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Ask the Mechanic
Spring 1999 Winter 99 | Fall 98 | Summer 98 | Spring 98 | Winter 98
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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 email@example.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.
Spring 1999 Questions (once again, Andy tells it like it is)...
I have an old TREK 620. The chainrings are worn out. Do you know where I can get replacements? I need a Shimano 50T, and 45T, 110 bolt pattern. If I can get the parts, I can keep the bike going. Otherwise, I'll resign myself to buying a new chariot.
Toothless in NH
110mm chainrings are readily available almost anywhere. We stock and highly recommend QBP engagement rings (qbp # CR3744 is a 44t inner, only Sugino makes a 45 #CR1163, #CR3750 is the 50). You can even get these in colors. Expect to pay around $45-$50 for the pair.
Both my wife and I are 59 years old and in good (but not great shape). We want to ride mostly on paved roads with a bit of dirt roads thrown in--but no mountain biking.
What brand and type of bike might you recommend?
I can only recommend what I sell, so it'll have to be either a Gary Fisher or a Fuji. Without spending a fortune, you should be able to find a '97 or '98 Fisher Zebrano for under $300. This bike is perfect for any use. It comes with pavement tires, but since it has 26" (as opposed to 700c) wheels, you can put knobbies on for off road use. It is probably the least expensive truly American made frame (as opposed to Chinese-made American made frames), is quite light, and decently equipped. The '99 Fisher SUBs have suspension stems, seatposts, and aluminum frames.
I am a researcher for career information used by high school students in career counseling courses in public schools (Canada and the United States). This week I am working on updating some information regarding the career "Bicycle Mechanic." I saw your name on the Ask the Mechanic page, and was wondering if you would be able to help with the following three questions about this field of work:
1) What sort of reading/writing skills are needed for this work?
2) What type of math do you need to do on the job?
3) Decision-making skills: What sort of decisions do you have to make on the job? Do you have an example of a tough decision you had to make on the job, and then what you decided to do? (I find this helps students understand what might be expected of them on the job!)
Thanks in advance if you are able to help out with these questions.
This job requires the ability to read and fully understand technical manuals and specifications. We often write estimates. In writing an estimate it is critical to make good decisions so that your estimate is accurate and that the unit is even worth repairing. Common sense is also of great value. Keep in mind that cycling is a high liability activity and good decision making is critical. Communication skills are also critical. Math and measuring are constantly used, whether for spoke measurement, gear ratios, or torque conversions.
Hope this helps,
I just had a 1999 Campy Record rear hub and a EXA cassette mounted to a Mavic open pro rim. The drivetrain is all 1999 Record as well as the chain. The problem is that the rear hub is very noisy in freewheel (loud ratcheting noise) and the chain in all gears is noisy as well. There is a grease port on the rear hub. Should I attempt to inject grease into the hub? I 've cleaned the chain and lubricated it but it still does not sound right.
Any advice would be greatly appreciated.
This is probably just a noisy chain and hub. Injecting grease in the rear hub could help. If it's not blowing up, I wouldn't worry too much.
I've got a new custom bike ( steel ) with Campy record (1997) 9-speed components. After riding the bike for seven months, I've had two occurrences where when shifting from the 19th to the 21st cog--in the big ring--the chain somehow gets wrapped up in the rear deraileur, jamming into the spokes. In the process, the deraileur and the deraileur hander get bent. After the first occurrence of this, I had the hanger straightened and the deraileur and the chain replaced. It then happened again. Have you heard of this happening with any other riders? Any ideas?
It sounds like you have a kink in your chain or your rear der is out of whack.
Hi, I have a problem: My rear cluster is making a banging noise when I spin it. What I want to know is how to remove the freewheel body to get a closer look inside and sort out why it is making the noise, or to see if I must replace the body instead of a whole new hub.
If you have a freewheel, the proper tool (there are at least a dozen different ones) will take it off. Most of us should not disassemble a freewheel. These can be replaced for under $20 usually. If you have a quality cassette body, it can be removed and replaced if needed. Hope this helps.
