Mountain Gear

Tech FAQ: How Does LZ Hang (His Bikes)?

Lennard Zinn on MTB bike storage and Shimano chains

Dear Lennard,
I’m moving to a new place and will need to store the bikes vertically on the wall to free up floor space, so I was going to store the mountain bikes front wheels up and the roadies/cx front wheels down. I’ve heard many reasons not to store mountain bikes with hydro brakes vertically, most dealing with the “fact” that the levers should never be lower than the calipers to prevent fluid leaks. Same deal with suspension forks — seals will leak if stored upside down.  Is there any truth to this?
-Mike

Dear Mike,
TechWidgetIt’s not so much that the brakes will leak, because you’d have other problems if that happened, but of getting air into your calipers. If you have air bubbles above your reservoirs, those can move into the calipers and then your braking is weaker or nonexistent until the air bubbles move back up above the reservoir in the lever. In the case of some brakes — Shimano comes to mind, the problem will clear itself up again soon with some vigorous pumping of the levers to move the air back up out of the caliper and the hoses. But not all brakes will pump back up without removing the lever from the bar and orienting it in a such a way that the metering hole that allows the air to go back into the reservoir is pointed up.

I’ve definitely seen suspension forks on bikes hung with the front wheel up leak enough oil from the damper that they have no damping. But generally for that to happen with a modern fork, the seal has to be shot. This happens if there is a scratch on the upper leg that tears the seal. So even if you replace the seal, the first time you ride, it’s scratched enough to leak oil when hanging up by the front wheel.

I actually hang my mountain bikes up by the rear wheel (I don’t have space enough to store them standing upright). By hanging by the rear wheel, I don’t worry about any fork leakage. But with one bike that has XTR brakes with a very slow fluid leak in a seal in the lever (for which Shimano has no rebuild kit), I have to pump the rear-brake lever to get it working again before riding. My bikes with Avid brakes don’t seem to be affected by the hanging, but that is not the case with all of them. Scroll down on this posting for more on the bike storage question.
-Lennard

Feedback on Lennard’s Jan. 11 column: Shimano Cogs and Chains

Dear Lennard,
In fact the 10-speed Dyna-Sys chain is not the same as the 10-speed road chains. And If I remember correctly you did an article calling out the differences between the 7900 chain and the 980 chain. I would be shocked if both chains didn’t work just fine on that setup though, interested to hear which one would work better if you have any insight on that.
-Jason

Dear Jason,
You’re absolutely right. The chamfers on the XTR chain are different to improve performance and durability in dirt and to better shed mud. The XTR chain does not have the cutouts on the back-side inner links like the 7900 chain has. As Shimano Media Relations Officer Devin Walton says, “the XTR chain was actually specifically designed for use in an off-road environment.”
-Lennard

Readers can send brief technical questions directly to Lennard Zinn.

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.

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