tyres : 23 or 25s?

[montage]

How much extra speed/difference will I feel if I scrap my 25s and whack on a pair of 23s?

 

[Will1985]

If changing within same make (eg: Conti GP4000 x25 to x23) there is a negligible difference. Between brands there is always going to be a bit of a feel difference I think.

 

[montage]

well, on my homeward journey from college (8 miles) I'm pushing between 25-27mph, and averaging between 17 and 20 mph on long club runs (a little sweaty!).....23s won't make any difference in speed at this level?

 

[Dan B]

My experience is that it will feel faster. Probably won't be faster, it's just the thinner tyres making it rattle more

 

[RedBike]

25mm tyres should in theory have a lower rolling resistance than 23mm tyres. The reason 23mm tyres are quicker is that they are lighter and more areodynamic.

Will you notice a speed increase. Probably only when accelerating / climbing steep hills.

 

[HJ]

25mm tyres should in theory have a lower rolling resistance than 23mm tyres. The reason 23mm tyres are quicker is that they are lighter and more areodynamic.

Will you notice a speed increase. Probably only when accelerating / climbing steep hills.

No, narrower tyres have higher rolling resistance when at the same pressure as wide ones, to quote Schwalbe's techinfo pdf (see page 15) "Wider tires roll better than narrow ones. This assertion generally generates skepticism, nevertheless at the same tire pressure a narrow tire deflects more and so deforms more." It is unlikely that you will be able to 23mm tyres to a significantly higher pressure than 25mm tyres.

But they do have lower air resistance and easier to accelerate because the rotating mass of the wheels is lower...

 

[Noodley]

Get a pair of 24s and get the best of both worlds
http://www.wiggle.co.uk/p/Cycle/7/Vittoria_Open_Pave_Evo_CG_Tyre/5360035176/

 

[Fab Foodie]

At the speeds you seem to be going, i'd proffer that the aero advantage will have kicked-in. In the summer I use a semi-aero rims and a 25mm tyre would kinda defeat the object.
Not all 23mm tyres are equal anyway, the old '23' Michelin PR2's were more like everybody elses 25's.
If I were you, I'd go for Michelin Pro-Race 3's in 23c.

 

[montage]

thanks for the help with all the posts so far...just saw that there is a 20mm any downsides to this?

 

[palinurus]

You can get a 19 mm clincher tyre if you so wish, although I doubt they offer any advantage if fitted to a standard rim. More for time-trialling on wheels for that purpose, at that level many opt for tubs rather than clinchers anyway. 23 is your narrowest practical tyre for general road use.

 

[Fab Foodie]

thanks for the help with all the posts so far...just saw that there is a 20mm any downsides to this?

Yes, they become very uncomfortable, need to be very hard to avoid snake-bite punctures, and when very hard are fine on smooth tarmac, but poorer rolling over the rougher more usual black-top. 19 and 20c tend to remain the preserve of Time Trialers these days for their aero-ness.