Tyre pressure

blahblah06

Hi guys what pressure do use all go for. I have mine at 7 bar or 100 psi. is that the normal?

Ryaner

Usually 110/120 PSI for road tyres. I ran them slightly lower while in france recently without issues.

blahblah06

really I didnt think you could go up that high. is everyone the same 110 120?

Cape Clear

blahblah06 wrote: »

really I didnt think you could go up that high. is everyone the same 110 120?

Best done with a track pump

snollup

I struggle to get mine up to 100 but using cheap as chips track pump from Agros. Must upgrade it.

blahblah06

i bought the pump from aldi today does the job. thats y im asking

Lumen

blahblah06 wrote: »

Hi guys what pressure do use all go for. I have mine at 7 bar or 100 psi. is that the normal?

Depends on your weight.

blahblah06

206lb

furiousox

100 front, 90 rear.

IM0

Lumen wrote: »

Depends on your weight.

+ 1,000,000

some of the people who dont realise this go on to post threads about being uncomfortable and wondering why :rolleyes:

the faster you go/more effort, the harder pressures you can get away with
I reduced mine about 10-15psi after I realised this finally! :pac:

if you cycle on heavy roads too, a lower tryre pressure will be much better too

RoughBag

Depends on what your rims & tyres will take.

The higher pressure you put in them, the less rubber on the road, less chance of flats.

Downside is you've less grip cornering in the wet.

I've decent Mavic wheels that I put up 8.5 bar in depending on the weather. My normal training wheels have 7 bar.

Lumen

For 206lb with 23mm tyres and 40/60 weight distribution, this chart suggests 90/140psi.

I'd probably go a bit less extreme and choose 100/130psi.

IM0

Lumen wrote: »

For 206lb with 23mm tyres and 40/60 weight distribution, this chart suggests 90/140psi.

I'd probably go a bit less extreme and choose 100/130psi.

I tend to go harder on the front than the rear, theory being my ass sits over the rear wheel! - worx a treat

Lumen

me@ucd wrote: »

I tend to go harder on the front than the rear, theory being my ass sits over the rear wheel! - worx a treat

Please explain that theory.

tunney

me@ucd wrote: »

+ 1,000,000

some of the people who dont realise this go on to post threads about being uncomfortable and wondering why :rolleyes:

the faster you go/more effort, the harder pressures you can get away with
I reduced mine about 10-15psi after I realised this finally! :pac:

if you cycle on heavy roads too, a lower tryre pressure will be much better too

Never mind comfort, the right (usually lower than expected) pressure will run faster too. Lower Crr

IM0

Lumen wrote: »

Please explain that theory.

:pac:

ok well when its not a race, and performance absolute top speed is less important than comfort enjoying the ride, letting down 10+ psi out of the rear is like the idea as adding gel to a saddle, except its a solution that works, not one which has been marketed as such from saddle manufacturers!

same principle that makes getting on a mtb after years of exclusive use of a road bike so much more comfortable, much wider tyres, much lower psi

IM0

tunney wrote: »

Never mind comfort, the right (usually lower than expected) pressure will run faster too. Lower Crr

I thought saying the last part was what Iwas saying without using the technical coeefficient of rolling resistance term

abcdggs

tunney wrote: »

Never mind comfort, the right (usually lower than expected) pressure will run faster too. Lower Crr

do you have a reference?

blahblah06

Thanks for that lumen

iregk

Too many factors to decide tyre pressure.

Your weight, yoru wheels, your tyres the route your taking etc...

at the moment i'm running 100/120 and im 85kg.

rcaz

I'd never thought about this that much. I just read the 'inflate to' bit on the side of the tyre and went with that.

So it's something everyone has to feel out for themselves?

IM0

El Pr0n wrote: »

So it's something everyone has to feel out for themselves?

like everything it comes with experience, like you [and most who dont hear otherewise] I inflated to what the tyres said, like you didnt know any different, then one day like yourself found out and changed it, thenran into a a dutch neo pro friend in france, who always had his tyres rock hard, but he was putting out 350w at 75kg @ threshold so thats what worked for him, I tried the same but at 300w at 69kg @threshold it didnt work quite so well. But it was enough to hear it, and I went back and forward for years with different pressures, now a bit softer [less hard] is better than a bit too hard

guy bono

Lumen wrote: »

For 206lb with 23mm tyres and 40/60 weight distribution, this chart suggests 90/140psi.

