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Ask the Mechanic
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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 firstname.lastname@example.org, 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.
Summer 1999 Questions & Answers (from our "Wise Old Wheelsmith")...
i just brought a bike recently and i wanted to change my front derailleur. they asked me if i wanted top swing or bottom swing. i want to know what is swing and what is are the differences? another question is.. i want to buy a fork and i want to know how to tell if it's threadless or threaded and how do you measure the diameter?
Older style derailleurs are bottom swing--the pivot is below the clamp. Top swing is a relatively new thing, the clamp is below the pivot, and this seems to work a little better, but not with all frames. You really only need to worry about whether the cable comes from the top or bottom and the clamp size. Threadless forks have clamped on stems, and threaded forks have quill stems. Use calipers to measure the diameter of the steer tube.
What are the most important parts of a mountain bike? Is the Raleigh M80 a good bike? Any other recommendations?
The frame is the most important part of any bike, and most Raleigh's fall miserably short in that department. They make the bike seem like a better value by putting above average parts on cheap frames. You can upgrade everything on your bike, but a heavy dead weight frame will always be just that.
Also, Raleigh has always taken advantage of domestic content laws, which allow them to stick an American flag and the words "made in the USA of foreign and domestic parts". The frames are make in China, and all the parts come from Asia, but since a crew of illegal immigrants dust them off and stuff them into boxes in Washington state, that constitutes domestic production. But enough rant.
Most folks must make several compromises when purchasing a new bike. Unfortunately, price is usually the driving factor. If you buy a cheap department store bike, you are wasting money, because you will not use, and you've already figured that out because you're looking at Raleigh's. I would try to find a closeout from 1997 or 1998 in a better quality frame. Forget V brakes and 27-speeds. Look for a good quality, light, all-chromoly frame, or a 6000 series (not 7000) aluminum frame, and consider all the parts as replaceable. We've sold a few '97 Gary Fisher Marlins for under $300, and these frames are worth upgrading, which is a lot cheaper than buying a bogus frame and replacing the whole bike.
Can you tell me what are the long-term effects of using narrow tires on wider rims (road bike)? I am trying to avoid having to buy new rims. College is sucking the money out of me :-( .
The ISO number (something like 25-622) on your tire should between 1.4 and 2 times the rim width. If you are not within these limits, aside from the difficulty in mounting tires and tubes, you risk flatting and/or rim damage, because the rim is not adequately covered by the tire. Most likely, if your bike came with 700x28 tires, the rims will be fine with 700x20. Old mountain bike rims usually do not work well with 1.25 or smaller tires.
Why do I need new levers when i switch from cantis to v-brakes? I have full sti XT circa 1996 and so I need to buy gear pods, levers and brakes. Can I get away with just brakes and keep my old levers/geapods on?
V-brakes must be used with compatible levers. They will not work properly because the standard canti levers won't pull near enough cable to properly engage the linear pull brake. You can use adapters, such as the QBP travel agent. These work well, and unless you need to upgrade other drive train parts, will save quite a bit of cash.
I took an old frame from a bike, put new tires, adjusted the hand brakes (rear), sanded all the rust off, and spent a lot of time fixing the bike up so I would have it for jumping ramps at the park with my friends. The next day the bike was stolen off my front porch while I was at school. My Mom's friend gave us another old bike but this one has pedal brakes. I want to fix this bike up for jumping, but I need hand brakes. Can this be changed? I put all my money into the other bike so I don't really have any to spend on parts till I can earn some more. If you can help I would appreciate it.
You can simply put a hand brake on the bike for under $20. In order to get the freewheel action, you'll need a new wheel, which will cost at least $40. If all you want to do is jump the bike, why bother with brakes at all? (that's a joke, son)
What size tubes are usable for a 700 X 40 C tire? Many thanks.
Lauch and Sandy McElhaney
Lauch and Sandy,
Several sizes will work, but you want to be as close as possible to 700x40. Most companies make a 700x35-40 size, which is roughly equivalent to 27x1 3/8. If you have to choose between a larger or a smaller tube, smaller is easier to install and less likely to pinch flat. However, like everything else in the bicycle business, some know it all weenie will tell you that using too small a tube will lead to its premature demise as the seams get stretched. Let's see--the reason we use rubber for tubes is its ability to stretch, therefore it must be stretched to work. So if we stretch it, it will die. Possibly the use of a 700x18 tube may result in stretch related failure, but I bet it would take as long for that to happen as it would to run over a piece of glass and flat. Does this make any sense? I have to listen to this kind of debate over minute details all the time, and sometimes, you get kind of loopy.
