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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. The squeaky wheel gets the grease! (Please, no old bike & antique questions.) E-mail to firstname.lastname@example.org, subject "ask the mechanic," fax to 724-962-0952, or mail your question directly to Ask the Mechanic, c/o Wheelcraft Bicycles, 2185 National Road, Wheeling, WV, USA 26003. Andy will e-mail or snail mail your advice and we will post it afterward. Take a look at our back issues to find answers to all kinds of bike fix-it questions.
Winter 2000 Questions & Answers ...
How's it going? I am a winter biker in Maine and I was wondering about a few things...
1) Patterns of studs.
2) What do I want to use for a liner?
4) What kind of studs/screws should I use?
Thanks for your help,
I'm not real sure what an effective pattern for studs would be, but I would try to imitate what Nokian does, which is to put around 300 studs in their Extreme tire, with one on each of the two middle knobs, and one on each of the outside knobs. I guess this would depend on what type of tire you have to begin with, and what kind of conditions said tire will be subjected to. Some of the Nokian tires are less aggressive and only use about 100 studs spaced diagonally. Use a Mr. Tuffy for a liner, you can also use it in the summer for thorn resistance. I'd run about normal psi, maybe a little lower than summer pressures.
I have two bikes: a 21-speed road bike with Shimano RSX components with a 7-speed rear freehub and a 21-speed hybrid bike with mixed Shimano components (most notably Deore XT rapid fire shifters) with a 7-speed rear freehub. Both bikes have 130mm rear dropouts.
I would like to replace the wheels on both bikes. It appears to be hard to get 7-speed freehubs anymore. Do you have any suggestions. What will it take to upgrade the bikes to 8-speed freehubs?
Any suggestions would be appreciated.
Seven-speed hubs, freehubs, and cassettes are widely available. An 8-speed freehub will accommodate a 7-speed cassette if you want to go XT or better quality. You need 4.5mm of spacers to adapt a 7-speed cassette to an 8 speed body. 8-speed freehubs can be installed on 7 speed hubs as long as the correct spacing is maintained. In other words, you can unbolt your 7-speed freehub bodies, replace them with 8-speed, adjust the non-drive side spacing so that you have 130mm, stick an 8-speed cassette on there and ride away.
I can't get rid of the chain rub in the highest gears (large chainring, small cassette) it rubs on the outer plate of the deraileur. Do you have any hints?
This problem is usually either caused by too loose a cable or the high limit screw needs to be loosened, or both. You could have a bent crank, spindle, or chainring, or your front der could be improperly positioned as well.
Simple question for you.
I recently purchased a new road bike which features Shimano STI Shifting. My old bike had the shifters on the down tube. I am new to STI, and was wondering how to adjust the gears, when the chain is in between gears...(not quite sure I verbalized that correctly).
I am talking about the slight rubbing noise I hear when I shift into a new gear. On my old bike I used to be able to slightly adjust the levers so that the chain was properly in gear.
Any advice you may have would be greatly appreciated.
Most STI shifters have a trim click to position the front der. When extreme gears are used. To use this feature, you don't push the lever all the way over, but sort of nudge it to the left or right, and the derailleur only moves enough to trim, but not shift gears. I don't think that RSX shifters have this feature, but rely on a wide cage der to eliminate the problem.
I'm looking for bikes for my kids. They are interested in all purpose bikes for riding in our neighborhoods. We are leaning towards the mountain bike style since our roads are not the best (chip and seal and lots of cinders). My question is: What is a good brand with out spending a fortune? My kids are 9 and 11 and will only be in them a short time before they grow out of them. A locale shop sells Raleighs that are in the $200-$240 price range. Is this a reasonable brand for kids? I want to avoid the K-Mart and Wal-Mart type bikes? Any quick thoughts?
The majority of shop quality bikes for kids have the same features and virtually the same price. Our Fuji 20" and 24" wheel mountain bikes are at $189 and $199, and are as good as or better than other bikes at over $225. It's worth spending a little more even though they won't be used for very long in that you'll get service, and have a trade in for when kids outgrow them. I don't know of any store that takes Pacific bikes on trade. The Raleighs are probably fine, but they sound overpriced.
Can I upgrade a Specialized Epic Carbon frame with down tube shifters to STI? I currently have a 7-speed. Will an 8-speed STI lever work or will I need more upgrading? My main concern is the compatibility on the shifter housing of the frame.
