Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Bicycle Mechanics (https://www.bikeforums.net/bicycle-mechanics/)
-   -   New tires- psi question (https://www.bikeforums.net/bicycle-mechanics/723896-new-tires-psi-question.html)

Stevestrat 03-30-11 01:34 PM

New tires- psi question
 
Just mounted a new set of tires- Serfas Seca RS folding. This was stated in one of the customer reviews: "After you mount them, ride your first 50 miles with no more than 100 psi. This will allow the tire to break-in (like any tire, even your car)Flats are most contagious at the beginning of a tires' life. Do yourself a favor and get a pair" Do you do this with a new set? I never have.....Thx- Steve

BCRider 03-30-11 01:45 PM

Never heard of it and never done it. Don't remember getting flats any more commonly in such tires than at any other time. Sounds like "falderall" to me. Although I could see where running them a touch on the soft side for a while would allow them to flex more and if there is such a thing as tire break in that it would speed up the process. But then I'm not a tire engineer either. But it's also odd that if Serfas is putting this in their instructions then it's the first company I've ever heard of saying such a thing.

Also the wording of "Flats are most contagious at the beginning of a tires' life. Do yourself a favor and get a pair" makes it sound like the idea is to get a couple of flats and get it out of the way early on so you can go a long time after without any. Sort of like once you get the measles you're immune for life.... :D

fietsbob 03-30-11 02:01 PM

Read the numbers impressed in the sidewall of the tire , and use them.

Vaccine , it comes from milkmaids having caught occupational Cow-Pox ,

being resistant to the more deadly smallpox.

Mmm , Cheese :lol:

Stevestrat 03-30-11 02:09 PM

BC Rider- Serfas isnt recommending this~ it was stated in a customer review of the tire. I have never heard of doing this either. Thx- Steve

davidad 03-30-11 03:00 PM

The sidewall pressure is a guide line. https://www.adventurecycling.org/res...SIRX_Heine.pdf

1saxman 03-30-11 05:42 PM

I find that filling the tube/tire with air, releasing and refilling a few times usually allows the tube to get straight and gets rid of tire gnarls. Probably riding it at 3/4 max pressure for a few minutes would do the same.

BCRider 03-30-11 06:33 PM


Originally Posted by Stevestrat (Post 12434698)
BC Rider- Serfas isnt recommending this~ it was stated in a customer review of the tire. I have never heard of doing this either. Thx- Steve

Then I would give it all the due consideration it deserves based on it being one isolated opinion and in light of the tire makers never having said any such thing at any time that I've ever seen.

The only "break in" that I use on new tires is to ride or drive a trifle conservative for the first few miles and/or leans into turns until I'm sure the waxy shipping or manufacturing coating on my car and motorcycle tires is scuffed off. Nothing like a silly dump at the end of the parking lot pulling away on waxy tires from the dealership.... You may laugh but YouTube is full of such first moment videos for sportbikes newly picked up or with new tires freshly mounted.

On our bicycles? Harly an issue since the "engine" doesn't have the moxie to produce such embarassing moments and there's so little contact that just riding for a mile is more than enough to scuff 'em fresh of what may be on them.

Burton 03-30-11 11:24 PM

The problem with user generated reviews is that there is no control over the credentials of the reviewer. The concept that ANY product would be more prone to failure when new and the components are in the best condition they will ever be is more than a bit ridiculous.

Motors have a break-in period because they have moving parts. When your tires develop moving parts I think its called delamination. Tire pressure should be determined by whats on the sidewall and the load on the tire. Tires do have load ratings and its speced against the maximum PSI.

DannoXYZ 03-31-11 01:07 AM


Originally Posted by Stevestrat (Post 12434523)
Just mounted a new set of tires- Serfas Seca RS folding. This was stated in one of the customer reviews: "After you mount them, ride your first 50 miles with no more than 100 psi. This will allow the tire to break-in (like any tire, even your car)Flats are most contagious at the beginning of a tires' life. Do yourself a favor and get a pair" Do you do this with a new set? I never have.....Thx- Steve

Sounds like BS to me. I worked in a shop for 10-years and have never heard of such rubbish.

MilitantPotato 03-31-11 05:26 AM

Someone recently mentioned a study/hearsay/anecdotal experience that tires "break in" (rolling resistance lowers) after a little riding.

