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Bikexchange.com logo, link to Home          Send your questions to bicycle expert Andy Wallen. (Cartoon image of Andy)Ask the Mechanic

Winter 1999      Fall 98Summer 98 | Spring 98 | Winter 98 | Fall 97
                                                                       
Spring /Sum 97 | Win 97 | Fall 96                                            

Stuck in gear and need expert advice? Ask Andy the Mechanic (a.k.a. Andy Wallen), the proprietor of Wheelcraft Bicycles of Wheeling, WV. (Please, no old bike & antique questions.) E-mail to ibike@bikexchange.com, subject "ask the mechanic," or mail your question directly to Ask the Mechanic, c/o Wheelcraft Bicycles, 2185 National Road, Wheeling, WV, USA 26003. Andy will e-mail your advice and we may post it afterward. Take a look at our back issues to find answers to all kinds of bike fix-it questions.

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Winter 1999 Questions...

Hi Andy,

I ride a Trek road bike, mainly on weekends. I've been training harder and harder as my interest increases. I'm interested in gear ratios and how to figure them -- I have 46/36/26 chain rings and a 11/12/14/16/18/21/24 flywheel. In my type of riding I stay mainly in 36/11 when a friend stays in 52/14 or 16 while at basically the same speed. My cadence is around 80/85; he doesn't have a cadence pick-up. I would say with his gear his cadence is a lot slower (not sure). When I shift to 46/11 I can't get anymore than 70 cadence on level ground with no head wind.

Please Help me to understand. Thank you,
Dan Bright Sr.

Dan,

I'm not sure what you're after here. Gear ratios can be changed somewhat, but you seem to want to keep your cadence up. There are two ways you can do this: train harder and/or stay in a lower gear. For comparison, you can figure gear inches by multiplying the tire diameter (inches) by the # of teeth up front and dividing this # by the # of teeth on the rear cogs. This will help you see where the gears overlap. An easier way to do this is simply move to 46T up
front and try a lower rear gear like 18 instead of staying in your high (11T) cog.

Andy

Andy,

I have just bought a pair of Crossmax wheels. Since I have been riding on them I have noticed that my forks bottom out really easily and also seem loose. Is it the wheels or is there something wrong with the forks? It almost feels as if there is something loose inside the fork, when I pull up on the fork there is a thud as if I have pulled the inner leg of the fork up to its limit.

Any advice would be most welcome.

Jem.

Jem,

The wheels have nothing to do with this unless the front bearings are worn or loose. However a loose front hub would not cause the fork problem. Most likely, you have either worn bushings, a loose bolt, an air leak, a blown cartridge, etc. It's hard for me to tell because I don't know what kind of fork you have and since a problem of this nature could be life threatening, take it to a qualified repair shop.

Andy

Andy,

I am trying to rebuild a Raleigh "Legend" bike from 2 bikes. One is the Legend itself, the other is a Raleigh "Portage". The Legend is an 18 speed and the Portage is a 15 speed. I would like to know if the cogset from the good Portage rims can be removed and replaced with the cogset from the Legend so as to maintain its 18 speeds. Both sets are made by Shimano. I would also like to know if it is necessary to have the special tools to remove the cogset from the rim or if there is some standard tools that can be used instead.

Thanks for your time,
Rick

Rick,

You can change the cogs if you have a Shimano freewheel tool.

Andy

Andy,

I saw on a MTB magazine the review of the newest "Dave's" 9-speed drive train. It features a new lacing system consisting an XT rear hub using single cross lace on the non-driveside and 4 cross on the driveside. All spokes are facing left, I mean, the bent is outside on the driveside and inside on the non driveside. The ninth speed is a lock ring with sprockets 10T.

They say that this kind of lace adds strength to the wheel with much less dish. I'm not interested on nine speeds but I wonder if I can use this lacing pattern on my STX-RC hubs to strengthen my wheel and get more power transfer.

