What pressure do you pump your tires to?

[jsull14]

Hi,

The guys at Performance Bike told me to keep it around 100 psi. My sidewall says 125 psi.

Being an amateur I would usually just pump until the tire was solid, but now I'm trying to be more exact. Today I tried 105 and it was fine, but it is still a tiny bit "mushy" when I press it with my thumb. I weigh 165.

So what pressure do you use?
Is there suppose to be a slight mushy feeling in the tire or should it be absolutely as solid as a rock?

Thanks

 

[RapDaddyo]

I wish I could lay my hands on an article I read awhile back, but my recollection is that the psi on your sidewall is usually higher than the optimal tire pressure because the manufacturers know that people associate a higher psi number with higher quality so they put the highest rating on the tire they can. IIRC, the rolling resistance is actually higher if you overinflate. Anyway, all that being said, I pump my tires (rated 130psi) to 125psi. Maybe I'm overinflating. I'm sure someone will tell me because there are people on this forum who know such stuff.

 

[531Aussie]

it depends on the tyres, the road conditions and body weight.

I would also find 105psi too mushy on pretty much all roads. I'm about 200lbs, so I like at least 120, and slightly more for smooth roads. Generally, I use 130 rear and 120 front. If i was 165lbs I might go 110/115psi

Some tyres feel harder than others at the same pressure, for example, Michelin Pro Races feel firmer tome at 120 than Vredestrein Tricomps, so I sometimes put 130 in the Tricomp rear and 125 in the front.

 

[gclark8]

At 75kg I started with 95 front 105 rear, still a little harsh, I'll try 90 front and 100 rear next weekend.

 

[domaindomain]

usually 100 upfront and 100 + one pump at the back

 

[capwater]

100 psi works for me since it's a nice big number on the dial.

 

[dhk]

Hi,

The guys at Performance Bike told me to keep it around 100 psi. My sidewall says 125 psi.

Being an amateur I would usually just pump until the tire was solid, but now I'm trying to be more exact. Today I tried 105 and it was fine, but it is still a tiny bit "mushy" when I press it with my thumb. I weigh 165.

So what pressure do you use?
Is there suppose to be a slight mushy feeling in the tire or should it be absolutely as solid as a rock?

Thanks

At 180 lbs, I use 100 psi front/105 rear.

Michelin Pro Race (at least the ones I have) show an inflation range of 6-8 Bar (87-116 psi). To me, this recommended range is a lot more helpful that just putting a max rating as most tires do.

As an analogy, my car tire sidewall says "max inflation 44 psi", yet the sticker on the gas cap shows values from 28 to 33 psi (front), depending on loads and speed.

At 100 psi or so, the tire will have some give when pressed hard with your thumb. "Rock hard" tires have lower road grip, poorer ride and handling, and are more prone to cuts and punctures. Have also seen reports that they have higher rolling resistance on anything but a smooth track surface. Believe this is because hard tires transmit all the road vibration and noise thru the frame to your body where it is absorbed and lost.

 

[MichaelB]

Most of my knowledge of tyres comes from motorsport which is different due to the temperature tyres run at. That is because a hot racing tyre behaves differently to a cold road tyre (car or bike) in almost everyway.

That said I cant help want to mess with tyres pressures all day. I'm not so interested in rolling resistance as I am in how they affect the handling and balance. On a bike they are the only thing which can be adjusted to have an effect on the handling (apart from seating positions which is fixed for other reasons). Clearly tyre pressures depend on which tyre you are running and your weight but also important is how old the tyre is and weather conditions.

The way I approach trying to figure out what tyre pressures are best is by setting the rear tyre pressure to a pressure as high as I can that gives good feel and grip under braking and without making the tyre grain. Thats a problem with a new tyre because they usually have a bit more grip in the dry but less grip and a nasty handling characteristic in the wet. You need to bed them in in the dry before they are any good. Like an all-weather FFord tyre!

Then I would concentrate on keeping the front tyre pressure high but without making the front wheel too sensitive, which has a tendency to reduce the front wheel grip. Usually on the cheapo tyres I run I use about 7 bar in the dry and 6 bar in the wet but I like having a little play with this pressure before I go out to check that front and rear are nicely balanced. You never need less than 6 bar. The rear is usually 8-8.5 bar. I weigh less than 140lbs (61kg). At the moment in these slippy wet-icey conditions my bike feels great with just over 6bar front and 8bar rear.

