so…my road bike tyre size is 700x25c….. it says the psi is 115 to 125 and 8.0 to 8.5 bar….
now i dont have to pump the roadie tryes up too much (abit different to your MTB etc….. but i normally ride with the following pressure in…4 bar which is just under 60 psi….this feels adequate to me and the tyres feel quite hard to the touch…. im approx 8 and a half stone in weight….- {what i dont understand is the psi says from 115)…..jesus the tyres would be solid as a rock or close to popping surely (lol)….i just darent inflate them to 115 at all.????..lol….. im only 7 months into road riding so prob got alot of roadie stuff to learn…… anyway just wondering bout the tyre pressure thats all.. 😉

I’m about your weight as well, running 23c tyres, usually go to at least 100psi, 120psi if I want a bit more speed. 80psi runs ok, anything less feels slow.

Don’t be scared, pump them up hard. I run my bmx tyres at 110psi (what’s recommended – that seemed scary at first..). Pump them up to 100psi, you’ll probably notice the difference. And no, they won’t explode.

Also 60psi just a little bit more then mtb pressures? What do you run on your mtb??

I’d run them at at least 80psi, 90psi if they were 23c. At 60psi you’ll run the risk of pinch flats if you hits pot holes or other large objects. Plus you’ll go faster (maybe)

Fairly new to roadying over here too. 60psi might feel tough but it’s flabby in comparison to 100. The bike comes alive when the tyres are properly inflated and it’s really ‘not that’ uncomfortable.

I run 100psi on my 23c tyres. Much lower starts to feel draggy.

i am 11.5 Stone and just pump the tyres hard, which means 120psi ish. I did max out the Vredesteins which meant 145psi which did mean a slightly harsh ride.

Don’t be afraid to pump tyres hard, they are small and it is quite possible to pinch puncture if your not careful and the pressures aren’t high enough.

Only one thing to add, watch your rim sidewalls as they wear.

If you want to be geeky measure the height of the tyre unloaded from the ground to rim Now when you sit on the bike it should be 9% smaller with the correct pressure for your weight

Best compromise for comfort and speed. I did say it was geeky

If you want to be geeky measure the height of the tyre unloaded from the ground to rim Now when you sit on the bike it should be 9% smaller with the correct pressure for your weight

Source? Is that tyre unloaded as in no reaction force between the tyre and ground?

I’m about 10st and ride 23c tires at 90 front 95 rear. Anything above that becomes too uncomfortable and has a corresponding loss of grip. You could probably happily ride with 85 / 90 giving a faster ride but still with comfort.

If you want to be geeky measure the height of the tyre unloaded from the ground to rim Now when you sit on the bike it should be 9% smaller with the correct pressure for your weight

Source? Is that tyre unloaded as in no reaction force between the tyre and ground?

Would have to be rider only, as it would be impossible to measure any reaction force.

All seems a bit teachy to me, run my tyres at 115psi whatever, commuting or taking part in long distance / chairty ride.

I weigh 91kg and run 100psi on 23c and have never had a pinch flat. 120psi does feel marginal faster on the 1% of riding I do on a perfectly smooth road. For the rest I prefer the comfort and control of 100psi.

I’ve pinched flat at 80psi. I use 125 now

The 9% thing came from bicycle quarterly

It’s measured it rest

I think the main danger of running road tyres that soft is that the tyre will creep under braking……meaning that when you brake hard the tyre can shift a little around the rim taking the tube with it. Eventually this leads to the valve stem being torn from the tube and a nasty puncture. A tell-tale sign of tyre creep is that the valve stem sticks out of the rim at an angle (with the valve at the bottom the valve will be leaning forward).

I’d pump them up a bit harder. Try them at 90psi.

SB

I ride 100 in winter a touch less if it’s frosty or wet. 120 for normal summer rides and about 140 for racing.

If you’re scared you might explode a tube pump up outside, an exploding tube in a confined space will give you a heart attack and make your ears ring for about an hour after. Must add That’s only happened when I’ve been rushing and pinched the tube when fitting the tyre.

ok i will try pump them up to at least 90 then (see if i can tell the difference when riding… are you guys sure ? lol….. the tyres are thin tho arent they…..
yeah the person who asked about the MTB pressures…i ride with 35-40 psi you get more grip with less air…i dont have them rock hard… but have nobbly tyres in winter for the gloop stuff on the fells..lol

It sounds like you’re running your mtb tires too hard and your road tires too soft!

Its nice to not check the road bike tire pressures for a few weeks, then when you do get round to pumping them back up to 110psi, your bike feels like a weapon.

Road bike tyres work the other way round, more grip with higher pressure (up to a point!).
The last thing you want is the tyre squirming and deforming when you’re cornering or braking, the whole bike will feel awful.

I run mine about 100 – 110psi. Bit more abroad where the road surface is better and a bit less if it’s wet.

It sounds like you’re running your mtb tires too hard and your road tires too soft!