You should be able to use STI on this frame. The STI kit comes with downtube cable guides which bolt to your shift lever bosses. For an 8-speed conversion, you'll need a minimum of RSX levers, rear der, and cassette, and if you want to use your existing wheel, you'll need an 8-speed freehub body and the appropriate spacers.
I recently got a couple of rims with Presta valves for my mountain bike, and I have only been riding them for 3 days. The first day I got two flats (one on each wheel) just below the valve, so I went to the bike shop, and they told me not to use the nut that comes with the tube when Im out riding, so I didn't. The second time (no nuts this time) I got two flats again, one on each wheel just below the valve.
So I went back to the shop, and they said the trouble this time was that I used a hand pump, and I must have been moving it I lot, so much that I damaged the valve. So I got a floor pump.
The third time, I put new tape inside the rims, I inflated them with the floor pump, and everything went smooth. I rode for about 3 hours, I have to say that I rode extra carefully, no bunny hops, no jumping or hitting rocks dead on. But the next morning when I took the bike out, I had a flat in the back tire. I took the tube out, and there it was again, a brake in the tube, right below of the valve, where the valve meets the tube.
I dont know what to do. I've been thinking how to make the hole on my rims bigger so it can accommodate my old friends--the Shrader valves. What do you think?
I'm not sure why you are having this problem. I would use the nuts when inflating the tire, and take them off if desired, but there should be no problems that you can blame on the presta valves. It is very simple to ream out the presta valve hole to accommodate schrader tubes, and the consequences of doing this are almost none.
I have a Shimano Nexus 7 hub on a bike I ride to work every day. Where can I get information on cleaning, disassembling, and reassembling the hub? It seems like it needs to be cleaned about every 2000 miles and I'd like to start doing it myself if I can. Thanks.
I would contact Shimano at 800-353-3817 and ask for the service manual.
My bike would not shift to the small cog on the rear derailleur. I turned what I thought were adjustment screws. I got the small cog but not the large one. Then with a few more turns of one or the other I got the large but not the small. Then neither. I finally stopped when I had the large but not the small, right where I started. I have no idea where to start to get this thing adjusted properly. Can you help? I can't find my manual.
I could use a little more information, but here are the basic procedures for rear der adjustment: 1)Disconnect the cable. 2) Rotate the pedals until the chain finds a cog to rest on. 3) If the chain goes off the small cog, turn the High limit screw clockwise. If the chain rests on a cog other than the small, turn the High limit screw counterclockwise until the chain goes onto, but not beyond, the small cog. Once this is achieved, turn the screw until you hear the chain rubbing the next to smallest cog, and back it off until the sound ceases. 4) Push the derailleur towards the wheel while turning the pedals. If the chain goes into the spokes, remove it and turn the Low limit screw clockwise, until the chain no longer goes into the spokes. If the chain does not go into the largest cog, turn the Low limit screw until it does, making sure that you cannot force it into the spokes. Allow the chain to return to the small cog. 5) Reconnect the cable. Whether you are using indexed or friction shifting, the cable tension could be the source of your trouble. If indexed, adjust the tension via either shifter or derailleur adjusting barrel so that the chain moves one gear per click ( too tight a cable will move or try to move 2 gears; too loose a cable will not move at all).
Many other factors can affect shifting. You can't have bent parts, gunked up cables, worn out chains, etc. Some parts, such as those found on Wal-Mart Mongoose bikes, were never meant to work and cannot be made to work even by a highly paid magician like myself.
I have a problem with my old Yeti MTB: It has 7-gear rear (130 mm axle) and nowadays, there are no derailleurs manufactured for it. Will a new 9-fold XTR or so work on it, too?
I think that the 9-speed ders should work ok. You can still buy XT and XTR 8 speed ders, and they would not be quite so expensive.
I have a problem. I am swapping forks from one bike to another. They are both AHEAD and are the same diameter--1". I swapped the rings that are on the bottom of the steering tube but I can't get the wobble out of either of the front ends. Are there different sizes somewhere? Any suggestions?
All the headset parts must be matched, so whatever came off one bike must be put on the other, not just the crown race, but the entire headset, bearings, cups, etc.
I have a headset question. Is there a tool required... or is this a job left to professionals?
