Are old type road tires (for example 27x1.25inch) noticably more difficult to ride than modern 700c type tyres

Question

It seems to me that since a 27 inch by 1.25 inch wide tire would create more drag on the road. However, is this noticable on long journeys or is the difference so slight as to not be of importance?

Answer 1

Oh Dear

Any bicycle that has tyres pumped up to the same pressure and carrying the same weight will have the same area in contact with the road.(contact patch)

E.G. A 200 lb bike and rider on tires inflated to 100 psi will have two square inches in contact with road. (easier to explain in imperial)

The energy required to deform the tyre to make the contact patch has the greatest influence on rolling resistance. Tyres with subtle sidewalls soft compounds and shorter WIDER contact patches will have lower rolling resistance.

Now before I get a shower of down thumbs. We all know that narrower tyres are faster. The reason for this is, that what the lose in rolling resistance, they more than make up for in wind resistance.

This link  should help explain.

http://www.cyclingnews.com/tech/?id=2005...

There is a lot more choices for good performance tyres on 700c.  The old 27 inch wheels usually don't have as many gears either. If you can get good tyres and fit similar numbers of gears differences wood be small.

I have meet people that swear the difference between different spoke counts is significant. So I'll leave it to you if small is significant to you.

Answer 2

Skinnier (Width) tires are generally "faster" tires since the surface area on the road is minimized.  Faster means less rolling resistance and therefore less energy lost to friction.  There is a significant difference from moving from 1.25" (approx 32mm) tires to the standard road tire of 23-25mm.  Part of this also comes from the fact that skinnier tires generally hold higher pressure, which means the tire deforms less by the road and again produces less rolling resistance.  In addition, skinnier tires generally weigh less, which will provide one with snappier acceleration as well.

However, these benefits are not without tradeoffs.  Wider tires are generally more durable as they are generally thicker, and thus will suffer fewer flats.  They are also significantly more comfortable to ride on.  People who do self-supported touring generally ride on tires as wide as 38mm do to the more comfortable ride and increased durability, both of which are highly valued for long-distance riding.  In addition, loaded touring generally places a large amount of weight over the back wheel, so having a wider surface in which to spread out the weight provides a much more stable ride.  Racers, however, will always want the lightest, least resistance tires and thus will generally go towards the skinniest tires possible at pressures upwards of 120PSI.

Road slicks will also be significantly more efficient than the knobby mountain bike tires as well, but will have worse traction in dirt and gravel.  Therefore for road riding I would strongly advise against any kind of knobby mountain tire.  

Most wheels can accomodate a range of different sized tires, so you can swap a number of different types to try them out.