I'd probably go a bit less extreme and choose 100/130psi.

Thanks for this:a dumb question - how do you figure weight distribution when it's just you and not any gear/bags on the bike?

ednwireland

100 front 110 rear 220lbs dont suffer too much on punctures

Lumen

guy bono wrote: »

Thanks for this:a dumb question - how do you figure weight distribution when it's just you and not any gear/bags on the bike?

Stick the front wheel on a set of weighing scales. Sit on the bike in the position in which you ride. If you're really fussy, prop the back end up so it's level, or weigh the back directly the same way.

This is obviously overkill for determining tyre pressures, but is useful for other things (like better understanding your bike fit).

doozerie

For what it is worth, here is a perspective on tyre pressure from Zipp, (from here - click on "Rolling Resistance"):

The Corsa Evo CS will be perfect for that wheel, and I would recommend 100-125 psi (6.9-8.6 bar) depending on your weight. You will want to run 0.2-0.5bar more in the rear than the front to account for weight bias. I personally weigh 155lbs (70kg) and run my tires at 105 psi front (7.2 bar) and 110 psi (7.6 bar) in the rear. When I was racing and lighter I ran them at 100/105, but now that I'm heavier it is safer to run a few extra psi and I may go even higher on bad roads, which has worse rolling resistance, but better protects the wheels from damage in the event of hitting a pothole or something else which could damage a rim or tire. The better option is to run a wider tire at lower pressure on rough roads, but that is just not always feasible, so I would rather have higher rolling resistance and protect the wheels than lower rolling resistance and increased risk of damage to the wheel.

Higher pressure is definitely slower on anything other than perfect surfaces. Think of it in terms of a bunch of 1mm tall bumps in the road. If you have a lower tire pressure, the casing of the tire will deflect over each bump (we'll assume the casing deflects the entire 1mm) converting a small amount of energy into heat as the casing deflects, but the amount of energy necessary to compress the air is almost non-existent. Now at a higher pressure, we will assume that the tire deflects half as much. Now the bike and rider are lifted by 0.5mm and the casing deflects by .5mm, the energy necessary to deflect the casing by .5mm is less than it takes to deflect it by 1mm, but is nothing compared to the amount of energy necessary to lift the bike and rider by 0.5mm, so the end result is that the total energy requirement for the high tire pressure condition is much greater.

The other thing that happens is that on smoother roads, high tire pressures keep the casing from deforming over and into small cracks and crevices and over pebbles, which means that some of the deflection is transferred into the tire tread, which is not as elastic as the casing. Excessive tire wear comes about as the tire rubber begins to fail in shear as it is deformed by the road surface, and this generates heat as well as breaks down the cross-linking within the tread material.... overall, you are using more energy to go slower and you're wearing your tires out faster. The problem is that high tire pressures feel fast as your body perceives all the high frequency vibrations from the road surface as being faster than a smooth ride.

Lennard Zinn had a great analogy when he said that 100kph in a Jeep will scare the crap out of you but 200kph in an S class Mercedes feels effortless...the same is true of bike tire pressures, but it's just hard to convince ourselves of that. As athletes we tend to buy into the 'if some is good, more must be better' philosophy, but this is rarely true. Of course the tire manufacturers have given up on this and continue to try and make higher pressure tires as that's what the consumers demand, as I think that they've decided that it is easier to just give people what they think they want than to try to educate and argue with them :-)

Lumen

I still don't understand the logic of using almost the same pressure front and rear if the rear takes 50% more load.

ipodrocker

whats a good price to spend on a track pump?

IM0

ipodrocker wrote: »

whats a good price to spend on a track pump?

€30

blorg

ipodrocker wrote: »

whats a good price to spend on a track pump?