I think it was mentioned in that ridiculous tire plumping thread.
I would say it's probable, but it would happen over time at a proper pressure anyway.

eddubal 03-31-11 05:52 AM

Sounds like a reviewer that doesn't know how to install a tube correctly and ended up with pinch flats.

1saxman 03-31-11 07:27 AM

'Flats are most contagious at the beginning of a tires' life.'

I'm thinking y'all are trying to make something of what probably was meant to be a wisecrack, not statistical data. You know, brand new tires and the first thing you do is get a flat, ha ha?

cyccommute 03-31-11 08:26 AM


Originally Posted by eddubal (Post 12437316)
Sounds like a reviewer that doesn't know how to install a tube correctly and ended up with pinch flats.

Yea...from not inflating his tires to the proper pressure:rolleyes:

If anything, tires that are older have more flat problems...although flats are still mostly random.

FBinNY 03-31-11 08:38 AM

I like the inflate to no more than 100psi during the break in. What do folks inflate to after break in. In 40 years of riding tubulars I've never found the need to exceed 7atm, or 105psi and that's using 25mm tires for loaded touring.

The only logic to starting out with lower pressure is to confirm proper seating, and that's with much lower pressure, and not while riding. Beyond that it pays to allow for slightly lower cornering traction until the skin and mold release are worn off (tire isn't shiny any more), but still always ride at normal pressure.

BTW- folks seem to forget that what's molded into tire walls is the Maximum rated pressure, not the ideal riding pressure which varies according to weight. If you use car tires as an analogy, the tires have the max pressure molded in, and the driver's door has the recommended pressure for that car, almost always lower than the tire rating.

Stevestrat 03-31-11 07:17 PM

Thanks all....general consensus is there is not much merit to this...for all I knew, this was something everyone had heard of but me- good to know I wasn't alone- thx for the replys....Steve

HillRider 03-31-11 07:46 PM


Originally Posted by Burton (Post 12436871)
The concept that ANY product would be more prone to failure when new and the components are in the best condition they will ever be is more than a bit ridiculous.

Not everything. Electronic devices tend to either fail very early (it's called "infant mortality") or last a very long time. However, there is no break in technique to avoid this.

FBinNY 03-31-11 08:01 PM


Originally Posted by Burton (Post 12436871)
. The concept that ANY product would be more prone to failure when new and the components are in the best condition they will ever be is more than a bit ridiculous.
.

Actually, first use is when a defect is most likely to show up. Tires aren't pressure tested at the factory, so the very first time they'll be stressed is when someone pumps them up the first time. This is also true of auto tires, which is why some tire shops have inflation cages, designed to capture tire shrapnel and keep an exploding auto tire from killing staff. Fortunately exploding bike tires pack much less punch.

operator 03-31-11 08:04 PM

The OP is quoting something ridiculously untrue from some random idiot on the internet.

How the hell is this news again?

Dan The Man 03-31-11 08:09 PM


Originally Posted by FBinNY (Post 12437924)
I like the inflate to no more than 100psi during the break in. What do folks inflate to after break in. In 40 years of riding tubulars I've never found the need to exceed 7atm, or 105psi and that's using 25mm tires for loaded touring.

The only logic to starting out with lower pressure is to confirm proper seating, and that's with much lower pressure, and not while riding. Beyond that it pays to allow for slightly lower cornering traction until the skin and mold release are worn off (tire isn't shiny any more), but still always ride at normal pressure.

BTW- folks seem to forget that what's molded into tire walls is the Maximum rated pressure, not the ideal riding pressure which varies according to weight. If you use car tires as an analogy, the tires have the max pressure molded in, and the driver's door has the recommended pressure for that car, almost always lower than the tire rating.

For road bikers it is almost always more efficient to have higher pressure tires. The only thing holding them back is the max pressure rating of the tires. Therefore, tires get pumped up to their maximum rating.

Retro Grouch 03-31-11 08:12 PM


Originally Posted by FBinNY (Post 12441036)
which is why some tire shops have inflation cages, designed to capture tire shrapnel and keep an exploding auto tire from killing staff.

Actually, tire shop inflation cages are for truck tires. Cars have drop center rims like a bicycle rim. Many trucks don't. Insted they have a "safety ring" that holds the tire bead. If the safety ring isn't seated perfectly it can blow off during inflation. If you examine a tire safety cage closely it's common to find a crease left by a safety ring that blew off.

