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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," and tell us where you live. 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 (do not submit a question if you don't want your Q&A posted in a future column). Take a look at our back issues to find answers to all kinds of bike fix-it questions. 

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Backyard Bike Mechanics Should Always Have a Handy Copy of ...
Bicycling Magazine's Complete Guide to Bicycle Maintenance and Repair
 by Jim Langley
OR...
Zinn and the Art of Road Bike Maintenance OR  Zinn & the Art of Mountain Bike Maintenance
both by Leonard Zinn
Urban Mechanics Who Like Their Repair Manuals With an Edge Will Love ...
How To Rock and Roll : A City Rider's Repair Manual
by Sam Tracy

Winter 2004 Q & A's (40 posted this season.)

Andy

Oh, please, please help me!

My stationary exercise bike squeaks horrifically, not immediately, but about 10 minutes into my cycling routine. I've tried spraying it with WD 40 to no avail. The bike is a DXC 5000 Dual Action Cycle. The initials "BH" are on the hardware. I'm not at all technically minded, but the screeching sound seems to be coming from somewhere around either the chain or the gears, I guess you would call them. It sure isn't the brakes, 'cause I'm not going anywhere! It kicks in after I've been pedaling for about ten minutes.

Christina

Christina,

While I do some servicing of exercise equipment, I can tell you that most of it, unless it came from a fitness specialty shop, is worthless, much like the department store bike counterparts. If it's not Cat eye, accursed Schwinn, Cybex, Lifecycle, etc. you won't be able to get parts for it, and if you could, repair costs can quickly exceed the value of the product. From what you describe, my best guess is dry or deformed crank bearings, which can be fixed for less than $30 in most cases. It's only a guess, though. 

Andy

Hi, "is the Mechanic in?"

I have a 2002 Cannondale Cyclocross bicycle: http://www.cannondale.com/bikes/02/images/xr800_02.jpg 

It has Shimano components and it has a triple chain ring with the outer ring having 52 teeth and the middle one 42T. I want to modify it by putting a 56T on it. By doing so will I need to use a larger size middle sprocket or will this combination of 42t/56t shift ok? Or will there be problems? Is there recommended sizing of chainring groupings to acquire trouble free shifting and the preventing of such problems as "chain suck?" If I make this modification, are there other things I need to do to make it work? Do I need a longer chain? Should I change the position of the derailleur or use a different type for larger sprocket?

Thanks for your help!
Steve Z

Steve,

You will have probably have shifting problems that can't be solved. No one makes a front derailleur with that much capacity. If they did, Shimano does not make a 56T chain ring that is shift-able--they are flat, designed for time trial bikes with one front chainring. Most people shouldn't try to push a gear that big, especially on a cross bike. Look at Page and Gully's bikes, or Dunlaps. These are the best in the country, and they either have a moderate single ring, or the same or lower gearing that you have. If you must gear up, try an 11-23 cassette. This won't present any shifting problems, and is much more reasonable, both for your legs and the bike. Nobody needs bigger than 53-11 on the road except in time trials, and most of us can't effectively push anything bigger than than in any case. If you use this bike as intended, unless you are superhuman or on EPO, you'll probably find a need for the new FSA compact crank, not a bigger one. 

Andy

Hi there,

My left Time Impact pedal is stuck in the crank arm. None of the bike shops have been able to remove it, and have broken many allen wrenches in the process. Any idea on how to salvage the pedal and crank?

Thanks!
Charles

Charles,

You can't get enough leverage with an allen wrench, so your best bet is to cut the crank away. Use ti prep next time.

Andy

Hi,

I am in the process of replacing my front derailleur (upgrading to 9-speed) and have been given a brand new front derailleur (XTR-953) with a clamp size of 34.9mm. However, I should be using a clamp size of 28.6. Is there any way that this can be made to fit securely?

Thanks and regards,
Kim

Kim,

While it's not the best idea in the world, you can shim the derailleur to fit. I think that Wheels Manufacturing makes these. 

Andy

Hey,

I have a question. I have a rear wheel with a 14 mm axle and a 18- tooth, 2- prong freewheel and I didn't have a freewheel remover, so I took it upon my self to try and remove it to put a 16- tooth on because a friend told me that he got his off with a screwdriver and a hammer. So I tried that and it messed up the groves. Now I can't get a freewheel remover in it and I must get it off because it has been left out side and is rusted and must be replaced. Also I am restoring my ' 02 Haro Zippo frame and had it sandblasted. I am going to spray paint and need to know what grit of sand paper to use on it to get a glossy black look.