One thing I do notice is that it is easier to balance on the spot with a high front tyre pressure but that's least important.

 

[jsull14]

Thanks for all the replies!!

 

[fix]

I wish I could lay my hands on an article I read awhile back, but my recollection is that the psi on your sidewall is usually higher than the optimal tire pressure because the manufacturers know that people associate a higher psi number with higher quality so they put the highest rating on the tire they can. IIRC, the rolling resistance is actually higher if you overinflate.

Not sure if this is the article, but I thought this was pretty helpful. Scan through the article and you will find a good explanation of tire pressure, overinflation/underinflation and rolling resistance.

http://www.sheldonbrown.com/tires.html

 

[Postie]

At 180 lbs, I use 100 psi front/105 rear.

Michelin Pro Race (at least the ones I have) show an inflation range of 6-8 Bar (87-116 psi). To me, this recommended range is a lot more helpful that just putting a max rating as most tires do.

As an analogy, my car tire sidewall says "max inflation 44 psi", yet the sticker on the gas cap shows values from 28 to 33 psi (front), depending on loads and speed.

At 100 psi or so, the tire will have some give when pressed hard with your thumb. "Rock hard" tires have lower road grip, poorer ride and handling, and are more prone to cuts and punctures. Have also seen reports that they have higher rolling resistance on anything but a smooth track surface. Believe this is because hard tires transmit all the road vibration and noise thru the frame to your body where it is absorbed and lost.

This sounds pretty much like my approach. I like about 107 front and back. Having it a tiny soft gives me better handling and far less flats then the people I know that run 130.

 

[dhk]

This sounds pretty much like my approach. I like about 107 front and back. Having it a tiny soft gives me better handling and far less flats then the people I know that run 130.

Yes, I've gotten no punctures and fewer cuts since I dropped pressure also. I like having the front tire 5 lbs lower than the back, since it's carrying less weight.

Checked out the Michelin Krylium package today at my LBS. It has a little graph on the side that shows recommended pressure vs. rider weight. It goes from 6 bar (87 psi) for a 50 kg rider up to 8 bar (116 psi, or max sidewall range) for an 80 kg (176 lb) rider, with nothing higher shown. Could Michelin be telling us that their lighter tires in 23 mm width aren't intended for riders heavier than 80 kg?

Anyway, again bought the Conti GP 3000s. Their box shows a recommended pressure of 110 psi for the 23-622 size, and a max pressure of 120 psi, without listing rider weight at all. Based on that, may go up 5 lbs on mine to 105 F/110 R.

 

[cydewaze]

110-115 for my Contis. Max is 120.

 

[Retro Grouch]

I used to use the highest pressure on the tire sidewall. Sometimes I even cheated a little and ran a little more pressure.

Three or four years ago conversations with several different people convinced me to experiment with using lower tire pressures. Today I run 100/110psi. I haven't felt any difference in how the bike seems to roll and the comfort and security factors definitely feel better. I don't get pinch flats at that pressure even on my tandem with 26mm tires. I don't see any downside to running these slightly lower air pressures.

 

[Postie]

Yes, I've gotten no punctures and fewer cuts since I dropped pressure also. I like having the front tire 5 lbs lower than the back, since it's carrying less weight.

Hmm... That's a pretty interesting point. Not only is there less weight on your front wheel but the front is responsible for much of the bike's control. Any idea if the pros fill less pressure in the front then the back?

 

[Adam-from-SLO]

usually 100 upfront and 100 + one pump at the back

Ditto

If its a super high-performance tire(Tri-comp, Veloflex) , I might go to 110F/120R - a clincher, that makes strides at being a tubular

 

[gclark8]

Yesterday I tried 90f 100r in the Conti GP4000s, better on the concrete paths with the joins, no noticable reduction in performance on smooth roads.

 

[wiredued]

I am 195lbs it seems I maintain my best average speed at 110psi to 115psi the max on the tire says 130 psi.

 

[jmurray89]

I have tubies that go up to 220 psi, which i run at about 120-130, and they are pretty solid at that point but still are a tad mushy, while if they are totally hard, rolling resistance increases because your rolling over bumps in the road and there would be nothing to dampen this, causing you to slow down.