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Technical Q&A with Lennard Zinn – Are old tires safe?

By Lennard Zinn

The Vittoria Pave

The Vittoria Pave

Photo: Matt Pacocha

Aging tires
Dear Lennard,
I have known people that have road bicycle spare tires in their garage for more than two years. Also, I have a nine-year-old Nokian studded tire on the front of my mountain bike for snowy/icy conditions.

I have a pair of Michelin Pro Race tires that have been in my garage for four or five years, and have only been pulled out of their boxes a few times. Although they have not been exposed to sunlight, I am concerned about the pressurizing these tires to 115-120 psi considering that they may have dried out.

Are they safe, or should I throw them away?
Wade

Dear Wade,
The nylon casing fibers are unlikely, if shielded from light, to be degraded with age (like old cotton or silk tubulars could be). So from a safety perspective, I doubt they would burst suddenly.

That said, the rubber itself is sure to be not as good as it was because latex (natural rubber) quickly degrades when exposed to ultraviolet light and to ozone. To protect against UV, you need to keep the tires out of the light or put some kind of sunscreen on them. Ozone, however, is a different matter. Rubber generally has wax in it to block ozone. As the tire flexes, it pushes wax to the surface. But when the tire does not move, the wax on the surface is used up and none comes from deeper down to replace it. This is why the tread of the tires on your relatives’ bikes is cracked, even though the tires have very little mileage on them and have simply been sitting in the garage for years without moving.

A little bit of use, and that would not have happened. So, if you want to store tires for a long time, I recommend using a treatment like 303 Aerospace Protectant to protect from ozone (and from UV, if you leave the tires where light can hit them).

Being a kayaker, I depend on this 303 stuff to keep the latex neck and wrist gaskets of my dry top from cracking. It works so well at that I started using it on tires I store and have been equally pleased with the results.
Lennard

Dear Lennard,
A couple issues of VN ago, you outlined how to replace bearings in the bottom bracket cups of the standard brands with the enduro bottom bracket bearing tool. I’ve replaced several bearings in Shimano and FSA bottom brackets with that tool. My question is with the SRAM BBs. How do you get that sleeve thing off/on the bearing on the non-drive side.

Will the standard Enduro replacement bearings (made for Shimano and FSA replacement) work in the SRAM bottom bracket if I can get that sleeve in ok? I know the ID of the bearings is correct, but the bearing thickness is different. Is this a problem?
Josh

Dear Josh,
You can easily push that reducing sleeve out with a socket or with a tool from Enduro and put it into the new bearing with the GXP insert on the Enduro tool. But the Enduro SRAM/TruVativ GXP bearing kit comes with a new sleeve anyway. And the kit also includes a thin (1mm) washer to put against it to compensate for the 1mm narrower bearing. The narrowness on the drive side bearing is of course irrelevant, because the TruVativ spindle indexes off of the non-drive bearing and is free to flat laterally in the drive bearing.
Lennard

Revised advice: don’t use Teflon tape on bottom bracket threads!
Dear Lennard,
I saw that you recommended Teflon tape for the threads of creaking bottom bracket. I was a bike mechanic for seven or eight years and I highly advise against Teflon tape. I tried this on a my mountain bike about six years ago with success, so I was convinced too. I used it on an ISIS bottom bracket on a second mountain bike to have the bottom bracket seize while threading in into the shell.

RaceFace, who’s bottom bracket I was using, recommended using only anti-seize compound on bottom bracket threads. About two years later I started working at another shop and they were in the practice of Teflon taping bottom brackets. I describe what had happened to me previously and they were surprised until fifteen minutes later a bottom bracket seized while being threaded into the shell.

A better solution to creaking bottom brackets is facing the frame, since even large companies, like Specialized, don’t do this in-house. Bikes delivered to bike shops come with bottom brackets installed and most bike shops don’t remove them to face the frame. Every bike I’ve seen creaking from this area can be attributed to frame facing.
Bruno

Feedback on carbon composites and fatigue failure:Dear Lennard,
I will add to the “electronic mountain” of emails about carbon fiber composites not failing by fatigue. Fatigue failures are most likely to occur in any structure at discontinuities and what is a carbon fiber composite but one giant discontinuity between the fibers and the resin matrix?