Thanx,
Wes Lasiter 

Wes,

If you can't use the correct tool to remove the freewheel, you'll have to destroy it. Using the aforementioned hammer and screwdriver, remove the outer race--it has two little holes that you can beat on with the screwdriver--by turning it clockwise. Empty the contents of the freewheel, and clean off the grease. You can then unscrew it by grabbing what's left of it with a pair of vise grips or by sticking it in a big vice. If you have all the paint off the frame by sandblasting, you don't need to sand, except between coats. I use 400 grit, but it depends somewhat on what kind of paint you are using. 

Andy

Andy,

I had a run-in with a rock on my new mountain bike, resulting in a nice gouge and sharp raised spot on the stanchion of the Fox suspension fork, sort of like the rim on a meteor crater, looks like this will damage the oil seal as the shock works up and down. The question is: What is the best way to sand down the rough spot on the stanchion? Many thanks.

Greg Jones
Victoria, British Columbia, Canada

Greg,

If possible, replace it. If you can't, use a fine grit sandpaper(400 or 600) and do it by hand, and only sand off enough material to get it past the seal. I'd presume that this may compromise the integrity of the stanchion, so look to replace it soon.

Andy

Andy,

I have a fairly new Trek Fuel 80 that needs constant adjustment to keep the the index shifter in adjustment and prevent the chain from slipping on the rear gear. I have also had some problem with the front gear slipping and the chain coming off.  I take it into the bike shop every time I ride for adjustments but that isn't helping, plus its very inconvenient. I have
read a few bad reviews on this bike with similar issues. My biggest problem is every time I hit a hill on the trails and have to downshift to the lower gears the chain slips and won't settle into gear. I am really frustrated as I have never spent this kind of money on a bike before, and previous cheaper Trek models I have had have worked fine. I am kind of heavy (220 lbs) which may contribute to the problems.

Any suggestions?

Thanks,
A troubled rider

Troubled,

Fairly new? What year? How many miles? Did it slip from day one, or did it develop over time? True slipping occurs when the chain will not stay on the teeth of a cog or chainring. This is due to elongation of the chain, deformation of the said cogs/chainrings, or both, and can be caused by defective machining, but usually develops at about 1000 miles (Shimano says to get a new chain at 500), and is attributable to normal wear and tear, whether you paid $199 or $8000, it happens, and it is not warrantable. If your indexing is out of whack, that's something else, and any idiot working in a bike shop should be able to fix that. 

Two issues that may apply to your specific bike: Trek (Fisher, Klein) used non-Shimano parts on these bikes, primarily to avoid dealing with Shimano, and thereby saving money. The Bontrager labeled cranks, along with Sram chains and cassettes, sometimes don't provide the crispest shift. The other issue is that these swingarms, particularly on smaller frames, could be ever so slightly out of alignment. This problem supposedly was solved with the 2003 products. In some cases, simply using a shorter crank spindle solves the problem. In others, I've had to replace all the non-Shimano stuff with Shimano stuff, and had excellent results. In a nutshell, a full suspension bike can work pretty well with the Bontrager/Sram stuff or a misaligned swingarm, but not both. 

Andy

Andy,

I like the compliant feel of steel, but most of the lighter bikes in my price range are aluminum, usually with a carbon fork. Should I just pay more for a light steel bike, or would aluminum with carbon forks and "bent" rear triangles (e.g., the Scanttate 550 which Supergo sells) give me a soft enough ride to do a century and not feel beaten up?

Thanks,
Bassim

Bassim,

Since I don't know what your price range is, I'll make a few suggestions. Don't buy from Supergo. Check out the new Lemond spine bikes. They are pretty light, very efficient, and comfortable. About $1900 for the BA with 105, to about $3500 for the Maillot Jaune with Dura Ace. 

Andy

Andy,

Is is practical to convert a 10-speed to a 15-speed?