I recently bought a 99 Trek Y3 mountain bike (full suspension, aluminum and chromoly). It has the 8-speed Shimano components with Acera crank and HG50 chain. After four weeks of very hilly, aggressive mountain riding (I weigh 200 lbs.), I started getting chainsuck, first when muddy and going up hill, then whenever going uphill (when the chain is under tension).
I noticed that the inner 22T ring of the crank was warn and would not let go of the chain. My bike shop replaced the crank with a Alivio 24T crank and, after another month, chainsuck again! Speaking to Shimano, they recommends using IG chains, as the HG chains (they come with the bikes) are not compatible with the crank. The Trek representative said they had no knowledge of this incompatibility. What's the difference between IG and HG chains? Why am I eating through the crank so soon?
I know the Shimano Acera/Alivio crank is entry level and that I should probably upgrade. What crank and chain would you recommend for durability and longevity?
The Acera/Alivio cranks are strictly ornamental and should not be used off-road with any chain. Supposedly a complement of IG components will eliminate chain suck (says Shimano). Realistically, chain suck will happen with any combination when you ride in mud. Get a crank with replaceable chainrings (Impel 500) and replace the small ring with a stainless ring. Use a good quality chain such as the KMC SS91 or Sachs (don't use Shimano). This should improve the situation 100 percent.
Please let me know what you think of the new Mega 9-speed stuff. I have 8 on now and I'm thinking of going to the XTR\XT 9-speed stuff. Do you think it's worth it or not? Will the crank creek or not? Let me know.
The Mega 9-speed stuff works well although we don't know yet how the chain-suck situation is yet. My only concern would be potential chain breakage due to less material in the chain. Crank creakage is related to frame material, bb tightness, crank arm tightness and chainring tightness. Some cranks or bb's creak and others, even the same models, do not.
I just purchased a Riley C200 with a 48/38/28 chainring. I had a 34-tooth granny gear put on the bike at the time of purchase. My question is this: Can I have a 26" chainring installed on the front? If so, that should bring the gearing down even lower with the cassette that I have now installed. Would this be an expensive change?
Assuming that you own a Raleigh C200 with a Nexave crank, you will have to replace the complete crank to get that gearing (around $60).
I have a Repco TR mountain bike with 21-speed Shimano gears. I recently was hit and run by a motorist and this resulted in my rear hub becoming very loose. I removed the rear wheel and tightened the hub and put the wheel back on. Since then I've had no end of trouble with gear shifting. I can't get to the first or seventh sprocket on the rear and the third on the front. I'm sure it's quite easy to adjust but I just can't quite get the hang of it. Do you have some basic tips for getting my gears back in full working order?
Desperate in Sydney Australia and limited by a smallllllllll budget.
This sounds like some bent, mangled, or misaligned parts. I would have the frame checked. The rear der hanger is probably bent among other things.
My son's handlebars will not stay tight, the bike is only a week old, and it seems that there's not much left of the grooves. I had the store assemble it and the handlebars were tight when we first got it.
My guess is that the h-bar was not tightened. The bars come on a bike but unless the assembler knows to tighten the stem bolt, the h-bars will loosen and strip out. Without seeing it, I don't know how much damage is done.
I have Shimano 105 components. The rear gear cluster has seven gears ranging from 13 to 24. Can I buy a new gear cluster with a different ratio and put it on my bike? I would like to get something like 11or 12 to 24 or 26. Is that possible?
Unless you have a really old hub (pre '93, I believe), you can put almost any 7-speed cassette on there. HG50 cassettes are still available in 11-24. I would get one soon, because road and atb standards are now 9-speed, cheap bikes are 8-speed, and 7-speed will become obsolete real soon.
I recently got a terrific deal on a Kestrel 200 SCI from a local bike shop. It is a terrific bike. The original equipment crankset is a Shimano 600 double with 53/42 chainrings. Being somewhat up in my years and living in a hilly area (north of Pittsburgh), I am very interested in switching to a triple (say, 53/42/30). I believe that Shimano makes a set that is essentially the same, but is a triple. My question is, what is the most cost-effective, easy way to go about making this switch?
Your assistance would be greatly appreciated.
