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Speed issues on flat stretches of road

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  • January 15, 2018 at 8:46 pm #28026
    slippy62

    I’m 5’11, 70kgs and fortunate enough to ride good quality, lightweight bikes.  I’ve been cycling a little over 3 years now.  I average 100 miles a week.  I live in the Cotswolds.  Lumpy when I need it to be, or flatish over towards the Malverns.

    I ride with two other ‘enthusasitc amateurs’ on a frequent basis and can hold my own on the climbs, but have always struggled on the downhills (I am very cautious, and sit on the back brake all the way down).  No problem so far (I’ll never master going fast downhill, and that’s fine by me).

    Where I seem to fade, or at least, drop back consistenly on my group rides is on flat stretches of road.  I just can’t figure out what I am doing wrong!  It’s very frustrating.  I am fit, have an FTP of 255w and I can easily hold a cadence of 95/100 for 8-10 minutes.  

    The guys I pedal with seem to make it look effortless, yet I am pushing threshold just to keep up, having to sprint to catch up and then work hard to keep with them.  It’s disproportionate in effort compared to climbing.  I would be much happier at a permanent 8-13% incline that suffer the misery and embarrasment of 2 miles of 1% open road.  I know the segments locally that cost me time.  I’ve gone out solo to try and crack them and just can’t get quicker.   

    Fellow Roaders, please help – your candid views are appreciated (e.g./ man up, pedal harder, do more miles)… but even better would be useful advice about how I can train to be better at this.

     

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  • January 22, 2018 at 7:51 am #910081
    0
    CXR94Di2

    In a recent 1hr chaingang
    In a recent 1hr chaingang pace line on Zwift, I had a W/Kg of 3.4 compared to 4W/Kg for the riders who weighed 65kg. So lightweight riders need about 0.5-0.6 more W/Kg than heavier riders like me @92 kg on flat courses

    January 21, 2018 at 10:08 pm #910079
    0
    HLaB

    My FTP last test was 255w

    My FTP last test was 255w (although I suspect it has went down with all the bugs going around 🙁 ) and I’m only 62kg and similarly to other folk here and you bigger riders can pull away from me on the flat but it is getting less often as my w/kg has increased.  I think you need to work on getting your w/kg up 😉

    January 21, 2018 at 7:53 pm #910077
    0
    Welsh boy

    Thanks Pete and madcarew,

    Thanks Pete and madcarew, some interesting reading and some total non-scientific boll0cks in amongst that lot.

    January 21, 2018 at 10:45 am #910075
    0
    madcarew

    Welsh boy to ad to Pilot Pete

    Welsh boy to ad to Pilot Pete’s list (thanks 🙂 )

    http://www.velonews.com/2014/12/bikes-and-tech/resistance-futile-tire-pressure-width-affect-rolling-resistance_355085

    http://www.velonews.com/2014/12/bikes-and-tech/resistance-futile-tire-pressure-width-affect-rolling-resistance_355085

     

    January 21, 2018 at 9:50 am #910073
    0
    wycombewheeler

    700c wrote:

    700c wrote:
    Jimmy Ray Will wrote:

    As an aside, I have always marvelled at how better climbers automatically assume they are simply better riders (I say this as an embittered flat lander), or more accurately that poor climbers are simply poor riders. Horses for courses innit?  

    Lol yes I’ve often thought this.

    In group rides I’ve sometimes found myself going off the front on the flats or descents and getting ‘told off ‘ for it, only for the same riders to drop me on every climb without any quarms!

    As you say, horses for courses.

    Snap I pulled off on the front on a descent with the climb in view to have some chance of reaching the top of the hill with the group and was told off. On the previous climb I had been dropped and had to chase them for a mile on the flat to catch up again. Working together apparently only applies to benefit the best climbers.

    January 21, 2018 at 2:21 am #910071
    0
    Pilot Pete
    Welsh boy wrote:
    madcarew wrote:
    The tyre pressure issue is not nearly that clear cut. In all available tests, rolling resistance is lower with a higher pressure than a lower pressure, in normal operating conditions (60 – 150 psi)

    A wider tyre at the same pressure as a narrower tyre has a lower rolling resistance than the narrower tyre. Wider tyres have more air resistance than narrower tyres, and in nearly all cases this far out wieghs the very few watts RR savings…. at the same pressure.

