Tire sizes: 700x23 or 700x25???
daveclow
Posts: 164
which do you go for?
do they both have their pro's or cons?
im going to buy a pair of Michelin Krylion Carbon's - after reading many reviews these seem to be the ones!
d
do they both have their pro's or cons?
im going to buy a pair of Michelin Krylion Carbon's - after reading many reviews these seem to be the ones!
d
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Comments
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Krylion carbons seem to come up quite 'fat' if you see what I mean. I have both sizes and the 25s are especially wide. Nice tyres.0
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25s are a bit more weight (235ish vs 270ish g) but a bit more comfort and grip and possibly toughness too.
Tyres - pay yer money, make yer choice. Can't have everything.Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer0 -
Depends what your after really. The wider the tyre it will generally be more forgiving on poor surfaces but the narrower tyre will have less rolling resistance. Wouldn't worry too much about the 70g in weight unless you haven't got an ounce of spare meat on you
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yeah i went for the 23's on the basis that they may have a bit less rolling resistance.
as for the weight, your right is tiny - a medium bowel movement would make up the difference if you went for the heavier lol0 -
I have just ordered the 25s , did you know they are on offer at CRC
http://www.chainreactioncycles.com/Mode ... elID=20460"BEER" Proof that god loves us and wants us to be happy0 -
Although your bowels probably aren't rotating mass, unless you had a particularly bad curry the night before...as for the weight, your right is tiny - a medium bowel movement would make up the difference if you went for the heavier lol
Fairly small amounts of weight near the rims of your wheels can make a perceptible difference to how lively the bike feels when accelerating (although not so much to your speed once you get going). 0 -
If you use the same pressure in both, exactly the opposite - the wider tyre has less rolling resistance.
Is that true? Not disagreeing but I just understood that more surface area = more friction :oops: hence why testers use (or did when I last raced) 18mm or 19mm tyres? Is that purely down to them generally having higher maximum pressures then?0 -
Quote "yeah i went for the 23's on the basis that they may have a bit less rolling resistance"
Compound for compound, pressure for pressure, the 25 will have LESS rolling resistance than the 23. A 28 probably even less.
The 23 has a slightly lower mass, which is usefull when accellerating, but makes no difference at steady speeds. Also slightly more 'aero' for the obsessive compusives.
I have setteled on 25's on the basis of the slightly better comfort, but 23c Vredestein Fortezzas are also very good in this respect.0 -
Pross wrote:If you use the same pressure in both, exactly the opposite - the wider tyre has less rolling resistance.
Is that true? Not disagreeing but I just understood that more surface area = more friction :oops: hence why testers use (or did when I last raced) 18mm or 19mm tyres? Is that purely down to them generally having higher maximum pressures then?
Im with you... I can't see how a tyre which has less contact with the road (23s) can have a higher rolling resistance?
Do 25c tyres go up to 120psi?0 -
sods_law wrote:Im with you... I can't see how a tyre which has less contact with the road (23s) can have a higher rolling resistance?
It's because rolling resistance is not caused (predominantly) by contact with the road, it is caused by hysteresis loss in the tyre carcass deformation required to produce the contact patch. Wider tyres (when run at the same pressure) have to deform less that narrower tyres, so suffer a lower loss - hence, lower rolling resistance. Note, however, that the difference is a) only true if you're runing at the same pressure, and b) small enough that the aerodynamic differences between 23mm and 25mm tyres becomes equally as important (IIRC) at practically achievable speeds. I remember reading an article that suggested 23mm front (for the aerodynamic benefits) and 25mm rear (where the seat tube reduces the aerodynamic benefit) might be optimum...
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Thanks underscore
Are 25mm tyres usually rated to the same pressures as 23mm tyres?
I assume that most racers use 18 or 23mm tyres, that the aero benefits of smaller tyres are significant enough to negate the increased rolling resistances?
Edit: just re-read your response. I assume the answer is 'yes', as aero becomes more a factor as speeds increase?0 -
According to Schwalbe wider tyres roll better than narrow tyres when pumped to the same pressure:
http://www.schwalbe.co.uk/pdf/techinfo.pdf
See pages 14 and 15.0 -
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Only die-hard testers use skinny 20mm tyres these days. Skinny tyres also puncture more easily IME - I run 25mm where possible, except on my race wheels, where I use 22mm tubs.Make mine an Italian, with Campagnolo on the side..0
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If your interested have a search on this site www.biketechreview.com
Not all tyres are measured correctly you might think you're buying a 23 where in fact it measures at 25 (it's a bit like shoe sizes from different manufacturers.)0 -
hence the benefits of tubeless - no tube/tyre friction therefore less resistance.Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer0
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25 s in real life are better for rolling on the average road than 23 s. This is , in my not expert opinion because the wider tyre seems more able to roll smoothly and without skipping up and down , wasting effort and loosing forward momentum.
IMHO no benefit gained from tyres above 85 - 90 psi. Pinch punctures often offered as a reason to inflate to 100 psi plus but dont seem to happen above say 80 ish.
Suspect most over inflation caused by it being somewhat counter intuitive that a "softer tyre " can roll { actually faster} than a rock hard one. In a velodrome on a snooker table smooth surface yes, on a normal road absolutely no.0 -
it also depends how you ride on the non-perfect road.
If you ride through stuff then you need more pressure, for a given rider weight, as opposed to floating over stuff where you'll need less.0 -
grindsuphill wrote:25 s in real life are better for rolling on the average road than 23 s. This is , in my not expert opinion because the wider tyre seems more able to roll smoothly and without skipping up and down , wasting effort and loosing forward momentum.
IMHO no benefit gained from tyres above 85 - 90 psi. Pinch punctures often offered as a reason to inflate to 100 psi plus but dont seem to happen above say 80 ish.
Suspect most over inflation caused by it being somewhat counter intuitive that a "softer tyre " can roll { actually faster} than a rock hard one. In a velodrome on a snooker table smooth surface yes, on a normal road absolutely no.
Does that not depend also on your weight as I am around 15st/93kg and find it hard work if my tyres are around 85-90psi but if they are around 100-110psi it rolls much better.0 -
What?
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