am back with conti 4000s which are nearly as good,  more practical but not as confortable.

      • Toggles

        I would like to see the data on tubeless tires as well.  I have found that they roll much smoother than just a normal tire/tube combination.  They actually feel very similar to riding tubular wheels.  I would think that they would have the least rolling resistance since there isn’t a tube.

        Alpuncho – The Hutchinson tubeless tires are a pain to get on (I hated having to install them when I was managing a bike store).  If you are willing to try tubeless tires again, try the Maxxis Padrones.  They are more expensive, but they were recommended to me by a friend that works at Shimano.  They are easier to mount (I used soap and water on the rim and bead of the tire) and they ride just like GP4000s (my favorite clincher tire).

      • Toggles

        I would like to see the data on tubeless tires as well.  I have found that they roll much smoother than just a normal tire/tube combination.  They actually feel very similar to riding tubular wheels.  I would think that they would have the least rolling resistance since there isn’t a tube.

        Alpuncho – The Hutchinson tubeless tires are a pain to get on (I hated having to install them when I was managing a bike store).  If you are willing to try tubeless tires again, try the Maxxis Padrones.  They are more expensive, but they were recommended to me by a friend that works at Shimano.  They are easier to mount (I used soap and water on the rim and bead of the tire) and they ride just like GP4000s (my favorite clincher tire).

    • lekoshe

      Schwalbe were claiming at shows that their upcoming Ultremo ZX Tubeless has the lowest Crr of their entire range.

  • shinyandfree

    I’ve read that there is a psi tipping point where too hard a tire actually has more rolling resistance. This makes sense to me especially since most roads are not perfectly smooth. Picture a ball bearing rolling over a sheet of glass; very low resistance of course, much lower than say, a basketball. However, picture that same ball bearing bouncing over a textured surface. In that case it seems intuitive to me that something with a bit of give might roll a bit easier. I wonder if these tests took surface texture into account. I guess I could just read the study… 

  • Rob

    Re: tyre width, just chuck a 25mm on the back, where aero isn’t such a concern.

  • Slhaydon

    25’s are so PRO

  • Troy van Trienen

    What a handsome man servicing the bike :)

    • shaninadelaide

      That’ll buy you a coffee next time you visit the store. (I am not being paid to alude to the fact that this photo was taken at a lovely LBS in Camberwell in my comment) 

    • shaninadelaide

      That’ll buy you a coffee next time you visit the store. (I am not being paid to alude to the fact that this photo was taken at a lovely LBS in Camberwell in my comment) 

  • ben

    Hey CTech, are there any facts or even factoids on the optimal profile height of a bike tyre? For cars they seem to have a fair range, and the lowest profile tyres are preserved for racing (and *bleep* hoons), but then I guess they are completely different in that they also have suspension.

    • CTech

       I’ve been wondering how much profile influences rolling resistance and whether wider tyres benefit from being wider, taller, or wider AND taller… I never came across anything while researching this article that considered this question. I’m not sure how much the profile of a road bike tyre can be varied without influencing its width when the shape of the tyre is essentially tubular.

    • Guest

      Open wheelers (Formula 1, formulla ford, karts) etc… all use high profile tyres, although in this case it’s more about suspension in the tyre than rolling resistance

  • Crothenb

    Here’s my 2 cents on the attached tyre test.
    Only looking at the top 20 tyres tested. If you remove all the tyres regarded as track, TT specific and 20mm width(who rides them nowdays) and concentrate on road, 22/23mm+ widths you get much more realistic results for most riders.
    The top ten tyres now fill only 2 positions with the number one tyre  being the mondo.
    FWIW the Mondo was one of the worst tyres I have ever used.
    As far as preasures go this test was conducted on a”very smooth” surface. I believe there is enough evidence/tests out there now that show that on nornal road surfaces (chip seal etc) that lower preasures generally produce beter Crr results.
       

    • Craig

      Edit.. Tubulars now only fill 2 of the top ten positions..Sorry brain fart!  

  • Hardo

    Ohhhhh wow, more pretty graphs!

  • tyre tech gold. Thanks Matt for bringing out the subtle point about latex tubes. 

  • Meck A Nic

    This is all well and good but how about some genius design a clincher that is actually easy to get on and off after a puncture! Thanks also to the 20+ riders who didn’t stop to help me last week in the pissing rain when i couldn’t get that damn Vittoria Rubino tyre back on.

    • Craig

       Gee I’ve never had a problem with getting clinchers on and off rims..ever!…its all technique!

    • Chris Dunbar

       Tires and rims have tolerances for diameters. Your 622mm rim or tire is not exactly 622. Continental makes their tires on the small side of the 622mm tolerance while Campy makes their rims on the bigger side. A known “issue.” That being said technique can actually go a long way.

      I’ve only used Vittorias once quite recently and they mounted somewhat tough on to a Velocity rim but not a struggle.

    • Notso Swift

       Since you are too Pro to carry tyre leavers I can suggest you use your QR’s as a leaver

  • purpletezza

    Regarding ideal tyre pressure have a read of this article. I kinda makes sense.
    http://www.bikequarterly.com/images/TireDrop.pdf

  • Notso Swift

    For those who have instant blow out issues on latex, well it does (very rarely)  happen on tubulars, but since they are not flopping around like a cock in a sock like deflated clinchers it isn’t as much of a problem.