I have a 1987 Trek 330 road bike (http://www.vintage-trek.com/TrekBrochure1987.htm).  It meets most of my needs as I am a fairly leisure rider. To push myself I like to ride some of the Kansas Survival Series rides. There is one infamous hill near Lawrence, Kansas (yes, that's right, there are some hills in Kansas), where I really could use some lower gears. After climbing that hill last summer my knees were so sore I cut short my ride that day.

I like the fact that I ride a 17-year old bike that I bought used for a $100.  I just can't bring myself to drop 10 to 20 times that amount for a new road bike. I would like to order a 3-ring crank set with a matching front derailleur, but my local bike shop told me "it couldn't be done."  Is that because of the frame geometry or something?

If you know what parts I need to do the job, I'll gladly order them from you!

Steve

Steve,

I see no reason you couldn't run a triple. Some of the old Suntour stuff had indexed front shifting, which can be switched off if necessary. You will need a long cage rear derailleur, new front der, crank and bb. Expect to spend at least $125 (Shimano Sora).

Andy

Andy,

I'm an NC State student majoring in Mechanical engineering trying to design a bike with a top gear ratio of about 8:1 for an English project of all things. In my design, I have the frame going in between the wheel and the gears. All the gears will be welded to each other so that the axle need only run through the center of the large gears and not through the small gears so that the small gears will not be limited by the axle size. My aim is to make the small gear with 3-5 teeth (preferably 3). I need to know the standard dimensions of bicycle teeth (how long and how wide) and the standard spacing between chain links to know how far apart to space the teeth. I need the tooth dimensions to calculate how much shear stress one tooth can handle before it strips off.  I don't know how a freewheel works--if you have or know where I can find a really good diagram of one, I'd appreciate that too.

Just wondering: Why don't they don't make bikes where the front gear has the same radius as the crank length? What's the largest gap a front derailleur can derail across?

The paper's due a week from today, so please get back to me soon. I really appreciate it!

Michael

Michael,

This is a little outside the realm of this column, but I'll tell you what I can. Your best bet is to contact a more technical, engineering sort of a person. I'm the guy who fixes stuff that's already designed. Gear tooth dimensions and shear strength are irrelevant, as we have to work with the parts provided by Shimano, and it's almost stupid to try anything that Shimano says not to try. We are slaves to Shimano, and maybe some guy like you might start a company and change that, but most likely, all the American drive train designs will go the way of the Paul derailleur: elegant, light, expensive, Shimano compatible, and quirky. In reverse order, they don't make a hugeass chainwheel for obvious reasons. Most people just want to ride from point A to point B without straining themselves too much. Superhuman feats, like trying to set an HPV record, or going after the hour record, may require more than 56 teeth up front, but even guys like Lance and David Millar couldn't push that for very long. I consider gearing that high beyond impractical, it's actually dangerous. You'll hurt yourself if you try much higher than the standard 53/12 high gear (119.3 gear inches). Front derailleurs are limited to 22-23 teeth capacity. No freewheel diagrams, but it's a pretty simple concept: pawls, pawl springs, and a ratchet ring. As for chain and tooth dimensions, there are currently two sizes of single speed chain in use, as well as 5 through 10 speed chains and corresponding cogs. The pitch of the single speed chain is 1/2" x 1/8" (some are 1/2" x 3/16") and a multi speed chain is 1/2" x3/32". Multi gear chains range from 6.1 mm wide for campy 10 speed, to 7.3 mm for a basic 5/6 speed chain. The only specs I have for cogs are center to center and thickness. Campy 10 c to c is 4.12 mm with 1.7 thickness. Shimano 9 is 4.34 and 1.78, and 7 speed cogs are 1.8 and 3.2.

You might try Lennard Zinn. He'd know a lot more about the engineering and physics involved here. I'm not sure how long it would take Lennard to get back to you, though.

Andy 

Dear Andy,

I'm currently having problems with my chain/cog (not sure which). I have a 21- speed bike and I haven't maintained it as much as I should. The chain slips (particularly on the large cog) and I'm not sure if this is due to the chain or not. 

The chain slips on all three cogs when in low gear and when there is higher pressure on the chain. How do I know when to change the chain or cog or both?

