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Technical Q&A with Lennard Zinn – Ti finish; That darn spoke protector

It's lemmony fresh, too!Dear Lennard,Could you recommend a good method and/or product to clean and maintaina titanium frame (unpainted finish)? Also, do you have any suggestionsto keep aluminum parts (i.e. Campy hubs, etc.) clean and shiny?E.J.Dear E.J.,You can clean the titanium frame first with soap and water and thenwith a solvent on the greasy patches that did not come clean. Be carefulyou don’t remove decals, if you use a really strong solvent like acetone(and make sure you wear gloves and a respirator). Usually, a biodegradabledegreaser is sufficient to clean it up. After cleaning,

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By Lennard Zinn

It’s lemmony fresh, too!
Dear Lennard,
Could you recommend a good method and/or product to clean and maintaina titanium frame (unpainted finish)? Also, do you have any suggestionsto keep aluminum parts (i.e. Campy hubs, etc.) clean and shiny?
E.J.Dear E.J.,
You can clean the titanium frame first with soap and water and thenwith a solvent on the greasy patches that did not come clean. Be carefulyou don’t remove decals, if you use a really strong solvent like acetone(and make sure you wear gloves and a respirator). Usually, a biodegradabledegreaser is sufficient to clean it up. After cleaning, apply Lemon Pledgeor WD-40 on the titanium frame. That gives it a little browner color andprevents fingerprints and grease from showing up on it. Lemon Pledge orWD-40 is what we apply to new titanium frames as soon as the decalsare applied and before the parts are assembled onto the frame, or it willbe covered with fingerprints and grease spots afterwards.Use any soft polishing compound on the aluminum parts from your hardwarestore. Alternatively, something like Turtle Wax or Pedro’s Bike Lust shouldalso work. A product we used 20 years ago but which I don’t know if itis still available is called Simichrome Polish.
LennardSeat back or crank length?
Dear Lennard,
I have read Greg LeMond’s book of cycling and use it for positioningand setup. My question concerns saddle setback position.I am 6 foot 4, ride a bike with 71.8-degree seat tube, 63 cm c-c (asper Greg’s formula), my inseam is 95cm = seat height considering low profileShimano pedals etc = 83.5cm, 180mm cranks.When I position my seat setback so that the front of my knee is 1cmbehind the pedal axle at the 3 o’clock position, my seat setback (from nose ofseat to c-BB) = 13cm. I find this position feels great on the flat, rolling big gears is great…but when I climb I feel that my weight (center of gravity) falls so far back,that I am not able to apply my power to the down stroke…I am disproportionately slow on climbs, losing many minutes on longer steeper (over 7-percent grade) climbs.On climbs of 2- to 3-percent, I am regularly able to drop less powerful riders…but once the gradient goes above 6-percent I am slammed.Do you have any advice? Am I too far back?
SteveDear Steve,
The super-shallow seat angle that tall bikes traditionally have islargely a function of cranks that are not proportionately as long for thetall rider as they would be for a short rider. If your cranks were thesame proportion of leg length as, say a rider with an 80cm inseam ridinga 172.5mm crank (ratio of 0.216), your seat angle would not need to beas shallow in order to get the same relationship of knee over the pedalspindle when the crank is at three o’clock. Once the crank and frame sizeare proportional, the only thing that does not scale up for a tall rideris the length of the saddle rails, leaving you with proportionately lessfore-aft adjustment of the seat than a shorter rider.If you were using a proportionate-length crank on a climb, you wouldthen benefit from not having your weight cantilevered so far over the backwheel (and correspondingly light on the front wheel), and the extra leverageof the long crank would also be an advantage. And if the crank is the sameproportion of your leg length as that of a shorter rider is to his or herleg length and your seat heights are adjusted by the same method, be itbased on measurements or based on knee angle at the bottom, the knees andankles of both you and the other rider would be moving through the sameangles, and your muscles would be reaching the same level of contractionand extension.I find a 0.216 proportion of crank length to inseam length (actuallymeasured inseam length, as directed on http://www.zinncycles.com/FitIntro.aspx,not your pants size) to work out well for road riders. That would be a205mm crank for you, which would bring your saddle forward an inch (25mm)and still maintain the 1cm-behind-the-pedal-spindle relationship. Of course,you would want to increase your stem length by that much as well. Thereis more on crank length theories on mywebsite.
LennardTime to upgrade?
Dear Lennard,
I have a Cannondale CAAD3 with an old (circa 1994-95) Shimano 105 gruppowith 7-speed cassette. The 8-speed rear derailleur is worn out aftermuch faithful service and needs to be replaced–it won’t shift over tothe 2-3 smallest cogs in spite of all the cleaning, lubing and servicingI can do. (Your books were very helpful, by the way.) This7-speed/8-speed setup has worked very smoothly and reliably, and I’d liketo keep the good performance I’ve enjoyed.
The latest 105 gruppo has a 9-speed rear derailleur. My friendssay this will not work well with the 7-speed cassette, although the guysat my favorite bike store disagree.Can you please tell me what’s your opinion? Can a 7-speed cassettework smoothly with a 9-speed rear derailleur? If yes, are there anyparticular tricks on setting up and tuning such a system? If no,is it better to upgrade the 7-speed cassette with a 9-speed, or try tofind an 8-speed derailleur?
ChrisDear Chris,
The 9-speed derailleur should work just as well as the 8-speed onefor your purposes, but the chain probably needs to be nine-speed to fitthrough the narrower jockey-wheel cage.
LennardSkipshift blues
Dear Lennard,
I’m riding Shimano 105s circa 2000. Recently the left STI lever beganto skip a ratchet point when upshifting. In other words, when I shift fromthe inner to the outer chainring, I have to move the lever twice. Its asif one of the ratchet pawls broke off. Can you tell me whether this isrepairable? Or, should I just go buy the Dura Ace Group I’ve been dreamingabout?
JohnDear John,
Unfortunately, it is not repairable. Shimano does not offer internalparts for STI and intends that the consumer not work it on. I have pulledsome apart and tried to get them back together. There are seven springsin there, all of which need to be tensioned before assembly, and they aretiny, there is little space to work in, and the tools you would use arenot obvious. I tried to make some little tools for it and gave up. Thereis a two-year warranty on STI levers, but it sounds like you are past that.
LennardFeedback from previous columns:
Dear Lennard,
I saw this reader report in your web column:

I have a pair of Mavic Ksyrium SSC SL’s I use for races. Theyare less than a year old and have less than 1500 miles on them. The problemthat I have been experiencing with them is that the freehub is so tight!I even sent them back to Mavic where they looked at them and lubed it up.It is so tight that when coasting it seems as though I have the brakeson. When I have my bicycle in a repair stand and turn the cranks counterclockwise(backwards) the wheel starts going backwards too. What do I do to alleviatethis problem? Do they still need to be broken in? How can I make the free-hubmore” free?”

Another possibility to investigate is the plastic spoke protector thatMavic includes with the wheels. I had the same problem as this reader,and the root cause turned out to be the fact that the plastic spoke protectorflexes and rubs against the spokes after the cassette is tightened downon the hub body. I could even see some rub/wear marks on the spokeswhere the spoke protector was dragging during freewheeling.

I tried a different spoke protector, but the same problem occurred.Only solution I could get to was to remove the spoke protector entirely.
LarryDear Larry
An experience I have had with that same Mavic spoke protector on Ksyriumsand on CrossMaxes is that its orientation relative to the innermost cogis critical, of the cog will push it into the spokes. The little tabs onthe spoke protector that fit in the freehub splines are asymmetrical, orat least staggered; there is not a tab for each spline. And the supportribs of the spoke protector need to be aligned in such a way that noneof them are contacting any of the rivets that hold the inner cog onto thesplined aluminum cog carrier, since that pushes it in toward the spokes,where the rivets are, the cog’s inner diameter is less. You will noticethat it comes in more toward the axle, where it can interfere withthe spoke protector, while in between rivets, the cog is merely a thinring that does not extend very far in toward the axle. It has seemed likea bit of a puzzle to me at times; it has taken some trial-and-error tofinally find the way to orient it so those rivet positions do not pushon the spoke protector.
Lennard


Technical writer Lennard Zinn is a frame builder (www.zinncycles.com), a former U.S. national team rider and author of several books on bikes and bike maintenance including the pair of successful maintenance guides “ Zinn & the Art of Mountain Bike Maintenance” and “Zinn & the Art of Road Bike Maintenance.”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.