Can you tell me how can I do this and if it's wise to do it?

Thanks for your help,
Martin Ocando
Barquisimeto, Venezuela

Martin,

You can use this pattern to reduce dish and to theoretically strengthen your wheel; however, the spokes must be carefully bent around each other. This is especially difficult to do with a 4 cross pattern. Bent spokes are not as strong as straight spokes, so there's a bit of a hole in this wheel building theory. Also, with the elbows out on the drive side, you will either need to really bent these spokes inward or use a shim (2 or 2.5 mm) so that the first cog doesn't rub the spokes.

Andy

Andy,

In February I got a new bike equipped with Shimano Ultegra 9-speed and Triple. I love the group except for the brakes. The pads are noisy, dirty and have almost worn out in about 4,000 miles. Do you know of any after market pads that I could buy to replace the stock Shimano pads?

Thanks,
Forrest

Forrest,

Shimano is currently making an upgrade pad w/ a different rubber compound due to complaints about the hard pads they originally made. These should be in stock and available now.

Andy

Andy,

Just purchased two new wheels from a local dealer, realized two days later that rims take Shrader valves and they put on my old high pressure Presta valve tire and tubes.

I called the dealer because I was concerned about pinching and blowouts at the valve stem and I would prefer wheels that were designed for Presta valves. They said it would not matter that my Presta tubes would work fine but if I did run into problems they would switch my inner tubes for me at no charge. They also said that the tube does not determine the pressure but the tire does and that I could run high pressure 115 - 120 lb. in a Shrader tube as long as my tires were designed for that pressure. Still I prefer Presta valves, 1. I have about 6 tubes in stock and 2. I think they look better.

Questions:
If I do run into problems does any one make a type of washer or insert to convert a Shrader rim into a Presta?

Maybe I could exchange for proper wheels, I never specified the rim type when ordering but they had my bike with my old wheels on it and they put my Presta tire and tubes on for me, I just assumed it would be a Presta rim, I have had for about 6 days and put on about 150 miles on these wheels, do you think this would be a legitimate complaint and exchange?

Maybe I have nothing to worry about, perhaps my Presta tubes will work as is, but part of the tube (small part) is sticking through rim, do you think I will experience blowouts at the valve stem?

Thank you in advance for your time and prompt response.

You can put a grommet or a Presta stem saver in your rims. You do need to do that to avoid problems. The stem can pull through the rim. There is not a lot of difference between PV and SV performance wise but decent road wheels traditionally have PV. If you had PV to start with you should have PV rims now.

Andy

Hi, Pleased to meet you,

I'm trying to fix my son's bike. The chain broke it's master link, fixed it but can't tell which is gear #1, when I put the chain back. It's working, but NOT right. Still can't switch gears. This is a 10-speed bike, with 3 sprockets, and 2 levers.

Any help or diagram would be a help.

Thank you,
Joe and son

Joe,

You're a little vague, but I'll do my best. If the chain broke then you should replace it. 10 speed chains don't have masterlinks, so if you installed one, it will never clear the pulley wheels of the derailleur. Generally speaking, 1st gear is the largest rear cog, but it is much easier to install the chain with it on the smallest rear and off the front sprocket.

Andy,

Hello! I'm also a mechanic but with only two years experience under my belt so I still haven't learned all the tricks. I have an old Suntour crank that has the crank threads stripped. I tried to install the crank arm removing tool but the threads won't hold. What other way can I pop this right crank of my bike. Please help...

Thanks,
Rick

Rick,

There is a thing that may remove this crank arm--A rather savage automotive looking instrument called a crank pry bar (ub tool #CV-22)

Andy

Andy,

A buddy of mine is having me help him put together a cyclocross bike. We're in the component selection process and I was hoping you could give me some insight into popular gearing. I'm not sure what gearing most cyclocrossers use. He plans on using it to commute in the winter on the road (New England winter) as well as for off-road use. I imagine he'll also be using it in the fall and summer months. Basically he intends to rack up some serious miles doing all sorts of riding. Please lend me some insight.