Gibsonia (Pittsburgh), PA
You can get the crank and bottom bracket cheaply enough, but I'm not sure what sort of shifters you have. If you have downtube shifters (probably not on this bike) then it's simple. If you're one of these guys who likes everything to match, you should still be able to get what ever kind of shifter you need to match your current set up, whether 8 or 9 speed. If economy is more important than vanity, you can get 105 front shifter which will shift 3 gears. Your total cost in parts will range from $275-$350.
I have a 1988 Univega Alpina Uno with a nylon or plastic Shimano rear centerpull break mounted behind the bottom bracket underneath the chainstays. Due to it's location, over the years the chain has chafed the end of one the brake arms to the point where it looks like the part that holds the hanger cable may break off. What's the best way to fix this problem? Thanks.
I would give some serious thought to a new frame. Anything with a U brake that has been ridden off road has got to be beat. There have been four generations of brake technology since your bike was produced! However, with budgets being what they are, one can still purchase U brakes that fit mountain bikes. You can't get cogs that were all the rage 2 years ago, but you can buy stinkin' U brakes! The Dia compe 990 is probably your best bet at about $40, or you can get away with a Tektro 909A for about $15. Either part will have to be ordered, as most shops gave up on U brakes when your bike was new. If you can't find these brakes anywhere, let me know, because I just bought a Tektro a few months ago.
I have a choice of buying two bikes, one is equipped with a 9-speed cassette, the other with the old 8-speed one. I heard that the new ones get gummed up and miss shift. Is this true? Which bike should I go with?
I certainly would not make a decision solely on 8 or 9 speeds. The 9-speed cassette works great; however, last summer, in order to be the first company with 9 speed, Cannondale half-assedly cobbled together some mountain bikes with a mix of road and mountain gear, resulting in an expensive, 9-speed bike with less of a gear range than the old 6 speeds! The frame is the thing. If your 9-speed bike has a crappy 7000 series, Chinese-made-in-the-USA-frame, and your 8 speed has an Easton program frame, then the 8 speed is the obvious choice. If you like the bike and are a sucker for the next big thing, you can always upgrade to 9-speed.
I've done a good job of building my own wheels for the last 20 years. However, I've had this rear wheel with an internal drum brake which is giving me fits. After the original spokes bit the dust (about 5 years) I rebuilt it with new spokes. I can't seem to get more than a year out of it before the spokes start busting out all over the place!
It's a Sachs drum brake with the drum flange just slightly bigger than the non-drum flange. I've always used a standard 3x spoke pattern. Are there any alternative patterns you know of that could help me out?
I'm not sure what to tell you here. Sometimes, with large flange hubs, the spokes cross over the flange, or have to be bent. Unless the spokes are excessively bent or are over tightened, they shouldn't just break, regardless of how they cross. I might suggest a 4-cross pattern, maybe even try all elbows out on the drive side, all in on the non-drive side. This is harder to do and requires a bit of careful bending, but sometimes results in a stiffer,if not stronger wheel.
If I used a wet lube, rode in the desert, and picked up a lot of sand, how would I clean the chain? What product should I use?
I personally use the Finish Line chain cleaning system and the degreaser provided with it. After using the product as directed, I either rinse it out and run it again with warm water, or I hose the bike off as the situation dictates. Thoroughly dry the chain (use rags, air, hair dryer, etc. ) and re-lube with your lube of choice. If your chain and cassette are more than a year old, and/or you have done extensive riding in sand and grit, it might be better to just replace the aforementioned items. If you do get a new chain, get a KMC or Sachs with a disconnectable master link. Then, you can remove the chain and soak it in degreaser or put it in your dishwasher to clean it instead of using the chain cleaning system.
Do you know where I might find information on either petrol driven or electric motors for bicycles?
Thanks in advance for your help.
The only product that I am familiar with is the ZAP (Zero Air Pollution) electric drive system. There are other electric systems on the market, and people still ask for petrol, which I really don't like because they stink, are noisy, heavy, and pretty much against all principles that principled cyclists hold. The ZAP system will charge itself to a certain extent, which avoids using whatever resource generates your electricity and saves money on your electric bill. It's heavy and expensive, but it seems well designed and efficient. You can contact ZAP at (707)824-4150. They offer complete electric bikes and drive systems that can fit almost any bike.
Could you please advise me about the durability of Shimano Acera Chain sets with average street use and no off road work.
