As an experienced cyclist with a lot of tandem experience: you are way over thinking this whole thing.

Assuming both of you are adults and not complete klutzes, you'll have it figured out well enough in a few minutes of trial and error. If you're not both adults, you'll still figure out within a few extra minutes.

Getting to be real slick starting and stopping instantly takes awhile to develop as a team, but just getting going is pretty easy. As andy256 said, the captain can ride around on it for 30 seconds to get a feel for it, then add the stoker.

Two of your comments to address:

The stoker can't just maintain "some" cadence, they have to maintain exactly the same cadence as the captain, unless the tandem is very fancy. Normally, both cranks are always in sync. It will be up to the team to manage it between themselves what the ideal cadence is.
The stoker should not maintain any balance per se. This is one thing some teams struggle with early on. The stoker should always be sitting 'upright', in line with the plane of the bike. The stoker should not lean to help steer. All steering is to be done by the captain exclusively. Attempts to steer by the stoker leaning can make it difficult for the captain to control the bike and maintain balance.

Also, while the captain is in control, the stoker is in command. The stoker decides how fast the team goes, where it goes, when it stops for a snack or to take a picture of a puppy, etc. The stoker has no control of the bicycle whatsoever, so by the stoker having control of the trip, will help make everything go much smoother.

Read http://sheldonbrown.com/tandem.html for instructions on how to get started, or don't, it's really not terribly complicated. And have fun, it's a blast.

  Wherever your relationship is going, your tandem will get you there faster.


I suspect there's a sort of nut on the back, with a slot for a screwdriver.  Difficult to reach without a specially shaped screwdriver, though.


safety of carbon fiber bonded to aluminum fork crown

Carbon fiber is a bit tougher to determine the safety of than steel or aluminum (where a thorough visual inspection normally reveals the serious flaws, along with checks of headset tightness and what not) - aside from a thorough visual inspection for cracks and damage all around, you really need a professional evaluation. Bikeradar has some tips for inspecting carbon fiber bikes - key points are bonding areas and essentially places where stress builds up and making sure the bike hasn't been crashed before. There are plenty of guides on buying used bicycles online and safety checks to perform on them.

As for lifetime, especially in the case of a high end carbon fiber bike, the lifetime is a function of how much it has been used. A crash can do a lot more damage to a high end carbon fiber bike than to a lower end steel/aluminum bike (due to likely higher speeds and weight savings). There was a previous question here which highlighted the lifetime of carbon fiber bikes (especially forks), which you should read. In particular, the article by Zinn is useful.


Flat bars are easier to learn on than drop bars (unless the latter have interrupter brake levers). At this stage low speed manoeuvrability matters more than efficiency. Some people with small hands apparently have trouble braking firmly from the hoods and getting into the drops is tricky for a novice (I dismiss starting in the drops as I've never got on with it). Then people like what they're familiar with if they lack a pressing reason to switch. Drop bars - as you said - need to be right to be comfortable, and the riders who get even the most basic bike shop fitting (not good enough for road bikes really) are in the minority.

Some people (e.g. me) like the extra height of flat bars for seeing and being seen over cars.

Cruiser bars (apart from being a horrible angle for your wrists if the top tube is on the short side and/or you have broad shoulders) lead to odd handling on some frame geometries, and make it hard to stand up on the pedals. So they don't work for MTB use. And MTBs have sold well since they went mass market (including in BSO form as evidenced in a recent question here). This may have something to do with the forgiving geometry - including the hands position. Don't underestimate the value of a bike that doesn't need much fitting (just saddle height) to be adequate.


Hill climb Time Trial pacing strategy for short steep hills?

Functional threshold power is defined as the maximum power you can produce for one hour. See for example, this blog.

Since you know that your events are much shorter, you don't have to be so conservative. And since you know your output for the approximate times those courses take,  you should plan that level of output for the race.

Even with that approach different people will have different ideas on whether to go at the same power all the way or keep some in reserve for the steep bits.

My thinking is that the slow sections are where you lose time, so keep some power in reserve for the steep parts.


Is a recreational bike sufficient for a 10-hour bike trip?

