Dear Lennard Zinn,
I have a Chorus Ti seat post (less than a year old) and Flite Gel saddlewith Ti rails. I cannot get the saddle to stay in the right place; it keepsslipping back and has to be reset every couple of days. I screw the boltas tight as I dare and keep the saddle rails and clamp grease free (withgrease it slips back in about 5 minutes). Previously I had the Daytonapost on the bike and did not have this problem (same saddle), but the clamplooks the same. --Peter

Dear Peter,
Check to see if there is some sort of obstruction that is preventingthe top of the clamp from moving downward fully. If you cannot resolveit yourself, or if the clamp is bent or broken and it is under warranty,send your seat post to Campagnolo USA. --Lennard

Why use mid-range when you can afford the best?
Dear Lennard,
Why do I see some pro bikes all built up with Dura-Ace, yet they choosean Ultegra BB? --James

Answer from Shimano:

Dear James,
That is an excellent question. The Dura-Ace bottom bracket is not asealed cartridge unit like the Ultegra bottom bracket. Instead, it is housedby two sets of roller bearings and two sets of ball bearings that are adjustableand serviceable by the user.

Along with the above features, the Dura-Ace bottom bracket creates avery stiff and lightweight crank and bottom bracket interface that is requiredfor a world-class racing platform. In order for the rider to benefit fromthese features, the Dura-Ace bottom bracket requires a more frequent serviceinterval than its cartridge counterpart. It is typical for Professionallevel racing bikes to have their Dura-Ace bottom brackets cleaned and servicedby the team mechanic after six consecutive days of training or racing (approx.30-50 hours). In wet and gritty conditions, it is highly recommended toclean and service the Dura-Ace bottom bracket after each ride.

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This leads us to the reason why many frame manufacturers opt to spectheir Dura-Ace equipped bikes for sale with the Ultegra bottom bracket.For the average consumer/rider who does not have a team mechanic to servicethe bike within the required service interval, this often creates a situationin which the Dura-Ace bottom bracket becomes neglected and will pre-maturelywear out. Also, for the efficiency of your shop’s mechanic, the Ultegracartridge bottom bracket adjustment and service requires less time, whichmeans you will get your bike back faster when you take it in for service.

As with any performance-related product, whether it be a bike, car,electronics or what have you, the more performance you receive from theproduct, the more service it is likely to require. So, when you see a manufacturersubstitute the Dura-Ace bottom bracket with an Ultegra, it’s to benefityou. Not to worry, the difference in cost of the downgrade has been workedinto the price of the bike. If you wish to have the higher performanceof the Dura-Ace unit, I’m sure you dealer would be more than happy to offerthat as an upgrade component for you.

Keep the rubber side down.
Jason W. Leith
Technical Representative/Cycling Components Division
SHIMANO AMERICAN CORPORATION

Mix and Match
Dear Lennard,
I noticed in VN online, you advised someone that Campy shifters can'tbe used with Shimano. I have been using the setup here:
http://www.hubbub.com/ergoleverswshim9.htm and it works fine. I'd be interested to hear if you've seen this done and perhaps an assessment of how it works...
--Pat

Dear Pat,
VeloParts (VeloPartsInc@hotmail.com)makes a "Shimagnolo adapter" that does the same thing and perhaps moreelegantly, namely it increases the derailleur movement with each leverclick. Something like this must be done to get the shorter Campy cable movement to get the Shimano derailleur to move far enough. --Lennard

Maxium double rather than a triple
Dear Lennard,
I have seen a different chainring configuration used on one of thebikes reviewed in your recent Buyer's Guide. The 53/34 combination seemsto be an interesting way to avoid the use of a triple chainring and wouldseem well suited for mountainous riding but might be less than ideal inrolling terrain.