I have a 1989 CILO 12 speed road bike which has a frame that fits me perfectly and still performs well. However, I would like to upgrade both the cassette and the chain rings to increase my gear ratio on both the high and low ends. I like hills, but the low range on my current set up has me standing on just about every hill. I would like to go up to an 8-speed cassette and add a third chain ring. What kind of problems do I face, and do you have any suggestions?
Web Systems Designer
Systems and Support Services
Yale University ITS
I'm not sure about what is on your bike, but if it's a 1989 vintage, it would be best to replace the whole works. About the only problem $800 in parts won't fix is the rear end spacing. If it's steel, any shop should be able to spread it to 130mm. If it's something else, enjoy your 12 speed. You could make significant changes in gear ratio without a complete replacement. a triple crank and new derailleurs will make a huge difference in low range without having much (if any) effect on high range.
Both my front and back brakes lock up on the tire rim after one squeeze....how do I rectify? Thank you, sir.
I really need more information to answer a question like this. Do we have a road bike or a mountain bike? If mountain, does it have cantilever brakes or V style brakes? Is it new or old? Are the cable housings full of rust and crud or new and clean? Do you have the innovative shimano Altus breaks that brake after about 20 uses? Are your brake shoes deformed so that they stick to the rim when applied? If an old type sidepull, is the center bolt too tight? Is only one side stuck, or both? If only one side, then it could be that some sort of centering device is not adjusted. The possibilities are endless, and my best advice given what we have to work with is to take it to a good mechanic.
I have a 7-year-old Trek 1200 aluminum frame road bike with 10,000 miles. It's been a great bike and I still enjoy riding it. My question is: "How long can I expect this frame to last?" I suspect the answer depends on how it is treated, but are there any general rules of thumb to determine when it's time to replace a bike prior to some sort of failure/accident?
Thanks a bunch,
All things are transitory, especially aluminum frames. The lawyer answer to your question is "Replace the frame last year, and for liability reasons, do not sell it." I generally don't recommend keeping an aluminum frame past 5 years if it is ridden hard (this usually only applies to ATBs). As for road bikes, I would carefully inspect a bike of this age twice a year for cracks, smut, etc. Dents probably are not serious, and I believe that you have one of those horrible bonded (read glued) frames, which develops cracks between joints in the paint that don't necessarily indicate trouble, but can look scary. If the bike has been crashed or bent at all, or if you are at all concerned about its safety for any reason, replace it. My rule, which most cyclists are too cheap to follow, is to replace aluminum road frames every 8 years, or app 10,000 miles.
Another factor aside from safety is performance. Aluminum is prone to cyclical degradation, meaning that each time a force is applied to the frame, in weakens minutely, and each minute weakening builds up until the point of failure (metallurgists and physicists, I apologize for this oversimplification, but this is bicycling, not rocket science). Between the time that your frame was nice and stiff and the time that it ultimately breaks, the tubing, particularly the stays, are being fatigued and are no longer as stiff as they were.
Do you have any knowledge of anyone who has built an extended frame where the rider lays on his stomach, feet extended straight out the back, for hard surface, high speed?
No, I haven't heard of such a death defying appliance, however, you could probably ride a street luge upside down. Andy
I am considering upgrading my Trek 2100 to STI shifters. Some of the newer equipment is described as "Flight Deck." What is the difference and is there that much advantage over the regular STI levers?
The levers are identical except that the Flight Deck-compatible levers work with the Flight Deck computer. If you ever plan to buy one of these, then you'll need the appropriate levers to control the computer. (I'm sure that somebody out there is trying to splice together a Flight Deck to a Cateye Solar, but my advice is to use stuff that works together). You'll also need a 9-speed drive train to use any of the new stuff except RSX
I work for a Department of Energy Contractor at the Oak Ridge former K-25 site. We have a fleet of Bridgestone NB-26 21-speed Mountain Bikes for use around the site. I rely very heavily on my bike for transportation. Each bike is equipped with Shimano Altus index shifters and Altus C-20 derailers front and rear. Our budget has been cut and no longer provides maintenance and upkeep for these bikes. So, I have been doing my own maintenance. However, this is the first experience I have had with index shifters. The rear derailleur cable recently broke. I did not know how to replace the cable, so I took an entire shift assembly and cable off a "parts" bike and put it on my bike. Now, the index shifter does not work when shifting to the large hubs. The shifter clicks, but the derailer doesn't move. After the shifter has indicated it has moved about three gears, the derailer will move these three gears all at once. There is no problem when going down to the smaller cogs. I have never had problems adjusting derailleurs before, but this bike has me stumped. Also, for future reference, can you tell me how to change the cable in these type shifters?