Your bike is definitely fine for this trip. I've ridden further on a cheaper hybrid bike fully loaded, and I saw a few guys who rode the same distance on scavenged department store bikes.

For a 10 hour trip, I would try to pack light. You should be able to fit everything in one pannier or a rack-top bag.  Make sure you have a few water bottles and food for the trip. If you plan to stop and eat, then you can carry a bit less.  Get some electrolytes too, either a Gatorade or electrolyte powders/pills for your bottles.

Make sure you bring a decent toolkit enough to fix a flat, adjust your brakes, and include a small adjustable wrench, bottle of chain lube, and a spoke wrench (probably have this on your multi-tool if you've got one) just for good measure.  Zip ties are always handy for repairs and hacks on the road.  Don't forget a couple extra tubes, pump, and a patch kit. I wouldn't rely only c02 for a long trip.

As for comfort on the bike, you will definitly want some padded shorts (and probably some chamois cream), some gloves, and eye protection.  A quality map as backup is nice in case your directions send you astray.

If you've got all that, then you should be fine.  Plan a couple stops to refill your water and restock on food if you're not familiar with the route.


8 speed free wheel with single speed crankset

You probably don't need to purchase a new crankset.

You can remove the the rings you don't need and simply add a new ring. You'll need to know the distance of the bolt holes of your current chainrings/crank. This is known as the BCD (bolt circle diameter) and you can usually find it stamped on the chainring. Common sizes include 130mm, 110mm, 94mm, etc.

Ideally, you'd want a chainring designed for single speed use. Rings designed for multi chainring drivetrains have pins, ramps and cut away teeth to help the chain smoothly move from one ring to another. Since the chain isn't moving, you don't need them.

You will also need single speed chainring bolts which are shorter than double ring bolts.

You may or may not need a new bottom bracket. In a perfect world you want the chain to be in a straight line to the middle cog in back. If you mount your single ring in the middle position of a triple ring crankset you'll probably be good to go. If you decide to go with a dedicated single ring crankset you'll likely need a new BB with a shorter spindle length.

Chain needs are more a function of the rear cogs/derailleur than the front. Any chain made for a 7,8 or 9 speed drivetrain will work fine.


Can anyone recommend a good maintenance-free rear shock?

All shocks require a little bit of love from time to time. A coil rear shock will require less maintenance than an air shock. The simpler the shock, the less maintenance you will need to do. I have only ridden fox in the back, but have never had any issues. I would recommend looking at the Fox Van R Coil. The Rock Shox Vivid would also work really well.

If you want to be able to pedal well, you should look at the higher end coils that have propedal, or airshocks.


The eyelets/braze-ons on my bike's seat stay are on the inside, not on the outside. Which Rear Rack will fit it, if any?

Most racks that use the common stainless flat stock type upper struts can be made to fit. Planet Bike Eco, Topeak MTX, and many more. Getting them on will require reworking the struts. Usually one must flatten the twisted end of the strut and put the twist back in further up to snake them in on arrangements like this without interfering with the brake cable. I always use a vise to do the flattening, dummy it up, figure out where the new twist needs to be and mark it, then put it back in the vise clamped at the mark and use an adjustable wrench to do the twist.

Tubus and the many racks that copy their strut design can usually work by flipping the strut carriers in opposite from normal, which means they then have to be accessed with a ball-end tip only. But it depends on whether they have a clear shot at that point, because the aluminum rod type struts they use shouldn't be bent around.


Road bike: can't shift down on front gears

Either the shifter, cable or derailleur is stuck.
Detach the cable from the derailleur, check the derailleur will move through its full range of motion. Tension the cable by pulling in it with a pair of pliers. Work the shifter and check the cable is payed out and pulled in smoothly. You can also pull the cable housing away from the shifter to expose the cable, grip the cable (gently) there, tension it and work the shifter. That should tell you what is jammed.
Often the cable gets stuck in the cable housing due to dirt, dried up lubrication or corrosion. Replacing the cable and housing is relatively easy and inexpensive.
If the derailleur is jammed you may be able to get it moving by applying a penetrating oil and pushing the cage back and forth to free the mechanism.
If the shifter seems to be the problem things can be a little trickier. The mechanism can be contaminated with dirt or corrosion, but sometimes shifters break and the only recourse is to replace them.