I assume that you are either trying to adjust or repack your headset. If it is thread-less (aheadset), all you need is the appropriate sized allen wrenches. If it is threaded, then you'll need the appropriate sized headset wrench. If you are replacing or installing headsets or changing forks, then you need about $100 in tools, or risk screwing something up. You need a headset press, crown race remover, crown race setter, maybe a star nut setter.
I'm an aging baby boomer who knows little about post three-speed Raleigh bikes, and am interested in getting back into casual biking after many years. My usage would be 95% on suburban roads (1 to 5 mile jaunts), and 5% dirt park paths. I can afford up to about $450, and have been looking at hybrid and sport comfort bikes. I found your comments on aluminum bikes and Raleigh illuminating in my quest for the optimal bike. In looking at Raleigh/Trek/ and Cannondale's web sites, it seems the main difference in bikes in this price range is derailuers (Altus cheapest, Acera cheaper, and Alivio middle of the road).
Do you think I'm better off with the 700x38 of the Hybrid vs. the sport comfort 26x1.95?
Should I stick with the chromoly (e.g. on the trek 720 vs 7300 the steel is only about two ounces heavier)?
If you could make a recommendation on one or 2 best bikes that you think meet my requirements and price range, I would greatly appreciate it.
Look at a Gary Fisher Zebrano. It has a lot of comfort features, like the saddle, suspension seatpost, and suspension stem. Unfortunately, like most other companies, Fisher has caved in to market pressures and almost abandoned the high quality steel frame in favor of aluminum, but there is a lot to recommend in this bike. It is essentially a mountain bike with smooth tires and a higher geared crank. This allows you to cruise at reasonable speeds on pavement (unlike a mountain bike with slick tires--it's still geared too low), and can be fitted with knobbies and used fairly well off road.
I have a 1997 Fisher Nirvana with a triple-butted true temper frame, and it is an excellent all around bike. I wish they still made this type of frame, but if it doesn't sell, why bother?
I have a 1990 Schwinn Tempo that was outfitted with a Shimano 105 group. I used the bike a bit from 1990 to 1993, than rode it about 300 miles a year until now. The chainrings were the Biopace style (oval) and I would like to replace them. The rear is equipped with a 6-speed freewheel.
What type of chainring can be used to replace this awful oval design and can I upgrade to a 8 speed cassette?
If I continue to ride I would get a new bike in a couple of years but I would like to upgrade some components for a little smoother ride.
The chainrings are no problem. You can either specify Shimano replacements, or buy any of several aftermarket rings. If you have a freewheel, to upgrade to 8 speed cassette will require a new rear wheel. If your bike is aluminum, you should not spread the rear triangle to accommodate 130 mm spacing. If your bike is steel, spreading the rear to 130 mm is no problem. You could probably get away with a 4 mm spread on the aluminum if you absolutely had to, but besides being hard to do, bending aluminum shortens its already limited life span.
I have a question I hope you can answer. I am nearly finished with rotary wing flight school for the US Army. We have a long tradition of the last person in each class to "solo" in the helicopter, that is, to ride a ridiculous mock-up of a helicopter, based on a bicycle chassis, at the "solo party." Through the years it has become necessary to replace the "solo cycle" ...needless to say I have been tasked to do just that! I have two weeks to build a bike that has a functional main rotor and tail rotor.
Here's where the question comes in. I have no problems figuring out how to get the tail rotor to spin, but do you have any suggestions on a simple way of converting the rotating motion of the pedals or wheels to allowing the main rotor to spin directly over head?
Warrant Officer Marshall M. Dillon
I really don't have any good ideas here. You need either some sort of worm gear or a universal joint. You may try to do something with belts rather than chains, as you can twist them if needed for short term use.
I want to become close to an expert on quality biking (components, part names etc.) is there a book that could teach me so I am not so ignorant?
There are probably dozens of books out there. However, I can only recommend books on repair and maintenance. Since virtually every bicycle made uses Shimano parts exclusively, I might suggest getting a current copy of Shimano's catalog. This will tell you why an Acera deraileur only costs $25, while an XTR costs $99.
With due respect for Sram and Campy, you may want their catalogs too. This will pretty much cover major components. Frame materials and bike brands are such subjective areas that expert advice is tough to find (this may be the only source of such advice, as I am not selling anything on this site, nor am I paid by any manufacturer to promote anything. My opinions here often run contrary to products that I must sell in house, due to market pressures; I like US built steel frames, but I the public demands Asian made cheap aluminum.)
i was wondering how i would go about trying to unbend the rear wheel on my own.
