Tyre Pressure?

Sorry mate, look at your pump again and give us a chance. Ask us what PSI or pounds per square inch we ride at! To all us yanks, a bar is where you get a glass of ale. In the US only divers know about bar. I'll try to answer anyways.
6.5 front and 7 rear, I ride michelin megamium clinchers.
I hope that means 100psi front 110 psi rear for all the americanos
Thanks.

BIANCHI_EURO said:

Some people inflate the back tire harder then the front tyre. There's people who inflate up to 11 Bar and people who ride at just 5 BAR.

WHAT KIND OF TYRES DO YOU USE AND UP TO WHICH PRESSURE DO YOU INFLATE THEM?

Regards, Frank.

p.s.
me? Vitoria rubino (6-8 Bar). Vitoria open corsa CX (8 Bar). (Please! tell me that you are not stuck with psi in USA in 2004)??!

Yes, US is stuck with psi in 2004. We thought about going to SI units several decades ago, but that's as far as it got. Since 1 bar is exactly 14.5 psi, at least the conversion isn't tough.

Like Hooben, I normally run 100 psi front, 105-110 rear. I'm at 170 lbs (77 kg) bodyweight. Don't ask me what that is in stones since I haven't a clue.

BIANCHI_EURO said:

Some people inflate the back tire harder then the front tyre. There's people who inflate up to 11 Bar and people who ride at just 5 BAR.

WHAT KIND OF TYRES DO YOU USE AND UP TO WHICH PRESSURE DO YOU INFLATE THEM?

Regards, Frank.

p.s.
me? Vitoria rubino (6-8 Bar). Vitoria open corsa CX (8 Bar). (Please! tell me that you are not stuck with psi in USA in 2004)??!

I'm stuck with a pump with only PSI units on it :eek:

I use Vittoria Competition (19) and inflate 90/100 (front/back) - guess that's 6.21/6.9 in bars 😄

Hi,

:eek:
Can't believe that in USA the people still use PSI. I guess it's a remain of cowboy time.... 🙄 When they changed the horse for the bike they should have changed the psi for Bar. Obviously they forgot! 😄

Anyway, DHK thanks for the conversion table. That'll do.

I have seen that I am not the only person in the world experimenting with pressures of up to 11 Bar (must be about 160psi I guess). After driving for about half a year on Continental super sport tyres (max inflation pressure= 11 bar) the tyres were torn apart by the inflation pressure. There is a seam in these tyres and it parted.

I am reading this biomechanical German book. The only thing that reduces drag induced by the tyres is inflation pressure. The size of the tyre (19 or 23mm) plays no role at all (amazed me).

Regards, Frank.

BIANCHI_EURO said:

Hi,

:eek:
Can't believe that in USA the people still use PSI. I guess it's a remain of cowboy time.... 🙄 When they changed the horse for the bike they should have changed the psi for Bar. Obviously they forgot! 😄

Anyway, DHK thanks for the conversion table. That'll do.

I have seen that I am not the only person in the world experimenting with pressures of up to 11 Bar (must be about 160psi I guess). After driving for about half a year on Continental super sport tyres (max inflation pressure= 11 bar) the tyres were torn apart by the inflation pressure. There is a seam in these tyres and it parted.

I am reading this biomechanical German book. The only thing that reduces drag induced by the tyres is inflation pressure. The size of the tyre (19 or 23mm) plays no role at all (amazed me).

Regards, Frank.

I've never run over max rating, but have found max pressures seem to result in more cuts through the tread (hence shorter tire life).

Also remember that clincher rims have inflation limits as well. Believe you'll find most are around 140 psi. Surprised you didn't bend or fail the rim sidewalls at 160 psi.

Believe the "common-sense" theory that tells us higher pressures/smaller contact patch yields less rolling resistance is only true on perfectly smooth surfaces. On a textured road surface, a hard tire will bounce, imparting vertical noise energy into the frame which more than offsets the friction of the smaller contact patch.

I'm not too anal with tire pressure b/c in my experience I can't really tell the difference +/- 10 PSI. I pump front up to ~100, rear to ~105, and leave 'em for around a week. When I check (unless there some kind of slow leak) they are ussually around 90/95 or 85/90.

Can you guys really tell a difference between +/- 10 psi given we're not talking about running 130ish+, or very low, levels?

BIANCHI_EURO said:

Some people inflate the back tire harder then the front tyre. There's people who inflate up to 11 Bar and people who ride at just 5 BAR.

WHAT KIND OF TYRES DO YOU USE AND UP TO WHICH PRESSURE DO YOU INFLATE THEM?

Regards, Frank.

p.s.
me? Vitoria rubino (6-8 Bar). Vitoria open corsa CX (8 Bar). (Please! tell me that you are not stuck with psi in USA in 2004)??!

Conti force/attack clinchers @ 130psi.

I run front and rear 120-125 PSI on my Michy Pro Races and Vittoria Rubinos.
Sure saves me pinch flatting on our [censored] New Zealand roads

DHK said:

Also remember that clincher rims have inflation limits as well.

I didn't know about that. Where can one find out about the max inflation pressure of his/her rim? I have also heard wheels can only carry persons up to so much a weight (they never give that info when you buy one, right)? I wouldn't think just 11 Bar can bend a rim??!

This reminds me of the accident I had with Vredestein Volante Tyres. They exploded both at the same time in this steep descent when just reaching a speed of 80km/h at the first day of use. Yes, I was lucky to survive. Actually I was able to stop my bike without even falling. But after riding at high speed on the rims for several hundreds of meters (busy stopping the bike), the rims were a total loss. Indeed the rim was bended heavily especially at one place (Mavic CPX33). But I did definately not inflate those tyres up to 11 Bar. I remember that right before the enduro started I put em on max inflation pressure (I believe it was 8 Bar).