Best kind of bicycle for lower back issues?

I have a touring bike and I find it quite comfortable. But them again, I don't have back issues. It's a bit more upright than most road bikes, and possibly more upright than some hybrids I've seen, as long as I'm riding on the hoods. Try to find a place that rents bikes or will let you have an extended trial ride in order to determine if it would help fix your issues. Spending $100 renting a few different models for a few hours at a time could save you a lot of money and help you find a bike that's comfortable for you.


If you use a 10-speed cassette, you'll need to use a 10-speed shifter as the spacing between cogs needs to match the amount of cable pulled by the shifter. If you want to use a 9-speed shifter, then use a 9-speed cassette and take out one cog. Also, You probably don't want to take off the smallest cog since it's the one designed to mesh up with the lockring. Any other cog (including the largest) should be fine.


How can I avoid thigh chafing despite already wearing cycling shorts?

Since it's on the inside of your thighs, it's a good bet that our seat is too wide, or not properly adjusted.

A chamois crème will help, but I think the saddle change is a better idea.


Lift the front wheel off the pavement and spin the wheel so that it moves freely. If you are hearing a clicking sound and/or the wheel visibly slows slightly in conjunction with the sound then you may have a bearing problem. You could open it up and repack the bearings. By repacking I mean clean out the old grease and put new grease on the bearings. There should be enough grease that the bearings don't fall out of their ring if turned upside down but no more than that. Do not use oil. Grease is what to use for bearings. Close everything up and reinstall the wheel. It should be a little bit sluggish for the first few spins because the grease is getting settled into place. Should be good to go from then on.
Make sure you inspect each bearing for damage/rust. If either is found then you need to replace the bearings as well. Good luck.


Briefly:

1) yes, you can re-use the existing rim.

2) yes, you could shorten the existing spokes, but that would be expensive and foolish.

3) The installation is the same except now you have wires so you need to plug them into the hub too.

The main issue is (2). Spokes are usually only reused when the rim is being replaced with an identical rim (usually a new one for a worn one), and even then most wheelbuilders will prefer new spokes. Spokes bend a little as they're built into the wheel, and getting those bends in exactly the right place when you rebuild the wheel is effectively impossible. So you'll build the wheel, ride it a little, the spokes will bend back and you'll have to re-tension everything. Usually more than once. If you're paying someone to do this it's cheaper to just buy new spokes.

It's possible to shorten spokes, there are spoke cutting tools for this. They're normally used to make really short spokes (for putting a dyno hub into a 16" wheel, for example) but these days it's possible to buy spokes online in almost any size. But you could sit there and shorten all the spokes in your wheel. But again, if you're paying someone else to do this for you it will be more expensive than a new set of spokes. The tool is also much more expensive than a set of spokes.

If your rim is in good condition that's the bit to keep. If it is worthwhile, you may be better off selling the whole wheel and buying a new rim anyway.


Again - Following up with an opinion from a self confessed conspiracy theorist. Its about the money - follow the profit tree to its roots

When there were only 26" wheels a small LBS needed to have one wheel set in stock, and one sized tire ( maybe 5-10 variations). They would special order specific gear the the customer wanted and could easily stock enough to supply of the shelf something suitable for most customers most of the time.  The LBS had a range of MTB in stock - a few (maybe 10 bikes) would cover the requirements for 95% of his customers, and he would target a particular but broad market (Typically either Family and weekend riders, or 'cashed up cost doesn't matter wannabes and elite cyclists).

Now, the small LBS needs to stock 3 wheel sizes, in disc and rim brake style (6 wheel sets). They also need about 50 different tires on the shelve. The number of bikes required to be stocked by the LBS has also increased. He needs at least twice as many on the floor to remain competitive, but that much stock will drive him out of business. This is beyond the capability of a small LBS to do and still remain profitable. Mum and Dad now need to stock 3 different spare tire and tube sizes at home (Dads 29'er, mums 26'er and sons 27.5er').

