SRAM 10-speed
Dear Lennard,
Now that there is a valid third competitor in the 10-speed road arena, I was hoping to see some lower prices. Do you know if the new SRAM 10-speed chains and cog sets are compatible with Shimano 10-speed drive trains?
Bob

Dear Bob,
Yes, they are, except that SRAM's 10-speed cogs will not fit on a Shimano 10-speed freehub body – only on a 9-speed Shimano freehub body.
Lennard

What's the advantage of ceramics?
Dear Lennard,
I have been trying to gather information on ceramic bearings. I have a set of Rolf Elans. The front bearings are tiny r4's that require frequent replacement since the smallest amount of wear is very noticeable. The cost for ceramics is nearly three times that of steel but would be worth it if they perform as claimed which is five to 10 times the life of steel.

Do you have any experience with them to relate? The pieces I am getting are about $14 apiece on the r4's and $30 apiece for the 15x26x7 rear wheel bearings of which there are 4.
Mike

Dear Mike,
I have no personal experience on durability. I do on friction, though. I just went through it again and turned in an article on the subject to VeloNews; it will appear in issue #21.

Our tests showed a large friction reduction with them, but it was not a long-term test, so I can’t say how they will last.
Lennard

A question of Q
Dear Lennard,
My training partner is a little gal, only about 5-foot-2. As she gets stronger, she's developing a knee problem. Riding behind her you can see her knees clearly bending towards the top tube. To remedy it, she has tried shims in various places, but they tended to exacerbate the problem, not fix it.

Then she went to the Boulder Center for Sports Medicine and they identified the problem as too wide a stance on the pedals. Simple solution, right? Well, not really. She's a mountain biker currently running XTR. Getting the q-factor down is a bit of mystery to me on an MTB - pedals with short spindles, move cleats outward, but what about cranks and bottom bracket? Her current bike has a 73 mm bottom bracket shell. She may also put an Ergomo power meter/bottom bracket on the bike.

What recommendations can you make to get the q-factor down for her?
Dave

Dear Dave,
This is a constant problem for many riders, and some give up mountain biking for this reason. If you must have a narrow pedaling stance, there is not much you can do on a mountain bike besides the things you mentioned, especially if you want to use an Ergomo bottom bracket.

Some frames – like the Swiss-made Walsers – have a very low Q. I’ve done the same with frames I’ve built. Here are detail photos of a frame I built with a super low Q with a 48mm wide bottom bracket shell, the chainrings overlapping over the shell, a machined seat tube section to move the front derailleur in enough, a machined chainstay yoke to fit between the rear tire and the chainrings, and 110mm wide rear hub spacing.

Here are a couple of photos. But these things will not work on a mountain bike very well, due to the bigger tires, mud-clearance issues, and gearing requirements. It should be noted that Ergomo bottom brackets come in standard widths.
Lennard

Follow-up from mylast column:
Dear Lennard,
The milk came through my nose after seeing the 'third eye' picture. A good mechanic will notice that the tail of the derailleur is in too far, and will push the chain off every time. At the Trek store here in Madison, I deal with this issue all the time, and a careful adjustment will cure it every time. Make sure the derailleur frame mounting plate, and the derailleur mounting bolt are both tight. Correct cable tension and the “starting point” of the limit screws are also critical.
Ray

Dear Lennard,
Responding to the question from a reader who was looking for a chain watcher type device that would work with oversize seat tubing:

AJ's Bike Parts makes an excellent chain-suck/derailment preventer for full suspension mountain bikes that mounts to the bottom bracket. It's heavier than a dog fang or other chain watcher, but is extremely effective. It would work fine on a rigid frame if you don't mind a few grams.
Doug

Dear Lennard,
You neglected mention of my personal favorite “Shimagnolo” solution: the Jtek Engineering ShiftMate. It operates analogously to a V-brake “Travel Agent”, and Jtek has models to perform various shifting adaptations. I use their model to allow a 10-speed Campy Ergo/derailleur combination to shift properly on Shimano 10 speed cassettes, and it works very well for me. They are not cheap ($40), but I’ve had absolutely no problems with them.
Harry

---

Technical writer Lennard Zinn is a frame builder (www.zinncycles.com),a former U.S. national team rider and author of several best-selling bookson bikes and bike maintenance including Zinn& the Art of Mountain Bike Maintenance, which is now availableas a 4-hour instructional DVDZinn& the Art of Road Bike Maintenance, and Zinn's Cycling Primer:Maintenance Tips and Skill Building for Cyclists. Zinn's regular columnis devoted to addressing readers' technical questions about bikes, theircare and feeding and how we as riders can use them as comfortably and efficientlyas possible. Readers can send brief technical questions directlyto Zinn. Zinn's column appears here each Tuesday.