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Narrower tyres improving speed!

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  • July 1, 2014 at 11:24 am #21806
    CXR94Di2

    I have only been cycling regularly for a couple of years. I spent the first 18 months on my Kona mtb, I used it for both off road then more on road by fitting 47mm road biased tread tyres. My average speed gradually increased to 14.5mph over 40 mile circuits.

    Then last winter I decided I would try and ride 100 mile sportive events this spring/summer. I got a Boardman cyclocross bike mainly due to me liking hydraulic disc brakes. I really like the bike and fitted 32 mm schwalbe marathon plus tyres. They were comfy and rolled quite quickly compared to what I had been used to previously. I am thick set built chap weighing mid 15st but carry a lot of muscle mass (early youth body building:) )

    My average speed went up immediately obviously a lighter road bike and tyres. My first 100 mile sportive I averaged 16.5mph. I could then average high 17mph over 30 miles. A few seasoned riders on the sportive mentioned I would go quicker and it would be a little less effort if I moved down to 25mm race tyres

    Yesterday I had my first outing on Schwalbe Durano 25mm . Over a 28 mile route I averaged 18.40mph. A noticeable jump in average, my previous best on 32mm tyres was just 18mph (optimal conditions). I don’t think I could get any better results by moving down to 23mm, I don’t think my weight/body could tolerate the harsh ride.

    The ride is slightly harsher with 25mm but I find I can hold a larger gear for longer. Has anybody been through this learning curve?

    A

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  • July 3, 2014 at 9:41 am #801731
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    notfastenough

    bikebot wrote:notfastenough

    bikebot wrote:
    notfastenough wrote:
    I think Charles Hunter is right, the mantra that “wider tyres are faster” is directed at road bike riders that assume the thinnest tyres they can find (23mm) will be quickest. 25mm are generally thought to be best for UK roads. I don’t think there is a suggestion that you will go quicker on 32mm.

    Unlikely on 32mm, but there’s a lot to suggest that many riders even in sportives should be using 28 rather than 25. And when it comes to your typical Sunday ride or commute, more so.

    I deliberately avoided 28, as I wasn’t sure either way!

    I could see comfort being a factor – on rough bits or even just speed bumps, I pause pedalling and shift the weight off the saddle for a second. Anything that ensured I just pedalled right through would have an effect on performance.

    July 3, 2014 at 8:08 am #801729
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    fukawitribe

    700c wrote:I read the article

    700c wrote:
    I read the article which explains why 25’a can only be a good thing. Maybe 25’s are marginally better in certain circumstances, and certainly if you fine 23’s uncomfortable then definitely a wider tyre is useful

    In defence if the 23mm tyre, however:-

    we’re talking marginal gains aren’t we? So you have to factor in the negative aerodynamic effect of having a tyre bulge over the rim.

    Or the financial burden of upgrading your rims to a new, wider one which will accommodate a 25mm without the bulging effect.

    And the weight penalty of the wider rim + wider tyre..

    I think the real gain is not out-right speed, but rather that you can get a noticeable improvement in comfort and grip from something that is no slower (and may be quicker).

    As for the rims, you don’t need to change them – although wider is definitely nicer – a 23mm will bulge on ‘normal’ 19-21mm rims anyway, and you still get much of the benefit from the 25s. The weight ‘penalty’ is marginal for the tyres (same model), non-existent for the tubes and more effected by the make of wheel than rim type, e.g. my 23mm Bontrager Race TLRs are lighter than my skinny Aksiums.

    In short, if you’re not on really smooth tarmac all the time, I personally think it’s hard to see the argument for23mm (or less) tyres on a road bike.

    July 3, 2014 at 7:05 am #801727
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    CXR94Di2

    Well I am now convinced that
    Well I am now convinced that 25mm tyres are faster I knocked over 10 minutes of my best 40 mile loop. They aren’t as comfortable on rough road but do roll much better.

    July 3, 2014 at 12:04 am #801725
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    bikebot

    notfastenough wrote:I think

    notfastenough wrote:
    I think Charles Hunter is right, the mantra that “wider tyres are faster” is directed at road bike riders that assume the thinnest tyres they can find (23mm) will be quickest. 25mm are generally thought to be best for UK roads. I don’t think there is a suggestion that you will go quicker on 32mm.