Furthermore, polymers (including the thermoset resin matrix materials used in composites) heat up during high frequency loading and can thermally degrade and eventually fail due to this form of fatigue. Fatigue failure means failure due to repeated, alternating stresses during service and is not limited to the archetypical “thumbnail” fractures so familiar in metallic fracture. Give me enough money, time and a good mechanical test laboratory and allow me the liberty of selecting the test conditions and I will give you fatigue failures of any carbon fiber composite bicycle frame, fork or component you can supply. Just be sure to send two of each so I can keep one as a “comparison”. You can start with a couple Pinarello Princes; I hear there is some composite in those.
Keith



The Wippermann chain revisited
Dear Readers,
First off, I should mention that when I submitted my July 1 column, I accidentally left it attached to a 69-page document of letters that I’ve answered but did not post for some reason or another. I occasionally go through that document and pull one or two out of it, and I had tacked on my response about checking carbon parts for damage on top of it.

Overwhelmed by the 28,000-word, cut-and-pasted document, the web editor picked out a few questions, cleaned them up and posted. (I’m sure happy he didn’t do the whole thing!) In this case, he pulled a couple of questions out of that document that have been in that list for more than five years. So while it is inaccurate that I have not used Wippermann chains, as my response said – I had written that several years ago – I’m glad it was posted, because I got a ton of letters about it. Most of them were very favorable toward Wippermann, but not all. I’m including a brief sampling.

My own experience has basically been good with them. I use a Wippermann chain on the Campy 10-speed drivetrain of my coupled travel bike, which I had with me at the Giro as well as my most recent trip, which included Mavic, DT Swiss and Schwalbe press camps and the Tour de Suisse. I use it rather than a Campy chain because of the convenience for traveling of its master link (note the comment from one reader about orientation of the link, or it will skip on your smallest cogs).

Durability is good and shifting is fine. I will say that it does not shift as fast as a Campy chain, however, at least when both chains are new. My theory is that it is due to being laterally stiffer. I took a new Wippermann and a new Campy chain, laid them out on my floor so that the pins were horizontal and flexed them sideways. The Campy flexed considerably further than the Wippermann. Of course, too much chain slop, which occurs with age, can become detrimental. On the other hand, the lateral push by the rear derailleur has to be able to make the chain grab onto the adjacent cog, so some lateral flex is necessary. The shifting is still quite good, and I will continue to use it without feeling any performance detriment while enjoying the ease, speed of installation and disassembly, and security of the Wippermann master link.
Lennard

Dear Lennard,
I, too, also had issues with Campy chains and ended up switching to Wippermann. Although I know better (15+ years in the bike biz plus years of racing back in the day) at one point I left the chain on my bike for more than a year (6000+ miles). When I installed a new chain I fully expected to pay the piper and discover a shot cassette due to my laziness. Instead, no issues, no skips, jumps, pops, etc. Although this may have been luck, it made a believer out of me in Wippermann’s quality. Thus a big thumbs up for Wippermann.
Bruce

Dear Lennard,
I have used a Wippermann stainless chain with Campy Record 10 in an effort to save a few bucks. It was an unsuccessful experiment and it cost me a large chainring in the end. Shifting was fine, but the front chain rings were eaten up quickly. Replacement of the big ring was required at the end of the chain service life (I replace chains every 1.5k to 2k miles). My theory on the rapid wear of the chain ring was the differing relative hardness of the materials (stainless chain aggressively wearing the softer aluminum chainrings). I have since used Record 10 chains with excellent performance. Chain ring/cassette wear is minimal provided I replace the chain at proper intervals. I have also been able to properly size/ install the chains using a traditional chain tool rather than the purpose built Campy chain tool with no issues.

It seems logical to use a material that would cause the chain to wear preferentially. Chain rings and cassette as both have a higher replacement cost. I’d rather replace a chain every 3 months than a cassette/chainring twice a year.
Patrick

Dear Lennard,
I only use Wippermann St. Steel 10 speed chains with Record/Chorus. They wear three times as long as other chains, don’t wear out the cassettes or chainrings. I am extremely satisfied with them. One item to be careful of: make sure the flat side of the Connex link contacts the cassette, not the rounded side.
Rich

Dear Lennard,
I’ve ridden the Wippermann chains on my Campy 10 speed record groups for about four years now and I feel they work better than the Campy chains (I’ve tried the new narrower one too). The actual best Wippermann chain is the 10S8, which is intended for Shimano. It is very quiet and the shifts are quick and crisp. I would not recommend the stainless variety as the wear limit is about 1600 miles max. I actually trashed a cassette because of this. I ride about 10,000 miles a year so wear is important to me and I can say that you can safely get 2000 miles out of this chain. I’m a big guy who rides a 180 crank and does a lot of Crits.
Stan




Technical writer Lennard Zinn is a frame builder (www.zinncycles.com), a former U.S. national team rider and author of numerous books on bikes and bike maintenance including the pair of successful maintenance guides “Zinn and the Art of Mountain Bike Maintenance” – now available also on DVD, and “Zinn and the Art of Road Bike Maintenance,” as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”

Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn. Zinn’s column appears here each Tuesday.