Retro Grouch 03-31-11 08:15 PM


Originally Posted by Dan The Man (Post 12441062)
For road bikers it is almost always more efficient to have higher pressure tires. The only thing holding them back is the max pressure rating of the tires. Therefore, tires get pumped up to their maximum rating.

Oh yeah? I remember hearing Phil Ligget say that TDF riders use around 115 psi in dry conditions. If I knew how to look that up from another source I would.

Retro Grouch 03-31-11 08:19 PM


Originally Posted by cyccommute (Post 12437877)
If anything, tires that are older have more flat problems...although flats are still mostly random.

I definitely think that older tires are much more prone to punctures. I think that frequent punctures is one of the ways that my tires tell me "It's time for replacements.".

FBinNY 03-31-11 09:15 PM


Originally Posted by Dan The Man (Post 12441062)
For road bikers it is almost always more efficient to have higher pressure tires. The only thing holding them back is the max pressure rating of the tires. Therefore, tires get pumped up to their maximum rating.

Actually the limiter on pressure is handling considerations. More pressure does lower rolling resistance, but after a point the improvement tapers off. Meanwhile more pressure makes tires more skittish (for lack or a more precise word) and causes them to bounce off small bumps rather than absorbing them through deflection. That decreases the connection to the pavement and lowers traction. Ideal pressure depends on conditions and reflects a balance between these conflicting goals.

Counter-intuitively there's good dyno data available showing that wider tires at lower pressure actually have lower rolling resistance than narrower tires at higher pressure. But don't run out and get fat tires right away. Fatter tires weigh more and create higher air drag.

Peak performance is obtained with the best balance of tire selection and inflation pressure for road conditions, and not simply highest pressure.

Burton 03-31-11 10:45 PM


Originally Posted by HillRider (Post 12440966)
Not everything. Electronic devices tend to either fail very early (it's called "infant mortality") or last a very long time. However, there is no break in technique to avoid this.

Think both you and FB are kinda stretching a point on this one. I`ll agree there is a very small percentage of items that fail due to warranty issues, but thats specifically because they didn`t meet the build specification. In most cases the problems are evident right out of the box so there`s no reason to `tread carefully`.

The point is pretty simple. Products don`t go through a break-in period and become increasingly reliable. They gradually wear out, deliver an ever diminishing performance and eventually get trashed.

Lets not get hung up on a few exceptions that aren`t representative of the intended product design. The OP has the tires already mounted so it should be safe to asume that the beads aren`t defective and since the tire hasn`t blown up, the casing is in good shape. The idea that the tire might be more suseptable to flats at this point than after some break-in period is ridiculous. The materials aren`t going to magically get stronger with use.

FBinNY 04-01-11 09:15 AM


Originally Posted by Burton (Post 12441622)
Think both you and FB are kinda stretching a point on this one. I`ll agree there is a very small percentage of items that fail due to warranty issues, but thats specifically because they didn`t meet the build specification. In most cases the problems are evident right out of the box so there`s no reason to `tread carefully`.

The point is pretty simple. Products don`t go through a break-in period and become increasingly reliable. They gradually wear out, deliver an ever diminishing performance and eventually get trashed.

I can't speak for Hillrider, but I was only responding to your comment that the concept that high rates of early failure was ridiculous. For the record I don't support the the OPs notion that tire break in makes any sense, though a checkout ride before a race or starting a long trip might.

But as for the point of early failure rates, folks in manufacturing and quality control are aware of the phenomenon. If you were to plot the number of failures against time on a graph you'd find an initial spike, followed by a long period of low failures during normal service life, then a steadily rising rate as the service life ended. It's the normal pattern for many items and in some cases that knowledge can be used to advantage.

For example if you were in charge of maintenance and had to replace bulbs in an atrium ceiling fixture, a complex and expensive process, you might burn a bulb in a fixture at ground level for a while to get it past the statistical spoke then install it with greater confidence that you wouldn't have to repeat the job within a week.

The simple reality in all things mechanical is that the highest chance of failure is after immediately replacement or adjustment. I scuba dive and 100% of my regulator failures were on the first dive after the annual service. I make it standard to make that first dive under controlled conditions as check out dives before venturing out onto open ocean drift dives.

As a race team sponsor and coach for many years, I warned the team against any major work immediately before a race, and had them ride at least 50 miles on anything new before using it for a major race. It's always better to have surprises when the stakes are lower.


All times are GMT -6. The time now is 04:16 PM.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.