I think the accident was due to the weak (light indeed) construction of the Volante tyre. I informed the Dutch headquarters of Vredestein about the accident but they were obviously only concerned about a possible claim for the rims and/or the tyres. Never heard of them again. Probably the first deadly victims of their tyres are a fact by now.

Regards, Frank.

BIANCHI_EURO said:

I didn't know about that. Where can one find out about the max inflation pressure of his/her rim? I have also heard wheels can only carry persons up to so much a weight (they never give that info when you buy one, right)? I wouldn't think just 11 Bar can bend a rim??!

This reminds me of the accident I had with Vredestein Volante Tyres. They exploded both at the same time in this steep descent when just reaching a speed of 80km/h at the first day of use. Yes, I was lucky to survive. Actually I was able to stop my bike without even falling. But after riding at high speed on the rims for several hundreds of meters (busy stopping the bike), the rims were a total loss. Indeed the rim was bended heavily especially at one place (Mavic CPX33). But I did definately not inflate those tyres up to 11 Bar. I remember that right before the enduro started I put em on max inflation pressure (I believe it was 8 Bar).

I think the accident was due to the weak (light indeed) construction of the Volante tyre. I informed the Dutch headquarters of Vredestein about the accident but they were obviously only concerned about a possible claim for the rims and/or the tyres. Never heard of them again. Probably the first deadly victims of their tyres are a fact by now.

Regards, Frank.

Mavic lists their rim inflation limits right on the webpage with the product description. EG, for 23 mm tires, the common rims are limited to 9.5 bar, or 138 psi. Believe the concern is that the tire will blow off the rim as the rim sidewalls spread under pressure. Mavic and others are now including wear indicators so that you can see and replace the rims before the sidewalls wear too thin to handle the rated pressure.

High speed downhills involving heavy braking can put a lot of heat into the tires, adding to the tire pressure when you least need it. Another good reason to stay away from the max limits.

BIANCHI_EURO said:

Some people inflate the back tire harder then the front tyre. There's people who inflate up to 11 Bar and people who ride at just 5 BAR.

WHAT KIND OF TYRES DO YOU USE AND UP TO WHICH PRESSURE DO YOU INFLATE THEM?

Regards, Frank.

p.s.
me? Vitoria rubino (6-8 Bar). Vitoria open corsa CX (8 Bar). (Please! tell me that you are not stuck with psi in USA in 2004)??!

No flat answer. To much depends on tire size,where you ride,weight of rider.

shokhead said:

No flat answer. To much depends on tire size,where you ride,weight of rider.

Hey we still use PSI in Australia as well.... its the rest of the world that is behind in going to PSI 🙂

I have 100/105 front and back, im 76 kgs..... Im want to buy some of these wheels that I have heard about that let you inflate up to 200 PSI ??? Or was this someone yanking my chain so to speak ???

Vittoria Diamante Pros 130 psi on both front & rear.

BIANCHI_EURO said:

Hi,

:eek:
Can't believe that in USA the people still use PSI. I guess it's a remain of cowboy time.... 🙄 When they changed the horse for the bike they should have changed the psi for Bar. Obviously they forgot! 😄

Since the Pascal is the standard SI derived unit (N/(m**2)); I use about 772kPa in the front and about 813kPa in the back. (currently 700x23c Conti GP 4-season). If I ever switch from using tires to using tyres, maybe I'll start using bars.😉

serenaslu said:

Since the Pascal is the standard SI derived unit (N/(m**2)); I use about 772kPa in the front and about 813kPa in the back. (currently 700x23c Conti GP 4-season). If I ever switch from using tires to using tyres, maybe I'll start using bars.😉

True, but since a bar is by definition 100 kpascals, it's not a tough leap to use bar.

dhk said:

True, but since a bar is by definition 100 kpascals, it's not a tough leap to use bar.

Need I say more? 😄 A little unhandy to work with Pascals with pressures up to 11 Bar.

Strangely enough it allways looks to me like all Americans want to change to the system the whole world is using. I wonder what's keeping them from doing that.

BIANCHI_EURO said:

Need I say more? 😄 A little unhandy to work with Pascals with pressures up to 11 Bar.

Strangely enough it allways looks to me like all Americans want to change to the system the whole world is using. I wonder what's keeping them from doing that.

Grocery products and the majority of consumer goods we now buy (ie, those made in Asia or Mexico) are sold with weights and dimensions in both english and metric. Most cars sold here have either all-metric hardware, or a mix of metric and inch standards.

Free trade is pushing these changes, not legislation. Believe the change to metric will continue to evolve in this way due to the enormous cost of legislated change.

Ride with my 23 mm Vittoria Rubino Pro tyres pumped up to 120 psi. For the record i weigh 13 stone 4 lb and i'm 6ft 2 ins tall :p

BIANCHI_EURO said:

Need I say more? 😄 A little unhandy to work with Pascals with pressures up to 11 Bar.

Strangely enough it allways looks to me like all Americans want to change to the system the whole world is using. I wonder what's keeping them from doing that.

Nope. As was previously inferred, the Bar is not part of the internationally recognized systems. BPMI is generally recognized as the governing body regarding SI ( see: http://www.bipm.fr/en/si/prefixes.html ). kPa or MPa are really the appropriate units to use in that range and not at all unwieldy. No 10^5 unit is either warranted or necessary. But that's not what is practiced.

Now if we all really want to be anal about units we can talk about threading standards, or why automoblile tires are sold with tread widths expressed in mm and wheel sizes in inches! 🙄