[Closed] Road Tyres - Will I notice a difference 550g p/tyre 32mm to 250g p/tyre 25mm ?

will they make a noticeable difference?

Yes

I've always found that a higher TPI count always feels better, not necessarily the weight difference.

That said 550/tyre is quite a lot

That's a huge difference. You'll notice for sure.

Probably you will 'feel' more of a difference than you will actually realise in an increase in speed. But also bear in mind that you're going to puncture a lot more with 250g tyres than 550g ones.

Think of it as being like the difference betwen Durex Extra Safe and Featherlite 😀

You'll certainly notice the first ride. After that, they'll just be the same as last time.

Why not get something a bit more halfway? Continental ultrasport 32mm are only 320g.

I commute on my road bike at the moment with 25mm tyres and it's fine, but for a dedicated commuter I'd happily go for a wider tyre so that I didn't have to wince so much each time I hit a pothole.

why not simply avoid potholes.

there's no reason to believe a 250g 25mm tyre will puncture more often than a 550g 32mm one either.

To be fair I would probably keep going with the heavy tyres for commuting as I do a 1.5 mile ish section which is on very rough forestry road and I dont think a Continental Grand Prix could stand up to that.

Just use nice tyres for weekend rides etc.

there's no reason to believe a 250g 25mm tyre will puncture more often than a 550g 32mm one either.

Does having much thicker and harder rubber and more layers of puncture resistant material between the inner tube and the road not make any difference then?

not always. no. do you also think the steel bead and poor quality carcass helps?

quality sub 250g 25mm puncture resistant tyres are available. just so you know.

do you also think the steel bead and poor quality carcass helps?

True.

quality sub 250g 25mm puncture resistant tyres are available. just so you know.

I think most tyres these days have some form of puncture resitant layer in them these days.

mtbel - Member
why not simply avoid potholes.

not always possible, often impossible.

somtimes, i don't even see them, i'm looking at the traffic instead.

and round here (sheffield) the road is a sea of holes, the route around one hole is through another.

I think you're wrong Geetee. bearing in mind "most" cycle tyres are generic cheap shit fitted to sub £200 bicycles and high end bicycle tyres only make up a tiny proportion of all tyres produced.

but talking of "thinking" do you "think" a 32mm tyre would have more or less chance picking up a thorn, flint or piece of glass than a 25mm one during a ride?

ah - that's some seriously poor cycling skills you're admitting to.

that's some seriously poor trolling you're attempting.

I think tyres with a softer and thinner rubber compound are more likely to pick up a shard of something and then subsequently have that shard penetrate the rubber and carcass and get to the inner tube.

I don't think the size of the tyre makes much difference.

If the rubber tread is 5mm thick on one tyre and only 2-3mm thick on another, and if the thicker rubber is also 50% harder, then I think the one with the thinner and softer tread will be more susceptible to punctures, all other things being equal.

asking people to think?

it might just save your life one day MrWhiles 🙄

You don't think a larger contact patch has more chance picking up punctures then Geetee?

I think tyres with a softer and thinner rubber compound are more likely to pick up a shard of something and then subsequently have that shard penetrate the rubber and carcass and get to the inner tube.

The larger tyre should puncture less all else being equal as it will be running lower PSI.

However all else is not equal as if the two tyres were the same make and model there would not be such a weight difference so no way of knowing.

You will however notice a difference when riding. It will feel generally more lively (acceleration, steering) but the difference in actual speed over any distance will probably be seconds rather than minutes.

The larger tyre should puncture less all else being equal as it will be running lower PSI.

Yes GW, some 250g 25mm tyres are probably more puncture resistant than some 550g 32mm, but assuming both are of some comparable level of quality, the heavier tyre is going to be thicker with more breaker layers, and more resistant to pinch flating too. And a 320g/32mm tyre is going to be just as puncture proof (same construction most likley) as a 250g/25mm tyre.

ah - that's some seriously poor cycling skills you're admitting to.

I was going to dig out some pics of 30mm tubs on pro's bikes at P-R, but this was the first pic that came up, so they're clearly pretty poor at this cycling lark too.

[img] [/img]

I have heard this quoted in the past.
Can you please explain how exactly this works in the real world?

Imagine a bit of glass, or a bit of metal, or a thorn sat between two bits of chipping in the ashfelt so that the contact patch maintains the same shape, it just suddenly meets something sharp. Now the tyre at 100psi is going to apply 100spi of pressure to it, the tyre at 50psi will apply 50psi to it (dynamic effects of the tyre casing deforming ignored). Lower pressure's should puncture less.

wow! that really was a pointless reply 😯

More or less pointless than trying to win an agrument based on "most tyres" refering to those fitted to BSO's rather than acceptingt hat "most tyres" proababluy refers to "most aftermarket tyres that STW'ers would likely be chosing from".

Or more or less pointless than just responding with [i]"wow! that really was a pointless reply "[/i] when someone responds to your question with an answer? Because that kinda makes is self fulfilling.

I've just changed the tyres on my hybrid from 32mm to 25mm - it's transformed the performance of the bike for the better. Only slight regret was not going a step further with some 23mm tyres.

my Saracen Hack has 550grm 35mm Contis as OE. I'll be riding them at Paris Roubaix this weekend.

I also have some sub 300grm 30mm Schwalbe CX tyres and 23 and 25mm road slicks.

It rides more quickly on the road with the CX tyres than it does with the OE slicks, which will be removed immediately after P-R!

So yes, you will notice a difference.

Not understanding why my reaction was to say "wow" I can only assume you're not even aware of how flawed and full of utter nonsense your reply was.

teef - Member
I've just changed the tyres on my hybrid from 32mm to 25mm - it's transformed the performance of the bike for the better. Only slight regret was not going a step further with some 23mm tyres.