Thanks,
Nick

Nick,

Traditional cyclocross bikes usually only have 2 chainrings, geared lower than standard road bikes. I would probably use a 12-25 or 12-28 rear and 39-52 up front---you may like a 38-50 with 11-25 cassette.

Andy
PS - You can get a little more info on the USA racing website.

Andy,

I have a Cannondale m300, pretty bottom-of-the-line bike, but it's my mudder and I'm getting ready for winter riding. Well, I was going through the bike the other day and found out my bottom bracket is pretty much trashed. It measures out to be a 68 x 118 but I was wondering if a 68 x 113 would work or would it throw my chain line off too much? Which brings me to another question: How do I measure the chain line? I'd appreciate any help. Thank you.

Cooney Family

Cooney,

Whether using a different bb size will screw things up is largely dependent upon the type of crank you are using. Usually 5 or 6 mm won't matter, except you'll have to adjust your front der to accommodate the length. (One of C'dales several boners of recent memory was to spec top swing ders on these bikes. The only way to use the stock der with the C'dale seat tube diameter is to increase the length of the spindle to the max chain line--not a good idea. An old bottom swing der works much better.) Basically, the chain line measurement is the distance from the seat tube to the center of the middle ring + half the diameter of the seat tube. We want this measurement to be around 50-53mm.

Andy

Andy,

I have a Giant Kronos with RSX STI 7 speed cassette, triple chainrings. I'm thinking of going to 8 or 9 speed cassette and need to know: Are my dropouts OK at 130mm spacing?

Does either cassette fit on existing freehub body? Or do I need a new hub complete?

How do I redish the wheel?

Steve Brown

   ____O
  -\ , < >              "Have Bike, Will Travel"
(  )  /  (  )

Steve,

You can do this without replacing the wheel, however, unless you are emotionally attached to this particular wheel, total replacement vs. reworking the old wheel is an insignificant percentage of the cost of this project. You will need an 8 speed body ($30-$35), an 8 speed axle set ($12-$15) and someone with hub tools, a self centering wheel jig and/or a dishing tool to correctly install these parts ($0-$25). An acceptable 8 speed rear wheel can be had for as little as $75, and it's a lot easier to install. You can't re-dish the wheel without a considerable investment in tools.

Andy

Andy,

I would like to upgrade my MTB with V-brakes. I have 5-year-old XT rapidfire shifter/brake combo controls and a 7-speed cog. I've been told that I would need to replace my shifter/brake controls because of the different pull length AND my rear wheel, deraileur and cog because the new shifters are all 8 or 9-speed.

Is there another solution?

Thanks!
Scott McFate

Scott,

You can use V-brake adapters such as the QBP Travel Agent for this project. Use a braided brake cable, and inspect the cable around the pulley often. These devices work well and are easy to install. Expect to pay about $18 each. I've heard from people who think that V-brakes work with old style levers. I've also heard that the Huffy Ironman is a good bike, and Elvis is alive and ruler of some third world nation. If you like your life and you want to keep your teeth, buy the adapters. If you want those expensive xtr v's to perform like stamped steel Murray calipers with greasy pads on chrome plated steel rims, use your existing levers.

Andy

Andy,

I recently broke (snapped) two of the screws attaching the cogs on my Shimano freewheel to the spider body. (I didn't think I had that much torque in my legs!). The problem is that I cannot remember exactly what freewheel it is (it came on a Norco Team Issue bike I got in 1993). Anyhow, I need to obtain a couple of screws (to replace the broken ones I extracted with a very small bolt/screw extractor) and possibly a couple of additional ones with retaining nuts (as due to the failure these worked loose and two are missing).

