Narrower tyres improving speed!

by CXR94Di2   July 1, 2014  

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

21 user comments

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Good work finding it out on your own and nice speed increase, some more reading if you want to.

http://velonews.competitor.com/2012/03/bikes-and-tech/technical-faq/tech...

https://www.google.co.uk/search?q=wider+tyres+are+faster

posted by Charles_Hunter [88 posts]
1st July 2014 - 12:04

1 Like

After the other rider comments I had read that wider tyres roll faster, so I held off moving to narrow tyres. I accumulated cycling times in the meanwhile. But switching to 25mm from 32mm contradicts the research , well at least in my case. I have read others say narrow tyres are faster. The links regarding schwalbe say larger tyre improved rolling resistance. There must be tipping point where larger becomes slower. Maybe that for me is 17-18mph on 32mm tyres!

posted by CXR94Di2 [228 posts]
1st July 2014 - 12:23

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When people say "wider tyres are faster" they assume the current tyre is less than 25mm width. What should be said is something like "for riding on britsh roads, 25-28mm tyres at the correct pressures are probably fastest."

posted by Charles_Hunter [88 posts]
1st July 2014 - 12:34

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I think the speed increase you saw in moving from a 32mm Marathon Plus to a 25mm Durano was due to the type of tyre, not the size. The Durano is simply lighter and grippier.

A lot of riders use a particular tyre for Winter or commuting which will see a bigger speed drop even though it's the same size as their regular set.

posted by bikebot [787 posts]
1st July 2014 - 13:08

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That's a good point a 23mm 4000s will I'd bet be faster than a no name brand 25-28mm. Then as you say you throw in a gatorskin type commuting minimise punctures tyre vs a race type tyre and the choice is more complex again.

posted by Charles_Hunter [88 posts]
1st July 2014 - 13:17

2 Likes

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..

posted by 700c [587 posts]
1st July 2014 - 13:54

3 Likes

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.

posted by CXR94Di2 [228 posts]
1st July 2014 - 13:56

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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.

posted by bikebot [787 posts]
1st July 2014 - 14:20

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Deleted, duplicate

posted by bikebot [787 posts]
1st July 2014 - 14:23

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posted by jason.timothy.jones [303 posts]
1st July 2014 - 14:29

2 Likes

posted by jason.timothy.jones [303 posts]
1st July 2014 - 14:40

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Good summary here of why 25mm tyres represent the sweet spot for road cycling…
http://inrng.com/2013/04/reinventing-the-wheel-25mm/

posted by Yennings [226 posts]
1st July 2014 - 14:45

2 Likes

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!

Last night I would have considered trading a very loud baby for a really nice bike.

posted by notfastenough [3466 posts]
1st July 2014 - 15:07

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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..

posted by 700c [587 posts]
1st July 2014 - 16:07

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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:)

posted by CXR94Di2 [228 posts]
1st July 2014 - 16:31

2 Likes

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.

posted by Grout [1 posts]
1st July 2014 - 16:48

3 Likes

wrong thread

posted by Adolphe [2 posts]
2nd July 2014 - 13:02

1 Like

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.

posted by bikebot [787 posts]
3rd July 2014 - 0:04

1 Like

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.

posted by CXR94Di2 [228 posts]
3rd July 2014 - 7:05

1 Like

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.

fukawitribe's picture

posted by fukawitribe [538 posts]
3rd July 2014 - 8:08

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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.

Last night I would have considered trading a very loud baby for a really nice bike.

posted by notfastenough [3466 posts]
3rd July 2014 - 9:41

1 Like