Optimal tyre pressure

gbs

Until yesterday I ran my tyres, Gatorskins, at max pressure of 8 bar but I was advised that 7 bar would be more comfortable with no loss in speed or puncture resistance. Today's run didn't contradict. Any views on the forum?

Kléber

If you use 23 or 25 section tyres, take your weight in KG and divide this by 10 and use this as your pressure in bar.

So 70kg = 7 bar. Google will help you convert this into PSI if needed.

roger_merriman

Kléber wrote:

If you use 23 or 25 section tyres, take your weight in KG and divide this by 10 and use this as your pressure in bar.

So 70kg = 7 bar. Google will help you convert this into PSI if needed.

I find for myself I like to run at least 1 bar below that namely that I'm 80KG plus and like 100PSI/7bar

Bhima

I find the best pressure is one where you can just about squeeze the tyre with your fingers, while the bike is supporting your weight (sat on it, leaning against a wall or something). Any more than that and I can feel power transfer inefficiencies through bouncing when i'm throwing the bike about in a sprint. You want the tyres stuck to the ground as much as possible.

gbs

I hadn't realised, but it is obvious if one thlnks about it, that weight is relevant. At 80kgs Roger M agrees with the LBS. Roger: any loss of puncture resistance at 7 bar?

Bobbinogs

Hi there GBS, there have been a few good threads on tyre pressure in the road beginners forum over the last couple of months (the search facility works really well). The general conclusion, though, was that everyone likes something different and that no one can agree on whether a softer tyre makes you more or less prone to punctures

hopper1

Bhima wrote:

I find the best pressure is one where you can just about squeeze the tyre with your fingers, while the bike is supporting your weight (sat on it, leaning against a wall or something). Any more than that and I can feel power transfer inefficiencies through bouncing when i'm throwing the bike about in a sprint. You want the tyres stuck to the ground as much as possible.

You can feel power transfer inefficiencies.... :roll:... Behave yourself....

FWIW, I'd go with the weight in kg's/10-1= Pressure in Bar. Never heard of that before, but excellent rule of thumb (for 23mm tyres).
Multiplied by 14.5 gives you ball park psi figure.

hambones

96kg here and run at just over 8 bar. 150 miles a week, one puncture in past 12 months.

roger_merriman

gbs wrote:

I hadn't realised, but it is obvious if one thlnks about it, that weight is relevant. At 80kgs Roger M agrees with the LBS. Roger: any loss of puncture resistance at 7 bar?

none but I get so few, I get 1 every few years, last was RP after Poo Pooing the surface change! chipping went though with ease....

Infamous

hopper1 wrote:

You can feel power transfer inefficiencies.... :roll:... Behave yourself....

I love how he talks about it as if he's an expert, like andrew coggan talking about power meters or something.

He's a 9 stone climber who has never raced...

Bhima

I can definately feel the tyres bouncing about in a high cadence sprint/descent if they're pumped up too much. No idea how much speed you lose from that but I prefer to have a more stable bike at high speed personally.

redddraggon

7bar on 23mm tyres for me. <7bar on 25mm.

malcolmfrost

Opening up another can of worms, should the tyres have different pressures front and rear?

hopper1

Bhima wrote:

I can definately feel the tyres bouncing about in a high cadence sprint/descent if they're pumped up too much. No idea how much speed you lose from that but I prefer to have a more stable bike at high speed personally.

Try pedalling in smooth circles and not hoiking on the bars so much, then...

hopper1

malcolmfrost wrote:

Opening up another can of worms, should the tyres have different pressures front and rear?

Not sure if they should, but mine do... A touch less in the front to help protect my fillings!

bennyhana22

What about cobbles?!

I am riding the P-R sportive in June and intend to be on Vittoria Pave 24mm (unless someone around the forum can give me a good reason for an alternative).

I KNOW that it's almost inevitable I will puncture but am desperate to minimise the risk/frequency.

I weigh 74kg and may be 1-2kg less at the time of the ride so...

1. What tyre pressure would you all suggest?
2. Any particular tubes that might help reduce puncture risk - can be a bit weightier than 'normal' as the flat parcours should make that pretty much irrelavent

Thanks!

ben

bennyhana22

*BUMP*!

Ben

roger_merriman

bennyhana22 wrote:

*BUMP*!

Ben

no one is going to be able to give you a exact pressure. you'll need to balance the risk of pinch flats and having the pressure so high it's uncomfortable.

ie trial ad error got some cobbles near you? try them out.

learning to ride light would help lots, I notice as some one who cut his teeth on rigid MTB how poorly most roadies do this, and don't get their bums of the saddle.

oldwelshman

bennyhana22 wrote:

What about cobbles?!

I am riding the P-R sportive in June and intend to be on Vittoria Pave 24mm (unless someone around the forum can give me a good reason for an alternative).

I KNOW that it's almost inevitable I will puncture but am desperate to minimise the risk/frequency.

I weigh 74kg and may be 1-2kg less at the time of the ride so...

1. What tyre pressure would you all suggest?
2. Any particular tubes that might help reduce puncture risk - can be a bit weightier than 'normal' as the flat parcours should make that pretty much irrelavent

Thanks!
90 psi on 32 spoke wheels.

ben

DaveMoss

redddraggon wrote:

7bar on 23mm tyres for me. <7bar on 25mm.[/quote Why less on 25mm if the carcass will withstand the pressure?.

contact area on the road times pressure equals weight of you plus bike and attachments, adding the two wheels together that is. So, perhaps surprisingly, for the same pressure, the area of tyre in contact with the road is the same for narrow os for wide tyres. If, like many, you have more wieght on the back than the front wheel, it makes sense to have less pressure iin the front wheel.

Rushie

This time of year with all the crud on the road and with the increase in potholes my priority is staying puncture free. So I have my Gatorskins pretty much at max pressure i.e. 120psi on the rear with the front a little less - 110psi - for a little more traction in the corners. On a recent group ride I was the only one of 12 who didn't puncture, so it seems to work. When the weather's improved I'll drop it a little - maybe 110 r/100 f. I'm around 78kg.

amaferanga

I rarely go above 100psi because if I do it becomes unbearable cycling on many of the roads I normally ride on. I weigh 68kg.

grindsuphill

Suggest 85 to 90 psi optimum pressure for all rider weights ie 5.8 to 6.1 bar g. Why shake your fillings out at absurd 100 psi plus pressures unless your a masochist ? Never seems to cause snakebike punctures in a lardy arsed 86 kg moi.