Then there is the hype - 26'er is old, 29'er is so much better.  Followed by "well, you need a 29'er for XC but AM and downhill a 26'er is better - to be a serious cyclist you have to have one of each (with spares of course). Now, we have 27.5 - So, that 29er I sold you last year really is to big, and you know that 26 so last decade, well, have I got the bike for you.... It's only $$$, but I'll throw in a discount cause you are such a valued customer.......

In effect it is being pushed by the larger retailers, who can afford the stock level, to push the small LBS out of business. The  elite custom-builders where pricing is less of a concern will do very nicely out of it as well (No competing LBS focused on "reasonable pricing" will drive some people to them).

The net effect of all this choice is that the cost to us will skyrocket as the competition is shut down. We won't have competing LBS that offer personal service (except those that provide for the high end market) and will have to deal with the large, impersonal chain stores. The idea of talking to the mechanic will be seen as quaint, as the salesmen run the front counter. "Why talk the the mechanic, buy a new bike.... "

I believe the changes are mostly (99.99%) profit motivated to get more bikes moving from shop shelves to unused garage ornaments.


Will you be in Hokkaido?

We toured there extensively this summer and cycled through several dozen tunnels: here our findings. They might apply to other parts of Japan.

Newest tunnels on big roads have wide side pavements where you can (and possibly are supposed to) cycle. Safety is not an issue but you might have to dismount to make it on the pavement and it might be only on one side of the tunnel. Lighting is not an issue, we found them very bright.
Slightly older or smaller tunnels still on big roads can have a smaller side pavement, sometime with a fence/chain separating it from the cars. It might be higher than the road or level. Safety is not an issue but if you have a wide load steering can be a bit tight. Visibility can be bad. Bring strong headlights.
Old tunnels on big roads can have a very narrow pavement where you can still push your bike, or you will have to share with cars. You will have to make the decision before getting in, as you might have a chain preventing you to switch. We found just one of those in Hokkaido (Otaru) and while safe, it was unpleasant. Visibility was poor. Surface was mud and sand.
Tunnels on secondary roads you will have to share with cars.

Things to keep in mind: you could have locals riding the other way on a narrow pavement without lights, often peasant/fishermen who are hopping across for their errands. Or pedestrians. Be very careful as you  might see them at the last moment.

We also met several roadworks in tunnels, and a few times on the pavement, with the chain preventing you to get back on the road, but the crews were all extra kind and we sorted it out.

In costal/heavy rain areas you will find sand/mud banks at the entrance of the tunnel or sometimes in some points inside. Not necessarily visible and affecting your steering.

Concerning heavy breathing, tunnels (with one notable 10% exception on a side road on a dam) were never steeper than 6% and this helped. We did not find fumes to be extremely bad, and sometimes just cycling in towns on a slope at a traffic light, for instance, you'd get worst exhaust.

For planning tunnel location, length, and possible alternative routes, refer to "Touring Mapple" (which you should not ride in Japan without!)


Changing sprocket sizes: will front derailleur still work?

According to the Shimano Tech Doc it looks like 48 teeth is the maximum recommended size and 48/38/28 is the recommended chain ring combination.

The spec sheet also indicates that the maximum jump between rings is 10 teeth, so even if you could fit a bigger ring, you would have to replace the other two as well.

I believe the Kaitai normally comes with a standard 11-32 rear cassette.  Normally 11 is the smallest number of teeth that you will find, but Shimano makes a cassette model called Capreo that you may be able to find and use that goes as small as 9 teeth if you are trying to get a "bigger" gear.  The nine speed cassette ranges from 9-26T, so you trade the bigger gear on the low end for a gear that will be much harder to pedal up hills.


For anyone following this thread, please reference the following that may be of some help.

http://www.cadre.org/Merckx/

Below is a list of serial numbers and descriptions for a variety of Eddy Merckx steel frames.

Serials are of the form --. When looking at the bottom bracket, with the frame vertical and the headtube at the top, read this as upper left, lower left, lower right, upper right. Sort of a U shape. Why? Because it sets a standard way for me to record this info, no other reason.

Only when either a frame has been date verified by Gitabike or the Merckx factory do I add a verified model year. Model year bikes are begun production the year before, and as such its possible for their date code to be somewhat different than what the pattern suggests

Pattern? Right, the patterns.

