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Lennard Zinn has a fork suggestion for a tall rider, plus more on the SRAM/Campy mix-and-match.

  • By VeloNews.com
  • Published Mar. 18, 2008
  • Updated Aug. 29, 2010 at 10:38 PM EDT

By Lennard Zinn

Look carefully … what kind of shifters do we have here?

Photo: Graham Watson

Dear Lennard,
Question for you re: forks for long head tubes. I’m 6’4″ and have a Seven Axiom with a roughly 30cm head tube and a Seven rebadged Reynolds carbon fork on it. It is a bit flexy when braking while cornering and I’d like to improve that. What options are out there and how do they rate vs. each other? I know Alpha Q makes one with a steerer long enough (as seen on your bike) as does Storck, but want to understand if they are better than the Reynolds vis a vis flex/rigidity.
Ted

Dear Ted,
The Alpha-Q Z-Pro is the only long steerer (450mm) carbon fork that I have much experience with. I can say that, since the wall thickness is double that of most carbon steerers, its rigidity is a lot higher than most other carbon forks when you need a 300mm or longer steerer on a tall bike.
Lennard



Regarding SRAM/Campy compatibility

Dear Lennard,
Interesting article on mixing SRAM Red & Campy. A few of us running Red have found that Shimano’s and Campy’s front derailleurs actually work better than the Red one, with the Red shifters. Any comments/explanation why in every photo I have seen of SRAM sponsored pro teams none of them use the Red chain? Have you played around with different chains?
Lastly any word on the shifters on this Rabobank rider’s bike? They do not appear to be electrical as one cannot see any batteries on the frame and it looks like actually cables coming off the handlebars.

Look carefully … what kind of shifters do we have here?

CJ

Dear CJ,
I think the chain issue simply has to do with availability, although I don’t know what the holdup has been. I have yet to get a Red chain. I have been using the SRAM 1090 chain.
I think that’s an electronic shifter on the Rabobank bike. I don’t see shift cables.
Lennard


Dear Lennard,
Would it work with any SRAM rear? Say, Chorus with rear Force/Rival?
Rory

Dear Rory,
I can’t see why not.
Lennard


Dear Lennard, ?
I thought Exact Actuation meant the cable pull for SRAM was the same for each shift regardless of position on the cassette, but with Shimano and Campagnolo you pull less cable for low gears/near the hub, and you pull more cable at for the higher gears.
James

Dear James,
I believe that you are correct. I started out by trying to measure cable pull on each click, but it turns out to not be easy to detect such small differences. It was easier to do nine clicks and average it. I am continuing to experiment with various combinations and to come up with better measurements, and when our snow melts again and I can get out some more on them, I’ll let you know.
Lennard


Dear Lennard,
In your March 17th story column “Can you run Campy shifters with a SRAM drivetrain? Sure, why not” you discuss a few different ways to run Campagnolo Ergopower levers with “non-Campy” rear derailleurs — thank you for a great piece!

For the front derailleur though, with the newer Campagnolo Ergopower levers that have ‘quick-shift” functionality, are there issues in using a newer Chorus or Record Ergopower lever with this “quick-shift” along with a Shimano front derailleur or does one need to use a Campagnolo front derailleur to make it work?

It sounds like you’re running your Ergopower levers with a full SRAM group — front and rear — so I’m wondering if you ran into this?
Andy

Dear Andy,
I used Centaur levers, which only have the numerous clicks of Record/Chorus on the upshift. Thus, you end up with a trim adjustment only on the inner chainring. It’s like SRAM Force in this way, except that if you are really determined to get an inward front derailleur position on the big ring, you can shift to the inner ring and then shift up to the big ring again, being careful to not go all of the way to the last click.
Lennard



Dear Lennard,
? The respective SRAM and Campagnolo componentry described in your “Can you run Campy shifters…” article is not designed to work together, and while the performance may be acceptable, it is not endorsed by us.
? Additionally, while SRAM componentry is made to be tolerant of poor frame alignment, sloppy setup, wear and tear, use and abuse, our pull ratios are different and we believe that eventually, as the system wears, the shifting performance will deteriorate significantly.
? Finally, SRAM has fantastic distribution in Italy; it is perhaps our largest market in Europe.
As always, we absolutely appreciate your enthusiasm for our product.
Michael Zellmann
Road PR & Media Manager
SRAM



Regarding the column on tubular tape

Dear Lennard,
I read your article on Tufo tape in this week’s tech tips. Just a few comments.

You wrote: “The reason is that test results that I have seen indicate that the rolling resistance is higher with the Tufo tape than with rim cement. This is presumably due to energy loss through hysteresis, caused by the tape squirming around.”

I know this white paper and its conclusions, but it makes no sense. The study was also very poorly done with too many variables between the cement and tape wheels. It’s too bad it gets continuously quoted. This is a common problem with bike lab tests; most are very poorly done, with no replicates and indication of statistical significance. (My favorite is wind tunnel tests of wheels that use different tires on each wheel).

Tubulars don’t squirm on all tape (there are many brands, I’ve used three different kinds, and they are different), but they definitely do squirm on cement. Anyone who has tried to reposition or remove a tubular by each method can tell you this. In fact, most taped tubulars are extremely difficult to remove if the tires are new, and can even lead to carbon peeling on CF rims if not careful. Tape is glue, it’s just glue held in a cloth matrix. If anything, tapes bond too strongly in some cases.

I’m an admitted convert from glue, but tapes are a far more reliable method of attaching a tubular than cement; this is especially true in humid days in summer. As for rolling resistance, many I know who have tried each method cannot detect any measurable difference or feel in the tires. Unless I see some real data, this falls into the myth category with some theories and a lot of hand-waving.

So why do pro teams still use glue? This was the topic of conversation in Milan last year at the Giro with some mechanics. All have tried tape and say that a tire will never roll off from tape, and one said their riders felt they had less rolling resistance (!), but the problem is that pro teams have to strip off the tubulars after every stage and replace them. This would be impossible to do with 24-plus wheels in one night if they taped. Glued tires come off in one good yank. It’s actually disconcerting to watch.

I use tapes (I use Continental or Jantex) because I can mount a tire safely in 30 seconds and be on the road, and I can replace a tubular on the road if punctured with the same level of safety without limping home on an unglued or poorly glued tubular. I think someone has made a better mousetrap. This is argued by traditionalists, but if one is really concerned about rolling resistance, they should be riding clinchers or tubeless.

There are two issues here. One is that Tufo tape is different from other brands of tape, but conclusions about Tufo get applied to all other brands, based on one poorly done study. This really isn’t fair, as there are even big differences between glues.

Second is that self-published Internet data done by students without peer review needs to be taken with a big grain of salt.

In the KTL lab report, for example, they conclude that Tufo tape is inferior to glue in roll-off. However, they test roll-off by pushing the tire on the sidewall, which is a poor model (they should at least push the rim); they test the tape and glue exactly once; and they don’t follow the tape instructions as supplied by Tufo.

Maybe VeloNews should test different rim tapes at some point. The same tires, the same wheels.

The easiest test is to just get a few different riders to ride the same tires mounted on the same wheels by different tapes and glues. See if anyone can guess which is which beyond just chance.
Ray



Dear Lennard,
I’ve been using tubulars, mostly for racing cross, and have found that the biggest reason for using glue is the cleanup factor. When you have to peel a tire, one mounted with just glue tends to be easier to deal with. Tape is often lumpy, can more easily peel base tape, and is a bear to remove. Also, Tufo tape can be a little narrow and not cover from edge to edge, often necessitating glue to be used.
Thom


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. Zinn’s column appears here each Tuesday.

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