Yours,
Confused and neglectful
David

David,

Chains and cogs wear together. If the chain is worn out, most likely the cogs are worn out, or at least a frequently used cog or 2 is. These parts wear out with incredible frequency, and the only way to stave off frequent cassette replacement is with even more frequent chain replacement. Replace the chain every 1000 off road miles, and don't use one gear more often than any other. You'll still have to replace this stuff often, but a new chain twice a year is cheaper than a new chain and cassette, or wearing out a chain ring with an elongated chain, or crashing because your chain slipped off a cog. 

Andy

Andy,

We have a 1992 Ross Pegasus 21- speed bike. It is ridden between 20-40 miles a week. Last week we had a problem where the freewheel would spin but not engage the wheel. We took it to a bike shop (the rim was also bent a little) they sold us a new rim and installed the same freewheel and gears on it. It worked well for two days and then the same problem. We brought the bike in doors to work on it and several hours later everything was fine. Took the bike back outside in the cold at 20 degrees F and after several hours same problem. What could be going on that is affected by the cold?

Maryann,

It is unlikely that cold causes this problem. What is likely is that a 14- year- old freewheel is begging to be replaced. When this happens, it is usually due to a broken pawl. Your freewheel has two pawls that engage a toothed ring when you pedal forward, but retract when coasting or backpedaling. You can ride with only one, but it sometimes doesn't catch until you pedal for a while, or not at all. It is possible that both pawls are intact, but dried out lubricant or rust is preventing them from performing as designed. Before you trash it, try flushing it out with Tri-Flow, and dripping some heavier stuff, like gear oil, or 30 weight in. Don't try to take it apart.

Andy 

Andy,

I have a creaking coming from my freehub and want to re-grease it and see if that solves the problem. Can you tell me how to remove the freehub, or regrease it, on a 2001 Specialized FSR with a Specialized S-Works rear hub? I don't see any places a wrench of any type would fit.

God Bless and Love,
Denise and Steve

Denise and Steve,

Generally, freehubs are removed via a large bolt in the center, with a 10 or 12 mm allen wrench. Some are reverse threaded, and most, especially generic ones, which is what specialized is in spite of it's brand name, are extremely difficult to remove. However, removing it is not going to help in your case. I service these by removing the axle and dust cap, and plugging in a Morningstar freehub service tool. With this, you can pump solvent into the freehub, and then whatever lubricant you see fit--Morningstar makes a freehub soup for this purpose, Paul and I have discussed exactly what should be put in here, and the soup seems to work pretty well. Morning star also makes tools to remove dust caps, and serviceable dust caps to replace the one than probably got all bent out of shape upon removal.

Andy

Andy,

I have a inexpensive Roadmaster bicycle. The brakes make a noise when applied. The brake pads appear to be made of a hard material not rubber. Could this be the reason for the noise.

Timothy

Timothy,

Brake noise, and poor performance can be caused by a number of features found on many Roadmaster bicycles. Hard or glazed pads, chrome plated steel wheels, excessive play in the brake pivots, flexy brake arches, flex in the frame, improper assembly, you name it. Softer brake pads usually work better and are quieter than harder ones, but they wear out quicker, especially when applied to steel wheels. Brake pads should hit flat when viewed from the front, with a slight toe in to prevent sqwawks. There is no cure for substandard equipment. 

Andy

Hi Andy,

Had a search through your website for some clues to my problem but couldn't find a similar problem! I ride a 2002/3 Cannondale and have put approximately 6500km of road on it. I noticed a ticking from the bottom bracket early into my mileage, and prompted the store, who informed me that my spds (Shimano m515's) were responsible.

Shortly thereafter the crank arms were having to be pulled up after every ride as they were loose. Bottom bracket was eventually replaced, and I queried about replacing the crank arms as well, but was told it wasn't necessary. Now it's two months since the bottom bracket was replaced, and the ticking has returned. I have no lateral movement in the crank arms that I can detect. Any ideas to the ticking?

Many thanks,
Mike

Mike,

If you are sure that the sound is coming from the crank and not elsewhere, you most likely need a new crankset. If the arms loosened, chances are the taper is worn, and they will never stay on. If you have an ISIS or Hollowtech crankset, then I'm probably wrong, but it sounds to me like a case of square taper wallow out. Another common problem with Cannondales is creaking due to cups not perfectly fitted to the bb shell. This is easily remedied with plumber's Teflon tape on both bb cups.