The left side of the serial gives model and (sometimes) size information. Sometimes there are some other letters I haven't deciphered. But here's the general gist

Letter  Model
A   (Professional?)
B   (Professional?)
P   Professional
C   Corsa
X   Corsa Extra
T   TSX (Century)
M*  Strada

On frames prior to, roughly, 1986, the M probably denotes a multisport or other model, and does not necessarily denote a Strada. If there's a Columbus SL style sticker on there (either no tubing type mentioned, or an SL), then its probably not a Strada - which will have either a Strada or possibly a Cromor decal, depending on the year.

Sometimes things don't match up -- there are multiple Corsa Extras marked with an H, for instance. Things to figure out as the sample space gets larger. Originally, I thought an S designated a Grand Prix (made of Seven-fifty-three tubing), but has shown up on a variety of other frames clearly labeled as other models.

The left side number will give the last digit of the frame size. C5, for instance, would be a 55cm Corsa. On some frames, this might show up as 5C, but it means the same.

The right side of the serial is less easily defined. The numeric portion seems to be at least semi-linear. The two identical Grand Prix differ by 1. Other frames from the 88/89/90 time frame show numeric portions radically different. Its possible the number portion is sane for a given model type.

The final letter, however, seems to be at least a somewhat reasonable marker for timeframe. Its possible that the letter corresponds to the catalog which the model comes from -- Merckx didn't necessarily issue a new catalog for every year, so the letter may indicate the catalog year to which the model is designed.

In general, the letters from 1986/87 and on seem to follow a somewhat recognizable pattern. 84/85, part of 86 maybe, also seem semi consistent:

Letter  Date Range
Z   85
A   86/87
B   88/89
C   90/91
D   92/93
E   94/95*
F   96/97
G   98
H   99
* The E is a tough thing to deal with -- a misdating of a frame in the table below as a 94/95 by Gita, when it is very clearly early 80's, strongly points to E as 94/95 when its an appropriate looking/constructed frame. But the E also appears for frames in the early 80's. So use the list wisely. If you have over-bottom-bracket cable routing, you don't have a 1990's frame.

Some bikes seem to slightly predate or post date the range. These may be bikes manufactured to the new specs in the year prior to the model year -- Gitabike indicates, for example, the Grand Prix's in the list to be 89 model year, while a 10th anniversary TSX frame also carries the B. Might be a late 89 build?

This list is (roughly) in the order that they were probably produced, based on the letter, claimed date, as well as look + model. As earlier frames seem less likely to follow a pattern, I've placed them first. At some point I'll make tables that break out by frame-type, where identifiable or strongly guessable.

I'd also recommend reading this blog post I wrote about using frame details for dating. As in, figuring out what time frame a frame is from. Last thing I need is for the wife to have written evidence suggesting I take the bikes out more than her.

Something else worth taking a peek at is a series of blog posts I did for team color schemes. Merckx has sponsored a slew of teams over the years, in a variety of liveries.

Full table is at the link quoted above.


By this do you mean pedalling when unnecessary (and without increasing the bike's speed), for example, on descents?

I will do this on long descents just to keep my legs turning over and to prevent them getting too cold. But I will mix it with coasting.

There is a theory that keeping the legs moving will keep your blood flowing and help pump lactic acid out of the muscles. I can go along with this as I've felt the benefit, or at least I think I have.

I've also heard it argued that it's advantageous as regards making your technique smoother, but I don't think that's particularly proven. But no personal experience, I've never really concentrated on my technique to that extent.

Further, you can talk to racing cyclists who will often say that soft pedalling is preferred when riding in a peloton, purely because coasting implies to other people that you're about to hit the brakes. Again, no personal experience. I know some of the regulars on here are either racers or ex-racers, maybe they can confirm?

In terms of speed (or power) surely it makes no difference, purely by the definition of "soft pedalling"?


Is Trek Emonda ALR have thinner or thicker diameter tubing than the carbon model?

That's a question with multiple answers depending on what you're trying to find out.

From a distance the Aluminium and Carbon bikes look almost identical.
 Compare these two Emonda bikes and see which you think is CF and which is Aluminium.  Try to ignore the wheel rims and different colour schemes, barsm stem, saddle, seatpost, and that both have a carbon fibre fork.