Wheel unbending is probably best left to the experts. To an extent, tacos can be ridden out of the woods by whacking the wheel against a log, but this is only temporary.
Steel wheels are crappie to start with; the slightest dent or wobble is usually hopeless. If you have aluminum rims, truing is usually possible, using the proper sized spoke wrench and a truing jig of some sort. You have to know whether to tighten or loosen your spokes, because over tightening may produce a laterally true wheel that is not dished (centered) or radially true (round). If the wheel is actually bent, even aluminum rims rarely straighten out satisfactorily. People use the term "bent" to refer to a wide range of maladies, from slight lateral imperfections to totally destroyed wheels.
I have a question,
I need some advice on resistance trainers. I am planning to get one but I am confused about the different types: adjustable fluid, hydro force, variable resistance unit...etc. Which type would you recommend as relatively silent and give you a good workout.. Thanks...
My advice with trainers is the same as my advice for bicycles: Cheap stuff costs a lot. If you buy a noisy trainer with a flimsy frame, you won't use it, and if you do, you'll constantly worry about it giving way in the middle of a workout. The fluid drive trainers are really quiet at all speeds. Mags are fairly quiet until you reach a moderately high rpm. I really liked the Cyclops products; they disappeared for a while, and did have some warranty issues with their fluid units, but they have been purchased by Graber, and should back in stores this fall. Expect to spend around $200.
My left pedal makes a noise when I pedal particularly when I am pedaling hard. It makes the noise only once a revolution at the top of the revolution. Does that make sense? I removed the pedal and it was very easy to unscrew. Could that be the problem?
If you could remove your pedal by hand, it definitely was a problem, and if you rode with it this loose, you probably have a damaged crank arm. Noises emanating from the bottom bracket area are usually due to a loose or worn out bb, loose or worn out crank arm, or damaged or poorly adjusted pedal internals.
I have a Cannodale F700 with Shimano LX derailleurs (I think it's a '95). I recently had a new cassette, chain and center ring put on at the bike shop. When I got it back it was having a little trouble going into granny (under stress--when you need it!), so I thought I'd take a crack at adjusting the derailleurs. I don't have a clue how to do it. There are two screws, inside and outside. Can you give me advice? Are you supposed to adjust them in tandem? I screwed it up, now its pretty much stuck in the center ring. I'd like to get into more adjustments myself, couldn't find anything at the Shimano Web site.
There are essentially 5 aspects of front der adjustment: 1) low limit, which either keeps the chain from falling off on the small ring or prevents it from going onto it--this is usually the outside screw on newer stuff, identified with an "L", 2) high limit, same function as low limit only on the big ring, 3) cable tension-- if too tight, you won't get the small ring, and if too loose, you won't get the big ring, 4) height--must be app 1-2 mm from the big ring when in the middle ring, and 5) angle--front of chain guide must be parallel to big ring when in small ring.
Some derailleurs, particularly top swing types, do not work well with Cannondale frames due to the size of the seat tube and/or length of the stock bb spindle. Also, there are other factors, such as alignment, old cables or housing, worn out shifters, the brand, profile, and spacing on the ring you replaced, that can cause problems that standard procedures for derailleur adjustment will not solve.
I have a Specialized Stumpjumper FSR XC Pro that I purchased in March of this year. A few weeks ago the Shimano XT V-brakes started making very irritating noises (prior to this time they were quiet). I have used sand paper on my wheels to rough them up a little to change the frequency of the braking noise, I cleaned the wheels, and sanded the brake pads, but nothing is working. The brakes are usually ok at low speeds on dry terrain with gentle brake pressure, but whenever I hit them fairly hard they make a lot of noise. Also, when they are wet they make a ton of noise at all speeds, and all braking forces. How can I eliminate this annoying brake squeal?
Mark in Flagstaff
Brakes usually squeal either because they don't hit the rim at the correct angle, they are worn or contaminated, or something is loose.
XT brakes, with the parallel push doohickey, tend to develop slop, which translates to increasing brake noise. This can be fixed by what Shimano calls a tune up kit.