Terry Harmon, NRRPT
Kelly Scientific Resources
Oak Ridge, TN
It sounds as if your cable is too loose. This can be adjusted on the fly via the barrel where the cable exits the shifter, or in extreme cases, should be pulled tight at the derailleur. Other possibilities include damaged cable housing, bent derailleur hanger, or defective shift levers. The cables are usually replaced through a small opening in the shift lever body. Sometimes, this opening is left open, sometimes it has a rubber plug, and on some models/years, there is a small access cover held in place by one or two small screws.
I have a 1993 Trek 7000 which works great (I've added V brakes and suspension fork) but I could use some lower gears. The mechanic in the shop said he thinks I shouldn't put the money into the bike (the entire drive train is worn) but should buy a new bike with lower gears. I don't have that much money, and anyway, I really like my bike, so I can change the parts myself. Can I go from 26-36-46 chainrings to 22-32-42, (Deore LX top pull derailleur)? As far as the cassette goes, I have 11-28 Hyperglide C, and my catalogs show the Hyperglide C available only in that. Can I use a Hyperglide (no C) which comes in other sizes? I've seen HG-70 and HG-90 cassettes listed, what's the difference? Also, I see HG-70 and HG-91 chains listed. Which goes with which? My rear hub is a Shimano STX Parallax, and rear derailleur is Deore LX.
First of all, you have a 6-year-old aluminum bike, which, if it has seen very much off road use, is very near the end of its safe useable lifetime. Second, you have a bonded frame, which was a mistake in the first place. If you insist on upgrading (incidentally, new aluminum frames really aren't very expensive) this borderline deathtrap, get a compact crankset (20-32-42) and corresponding front der. Your existing drivetrain can probably handle up to 30 teeth, possibly 32. As to the IG, HG, UG designations, I often find it useful to ignore them. These systems do work best with a total IG or HG package; however, I have not seen any explosions or deraillments due to mixing IG, UG,or HG components. Buy a Sachs or KMC chain, as they are less prone to user error during installation and last longer. You can probably buy a new bike that outperforms yours in every aspect for under $600, so I would have to think long and hard about dumping money into this one.
I have a 1994 Bianchi Eros with a standard threaded headset. Is there a way for me to install a double shock fork on this bike at 700c? Does someone make a 700c double shock fork? I would like to turn this bike into a "city bike" that would smooth out the rough roads. And while on the subject, would adding a seat stem shock post relieve some stress on the rear wheel on rough roads, or would only a rear suspension and/or different wheels (say 26") and tires do this?
There are several suspension forks to fit 700C bikes. The Rock Shock Ruby series is probably the best and most expensive. I would consider an RST fork for this bike. I think they can be had for about $135-150, and the quality is quite nice. Seat suspensions are usually viewed as comfort items. Recently, Travis Brown has been winning mountain bike races with a Thudbuster, so you might say that they positively affect performance. We've sold several different types, and no one has complained about any of them. You must make sure that you can have about 2.5" of your seatpost exposed, or you won't be able to get your seat low enough with the suspension post.
I'm about to rebuild my wheels with Sun Rhino rims and came across a refernce for a 4x lacing pattern. How do I differentiate between 3x and 4x ? It is the number of spokes a given spoke crosses on the same side, correct? How do I lace for 4x? I think I have 3x in the front and back and would like to add a bit more strength to the rear. My mass is 110 kg. (230 lbs.).
Thanx in advance,
4x means just that: each spoke crosses 4 other spokes on its way to the rim. Sometimes, this pattern is tough to do because of flange sizes and angles. It does create a stiffer wheel, but for most people, I don't believe it is worth the trouble. We sometimes use 4x on the drive side and 3x on the non-drive side. You'll need longer spokes, and a bit more patience.
Trying to break loose 1/4"bolt with 6mm phillips head. Bolt was installed with thread lock compound. Any suggestions?