I am specifically interested in any mileage statistics that you may be aware of?
My thanks for your help,
I'm not real sure which aspect of the coveted Acera drivetrain you are referring to, but as a near bottom of the line component group, it is designed to work when you test ride the bike. Any life of the system beyond the test ride is purely coincidental and entirely due to luck. There is no such thing as an Acera chain; if you have an acera bike, it probably comes with an IG 31 chain, which may actually break on the test ride (it has happened more than once). Some bikes in this price range get a Sachs chain which may outlast the rest of the drivetrain. Remember, regardless of how much you spend or how hard you ride, any chain will elongate by about 2500 miles (much less for ATB racing) and as the chain elongates, it deforms the cassette and chainrings. Acera chainrings cannot be replaced, so the elongation of the chain necessitates a crank replacement after approx. 2500 miles. Whether you spend $10 or $100 on a chain, keep everything clean and lubed and recycle the chain at 1500 miles (1000 if you are abusive, muddy, fat, etc.)
I purchased a Cannondale about a 1.5 months ago and the front brake started squeaking a little after. I don't know the correct term - v-brakes or side pull cantilever - is there a difference? But I can't figure out how to toe-in the brakes. Any help would be appreciated.
Generally, one can toe in V brakes by rotating the front of the shoe on the conical washers. The front of the shoe should contact the rear about 1mm ahead of the rear. My experience with most V type brakes has been that they tend to work best without toe in, as Shimano suggests. They are noisy, but toeing them in reduces their power somewhat. Also, you did not identify the type of brake we are dealing with. If it is an XT or XTR, it could need a "tune up kit" which reduces the slop in the parallel push mechanism.
I have a Mongoose bike. It is a S20 series and when I push down on the front suspension nothing moves. How do I go on adjusting this suspension. The type of Shock is called Ballistic.
You are a casualty of Wal-Mart. This is what has happened when people see a "Mongoose" in Wal-Mart and expect it to perform the same as the "Mongoose" that independent bicycle dealers have worked hard for the last 15 or so years to promote. Simply stated, shocks that work cost $150. Bikes that work cost $150. Bikes with shocks that cost $150 don't work. The fork on this bike is not serviceable. If you line up 5 of these forks, one of them may bowing slightly, and the rest of them will be stiff as rocks. These are installed for cosmetic reasons only. Also, what you have is an MGX, not a Mongoose. For the moment, the Mongoose line still gets a miniscule amount of respect; give the Brunswick/Wal-Mart/Dicks monage-a-troi (pardon my French) a few more months and they will be firmly etched upon the Wheelcraft fecal roster.
I've got a 7-speed internal hub and the cog turns the axle. Does this make sense? Under heavy pedal pressure the axle turns clockwise and wraps the cable up into the drop outs. I've tried lock washers and this helps some. Any ideas?
I don't have enough information to fully answer your question. I assume that you have a Nexus hub with a roller brake; a coaster hub might behave differently, as would a Sachs or Rohloff hub. What I can deduce is that something is very wrong. Either the bearings are way too tight, or there is some interaction with the braking mechanism. You can check the bearings by removing the wheel and turning the axle with your hand. You don't need a Ph.D. in astrophysics to determine that if it doesn't turn, it's too tight. Almost all of these hubs have a little rectangular washer with a tab that is bent toward the frame on the drive side. This washer must be between the axle nut and the frame, and the little tab must fit into the front (usually) of the dropout. If it is not one of these problems, then you'll have to find a shop that can work on whatever brand of hub you have. In this day of 27 speeds, rapid rise and grip shift, it may be difficult to locate anyone who wants to delve into this one.
I just purchased a HG90 13x26 7-speed cassette (black) for my road bike. The bike has Shimano RSX free hub, HG50 11x24 7-speed cassette and HG50 chain. I had called a couple bike shops and one of them told me that Shimano RSX 7-speed cassettes are not compatible with HG90 or HG70 7-speeds cassettes. Is the new cassette--HG90 13x26 7-speed--going to fit in my bike? Since I am going to get a new chain, do I need give a couple extra links to compromise the bigger cassette?