They probably start about €30. Topeak Joe Blow are good. Basically you want something with a metal barrel that is rated to at least 120 PSI. Personally I would tend to err towards something rated higher, not because you will ever need to go that high (you won't) but because pump manufacturers lie as to what their pumps are actually capable of. So if you get something rated to 160 PSI you can be happy that it should go to 110.

keane=cock

blorg wrote: »

They probably start about €30. Topeak Joe Blow are good. Basically you want something with a metal barrel that is rated to at least 120 PSI. Personally I would tend to err towards something rated higher, not because you will ever need to go that high (you won't) but because pump manufacturers lie as to what their pumps are actually capable of. So if you get something rated to 160 PSI you can be happy that it should go to 110.

any suggestions on where to buy a good pump> on line or anything? was looking at the one in aldi that was mentioned earlier but wasnt sure if it was worth the 30euro

murph226

Got one of these last week, bit on the dear side but a great piece of kit!

http://www.chainreactioncycles.com/Models.aspx?ModelID=27796

gman2k

Got a Joeblow recently in Halfords for a good price

blorg

I have this and it is good. Key things are metal barrel and rated for high PSI I think. We got an own brand pump in Decathlon for €20-25 that was grand while we were in France.

dave2pvd

blorg wrote: »

I have this and it is good. Key things are metal barrel and rated for high PSI I think. We got an own brand pump in Decathlon for €20-25 that was grand while we were in France.

I'm on my second one of those. An excellent investment, IMO.

Of all the components on a bike, tyres are mechanically one of the more simple from a user perspective. Yet they frequently seem to be poorly understood/maintained. Many of the comments on here appear to back that up.

Lumen is on the right track for sure: look up the manufacturer's inflation pressure chart. DO NOT automatically use the max inflation pressure on the sidewall.

Here is Michelin's pressure chart. I am biased by the type of racing that I do; I usually opt for maximum cornering grip. This has me running Pro Race 3s a little below the Michelin chart. Weighing 165-170lbs, I run minimums of ~100-105psi rear and ~95 on the front. That will vary based on conditions. For a TT or RR on good surfaces, I will use higher pressure. Except in the wet.

Incidentally (and OT), I would probably never use PR3s if I raced in Ireland. Too soft/not enough puncture resistance. There are lots of tyres out there that meet the durable/puncture resistant criteria needed. They usually cost a bit less than PR3s too.

IM0

dave2pvd wrote: »

raced in Ireland. Too soft/not enough puncture resistance. There are lots of tyres out there that meet the durable/puncture resistant criteria needed. They usually cost a bit less than PR3s too.

yep, Krillion carbons for one [michelin] and Conti GP4000's for two

blorg

dave2pvd wrote: »

Incidentally (and OT), I would probably never use PR3s if I raced in Ireland. Too soft/not enough puncture resistance. There are lots of tyres out there that meet the durable/puncture resistant criteria needed. They usually cost a bit less than PR3s too.

I have the same experience with Pro3s, lots of punctures. They are also an absolute bitch to get on or off the rim (Mavic) when they do puncture. My favourite tyre would have to be Schwalbe Ultremos although Conti GP4000S are also decent. Both have very good puncture resistance IMO.

dave2pvd

blorg wrote: »

I have the same experience with Pro3s, lots of punctures. They are also an absolute bitch to get on or off the rim (Mavic) when they do puncture. My favourite tyre would have to be Schwalbe Ultremos although Conti GP4000S are also decent. Both have very good puncture resistance IMO.

Both good ones, from what I see of teammates using them.

I use PR3s racing, typically. For training, something cheaper like Maxxis Detonator or Vittoria Zaffiro Pro. Although Michelin Lithion is available in 25mm now....

blorg

dave2pvd wrote: »

Both good ones, from what I see of teammates using them.

I use PR3s racing, typically. For training, something cheaper like Maxxis Detonator or Vittoria Zaffiro Pro. Although Michelin Lithion is available in 25mm now....

I used Maxxis Columbiere in 700x25c all winter. Fantastic tyres, very light for a 25, great grip and held up well over many thousands of winter km. Schwalbe Stelvio are also good and available in wider sizes. Now rebranded as Durano I believe.