Technical FAQ: Nibali’s Giro seatpost, mixing parts, and more

Lennard Zinn takes questions about an adjustable seatpost, mixing drivetrain components, and updates on previous columns.

Nibali’s seatpost

Dear Lennard,
In all the hype surrounding Vincenzo Nibali’s glossy pink frame for Stage 21 of the Giro, a point of interest appeared in the photos that weren’t discussed in any of the captions.

What the heck seatpost is that? Scroll through these photos.

Seems like some sort of adjustable post. But that wouldn’t seem to make sense for obvious reasons. FSA’s website provides no help.
— Gordon

Dear Gordon,
You’re right; it is indeed an adjustable-height seatpost. See below.
― Lennard

From FSA:

FSA has been making this post for teams only now for many seasons. It allows the rider to adjust the position of the saddle in 1mm detented increments, in total 18mm (18 different positions).

Some riders favor it for particular stages because it allows them to change the position while riding.

The riders can change the height on the fly, and each click is 1mm, so they can count the clicks.
— Joel Richardson
Product Manager, Full Speed Ahead

Mixing components

Dear Lennard,
Will this setup work?

SRAM FORCE 22 Crankset
AERO TT 500 Shifter
SRAM FORCE 10-speed RD

If it does, which chain should I use: PC-1170 (11-speed) or PC-1071 (10-speed)? All of my cassettes are 10-speed (PG-1070).
— Will

Dear Will,
Yes, that setup should work fine. The shifters are 10-speed, which matches your cogs. Which chain you prefer will be a matter of experimentation. The cogs and rear derailleur should be better tuned to the 10-speed chain, while the crankset and front derailleur should behave ideally with the 11-speed chain. I think either chain will work.
― Lennard

Dear Lennard,
Compatibility issues across different components were covered many times, but I am getting conflicting answers and would appreciate your expertise and advice.

I have a Cannondale SuperSix Evo with Ultegra 6700 components. I don’t like shifting on this bike, as it is not precise and certainly not smooth. I would like to upgrade but only some components, such as the FD, RD, 11-speed cassette, and chain. Can I use Dura-Ace 9000 or Ultegra 6800 components with my 6700 crank?
— George

Dear George,
Yes, Dura-Ace 9000 (11-speed) or Ultegra 6800 (also 11-speed) components will work fine with an Ultegra 6700 (10-speed) crankset.
― Lennard

More on rolling resistance of tubular glue vs. tape

Dear Lennard,
You mentioned that you have not seen any scientific data showing rolling resistance between tape and glue. I would like to point you to Al Morrison’s Roller Data, available here.

The results show that a Bontrager Race X Lite Tubular, properly glued (he defines “properly glued” in his results) vs. one that is taped using Tufo tape, has a lower Crr of approximately 8.8 percent (0.00239 vs 0.00260).

Of course, this data is 10 years old, and we have no clue about the newer types of tape!
— David

Dear David,
Thanks for that link. Too bad there is only one data point on the glue vs. tape; it would have been interesting to see if there is variation in this depending on tire used, width, pressure, and other variables. And yes, it would be great to compare to other tapes, too.
― Lennard

More on soda can seatpost shims

Dear Lennard,
In regards to the soda can shim, I’ve been using one for 2 years. I had a seat tube that would not stop slipping, and it made rides miserable. I tried carbon paste and that didn’t work. I ended up stripping the screws due to constant tightening. The soda can worked fantastically and still does after two years. It’s thin, malleable, and could be cut with scissors. I cut a piece to fit and actually folded in half with a little lip to catch the top of the frame, and the seat collar slides right on top to hide it all.

It’s a free fix.
— Matt

Dear Lennard,
What’s not to like about this solution. Simple and it works. Take a good look at these pictures (here and here) and you’ll see good old Coca-Cola red where the tri bars attach to the bull horns.

I remember reading somewhere that Greg LeMond’s tri bars slipped during the stage 5 time trial and that Otto Jacome used Coke cans for the final time trial.

I’m thinking that keeping his tri-bars in place saved him at least 8 seconds.
— John

More on Rotor Uno

Dear Lennard,
You wrote: “Rotor claims that Uno is the lightest disc-brake group on market, at 10 grams less than SRAM Red22 HRD and 417 grams less than Dura-Ace DI2 disc.”

Do you mean R785 brakes? And over a pound weight difference?
— Phil

Dear Phil,
Yes, I did mean the R785s. And there are 454 grams in a pound, so that’s less than a pound of weight difference. See below.
― Lennard

From Rotor:

I forwarded your email to David Martínez, who’s been with the UNO project since day 1, and he replied with the following:

“As there is no “proper” Dura Ace groupset for disc brakes (up to now, new DA for 2017 will have a disc brake option) we took a mix of all Dura Ace Di2 parts where they exit, and R785 for the shifters, calipers…”

There was one minor correction that I wanted to comment on. While it’s perfectly reasonable to execute a currency conversion when a price is listed just in €€ (or ££, or ¥¥ etc.), in the case of UNO the price from €€ to $$ is lateral so it’s the same in dollars as in euros ($2,499). I wouldn’t want to lead people to believe that UNO is priced way above and beyond one of the rival groupsets.
— Wendy Booher
Rotor Bike Communications Manager

Update on thumb pain while shifting

Dear Lennard,
I have mild arthritis in both thumbs. I find that shifting my regular bike with Campy Record 10-speed shifters (from 2009 or so) causes much less pain than shifting the bike I keep at my daughter’s place to ride when we visit the grandkids. The latter has Shimano shifters and the longer throws and the requirement to swing the fingers for both upshifts and downshifts while using the thumbs to counter the force puts more strain on my thumbs than the Campy setup. I haven’t ridden them, but I would imagine that the newer Campy thumb buttons that lay flatter to the brake hood would be even better — whether it’s mechanical or electronic shifting.
— Larry