I would like to know how this would be best setup and if you think itwould work well. --Mark

Dear Mark,
You are referring to the Pinarello carbon crank. I have not tried it,but it seems like a great idea to me, as an alternative to a triple. FaustoPinarello raves about it on his bike and rides near the front on many long,mountainous Gran Fondo races in Italy. It would be lighter, and it wouldseem that it would shift faster, by virtue of short-cage derailleurs. Thedownside would be that the small spider would make replacement chainringshard to find. --Lennard

Base tape repair?
Dear Lennard,
I just glued my first tubular tire by following the guide in your book,"Zinn & the Art of Road Bike Maintenance." While I'm young enough thatI've always ridden clinchers, I just bought an old Colnago with tubulars,so I've been forced to learn how to glue tires on. When I was pulling offthe old tires to re-glue them (the last owner said the tires hadn't beenglued in around five years), the base tape came off from the tire sidewallin a few places. Can I re-glue the base tape or should I just buy a newtire? If I can re-glue the tape, should I pull it all off and re-glue itor just glue down the parts that came off? --Christian

Dear Christian,
You can glue the base tape back on with Barge Cement or another strongcontact cement (NOT with rim cement). --Lennard

No spring in your spring?
Dear Lennard,
My road bike has Shimano 105 with the integrated brake/shift mechanism.It won't drop the chain down to the smaller gears especially when cold.This happens front and rear, although rear is much worse.
Sometimes the only way I can get it to work is by pushing the smalllever forward while moving it in to shift. --Gene

Dear Gene,
Your cables are sticking too much for the derailleur springs to beable to return against the friction. Pull them out, wipe them down, andlube them with chain lube. If that does not work, replace the cables andhousings. --Lennard

I wear out cogs, not the whole set
Dear Lennard,
I noticed recently that when I wear out a cogset, I invariable wearout the same one or two cogs all the time. These are usually the 7 and8 cog, so they are not clustered together. I was wondering if you knowanyone who sells individual cogs that are nine speed compatible. I figurethat I can save around $40.00 if I replace a single cog instead of plunkingfor a whole new cassette. --Rob

Dear Rob;
Shimano sells cogs individually through distributors. Any bike shopcan order them. --Lennard
 

Will that work with....
Dear Lennard,
My son has decided he is a Tri-head and I am happy for him, however,any way to get my old Zipp disks with a threaded hub to work with his Mirage-9gear system??? --DJ

Answer from Zipp

Dear DJ,
ZIPP discs first came onto the market back in 1988 as a then "stateof the art" convertible 7 speed freewheel hub and track combination. Thiswas quickly followed by an eight-speed freewheel/track hub and just a littlelater by an 8 speed cassette hub. Of course this was long before today's9 and 10 speeds systems were even thought of.

Up until November of 2002 ZIPP offered a hub upgrade path for everyZIPP discs ever purchased. This allowed the disc’s owner to re-hub theirexisting disc with the then current cassette or track/freewheel hub. Infact, last year we put new hubs in 3 of the first 25 discs ever sold byZIPP.

For 2003 we introduced both our new ABLC dimpled disc and an "industryfirst" rapid transition disc hub which allows the user to quickly convertbetween a Shimano or Campagnolo cassette free hub or to a track configurationsimply by removing the cassette body and exchanging the axle. It takesthe average person with a little practice less than 3 minutes to make theconversion. The system is designed with an oversized 15mm axle for theroad and a solid stainless steel and track nut combination for the track.The engineering requirements for this system and the changes required tothe internal structure of the disc mean that older discs can no longerbe adapted to the new system. Because, however, literally thousands ofour older disc models going back to 1988 are still in use, ZIPP has extendedour 5-year no fault crash replacement pricing to cover ALL older modeldiscs. Essentially, if the rider has one of these older models, he or shecan exchange it directly through ZIPP for a new 2003 model at approximately35% below suggested retail. In the process, the rider may lose as muchas a pound or more of weight from the wheel and gets not only the slickest,most versatile hub systems available, but also gains the benefit of thelatest aerodynamic technology. They can give us a call at 1 800 447 8372and we will be happy to explain the details.
--Bill Vance
National Sales Manager / ZIPP Factory Guy
ZIPP Speed Weaponry

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VeloNews technical writer Lennard Zinn is a frame builder, 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 VeloNews.com 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 each Tuesday here on VeloNews.com.