Unless you have a real old (3 or more years is old in bike years) hub--one with equally spaced notches and a thread on small cog, you can use almost anything.
The compatibility issue may arise from the UG, HG, IG question which really involves chains and other stuff, and really only amounts to a slight degradation in shifting performance, not what I'd call incompatible at any rate. Sometimes, when you put a compact cassette on a non compact hub body, there is some slop which can be cured by putting a thin spacer behind the first cog. The chain length may vary somewhat.
Tubular vs. Clincher?
I know the difference between the two. . . But what are the good sides and bad sides to each? I mean there must be some reason why tubulars exist. Clinchers seem so much easier and more practical than tubulars, so why are sooo many wheels out there tubulars?
This is an area that could be debated until the next big thing in tire/wheel technology comes around. Most people who use tubulars have used them for 20 years, or were forced to use them by some old fart who won't ride with anyone who uses clinchers. The fact of the matter is that there is no good reason to lay out the cash for tubulars. 20 years ago, you could buy a 300 gram rim and a 220 gram tire and have a very light tubular set up. Nowadays with all the litigation and extremes that we all must go to to prevent it, nobody makes a 300 gram rim. The weight of expensive clinchers and inexpensive tubulars is about the same, and the clinchers are much easier to deal with.
Due to said litigation, I no longer glue on tires. I've done it hundreds of times and I won't do it anymore, so you should consider the experience of the tire gluer when having this procedure done. Tubulars "ride nicer", that is if you have a stiff as a board aluminum bike, they take the edge off. And, if they don't roll off due to a poor glue job, they corner better. However, the risks, hassle, and expense of using them just does not make sense. Tubies can be repaired, but I would only fix (or pay to have fixed) a fairly expensive tire due to the time and or expense involved. Personally, I love tubies, but I cannot recommend them to anyone under the age of 50.
I've been working on my own bike and those of several friends and coworkers for years, but recently have started a new job as a full-time wrench. I've been on the job for about three months now, and I've noticed a slight allergic type of reaction on the back of my hands. There are small, raised bumps, rather like pimples, and they don't hurt, itch or otherwise. I am almost certain this is job related, as I went on vacation for close to two weeks and the problem went away, only to return again upon my return to work. Have you ever heard of this, and if so, any ideas to alleviate the problem? Although it isn't a bother, it does look rather odd. I have noticed in several bike mags, when they do tech updates, that the techs in the photos are wearing gloves. Any suggestions of mechanic-specific gloves (other than latex, of course)?
Thanks for all the great info,
I'm not sure what causes your malady, and I don't really know about gloves. I used to work in a shop with highly toxic Safety Kleen, and we used a product called Zep Barrier Cream. It's worth a try.
I have a 1994 Marin Bear Valley SE mountain bike and I cannot get the bb out. BB is Shimano LX. Any ideas ?
Either your bb was installed too tightly from the start or you have waited a little too long to replace it. In extreme cases, we sometimes cut the cups out. For this bb, you will first need to pound out the spindle and what ever else comes with it (away from the drive side---this is a very unsound method which I would never recommend, but sometimes, you have to get primitive with your bike). Then, you can run a hacksaw blade through and very carefully saw through the cup until it either caves in or spins free. Before you do something this stupid, make sure that you can't get it out conventionally, that you are using some sort of penetrating oil, that you are turning the correct direction to loosen, and that the tool is engaged and held firmly in place. Wrench Force (a.k.a. Snap On/Trek) makes the best bb cup tool and a bolt to secure it in place while you wrench on it. You should be working with at least one very good friend on this project.
We're replacing the bottom brackets in our tandem (he does his end, I do mine) and the should we or shouldn't we question is....anti-seize grease on the bb spindle where the crank arm attaches? aluminum crank vs. steel spindle and will it seize up since we now have da-ta-da-daaa sealed bottom brackets!? Help!
The spindle and the taper interface of the crank arm should be thoroughly degreased, clean and dry. Any lubricant on either part will allow the arm to slide too far onto the spindle, shorting its life considerably. This is a press fit, dependent on the proper amount of torque to press the arm onto the spindle. It is essential that these parts be clean and dry, and that the mfgr's torque recommendations are followed and checked periodically (usually around 200-250 inch lbs).
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