That's a whole other argument right there. Current thoughts are that 25mm tyres are quicker then 23mm ones (in the same tyre range)

...because a larger carcass requires less energy to deform and therefore creates less rolling resistance. Apparently this holds true up to 28c, where after apparently the increased weight as a penalty outweighs the decreased rolling resistance.

I'm just regurgitating what I've read....

mtbel - Member
Not understanding why my reaction was to say "wow" I can only assume you're not even aware of how flawed and full of utter nonsense your reply was.

POSTED 32 MINUTES AGO #

Perhaps you would be better off trying to educate people so that they understand the point that you are trying to make rather than coming out with "wow" which just makes it look like you are trolling . Oh wait a minute !

Not understanding why my reaction was to say "wow" I can only assume you're not even aware of how flawed and full of utter nonsense your reply was.

Go on then, enlighten us.

Explain how applying a greater pressure to the glass/thorn/puncturing object doesn't result in a greater force.

Or is this a strange variation "better to remain silent and appear stupid than to open your mouth and remove all doubt" and by just going halfway and not actually offering anything constructive up you just look a bit of a tool rather than outright stupid?

I'm not a teacher Ramsay.
it shouldn't take a genius to understand that everything thisisnotaspoon typed was either completely incorrect/made up or in the case of the pic hugely irrelevant and only posted to try and get a reaction.
"Wow!" was simply an exclamation of shock at being presented by all of the above.

Are you honestly telling us the force exerted on the ground increases when we run a higher pressure in our tyres?

Well, tonights job is changing from winter wheels with 23mm, 350g, 60tpi tyres with a hardness level somewhere north of granite to nice wheels with 25mm. 225g, 330tpi GP4000s II's 8)

I expect the difference in comfort and speed to be comparable to that of the difference between hardtail and full suss

I loves summer I does.

Are you honestly telling us the force exerted on the ground increases when we run a higher pressure in our tyres?

No, I'm saying the pressure exerted at any given point is increased. Halve the pressure in the tyre and the pressure between it and the ground halves.

Now scale that down to the area made up by a sharp object. Call that area 'A'.

F = P x A

Now if A is tiny, <<1mm square it will not affect the area of contact between the tyre and the road in any significant way.

So you've got 2 tyres, one with half the pressure of the other, we're only talking about the area in contact with the puncturing object which is constant between the two tyres.

Double P, the same area, what happens to the force?

again Wow! 😯

you really don't have a clue do you?

OK, and here is is in pretty pictorial format for you, in the top example there is half the contact area and double the tyre pressure. Overall force is the the same, on each of those black spikes representing the road surface the force is 1/7 of the total, the flint/glass/whatever is the remaining 1/7.

In the second, there are a nominal 12 points of contact (twice the area), each taking 1/13 of the force, the remainder (1/13) being the flint/glass/whatever.

1/7 > 1/13

you really don't have a clue do you?

[url= https://farm8.staticflickr.com/7618/17068191991_d2a5092494_o.jp g" target="_blank">https://farm8.staticflickr.com/7618/17068191991_d2a5092494_o.jp g"/> [/img][/url][url= https://flic.kr/p/s1fWQg ]Untitled[/url] by [url= https://www.flickr.com/people/7614571@N05/ ]thisisnotaspoon[/url], on Flickr

ha ha.. 🙂 your awesome ms paint skills aside, what on earth is the above attempting to prove?

FACT is that the chance of picking up a Puncture from rolling over a sharp object is NOT reduced by lowering tyre pressure.

That half the pressure, when applied to a constant area (the size of the flint/whatever never changes) equals half the force. Half the force means less likely to be able to puncture the tyre.

Are you actually struggling with this, or just playing dumb?

Crikey there is some cod science here! - and no I can't be bothered reading all the responses.

Lower pressure's should puncture less.

Lower pressure means a greater contact area meaning you also increase the odds of running over a sharp foreign object. It would take a scientific experiment or two to work that one out!

To be honest I read lots of guff in this thread but I can't be bothered picking any more up. Think I'll go out on my bike with Conti four seasons - very light, on about my third set with no punctures......

The force of gravity acting on the rider and the bicycle is what causes sharp objects on the ground to puncture tyres.
lower pressures will not stop this.

actually... what will make this stop?

is your tea not ready yet?

Go have a think about what the difference between force and pressure is. The force (yes, the one generated by the effect of gravity, but that's irreverent, it could be a centripetal force going round a velodrome). You halve the pressure, they tyres contact patch is doubled.

The area of your sharp object is remaining the same, the pressure is reduced, so what happens to the force applied to the sharp object?

it still forces the sharp object through the tyre easily and punctures it! that's what.

Went out for the first ride on the Conti Grandprix's. My old tyres came in at a wopping 650g per tyre, 400g per tyre heavier!

The ride was harsher at 100psi on the new Contis, but the bike feels much more lively. It probably has given me 3 ish mph on the flat and hills you feel like you are not having to lift a rotating mass each tyre rotation.

Strava times are all PB's.

Im sure in 2 months time it will be back to normal feeling but for now its good.

Not sure 25mm tyres will handle my offroad section of my commute though, I think pinch flats would be an issue.

Folk keep taking the bait! Better to ignore the trolls, get some sense and discussion without constant put downs and annoyance.

The wee tyres will feel amazingly nippy but you WILL get a harsher ride and WILL have more problems with punctures/rim damage. For city commuting I'd always choose 28-32c. Rural and suburban and longer distances yes, light skinnies will be best.