I prefer a good quality soft pad, both for quiet(er) operation and better braking, especially in wet stuff. Sometimes, replacing the Shimano pad with a Kool stop gray or red can really quiet things down. I don't like to toe in V brakes, as this diminishes their effectiveness. They should hit the rim flat, when viewed on both planes, and a slight toe in is ok if quietness is more important than brake power.
I have a 1996 GT karakoram with cantilever brakes. I recently purchased a new xt v-brake/shifter combo with fr and rear v brakes. How do I properly install the rear brake? The frame is set up with brake guides for cantilever style brakes only.
You need a clamp on cable guide. We sell the Alloy accents brand in various colors and sizes from about $8 and up. I have seen people try to rig this up, and you really should not try to use anything other than the cable guide. Of all things to be cheap about, $8 for a rear brake (something that can actually prevent death) is not one.
My wife and I just purchased a pair of Bike Friday New World Tourists which are suppose to have 7 speed Shimano RSX derailleurs. Hers came with the RSX, mine with something that looks like 8SIS stamped on it. Mine has a longer arm on it also (which I guess is a MTB derailleur). They said they were of equal quality. I am ignorant of the different quality levels of derailleurs, so I don't know if they are equal or not. Also, what is the difference between (advantages/disadvantages) of the shorter road bike deraileurs and the longer MTB derailleurs. Our use is mostly on road.
Sounds like you have an Alivio der instead of the rsx. The rsx does cost about a buck more at the wholesale level, and neither der rates a weight in the QBP catalog (either too heavy to print or too cheap to consider the grammage). Road length cages are usually lighter, and possibly slightly less sloppy when used within the recommended limits. ATB cages can handle a larger variety of chainwheel sizes, but should perform as well as road ders for what you have.
How can you tell if your bike downtube is threaded or thread-less? Can you install a thread-less fork into a threaded downtube? Why is it that you recommend against buying anything for anything other than a 1-1/8" downtube? I have a 1" downtube. Is there a danger for installing a 1" thread-less rock shox into a threaded 1" downtube?
The steerer tube of the fork is the part that can be threaded or thread-less. The downtube, hopefully, is securely welded to the head and seat tubes. Threaded headsets are usually found on old or cheap mountain bikes. If there is a stack of things that look like nuts, with flats that a wrench can fit on just above the head tube (below the stem), it's threaded. If you can move the stem up and down, it's threaded. If the stem is clamped onto the steerer by at least one or two pinch bolts, it's thread-less. 1-1/8" thread-less has become the industry standard. Try buying a SID, Superfly, or Monster T in any other size. Chances are if you are buying a used mountain bike with a 1" steerer (exception: Bontrager), it's too old, or too cheap to be worth upgrading, and your selection of available forks will be very limited. Threaded or unthreaded forks are interchangeable, but you must install the proper type of headset, and use the appropriate stem.
I just bought a '97 Shimano XTR front derailleur, which I plan to install on a '99 Fisher Kaitai. Will this work? My understanding is that there may be problems because the largest and smallest stock chainrings have too few teeth (are too small, essentially) for optimal shifting performance with the XTR. I think these chainrings have 42 and 22 teeth, respectively.
Any truth to this? Thanks!
The XTR deraileur is designed to work with standard (non-compact) chainwheels, with less than 44 teeth on the big ring. If you use it on a compact crankset, it will not shift as well as it should, and the chain may drag in certain gear combinations. Many people think that since XTR is the most expensive, it will enhance shifting and performance. In this case, you would be much better off in terms of expense and performance to use an XT designed for compact cranks. While your at it, replace that stinkin' Alivio crank!
My son just bought a Huffy Ironman mountain bike with 21 speeds and index shifting. It has the problem of shifting on the front sprockets. The shift system is labeled SRAM and is an index shifter. When he clicks the from derailleur from gear 1 to gear 2, the chain actually goes from gear 1 to gear 3. When he shifts to gear 3, the chain goes off the outside of the sprocket. How do we adjust to correct this overshift?
The level of quality of these components, including the frame, almost always causes shifting problems that can never be resolved. Keeping this in mind, aside from probably being too high (over 3mm) and not parallel to the chainrings, your front derailleur needs its high limit screw turned in so that the chain only comes off 3 shifts out of 10, rather than every time. It will still come off, but you can probably cut down on the frequency and still get into the 3rd ring once in a while. It also sounds like the cable is too tight. This would cause the chain to go into 3rd when you want 2nd.
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