The rear derailleur is an XTR but I am not sure about the freewheel. The freewheel was currently on a Deore LX Parallax FH-M565 hub. This hub was an emergency replacement - I believe the original hub was an Ultegra 600 (??). When I took it apart last night, here's the details... The spider body is labeled "Type Q" and "CS-M900" while the outer ring is labeled "HG Hyperglide." The 8-speed cog combo is 12-13-14-16-18-21-24-28 (I'm sure you do not need the actual placement codes.)

Any idea which freewheel this is? I can't seem to get any help from the Shimano web site (what's new!).

Any info would be appreciated.

Neil Farish
Ottawa, Ontario, Canada

Neil,

The number indicates that you have an XTR cassette. You can't buy the bolts, so unless you can rig it with something else, it's history. If you've been using this since 1993, you should have replaced both the cassette and chain 2 or 3 times by now.

Andy

I have an old 5-speed touring bike which I have held on to for sentimental reasons but would like to upgrade it to make it less of an antique. What steps do I need to take to convert it? I am planning to increase the rear wheel spacing from 120mm to 125.5mm or 126mm but am not sure what I will need for new parts. Here is what I have now: a pre-1985 Kalkhoff equipped with a Shimano Uniglide 5-speed drive train.

Is it possible to use the existing rear hub (Weinmann Normandy, I believe) with a 7-speed cog or do I need a new one? If so, wouldn't it be better to go with a 130mm spacing and 9-speed rear components so as to not limit future upgrades by too much?

My other question is regarding the compatibility of Shimano parts in general. I recently purchased a bike equipped with the new Shimano 105 9-speed group and would eventually like to upgrade the drivetrain to Ultegra or Dura Ace over the course of next year as I have the finances. Can this be done piece by piece? Can I, for example, use a Ultegra or Dura Ace 9-speed rear derailuer with 105 9-speed gears? Will Ultegra/Dura Ace cogs work on a 105 rear hub? Can I use Ultegra/Dura Ace cranks with a 105 bottom bracket? ETC., ETC.

Thanks in advance for your help!
Joao de Sousa

Joao,

You should have your frame spread and aligned by an experienced mechanic. Don't go any less than 130mm spacing. You need a longer axle and spacers. 130mm will let you use a 7 or 8-speed freewheel. For 9-speed you need a cassette hub, or, more than likely a new rr wheel. As far as I know, all Shimano 9-speed parts are compatible.

Andy

Andy,

I'm having a problem with my chain slipping when I am in my lower gears. It started a few months ago intermittently, but now I can't even use the low gears on hills because it slips every time. Any suggestions? Thanks in advance for your help.

Micki T.

Micki,

You need a new chain and new cogs. You should have your gear adjustment checked.

Andy

G'day,

My name is Tom, I'm from Adelaide, Australia. I've pulled apart my 636'es, and regreased everything. I put the cone and locknut on and left the pedal in my shed whilst I went to the shop to see if the tool I ordered had come in (TL-PD63, a special tool you need to tighten the locknut on the cone correctly). It hadn't, and it won't be. Is there any way you can think of that I can hold the cone whilst tightening the locknut?

Tom

Tom,

I don't normally get into pedal repacking because it's more trouble than it's worth. You ought to be able to get the tool through a qualified shop. We would sell it for about $35.

Good luck,
Andy

Andy,

I have a bmx bike and I was told that to be competitive in this sport, I need three piece cranks.. I have a small chainwheel and chain. If I put three piece cranks on my bike, would I need to buy a new chainwheel and chain?

Thanks,
trent lennon

Trent,

Most 3-piece cranks will require a different chainring and chain. Make sure you have a good frame and wheelset before you put $175-250 into your current bike.

Andy

HELP,

I have a Union Wing 3 dynohub. It is two years old and has travelled approx. 4,000 miles. Now the bearings have become very loose and I have been told by the shop that supplied it that they are not adjustable! I always thought Union were very reliable (and this dynohub was not cheap.)

Have you any ideas on how it can be rescued or how I can contact Union to complain.

