Is there an advantage in changing to narrower tyres

[GrasB]

A quick google would have resulted in a wikipedia article. In which the second sentence is:

It is mainly caused by non-elastic effects, that is, not all the energy that is needed for deformation of the object is recovered when the pressure is removed.

Ergo, the main factor of rolling resistance is the amount of energy it takes to deform the tyre, absolutly nothing to do with frictional losses.

 

[Dragonwight]

A quick google would have resulted in a wikipedia article. In which the second sentence is:

Ergo, the main factor of rolling resistance is the amount of energy it takes to deform the tyre, absolutly nothing to do with frictional losses.

Here you go hope this helps. As you can see the deformation of the tyre is caused by the mass or weight applied. Hence why i said the only forces to be concerned about really are your weight and the coefficent of friction.
Rolling friction equation for tires

You can apply the standard friction equation for rolling wheels to try to determine the value of rolling friction. That equation is

FR = μRW​

where:

• FR is the resistive force of rolling friction
• μR is the coefficient of rolling friction for the two surfaces (Greek letter "mu" sub R)
• W is the weight of the wheel plus the weight of the person\bicycle
• μRW is μR times W

 

[GrasB]

The coefficent of friction is mute in these equations (it's about 2.5w @ 100mph iirc) & weight it's self doesn't actually tell you how much you're being slowed down by the deformation of the tyre!

 

[Dragonwight]

The coefficent of friction is mute in these equations (it's about 2.5w @ 100mph iirc) & weight it's self doesn't actually tell you how much you're being slowed down by the deformation of the tyre!

Which just confirms what I have said that the only two variables are the coefficent of friction and mass excluding air resistance and surface area makes no difference.

 

[Accy cyclist]

IMO, the width isn't the important factor but the pressure used.

Serious question Norm....If i could pump 100psi into my touring tyres would i be able to do the same speed as 100psi in a narrow road(schwalbe Lugano)tyre?

 

[Norm]

I don't know whether using the same pressure would give the same level of squish in the sidewalks. Intuitively and all other things being equal, I'd think that a fatter tyre would need more pressure to be as rigid as a narrower tyre, but all things are not equal and you'll have different construction techniques etc used In the two.

I'll happily defer to others on the details of the subject, though.

 

[StuartG]

Thinner tyres have less mass so improving acceleration and deacceleration. So, other things being equal, they 'feel' faster.

Oh and they pump up faster!

 

[GrasB]

Which just confirms what I have said that the only two variables are the coefficent of friction and mass excluding air resistance and surface area makes no difference.

Power isn't actually effected by mass a huge amount, in other words if we keep the tyre pressure the same the Crr drops as weight increases. So if we take my high-racer at 50mph unloaded it takes 148.8w to overcome Crr. If it's loaded up with all my gear etc for work, that's another 8kg or so the extra power required is 0.3w, if I extrapolate out the same tyre droop I find that the power consumption of the tyre would be the same +/-0.02w. However if the Crr stayed the same the extra power would be very close to 10w.


Now let's take a look at the coefficient of friction. So the tyre with the highest coefficient of friction are my Schwalbe Ultremo ZXs the 23-622 tyres give a Crr of 0.00621 on my TT bike, if you look at my least grippy tyres at the same size & at the same pressure, Schwalbe Durano, their Crr is 0.00711. In the middle with regard to coefficient of friction there's the Conti GP with a Crr 0.669. So the coefficient of friction appears to be inversely proportional to Crr.

The only thing that's really left is tyre deformation, which guess what, is where all the R&D for tyres go in terms of reducing the rolling resistance.

Serious question Norm....If i could pump 100psi into my touring tyres would i be able to do the same speed as 100psi in a narrow road(schwalbe Lugano)tyre?

Probably not, the touring tyre construction would be heavier so you'd use more power deforming the tyre.

 

[al78]

Which just confirms what I have said that the only two variables are the coefficent of friction and mass excluding air resistance and surface area makes no difference.

What about the ease at which the tyre deforms under load?

 

[Cyclopathic]

Re the original question...A simple yes or no.

 

[dellzeqq]

yes

 

[RecordAceFromNew]

All else being equal, the effect of tyre width on rolling resistance per se is very limited, as GrasB indicated in one of the above posts, as well as concluded by Schwalbe in some of their experiments.

What do make a hell of a lot of difference to rolling resistance, all else being equal, are:
1) pressure, where as Norm said high pressure would reduce rolling resistance quite significantly (see e.g. these test results) assuming you are cycling on smooth roads (else the opposite is true!), which therefore has implication on choice of tyre since different ones, even within the same "model" and the same make, can have different pressure rating - though generally speaking narrower tyres tend to have higher pressure ratings, and
2) tyre choice, which can easily make a difference of over 50% to rolling resistance even between 23mm road tyres, and therefore ~10% difference on overall power requirement at 35kph as demonstrated by results in these tests.