Big Tony Posts: 16
in General Chat
Just curious to hear what width of tyre people use. I always thought that the thinner the tyre i.e 700x23 offers less rolling resistance and was therefore faster than say 700x25 or 700x28 which offer more comfort.
My local bike store all new bike and people are all using 700x25
What does everyone else think?
Also need to consider weight. 25 (225g) & 28mm (260g) tyres will be heavier than 23mm ones (205g for GP4000II). Going uphill they will slow you down directly proportionally to the extra weight over the total load. As it's quite small the effect will be minimal. On the flat once up to speed there should be no difference. Accelerating a heavier tyre to race speed takes more power (rotating mass & all that) as the extra weight is all at the rim.
Bigger tyres on the same rim generally have a wider frontal area giving greater wind resistance. Again this is disproportional to speed. As 80% of wind resistance is the rider the extra caused by the wider tyres may not be significant unless you have your aero position perfected. They also have a greater side profile but this shouldn't be significant unless there are significant cross winds and you are used to shallow rims.
I will be sticking with my 23mm tyres but the balance of factors may lead you otherwise
A lot of generalisations there and I don't think they all hold true.
The aero comments are a horrendous, and frankly entirely inaccurate over-generalisations. The number of variables on wheel aerodynamics means that any such comments are ridiculous. For example a number of wheel designs now recommend a 25mm for optimum aero performance.
Also on a number of points, see this from 2014 http://www.competitivecyclist.com/learn/25-vs-23
Regarding weight, yes there's an extra 20g... not being funny but the dirt on your bike probably weighs more than that and I defy anyone to notice a tangible difference of 20g between 1 bike an another... here's the dirty little secret, there isn't a single one of us who couldn't save 20g on out bike on any given day, heck, ditch the socks, ride shoes with less buckles, drop your bottle at the bottom of the hill, skip breakfast, just generally lose 20g of fat, include one less wrap of bar tape, cut the extra length off all your cables, I mean seriously, if you aren't trying to claim the yellow jersey up an alpine pass with your life depending on it to care about 20g is ridiculous.
I am in the process of switching to 25s as my 23s die out...
When i got new tyres to replace my worn out 23's i purchased 25's. Haven't noticed any speed change, although i haven't had a power meter with exact same conditions! 25's are much comfier too.
All in all, i would definitely recommend 25's
Check this out http://www.cyclingpowerlab.com/tyreselection.aspx See how many of the wider tyres perform better than their narrower counterparts over 40km
I bought some Prolite Bortola A21's wheels, these are wider than many rims and in fact a 23mm tyre on these ended up the same width as 25's on my old Shimano rims.
I also shelled out on some Vittoria 21mm high tpi cotton racing slicks a couple of years ago...used them twice. Uncomfortable, squirmy in the bends and since finding the above database probably slower than many mid range 25's