Thanks ..........Tom

Dear Tom,

This not an American or a current part; I haven't seen this type of thing since military issue Raleighs from the late '60s. Union is now known as Marwi and I doubt that the new company can help you with this. You can contact them at (618)395-8471.

Andy

Andy,

Will road salt effect my aluminum frame, especially where the paint is rubbed off?

Michael

Michael,

My educated guess is that since salt is a corrosive, and since aluminum does "rust" (you can say that it oxidizes or some other euphemism, but, in truth, it rots, just like anything else), then any corrosive will accelerate the rusting action. This is not as obvious as what happens to your '73 Pinto after a few Northern WV winters, but is probably somewhat dangerous in a sneaky sort of way.

Many factors contribute to the breakdown of an aluminum frame. Any one of these factors, and I would include corrosion, could cause an imperceptible crack to develop. Cyclical fatigue can turn these little cracks into catastrophic failures rather quickly. My rule, which everyone is too cheap to follow, is to replace aluminum ATB frames every five years, and road frames every eight. If either was crashed, regardless of the lack of any apparent damage, replace it. If your paint is bubbling up because of corrosion, I would replace the frame rather than risk death or injury.

Andy
PS: On the sales floor, we are often hit with the concept that "Joe the Know-It-All Mountain Biker"--who rode in a race once--said to buy an aluminum frame because it won't rust and will therefore outlast steel. While it is true that the type of breakdown that generally occurs in a 20-year-old, abused steel frame is not is obvious in aluminum, aluminum is prone to cyclical failures, corrosion, and once bent it should never be straightened. It is also the most popular frame material on the planet (and The Backstreet Boys is the most popular singing group in America, and Bill Clinton is the most popular president since George Washington).

Andy,

I plan to switch from Ultegra 600 with a 53/39 front chain ring combo to the new Ultegra Triple 52/42/30 combination. I have heard conflicting stories about changing the chain ring sizes, i.e., replacing the 52 with a 53. If I can't change the rings, can I go with an 11 rear cog?

What do you think?
BB

BB,

The stock set up is 30-42-52. The 52 can be replaced with a standard 53x130 chain ring. 53x12 yields 119.3 gear inches; 52x11 yields 127.6. So. you'll go faster with fewer potential problems (a matched set of Shimano rings works a little better than mixed combinations) with the stock 52, with 11-23 cassette. If the 30x23 is not low enough for your needs, you can get a 12-25 or 12x27 and replace the 12 with a 11 for about an additional $9.

Andy

Andy,

I just bought a second-hand Pinarello with four-year-old Dura-ace and Ultegra/600 components, and I love it. However, in recent races I've noticed that other people starting at the top of a hill at the same speed can coast faster than me and accelerate past me without pedaling. The bearings & brakes do not seem to be binding although I have not re-packed them. Any suggestions?

Richard

Richard,

Coasting is one of those things that can be influenced by several physical and mechanical variables. To make a valid comparison, you must ride the exact same hill under the exact same conditions on 2 different bikes. Assuming you have done this, we can address issues such as bearing/grease in the wheels, width and air pressure in the tires (skinnier, higher pressure=faster), handlebar width/positioning (narrower, lower=faster), bike and/or wheel weight. Light wheels have only one downside: they usually don't roll as fast downhill. It's a simple question of momentum, once you get a higher mass in motion, that higher mass has more potential inertia. This applies to the mass of the entire bike and rider as well. So if your bearings are good, you ride in the same aerodynamic tuck as your friends, etc.

Maybe its light wheels/tires, or maybe you need to put on a few pounds. Fat guys on cheap bikes can just fly down hills. This is one reason spoked-molded wheels are so popular (Spin, Spinergy, etc.) Most of them are considerably heavier than good wire spoked wheels, but the combination of aerodynamics and added rotational inertia, make them seem very fast, and they are unless you're climbing.

Andy 

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