Its nice to not check the road bike tire pressures for a few weeks, then when you do get round to pumping them back up to 110psi, your bike feels like a weapon.

+1 to all of that.

I rarely run more then 30psi on my mtb, and rarely less then 100psi on the road bike.

Heaps of myths about tyre pressure as Realman amply demonstrates…

There was a very convincing article online re. “15% pressure” – the pressure that makes your tyres compress 15% of their height – this changing according to your weight and tyre width (I think) – where did you get 9% from AW?

EDIT

Road bike tyres work the other way round, more grip with higher pressure (up to a point!).

Eh? 8.5 stone rider squirming tyres at 60psi?

12st and run 110psi.

okey dokey ive pumped both tyres to 100 psi…was quite hard going tho… the bike pump almost blew its self off the valve…lol yep tyres rock solid now….will have to have a trial run in a few days… hope i go faster ! lol…. ok cheers guys, so if its wet or frosty i should take about 10 psi out then shud i… 😉

Eh? 8.5 stone rider squirming tyres at 60psi?

why not?

I personally fail to see how you can run mtb tyres as soft as some claim, anything under 35 and i can almost roll them off the rim, and the ride is abismal.

At 8.5 stone running 100 psi will feel like running solid wooden tyres!
Unless you’re racing try around 70 to 80 psi and have a comfy ride.
Usual macho crap in abundance advice so far. :-
Edit: If your running 60 psi with no ill effects don’t worry.

Eh? 8.5 stone rider squirming tyres at 60psi?

Yes.. 60psi on a road bike feels horrible.

I personally fail to see how you can run mtb tyres as soft as some claim, anything under 35 and i can almost roll them off the rim, and the ride is abismal.

Well it can be.. Different tyre/rim combos maybe?

ok cheers guys, so if its wet or frosty i should take about 10 psi out then shud i…

Yeah that’s the generally accepted idea, 10 or 20psi less if it’s wet and horrible. I usually don’t bother though.

112.5 rear
107.5 front

I might go down 6% if the roads are wet

Well it can be.. Different tyre/rim combos maybe?

Maybe, might be riding style, rider weight, rider environment etc.

Opps just found the article in bicycle quarterly and it says 12-15% my mistake
It’s in vol9 no.4 summer 2011

I’m unhappy if I’ve not got at least 100psi in my road tyres.
Track bike will go higher.

About 12.5 stone here. I don’t think I’ve ever had a pinch flat on the road but it’s not about that, they just corner poorly when softer and you can feel the difference in drag with lesser pumped up tyres.

http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpressure.view

geez ok im thinking around 80 -90 psi then for my weight 8.5 stone….
ive ridden the bike for 6 months prob once per week and had no flat tyres at all !!!!!!! (touch wood)….been over a few little pot holes too… i must admit tho you do feel every bump you ride over tho ( i guess thats the comfiness of the MTB stepping in there then with nice fox forks..lol
does it feel less bumpy with more air in the tyres then or wot…

well thanks there Mcavity but that chart is double dutch to me..can you work it out for me…. 🙄

does it feel less bumpy with more air in the tyres then or wot…

too soft you risk damaging the rim, punctures etc, too hard is harsh and a little less grip.

so it is a matter of balance

wots too hard then….geez they feel rock solid at 100 psi i just put in…think im going to put 90 psi in see how i go….. its goota b better than the usual 60 psi anyway 😉

Macavity, thanks for that link. I inadvertently appear to have been using the right pressure for my 12-and-a-bit stone! Generally about 95psi rear and 90 up front on a 25c.

ok ive sused that chart out and for my weight which is 120 pounds just under im looking at 73-80 psi…. so thats wot ive gone for now… 😉 80psi…c how i go….

If you’ve only ever run underinflated tyres make sure you keep the tip of your tongue touching the roof of your mouth to avoid biting it off once your tyres are properly inflated 😉

My old team leader was just phenomenal downhill (on the road), taking so much time out of the rest of us in the twisty stuff. One of his top tips was never to run tyres (23c) at above 100psi in a road race, less in the wet. Quite a bit higher in flat straight TTs would be expected.

At your modest weight and with you using slightly wider rubber I’d have thought 80psi would be bob on.

At your modest weight and with you using slightly wider rubber I’d have thought 80psi would be bob on.

okey dokey ive gone for 80 psi will stick to that see how i go… 😉
one more thing.. some of you talking are using 23c tyres…..is that the norm ? im just using what came with the bike…. its only 44′ frame so im guessing ive bigger wheels to compensate… yep im riding a ‘Specialized Dolce’…nice bike for the price realy… it even has Zerts inserts…. BTW …. brakes pads are good too = they dont wear down as quick as the MTB (+1) 😉

+1 80psi sounds about right for you though I’d give it a go at 100psi to see.

I guess the thing is that it’s quite normal for the road to feel quite bumpy – certainly much more so that on an mtb on the road.

Road bikes with tyres at the right pressure whizz along (sometimes!) – at too low pressure, they lose that lovely feeling.