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Hops4daze
Posted on Wednesday, June 13, 2007 - 03:40 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ok so I just had these tires mounted and balanced, not even 100 miles yet and I was wondering why they put 32/34 psi in them when the side of the tire recommends 40psi what would the reasoning for this be. Maybe for more aggressive riding, I am curious because if more psi means longer lasting then thats what I should be going for.
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Mikef5000
Posted on Wednesday, June 13, 2007 - 04:20 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I also have these tires. The shop put 36 in mine front and rear, and that's what I've left it at for the past 2500 miles.

I've also been wondering what pressure I should put them at.
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Naustin
Posted on Wednesday, June 13, 2007 - 05:56 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I'm running my 36/38 cold. I have about 1,500 miles on them so far and I like them a lot. Last weekend was 700 miles of straight flat minnesota highway, so the middle is just starting to show a dent in the origial profile.

I was actually thinking of running 40 in the rear (cold) but I don't trust the accuracy of my .59 tire guage and I don't want to over do it.

(Message edited by naustin on June 13, 2007)
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Bad_karma
Posted on Thursday, June 14, 2007 - 03:20 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I think the 40PSI is a max rating. Check your manual for recommended tyre pressure.
Joe
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Blublak
Posted on Thursday, June 14, 2007 - 06:55 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Sounds like they are thinking you will be doing some aggressive riding. The lower pressures are used to allow for the heating of the air inside the tire, which of course causes it to expand and develop more pressure inside.

Also, remember that each brand of tires is different and prefer various amounts of air. i.e.: Dunlop Sport/Track type tires usually like something along the lines of 30/30 - My Pirelli DCIII's actually seem to handle best at 34/33 (go figure, but one of Pirelli guys said to try it), Michelins (I think) are noted for having very low recommended pressures.

A lot of this is also based on your type of riding. If you're doing the tour thing, you'll want more air for the slab shots with more weight on them. So, based on what I've read.. There is no way to suggest a good pressure. There is more to it then 'All tires get X'.

I know it sounds confusing, but after a little while, it'll make more sense. If you still need more help, give a little more info and we here will see what we can do to clear it up for ya.
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Hops4daze
Posted on Thursday, June 14, 2007 - 04:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ok, thanks for the advice. I put 40/40 psi in it as the recommended on the side says 42 and I do ride a little on the aggressive side. So far it handles like a dream, and even when I'm going over bumps or swerving around objects on the highway its predictable, and sticks like flies on shit ;)
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Blake
Posted on Thursday, June 14, 2007 - 11:49 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I also suggest you set pressure to what your owner's manual specifies.

As stated above, the number on the side of the tire is the tires maximum pressure rating.
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Alchemy
Posted on Friday, June 15, 2007 - 07:26 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I just had Metzlers installed at Americade where there was a Metzler factory rep. I asked about tire pressure.

He said after the initial break-in period of scuffing the tire and at about 100 miles that the pressure should be checked. The pressure drifts lower as the tire seats to the rim. After that the pressure is more stable.

He said to ignore the manual unless the new tire is the same as the original factory brand. I questioned him on that but he emphasized very strongly that the data on the tire was the critical data.

Start at the max pressure (when cool) and ride. Lower the pressure to get the tire performance you want. He mentioned dropping the pressure by one or two psi and checking the performance until it is what is wanted. But understand that the life of the tire goes down about 1k miles for each PSI the pressure is dropped. This may apply more specifically to the Metzler M3 but it is generally useful information.

I can now see the utility of an accurate pressure gauge and how it can pay for itself in better tire life.
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Mikef5000
Posted on Saturday, June 16, 2007 - 09:59 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I'm my auto school, they can't stress enough to go by the cars recommended tire pressures, not the tires max pressure.

My argument is that the manufacturers of the car don't care about my tire life, they just care about making the car as confortable/quiet/customer pleasing as possible.
Maybe I'm willing to have a slightly bumpier ride, if it means better handling or longer lasting tires. Which I do. My car says run tire pressures at 29. I run them at 42. I love the handling, and I can tell when the pressures drop below 35. It is very noticable.

I recently bumped the pressures in my bike tires up to 40 rear and 38 front.
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Blake
Posted on Saturday, June 16, 2007 - 12:00 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Adding "safe" to your list of vehicle manufacturers' concerns might be valid too.

Increasing tire pressure, reduces the amount of tire that is in contact with the pavement. Going from 36 psi to 40 psi would reduce the area of a tire's contact patch by roughly 11%. This can reduce available grip. For an automobile more so than for a sporting motorcycle, higher tire pressures can increase the distance required to stop in a panic situation.

On the racetrack, tire pressures are set for optimum grip and handling. Once they come up to temperature, DOT track tire pressures are a bit lower than what is recommended for street use. That seems to indicate that pressures slightly lower than those specified by the motorcycle manufacturer are closer to optimum for one-up performance. Maybe a perusal of the Pirelli site will reveal more information on the issue.

On an automobile, running tire pressure too high can cause the tires to wear abnormally and excessively, shortening tire life. Higher tire pressures will increase fuel efficiency as you say.

Did I actually say "contact patch"? Yeah baybee! : D Bring it! : D

(Message edited by blake on June 16, 2007)
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Ridrx
Posted on Saturday, June 16, 2007 - 06:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

After I installed my Conti-Roads, I contacted Continental and was given 36f/42r as the recommended pressure. They handle great and show little to no wear after 700mi., half of that on a slab.
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Hops4daze
Posted on Wednesday, June 27, 2007 - 04:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Yeah I have the Bt021 tires from Bridgestone and I talked to the people at Bridgestone they told me 38/42 for mileage and anything lower as I see fit for performance. But to remember the lower the less mileage you will get out of the tire. I must say at 38/42 it handles extremely well but if you feel like scraping footpegs I would recommend lower.
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Bad_karma
Posted on Thursday, June 28, 2007 - 12:50 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

This is interesting, appears there is a change in tyre air pressure to go along with tyre technology or are the manufactures trying to get more mileage from the tyres?
Joe
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Naustin
Posted on Thursday, June 28, 2007 - 10:25 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I think the Bike manufacturer recommends their tire pressures based on the best combination grip, performance, and comfort.

The tire manufactures recommend higher pressures because they feel that for the average street rider (especially one who calls them asking about tire pressure for mileage purposes), the minimal compromise in grip and handling is worth the trade off for more mileage.

Riders who actually push their bikes to the limit and who need the extra performance that can be squeezed out of a street tire by running lower pressure probably don't need either the bike manufacturer or the tire manufacturer to give them advise and are more likely to rely on their own feel and judgment than anyone else’s recommendation anyway.
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Mikef5000
Posted on Friday, June 29, 2007 - 04:40 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

These are also the most touring oriented tires in this line, so they're going to try to squeeze the most life out of them as possible.
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Bad_karma
Posted on Friday, June 29, 2007 - 11:56 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

It's funny I have never seen tyres, air pressure or oil on any of the TV's series like, say "great unsolved mysteries".
Joe
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