    Very interesting and goes with what I have always suspected.  You dont see team pursuit riders (or any track riders come to that) using wide tyres inflated to low pressures so in events where speed is the only criterion riders are still using narrow tyres at high pressures.  I think the whole wide tyre, low pressure has gone out of all proportion and has become another marketing fad repeated without thought on cycling forums and clubruns, after all, wheel and tyre manufacturers need to sell more product dont they.  I went out yesterday on 23mm tyres after 2 years on 25mm tyres, same pressure, same roads, same level of fitness and over 3 hours I was 0.5mph quicker than usual!

    Madcarew, out of interest, could you point me to any of the research (serious question, I am not being funny, I would like to see my long held belief scientifically proved).

    A little explanation from tyre manufacturer Schwalbe https://www.schwalbe.com/en/rollwiderstand.html

    And Continentals thoughts on it; http://www.conti-tyres.co.uk/latest-news/165-wider-tyres-go-faster

    A video from GCN explaining it; https://youtu.be/yrHxQg1OW0A

    And the very reliable Steve at intheknowcycling; https://intheknowcycling.com/2016/04/03/best-wider-road-bike-tires-wheel-sizes/

    Hope that gives some insight into the theory.

    PP

     

     

    January 20, 2018 at 11:03 pm #910069
    0
    matthewn5

    Stay on the hoods, sit back a

    Stay on the hoods, sit back a bit, roll your shoulders forward to cut frontal area and bend your elbows. It’s like free speed.

    January 20, 2018 at 9:55 pm #910067
    0
    sergius
    efail wrote:
    I did the reduce tyre pressure thing last year. All it seemed to do for me was increase the number of punctures on crap, Cumbrian roads. I normally have about 100psi and reduced that to 85 ish psi. That’s about as scientific as I can be.

    I concur with this – my attempts to run reduced pressures just led to a massive increase in the number of punctures I received.  Tubeless is way to much hassle for me to consider it.

     

    Weighing 62kg…. (so none of these are snakebites)

     

    25mm @ 70 PSI = 4 punctures in the 4 months I experimented with it (~2000km)

    25mm @ 85-90 PSI = 2 punctures in the last 3 years (~15000km)

    28mm @ 85-90 PSI = 0 puntures so far (only done 1300km on that bike yet though)

     

    Arguably there is no objective difference in my speed based on tyre pressure – nothing that Strava can highlight.  Likewise, I would be hard pressed to objectively differentiate between the ride quality between 70 PSI and 90 PSI.

    January 20, 2018 at 8:00 pm #910065
    0
    BikeJon

    efail wrote:

    efail wrote:

    I did the reduce tyre pressure thing last year. All it seemed to do for me was increase the number of punctures on crap, Cumbrian roads. I normally have about 100psi and reduced that to 85 ish psi. That’s about as scientific as I can be.


    Tubeless would prevent the pinch punctures.

    January 20, 2018 at 6:23 pm #910063
    0
    efail

    I did the reduce tyre

    I did the reduce tyre pressure thing last year. All it seemed to do for me was increase the number of punctures on crap, Cumbrian roads. I normally have about 100psi and reduced that to 85 ish psi. That’s about as scientific as I can be.

    January 20, 2018 at 5:22 pm #910061
    0
    check12

    Speed on hills is power vs

    Speed on hills is power vs weight

    speed on flats is mainly power vs aerodynamic drag

    so if you’re a lot lighter with a bit less power you win on hills but straight power wins on flats. 

    January 20, 2018 at 5:20 pm #910059
    0
    check12
    Welsh boy wrote:
    madcarew wrote:
    The tyre pressure issue is not nearly that clear cut. In all available tests, rolling resistance is lower with a higher pressure than a lower pressure, in normal operating conditions (60 – 150 psi)

    A wider tyre at the same pressure as a narrower tyre has a lower rolling resistance than the narrower tyre. Wider tyres have more air resistance than narrower tyres, and in nearly all cases this far out wieghs the very few watts RR savings…. at the same pressure.