    Since you are only using the extra speed of Latex for racing and clinchers are only for training there shouldn’t be a problem ;-p

  • Tony R.

    I’m wondering how much difference these rolling resistance number make on the road. For instance if I was to ride a 40km ITT using the GP 3000 then the Mondo,on an average Australian road.What would be the difference in actual performance. If I was able to average 40kmh what would the wattage difference between tyres? Or is there some other way of quantifying what my performance would be like between the two tyres. 

    •  Tony, in general you can do this sort of calculation using the calculator at Analytic Cycling.

      • Tony R.

        Thanks for the link Robert,site looks very interesting.

  • Kim

    Matt great article once more. It was well summarised also at the end. My question is about tread and patterns do they make a difference. Once upon a time in motor vehicle tyre tread patterns were everything but not any more everything seems to have moved to slicks. 

    • Rob

      Cars have tread to prevent aquaplaning. A road bike tyre is too thin to aquaplane at reasonable speeds. 
      Racing cars do often have slick tyres, but this only applies during dry racing – as soon as the rain starts, the wet weather (non-slick) tyres go on.
      Of course, this doesn’t apply for mountain bikes where the tread pattern is designed to grip gravel and other loose surfaces.

      • Kim

        Thanks Rob, makes sense.

      • Kim

        Thanks Rob, makes sense.

  • Tony B

    I reckon wider tyres will have the same contact patch size as narrow tyres. ie Put 100 pounds per square inch in each tyre, add a 200 pound load and you will have 2 patches of 1 square inch. The shape will be different, and the deflection of the narrow tyre will be greater. I think is is the friction caused by  the deflection is the main factor in rolling resistance.

  • Anonymous

    I understand that the tests referred to included a bumpy roller to simulate rougher roads, but in the absence of more detail I do wonder whether they were sophisticated enough to pick up the energy losses caused by bouncing the bike and rider. There may be a lot of roller data, but if it all misses out on accounting for rider and bike bouncing losses then it’s flawed for all but smooth roads. By contrast, the Bicycle Quarterly rolling downhill test would have picked up all resistances.

    It has been remarked that higher pressures are associated with lower resistance because the increased vibration experienced by the rider gives an impression of higher speed. I can relate to that, but I run 120/80 based on a 15% drop rear and front.

  • hamburger

    This is a great article with plenty of facts & figures. A pity though that most Australians don’t have access to the Tour magazine reviews. Tour have the most advanced reviews when comes to product testing, undertaken by qualified German engineers. Their data sets take a lot of myths out of the discussions for many reasons. Tour have recently released a new ranking for lowest rolling resistance in their 09/2012 issue. Conti 4000s comes in 5th overall… The times of tubulars are clearly over when comes to rolling resistance. None of the current top-level tubs is able take on the best clinchers. But the reviews also underline the importance of tubes and glue for both. Further, the review compares the actual time + Nm needed, for a spike to puncture each tyre. Im combination with weight and the grip (tested with a special vehicle in wet & dry conditions on the Continental test area where they can wet/ice the roads, etc.) you can figure out which tyre is to choose for race day.

  • Harry Major

    “Increasing air pressure in a clincher or tubular will decrease its rolling resistance (for example see Figure 5). This relationship is obvious one and accounts for the willingness of many riders to test the maximum inflation of their tyres. However, there comes a point where the reduction in rolling resistance becomes minimal and the rider has to contend with the disadvantages of over-inflated tyres, which include a harsh, unforgiving ride and a loss of traction.”

    This, in fact, is not true on real road conditions. 
    You mention Bicycle Quarterly early on in your post. This is good, because the testing of tyres in BQ and the work they have done to understand the performance of tyres is more far reaching than anyone else that I am aware of (it also seeks to re-examine the basic assumptions, and not take them for granted). BQ identified early on that steel drum tests do not replicate what actually happens on roads. Steel drums show that the rolling resistance deceases by having wider tyres at higher pressures. This is true, in theory, but when on real roads this doesn’t hold true. The suspension losses in the rider caused by the vibrations account for a greater waste of energy than the gain caused by higher pressures. In essence (and quite surprisingly) what BQ seem to have come across is that wide tyres at lower pressures roll faster. 
    See http://janheine.wordpress.com/2012/08/12/suspension-losses/ for some more info (all though you need to actually buy the relavent magazine for the full details). 

    In a question of rolling resistance vs aerodynamics vs weight, the conclusion that seems to be becomming more prevalent amongst those that care to spend all day talking about tyres is that wider tyres are faster unless sprinting or climbing. And so the rider must make a choice; which is more important, or come to some sort of a balance. I’ve personally been doing some anecdotal tests on my own bike, and have found that for speed aprox 33c is ideal. But meh, take that with a pinch of salt. You also have to bare in mind that while aero wheel makers exclaim in horror at the extra drag caused by a slightly wider tyre, the truth in the aerodynamic damage to the complete unit (bike+rider) is really not very big. Lower your handlebars by 0.5cm and ride 5mm wider tyres and you’ll gain a greater aerodynamic advantage than you started with…. plus your tyres could roll up to 30% faster….

    The real key that come across from BQ though is that tyre construction matters the most. A light and supple tyre will roll much much faster, since it deforms better. The BQ test data proves this convincingly for those that care to read it. 

    P.S. Wide tyres feel slower. It doesn’t mean they are. BQ testing has on numerious occasions proved that the “how fast tyres feel” has no relationship to how fast they roll.

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