Is there really much difference between 700cx23 and 700cx25 tyres

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Hi again.
I've been enjoying many miles of cycling recently and my poor old tyres are starting to look a little worse for wear.
On my 2 road bikes im still using old school 23mm tyre's. Gatorskins on the winter bike and Specialized All Condition tyres on my summer steed.
I'm quite keen at trying to be a fast cyclist (even though im over the hill lol) and have been watching loads of YouTube clips on how 25mm tyre's are now deemed as the choice for better rolling resistance and all round comfort. Watching all these videos would have you believe there the new miracle to help you propel along the roads faster with less road buzz from our poorly surfaced roads. I usually average around 17mph out on a ride and would like to (if possible increase this).
I'm thinking of purchasing some Continental Gp4000 next time in 25mm but before i do, i thought it best to ask you good members what you think of wider tyres.. As you are all cyclists and living in the real world i would take your advice over any promotional adverts anyday on whether a 25mm tyre is the way to go over a 23mm. I currently run my tyres at around 100 psi to help prevent pinch flats but i do find the ride to be harsh sometimes especially after a long day in the saddle which is what i enjoy the most.
All views will be greatfully read and thank you for your advice in advance..
Johnny :bicycle:
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Legendary Member
23mm are lighter, all things being equal. The construction of a tyre makes more difference than its width. Again, all things being equal, a 25mm may well roll better but a supple 23mm with high TPI and thin sidewalls will be much smoother than a 25mm with stiff sidewalls and a less pliant tread.
Good morning,

As a generalisation I do find that 25mm tyres both more comfortable and on certain roads that I ride on faster. I am close to 210lbs so need quite a high pressure to avoid pinch flats but on many poorly surfaced country lanes rock hard 23s result in the bike going up and down rather than the tyre deforming which is definitely slower.

As a circle with a diameter of 25mm has an area of 490mm and one with a diameter of 23mm has an area of 415mm making that into a cylinder and wrapping it around the wheel clearly means a lot more air, so some difference in ride would be expected.

Of course 2mm is such as tiny difference that manufacturing and labelling could mean that a 25mm tyre is the same width as a 23mm. :-)

I did try a 28mm once but it rubs against the seat stay bridge and back in the 1970s I used to use Wolber Junior tubular tyres and they were 25mm so 25mm it is hardly a wide tyre.

Have you seen ? Whilst you can easily dispute the relevance to real road riding I did find the range of rolling resistances from different tyres surprising.

Even if the 25mm tyres are not any faster or more comfortable they won't be much slower or less comfortable, Continental Ultra Sports can be got for around £12 each and if you ride enough you can wear them out within a couple of months. :-)

In practice I found a definite difference as I was looking for it the day that I changed tyres, but if the fairies changed my tyres overnight I probably wouldn't really notice it.




Legendary Member
A 2mm fatter tyre won't make a noticeable difference. What will make a difference is a nice lightweight cotton-wall tyre like a Veloflex Open Corsa or the same tyre branded as Vittoria. These are beautifully smooth-riding tyres, not robust enough for commuting, admittedly, but a real connoisseur's tyre for the plush ride and superb grip. I never use anything else and on my best bike I pair them with latex tubes making them even smoother. They are so light with latex that they run with a lovely ringing sound. You can get a pair of the Veloflex Open Corsas from Ribble for a reasonable price.


I'm just about to build my bike up for Spring 40mm G Ones tubeless wheelset is going on. So nice running 45psi, super cushioned ride


I used to run 23mm tyres on my road bikes at 110psi, then about a year ago I swapped to 25mm and run them at 95psi. The main reason I changed was to reduce the likelihood of pinch flats on our crap road surfaces. I'm using the same tyres as before - Vittoria Rubino Pro's.

They are more "comfortable", especially on the carbon where the ride is now noticeably less harsh, but whether this is due to the wider tyre or the reduced pressure I can't say. Probably a bit of both.

I haven't really noticed any improvement in speed though, but then I'm no racing snake.


Eh up
If all the roads were smooth tarmac 23 mm pumped up 100 psi + would be the way to go but your lucky to find any smooth tarmac out there, so I would think the 25 mm with a lower pressure would have the advantage for speed and give a bit more comfort, I don't ride anything below 32 mm nowadays and run tubeless with lower pressures, very comfortable and not noticeably slower.


As a quick comparison, i ran 23mm duranos, around 100psi.
They were hard and viby, solid tyres with stiff sidewalls
I got some Michelin pro race 3s 23mm and run them at 100 psi. Transformation comfy, no buzz and faster by a good amount.
Less protection...
Very supple tyres, soft sidewalls

I have 25mm tyres on my road bike now but there still unused. But i suspect they will feel even better.
There specialized tyres which claim to be the fastest rolling in a group test.
Sidewalls are everything when it comes to trye comfort.
Its then volume and tread which is not always possible with a road bike.


A little off topic about smooth roads, but the highway agency has decided to resurface the road outside my house this morning. Sunday morning sitting here with a cup of tea and the noise outside is deafening. The road plainer came past scrapping the top surface off and the vibrations within my house ended up with my hanging pictures falling off the wall!!! Its time for a bike i think ,to get some peace and quiet.
Thanks for all the input on tyre sizing. I think i will opt for the 25mm version when i replace them as I'll have nothing to lose, and hopefully better comfort and less rolling resistance (even if it is only small) but every little helps at my ripe old age lol.
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