    Unlikely on 32mm, but there’s a lot to suggest that many riders even in sportives should be using 28 rather than 25. And when it comes to your typical Sunday ride or commute, more so.

    July 2, 2014 at 1:02 pm #801723
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    Adolphe

    wrong thread
    wrong thread

    July 1, 2014 at 4:48 pm #801721
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    Grout

    On surfaces that are rough,
    On surfaces that are rough, to poor I feel that I am faster on 25mm tires.
    This is coupled with lower pressure and reduced vibration which I think translates for me into holding speed better.

    On better smoother roads I think 23mm is actually faster for me.

    Is one size of tire faster than the other… not sure if that is true unless we are talking about the quality.

    I weigh about 80 kilos and am an older rider. I mention this because I expect a younger lighter rider may not be as bothered by poor road surface.

    Again , all this is only subjective.

    For riders heavier than me , I can’t see any downside of running with 25mm tires.
    Currently I have 23mm on the front and 25mm on the back of Hed FR.

    July 1, 2014 at 4:31 pm #801719
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    CXR94Di2

    Yes flat ish route with some
    Yes flat ish route with some short hills. My data shows 20 to 21mph on the flat sections. I do struggle to drag my bulk up anything more than a steady gradient, but I am slowing honing my technique of steady pacing so I don’t blow up. Hills upto a mile long I can manage, I will have to train more on longer hills to condition my body and my mind to the pain:)

    July 1, 2014 at 4:07 pm #801717
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    700c

    I read the article which
    I read the article which explains why 25’a can only be a good thing. Maybe 25’s are marginally better in certain circumstances, and certainly if you fine 23’s uncomfortable then definitely a wider tyre is useful

    In defence if the 23mm tyre, however:-

    we’re talking marginal gains aren’t we? So you have to factor in the negative aerodynamic effect of having a tyre bulge over the rim.

    Or the financial burden of upgrading your rims to a new, wider one which will accommodate a 25mm without the bulging effect.

    And the weight penalty of the wider rim + wider tyre..

    July 1, 2014 at 3:07 pm #801715
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    notfastenough

    I think Charles Hunter is
    I think Charles Hunter is right, the mantra that “wider tyres are faster” is directed at road bike riders that assume the thinnest tyres they can find (23mm) will be quickest. 25mm are generally thought to be best for UK roads. I don’t think there is a suggestion that you will go quicker on 32mm.

    That said, I’m still on 23s. Conti 4000s Black Chilli and by heck are they quick. Look forward to trying 25s.

    Nice aerage speeds there, as well. I hope this is a flattish route, otherwise your 15st bulk must have ridiculous power on the hills!

    July 1, 2014 at 2:45 pm #801713
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    Yennings

    Good summary here of why 25mm
    Good summary here of why 25mm tyres represent the sweet spot for road cycling…

    Reinventing the Wheel: The 25mm Revolution

    July 1, 2014 at 2:40 pm #801711
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    jason.timothy.jones

    and this
    and this http://www.cyclingnews.com/features/tech-feature-the-work-of-wheel-energy

    July 1, 2014 at 2:29 pm #801709
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    jason.timothy.jones

    read this
    read this http://janheine.wordpress.com/2012/06/13/bicycle-quarterly-performance-of-tires/

    July 1, 2014 at 2:23 pm #801707
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    bikebot

    Deleted, duplicate
    Deleted, duplicate

    July 1, 2014 at 2:20 pm #801705
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    bikebot

    700c wrote:Size and weight

    700c wrote:
    Size and weight are linked though, aren’t they!

    Personally I don’t think there’s much to split 23’s and 25’s, but it’s 25/ tough type in winter and 23/race type in summer for me..

    It is, but because of the techniques that go into the construction it isn’t the simple linear result that you should expect from circumference being PIxD.

    I use a set of tough gator hardshells for commuting, I originally intended to buy 28mm but after checking the manufacturers spec sheets the weight penalty in going to 32mm was just 5g. So I went for the bigger, fatter more comfortable tyre.

    The weight difference from the construction of a commuting/touring tyre compared to a race tyre is much, much bigger than the weight difference you’ll see from the diameter. Oh, and always buy folding tyres, that saves lots of weight.

    July 1, 2014 at 1:56 pm #801703
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    CXR94Di2

    Complex subject it is. I
    Complex subject it is. I will stick with the Durano for next few months and 100 mile sportive I have booked and compare my results.

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