Some threadlockers must be heated. Use a high powered hair dryer, or indirect heat (we usually don't take blowtorches to bicycles). I sometimes use an old handlebar to increase the leverage on the allen wrench, but you must make sure that the hex fits tight.
I broke a rear spoke and must remove the freewheel and the spoke protector to replace it. It is an old 10-speed (bought 1982) with a Sun Tour freewheel. I have managed to take the gears off (boy are there alot of ball bearings) but since it is not a cassette design I don't know if it is a spin off or if it is held on by a shim or boss. I would hate to twist and damage something.
What do you think? Can I still do this job by myself? Remember it started off as only a broken spoke.
You should not have taken the freewheel apart. Expect great difficulty in reassembling it. You need a Suntour freewheel tool to remove the remains of the freewheel. It is either a 2-prong or 4-prong tool. There are no substitutes.
I have a Cannondale F400 with a stem that is too long. (120mm on smallest Cannondale frame.) I looks to be like the steerer tube diameter is 1.555. It doesn't look like there are many options for a shorter stem with maybe more rise than the 15 degrees I already have (70 to 90mm would be about right).
Any ideas for alternatives? Also have you run across any good documentation on the adjustment and maintenance of the HeadShock suspension forks. Cannondale doesn't supply anything with the bike.
Sources for HeadShock stems are fairly limited. The widest variety is available from Cdale. Offhand, I'd say that they do not offer anything this short, but you can call them to find out (800bikeusa). They like to make short TTs and compensate with long stems, which makes for some squirrelly handling. The HeadShock thing is best left to the experts. It is very difficult to work on and you need Cdale specific tools. Manuals are available, perhaps you can ask them when calling about stem lengths.
Andy the Mechanic,
I took apart the rear wheel of a bike with a coaster brake and am having considerable trouble putting it back together again! Please help.
Confused in Kalamazoo
You should have taken a picture of it before you ripped it apart. Since there are several configurations of CB hub, it would be difficult to specify what to do here. They generally only fit together one way--with the shoes on the clutch, slip the hub over the shoes (using the end of the hub that fits over this side).
I am considering purchasing a used Trek Y22 bike. I have heard that the OCLV is somewhat prone to fractures. Is this true and if so, is there a way to detect their presence before I buy? Thanks.
Probably the only thing worse than a used full suspension bike is a used carbon fibre full suspension bike. Full suspension bikes are likely to be abused by large people who think that if a bike cost more that $1,000, it should be able to withstand incredible abuse with no maintenance. Such behavior led Trek and Cdale to rescind lifetime frame warranties a few years ago (I understand that the new, improved OCLV frames now have the lifetime warranty). I know what people do to these bikes, and I would never buy a used one unless it was ridden by a little old lady to church and back. In fact, I would not buy a used full sus unless it was Ti or I knew exactly where it has been and who it has been there with.
I know a guy who bought a CF road bike which had been struck by a car. I advised him not to, but since he was a doctor, he had it X-rayed and thought it was ok. After about 3 months, the top tube developed a separation. You can send frames to Trek for inspection. I would say that most versions of this bike are prone to cracks.
I am an "aging" soccer player, runner. My knees don't like these activities anymore, so I am going to switch to cycling. I want to do several centuries this summer, I am signed up to do TOSRV but I dont think I am going to become interested in racing.
My question: What frame/bike would you recommend. From what I have gathered so far Aluminum is at the bottom of my list. My choice should be between steel and carbon.... I have searched the net for a used bike ( I thought it may be a better way to start out) and almost bought a 3-yr-old Trek 5200, but it slipped away....
What do you think? Steel or carbon... any brands
PS. I need a 54cm, I am 185lbs, athletic, and have always played sports.
Steel is by far the best choice. It is more comfortable, repairable, and will last as long as you will. CF and Al have limited lifetimes. Get a Lemond Zurich. It is a very good value, and I wouldn't hesitate to buy a used one.
I removed the front wheel of my new GT ricochet mountain bike today, and when I reassembled it, the retracting spring tension in the v brake calipers was almost non-existent. How do I fix this?
You may find this hard to believe, but I don't know every spec of every model year of every bike manufactured, so I don't know what kind of brakes you have. Most of them either use a tension screw on both brake arches, while some use a tensioning device which requires you to loosen the stud bolt and tension the spring with a flat wrench. If you have a spring which extends to near the end of the arch like most Shimano and knock off brakes, sometimes this spring gets unseated, and sometimes you can increase tension by bending it away from the arch.
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