Dear Lennard,
Watching the super-human performance of the Tour riders is an incredible experience. But I was wondering what kind of gear selections do they run for the different stages? I recall on today’s time trials they mentioned that riders were using a 57 tooth front ring. What do they run on the rear? 25-11? What do they run in the extreme hill climbs where the up hill grades are 7 percent and yet they will run nearly +65mph downhill. What gears do they run?
-Steve

Dear Steve,
In a time trial without a major climb in it, cogsets would tend to be 11-23 or 11-21. For mountain stages, you usually don’t see anything highly unusual. A 53-39 with an 11-25 is what I would expect to find on most of the bikes in tomorrow’s L’Alpe d’Huez stage. You generally won’t find a compact crank or, rarely, a triple, except on extreme climbs like the Monte Zoncolan or Plan de Corones of the Giro or the Alto de l’Anglirú in the Vuelta.
-Lennard

Dear Lennard,
A Dura-Ace shifter cable is slightly narrower than a typical brake cable. On a triathlon bike that uses bar end shifters and brake levers in the basebar, can a shifter cable be used in place of a rear brake cable to decrease friction through the housing? Or is it too weak to hold up to braking forces?
-Mark

Dear Mark,
Don’t do it. The cable head is different and not made to hold up to braking. You should make sure your housing has the largest ID you can find and of course has a good, low-friction liner and is new and clean. You should be able to keep the friction low enough.
-Lennard


Dear Lennard,
I noticed that you wrote not to shorten a 10-speed chain and found that odd. What's wrong with shortening a chain? I wouldn't think it would be much different from putting a new one on, like I just did last weekend. It had three too-many links, so I used the chain tool and took them off, then joined it with the PowerLock link.
-Dave

Dear Dave,
I meant that one should never to push a link pin out of a 10-speed chain (or a 9-speed one for that matter) and push it back in. If you use a connector link, it’s not a problem. Sorry I did not make that more clear.
Lennard

Dear Lennard,
Everything that I’ve read of late, including your column, suggests that—at equal pressures—clinchers have a lower rolling resistance than tubulars. Why, then, are tubulars so popular at the track? Even equipment manufacturers seem to target the track market with only tubular products….
I find it hard to believe that the extra weight of clinchers is the issue (the banked corners aren’t that much of a climb!). Is it the increased tire pressures that riders can achieve? What would you recommend?
-Ron

Answer from Schwalbe:
We are also wondering for years already why the professionals are still so keen on riding tubulars and why the sales figures of tubulars are even rising again.

In terms of rolling resistance or weight we can achieve at least the same result with a good folding tires. But there are some arguments for pros to use tubulars

1. Safety: When you have a sudden blow out, the tubular does not come off of the rim.

2. Weight: You can hardly save any weight on the tire. But you can save quite some weight on the wheel, because the rim does not need to have (pressure proof) hooks.
So all the extreme lightweight wheelsets are made for tubulars.

3. Suplesse:That is what the pro riders claim. The "feeling" would be better. There is more "life" inside the tire, meaning the rolling and cornering properties of the tires would be better.
And if we are talking of real handmade tubulars (in contrast to a vulcanized tubular) the complete construction is indeed more flexible and adaptive. We cannot measure the difference with our test equipment in the lab but on the more rough surface in the real world this can be an advantage.

4. Pressure: And this argument counts only for the track. You can ride tubulars with higher pressures. This makes only sense on the very smooth surface of a track. On a road it would be no good to use pressure of more than 10 bar (140 psi).

Our conclusion: Tubulars are fine if you want to ride same tire as the pros ride and if money and time do not matter for you. In the ideal case, you have a sponsor who is paying for the expensive handmade tubulars and a mechanic who is doing the nasty and time-consuming tire mounting for you.
-Carsten Zahn, Schwalbe tire product manager

Dear Lennard,
I put your bearing replacement article to good use. I replaced all of the bearings in two pairs of Ksyrium wheels. My question is with an old set of Helium wheels. I'd like to service the rear hub but I have yet to figure out how to remove the free hub body and the axle. Aside from replacing the bearings, the free hub needs lubed. I've searched the web for a technical diagram of the Helium hub without success. Any advice?
-Rhett

Dear Rhett,
The bearing change is the same for the Helium as the Ksyrium with the exception of the tools required for the axle. A 5mm hex key in either end of the axle will loosen it. If the end cap on the non-drive side unscrews, as it may on an older wheel, it should be super-glued in place and when allowed to properly set up it will release as intended.
-Lennard

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Technical writer Lennard Zinn is a frame builder (zinncycles.com), a former U.S. national team rider and author of numerous books on bikes and bike maintenance including Zinn and the Art of Triathlon Bikes and 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's 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 Thursday.