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Technical FAQ: Cable stretch, oil vs. grease, QR lever placement, and more on tubeless

  • By Lennard Zinn
  • Published Jul. 30, 2013
One reader asks why his local shop is treating his bottom bracket and hubs with oil instead of grease. Photo: Nick Legan | VeloNews.com

Last week’s column on tubeless tires piqued some interest and before we answer a few follow-up questions, we’ve had a number of interesting questions come in on cable stretch, using oil in bottom brackets and hubs, and quick release placement on disc-equipped bikes.

Cable stretch or housing contraction?

Dear Lennard,
When I put new cables on my bike, do new cables stretch, does the new housing settle (contract), or is it some combination of the two? I have a hunch that it’s the housing, but I’d like a more definitive answer.
—Jay

Dear Jay,
That is a very good question, although I’m not sure what difference the answer makes, as the fix is the same either way. And I’m only guessing at the answer myself.

Bike mechanics always describe the settling in as “cable stretch,” although I’ll bet it’s more likely that the majority of the looseness in the cable over the first few weeks is the cable housing ferrules settling into the frame cable stops, the housing settling into the ferrules, and the housing compressing. Cables do stretch, however. I used to work at a ski area, and the length of the cables driving the ski lifts changed over time, as well as with temperature.
―Lennard

Why are they oiling my bearings?

Dear Lennard,
My local shop insists on dribbling tri-flow oil into sealed bearings when I bring my bike in with wheels or a bottom bracket (BB30) that seems to be turning a bit rough and in need of new bearings and/or cleaning. Won’t the oil just strip out any grease actually left in the bearings and attract dirt? Is this actually a good idea? I have my doubts, but they insist that only oil is to be used on sealed/cartridge bearings.
—Paul

Dear Paul,
That is an interesting theory, and it makes no sense to me. If oil were to be used in sealed bearings, they would have come with oil in them in the first place.

Oil is not a good choice for ball bearings because the pressure on the bearings under load can squeeze it out from under the balls easily, thus increasing wear. Back in the day (30-plus years ago), Campagnolo hubs (which have loose ball bearings) had on oil hole in the center of the hub shell covered by a little black clip. For important races and record attempts, riders (and especially track riders) would squirt oil in there to make them spin more freely in the hand. I’m not sure whether that translated to more speed under load, but the riders probably rode faster simply because they thought that their wheels were spinning more freely. It was universally accepted, though, that the oil should be replaced with grease after the race, because it was not a good bearing lubricant for durability or in hot conditions. There were stories (that I never verified with my own eyes) of bearings cracking at high speed on hot days with oil alone in them.

You are probably right that the Tri-Flow would thin the grease in the bearings and tend to let it run out. As for dirt, certainly oil around the bearing will attract dirt, just like grease around it would. Whether that dirt would creep in around the seals and into the bearings any more than it would with grease is an open question.

In any case, I do not think it is a good idea to lubricate ball bearings with oil, whether they are sealed cartridge bearings or loose-ball, cup-and-cone bearings. I’m certain that the bearing will have a shorter lifespan than if the bearing were instead lubricated with grease.
―Lennard

Should levers on disc bikes go on the drive side?

Dear Lennard,
I’ve heard lots of arguments about quick releases on disc brake-equipped bikes. Which side should the lever be on? Does it really matter? Having them on the drive side just doesn’t seem right to me…
—Tony

Dear Tony,
On the rear, the lever should go on the non-drive side, same as a rim-brake wheel, else it would interfere with the derailleur.

On the front, I think the lever should go on the drive side. This reduces the chance of bending the rotor by either using it to help tighten the lever by squeezing the two toward each other. It also reduces the chance of burning your fingers on a hot rotor when removing the wheel immediately after coming down a fast and windy descent. Furthermore, the likelihood of getting grease from your fingers on the rotor is reduced. The front wheel tends to be taken on and off frequently for transport, so the likelihood of these problems due to a non-drive-side lever is higher than on the rear anyway.

If you’re careful and attentive to these potential issues, it doesn’t really matter, and you can have the lever on the non-drive side.

I realize it looks funny to have the lever on the right. I have taken abuse for having my lever on the drive side on mountain bikes for years, and now through axles have eliminated the choice. On road bikes and cyclocross bikes, the aesthetics battle over this has only just begun!
―Lennard

More on tubeless tires

Dear Lennard,
Why would I ride tubeless road tires instead of tubulars? Pros and cons.
—Chuck

Dear Chuck,
Tubeless tires are cheaper, and are easier and faster to install and change on the road than tubulars. You can’t pinch flat a tubeless tire. For this reason, you can run them at lower pressure and consequently get lower rolling resistance.

Other than a casing cut, a tubeless tire with sealant in it is unlikely to get a flat, although I just flatted one in the Mount Evans hill climb on July 20. Somehow I got a piece of glass through the tire enough off-center that the sealant didn’t fill the hole.

Tubular wheels are lighter, as they don’t have rim walls to retain the clincher beads. A high-end tubular will generally roll faster and turn more nicely than the best tubeless tires, due to higher thread count and round versus bulb-shaped cross section. However, better tubeless tires keep appearing, and they should roll faster than clinchers, at least, due to no tube inside.

A tubular is very unlikely to pinch flat, due to the flatter rim without clincher bead-retaining walls and a latex tube that is less likely to tear on impact, but it does have a tube, and it can be done. A rider can run a wide range of tire pressures from very high to low to optimize rolling resistance for the given surface, from a smooth velodrome to a rough road.

Both tubulars and tubeless tires on tubeless-specific rims with bead locks tend to stay on the rim in the case of a blowout better than clinchers do, providing increased security.
―Lennard

Dear Lennard,
I’ve been running tubeless for over two years now with good luck. I just mounted two Schwalbe Ultremo tubeless tires, as I wanted to try something different than the Hutchinsons, which I think could be more durable. Great to see some other choices coming out as well. The Schwalbe kit includes a bead lubricant, which worked great; I could almost mount the tires without a tool. And yes, by all means finish at the valve stem.

I put the sealant in by deflating the tire after the initial inflation and removing the valve core. I get the small ear rinse squeeze bulbs from the drug store. They hold just the right amount, and the nozzle fits just inside the valve stem; I rarely spill a drop. Also, they clean easily.

I just came back from riding l’Etape du Tour and learned a travel lesson. The airline managed to break several spokes (yes, inside a travel case) so I needed repairs. I brought my favorite climbing wheels (DT Swiss Tricons), which use a special spoke. They were impossible to find on short notice; I checked a half dozen quality shops all over eastern France. So if you travel with sexy or unique wheels, bring spare spokes!
—John

Dear Lennard,
Regarding Aaron Hersh and the Easton wheelset article. Motorcycles do not use tubeless tires. And yes, tires can also go flat (like a tube).

Also, don’t all tubeless-ready rims also work just fine with tubes if need be?
—Dave

Dear Dave,
Yes, tubeless-ready rims work just fine with inner tubes and standard clincher tires.
―Lennard

FILED UNDER: Bikes and Tech / Technical FAQ TAGS: / /

Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance 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. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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