Andy

Hi Andy,

I'm an American living in Belgium and use my trusty bike to get around town (Antwerp). I recently bought a dynamo-powered light set, but can't for the life of me figure out how to get the thing set up and running. I have inquired with friends and always steal peeks from other bikes on the street.

For me, the wires are the issue. I have easily attached the lights to their particular location, though I had to put the dynamo on my back tire because my front fork is too fat for a secure, tight fit for the dynamo. What I've come up with is that I need to "complete the circuit" as there is only two wires--one connects to the dynamo from the rear light and one connects from the front light to the dynamo. It's driving me completely bonkers, as my frame is supposed to complete the loop somehow. Do you have any suggestions as to how I can make it work?

Thanks!
Andrea (currently roaming streets of Belgium without headlamp)

Andrea,

Most of these systems require the use of the bike frame as a ground.  You have to scrape off some paint and there should be a pointed set screw which digs into the frame a little bit to complete the circuit. I suppose if you don't want to scratch your paint, you could hardwire the thing, but that would be kind of sloppy.  

Andy

Andy,

I ride a 2001Giant OCR 1.  I've put about 2,500 miles on it and have been very satisfied.  Have had normal maintenance and recently had all cables replaced. For the last two weeks there has been a very annoying clicking or creaking sound coming from the front crank. I thought it might be my pedals at first, but have determined that it is not.  There is a distinct click with each rpm when I pedal and sporadic "non rhythmic" clicks as well.  Any advice on what it could be and how to fix it?  It's driving me crazy.

Thanks,
CDC

C,

You have many possibilities.  Loose crank, loose bb cup, bb shot, chainring loose, pedal, either bearings or bindings, wheel skewers, especially ti--grease them--check your new cables for rubbing or ends catching on the crank.  Remember that it's hard to localize noises while on the bike because the frame acts as an acoustical conductor, so sometimes a wheel, seat, or handlebar noise sounds like it's coming from the crank.  Check your seat/seatpost and all related bolts.  You may grease the seat rails as well.

Andy

Hi Andy,

I have a Specialized Allez that is about 10 years old (or so).  It has Shimano 600 Components with horrible Biopace chainrings.  I hate them.  My question is: In order to replace them, as I have suffered long enough, can I just replace the chainrings or do I replace the crank arms too?  Do I need to replace the entire drive train? 

Thanks for the help,
Staci

Staci,

You can replace them with almost any 130mm bolt circle chainrings. I suspect that along with the Biopace, you have downtube shifters, which means that cheap chainrings will work fine. The ramped and pinned rings may work better, but if you had STI shifters, you really need Shimano type chainrings.

 Andy

Hi Andy,

I have a Diamondback Vectra mountain bike and up until an accident I had six months ago I have never had much of a problem with it. This accident bent my front wheel and generally gave the bike a good bashing.

I had the bike repaired and serviced, but since then I have had troubles with the v-brakes. Braking on a flat surface is fine, but downhill the brakes start to slide and make a loud friction sound.

I took the bike to a different mechanic and they replaced the brake pads and cable as well as tested the bike thoroughly around their workshop (which of course is flat). The problem remains and whilst braking downhill always works to some extent, I don't have much confidence in the front brakes which consistently skid against the rim of the wheel. The steeper the hill the worse it is, and even if I go very slowly down the hill the brakes skid badly.

One final clue is that releasing the brakes and reapplying them gives them renewed strength and stops the skidding momentarily.

Any idea what could be causing this annoying problem?

Thanks very much,
Anthony.

Anthony.

It's hard to diagnose these types of problems.  If you are using a good quality brake pad, and your rim is not ground down too far, I'd look for a loose brake mounting boss, or look at your fork while braking, and observe whether the legs flex out or not. If you have flex--and this is much more common in the rear than with suspension forks--a brake booster may solve the problem.

Andy

Dear Sir,

I plan to buy/build a road/racing bicycle. I want to use Sturmy Archer 8-Speed (roller brake). The problem is to choose the frame that can accommodate the application of the internal gear hub, especially the kind of drop out. Would you give me a suggestion on the aluminum frame (brand name) that I should use? My budget for the frame is about $230US.

Thank you very much for your help.

Albert

Albert,

Off hand, I don't know of any aluminum frames that fit your needs.  The best price for something like this (new) would be a Surly 1x1 or Steamroller, but they are made of cromoly and cost about $400.

Andy

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