    Very interesting and goes with what I have always suspected.  You dont see team pursuit riders (or any track riders come to that) using wide tyres inflated to low pressures so in events where speed is the only criterion riders are still using narrow tyres at high pressures.  I think the whole wide tyre, low pressure has gone out of all proportion and has become another marketing fad repeated without thought on cycling forums and clubruns, after all, wheel and tyre manufacturers need to sell more product dont they.  I went out yesterday on 23mm tyres after 2 years on 25mm tyres, same pressure, same roads, same level of fitness and over 3 hours I was 0.5mph quicker than usual!

    Madcarew, out of interest, could you point me to any of the research (serious question, I am not being funny, I would like to see my long held belief scientifically proved).

     

    also depends on road surface, velodrome, yeah 22mm at 140psi, crappy back road with naff tarmac, 25mm at whatever suits your weight, say 80/90psi all about absorbing the imperfections vs bumping you up and down and you loosing energy dealing with those stresses, it’s got a name but my brain isn’t remembering it for me the the moment. Was a study done on tank driver seats and the bump absorption they gave, more was better I.e lower pressures tyres on a bike give you a smoother and faster ride. 

    January 20, 2018 at 4:35 pm #910057
    0
    Welsh boy
    madcarew wrote:
    The tyre pressure issue is not nearly that clear cut. In all available tests, rolling resistance is lower with a higher pressure than a lower pressure, in normal operating conditions (60 – 150 psi)

    A wider tyre at the same pressure as a narrower tyre has a lower rolling resistance than the narrower tyre. Wider tyres have more air resistance than narrower tyres, and in nearly all cases this far out wieghs the very few watts RR savings…. at the same pressure.

    Very interesting and goes with what I have always suspected.  You dont see team pursuit riders (or any track riders come to that) using wide tyres inflated to low pressures so in events where speed is the only criterion riders are still using narrow tyres at high pressures.  I think the whole wide tyre, low pressure has gone out of all proportion and has become another marketing fad repeated without thought on cycling forums and clubruns, after all, wheel and tyre manufacturers need to sell more product dont they.  I went out yesterday on 23mm tyres after 2 years on 25mm tyres, same pressure, same roads, same level of fitness and over 3 hours I was 0.5mph quicker than usual!

    Madcarew, out of interest, could you point me to any of the research (serious question, I am not being funny, I would like to see my long held belief scientifically proved).

    January 19, 2018 at 9:26 pm #910055
    0
    madcarew
    peted76 wrote:
    Just another thought… and I might get poo poo’ed for it.. but a heavier and or more aero set of wheel rims/tyres is easier to ‘maintain speed’ than that with than a lighter or less aero rim/tyre combo. 

     

    More aero makes a good difference in the wheels, extra weight makes almost no measurable difference at all until the road really tips up. It certainly doesn’t have any realistic ‘flywheel’ effect. Spot on with the aero though.

    January 19, 2018 at 8:55 pm #910053
    0
    madcarew
    andyp wrote:
    BBB wrote:
    andyp wrote:
    BBB wrote:
    250w is too little and 90PSI (for 28mm tyres) way too much.  

    what a strange answer. 250w is way too little for *what*? and 90PSI for 28s is way too  much…why?

    It’s not a strange answer. It’s a very simple one. 

    Objectively 250W is a moderate amount of power and clearly not enough to keep up with the other guys.

    90 PSI in 28mm tyres at 70kg is simply too much pressure. On typical UK roads it’ll slow you down, reduce comfort and distrupt the pedaling rythm. Far too many people still don’t understand what pneumatic tyres were invented for.

     

    That’s much better. Well done for qualifying your answer with some thought.

     

    The tyre pressure issue is not nearly that clear cut. In all available tests, rolling resistance is lower with a higher pressure than a lower pressure, in normal operating conditions (60 – 150 psi)

    A wider tyre at the same pressure as a narrower tyre has a lower rolling resistance than the narrower tyre. Wider tyres have more air resistance than narrower tyres, and in nearly all cases this far out wieghs the very few watts RR savings…. at the same pressure.

    So our OP, riding wide tyres at a high(er) pressure is taking advantage of better rolling resistance than those at lower pressure, while his air resistance is of less issue as he is slipstreaming, so he is in the fastest conformation (tyre-wise) for his situation. He would be even faster (more energy efficient) if he pumped the tyres up to 120 psi. The savings are miniscule though. The tread pattern on his tyres has far more effect.

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