SE Bicycles doesn't offer the Spoiler markup tag.....
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The top bike is the aluminium Trek Emonda , and the bottom is the carbon fibre version of the same bike.

Differences:

The CF bike has visually chunkier tubing over the AL one.
The CF downtube appears to be consistent thickness whereas the AL one tapers thinner as it drops to the BB
That head tube on the CF bike looks enormous compared to the AL head tube.
CF bike has thicker chainstays and seat stays over the AL bike
The seatpost clamp area looks quite different too - the AL bike has tubes that stop at the welds whereas the CF bike has curves merging one tube around a corner into the next tube.

Curiously, the only tube that looks the same on both frames is the seatpost tube.

However the hidden difference is that the CF bike could be as much as a kilo lighter than the equivalent AL one.


Compatibility of 38T chainrings to Deore crank

There is no difference between a Shimano 11-speed 1x chainring and a 10-speed one. There is a slightly difference in the OUTER ring(s) of a 2x or 3x chainset, because 11-speed chains are slightly narrower and this affects shifting from smaller to larger. However single speed rings are completely identical between 10 & 11 speed, so you don't need to worry about 1x '11' per se.
A 1x drivetrain is quite simple upfront with much less to go wrong in terms of poor shifting performance etc. Normally you'd have to worry about derailleur capacity etc. but with only one chainring that's not an issue.
The only considerations might be:

material - some materials will be lighter, which is not a major concern at this size, others might be more durable e.g. hardened steel
narrow/wide - this is a good idea for chain retention on 1x drivetrains
BCD & bolt pattern - you have noted this already
price - if you buy something very expensive you could end up spending more than a new chainset, where your current one is a simple one with solid arms, whereas more expensive models have hollow (lighter, possibly stiffer) arms. So you don't probably want something too complicated


Personally, I would install both levers for safety.

No matter how careful you are, eventually you will get in a situation where you need to perform an emergency stop when your hands are on the tops, even if you are travelling relatively slowly. (I have experienced inattentive pedestrians stepping directly into my path only a few feet in front of me.)

In an emergency stop situation you will want to brake with both wheels, and the front wheel provides more braking power than the rear.


What photos should I include in an ad of a bike?

Short version: As many as you can.

Slightly longer version:
I always include an overall photo from drive-train and non-drive-train side. In addition to that one of the cockpit and close ups of the drivetrain and brakes. That should include most parts of interest. In case of suspension photos of the sliding surface of fork and damper could be of intereset for potential buyers.


Long-arm vs short-arm v-brake linear-pull brake: understanding the sizing

I just measured some Tektro brakes that I have. The measurements coincide with a center to center distance. I measured from the center of the brake arm mounting hole to the center of the cable clamp bolt. One consideration is tire size. Larger tires may hit the brake cable on the short arm models.


Would a person standing on the top tube damage a carbon fibre road bike?

At the risk of getting beat up on carbon will give it a try.
CF seems to be a sensitive subject.

I don't agree with your assertion CF are engineered to be strong in certain directions and relatively weak in others.  They are designed to have different flex in certain directions - not weak.

If I had 4 bikes I need to use as step stools I would go with this order (and I really have all but aluminum):
1) steel
2) titanium
3) carbon fiber (CF)
4) aluminum

There is a bit of discussion and comments that bearing weight on the top tube is not a stress a bicycle is designed for (and weak).  That is a stress a bike must handle.  If I take a tube and hold it at both ends and try and bend it that is the same type of stress as if I took the tube and put either ends on rocks and pushed on the middle.  The primary force a top tube takes is bending from the ends.  If you watch the video you can see top tube bend and when it fails the two pieces are bending displacement.
Santa Cruz Bicycles - Test Lab
And you can see the CF held up pretty nicely.

CF takes criticism as it fails brittlely which is true but it takes a lot to get it to fail.

I would not want to ride any bike that would fail with my weight on the top tube as that is a scenario (crash or drop off) I expect and need it to not fail.

With that said there is not one CF.  A lot of variance in the construction / layout.
If you are going to ride a CF then buy a good one.

I don't mean to advertise a brand but Niner has 5 year warranty including racing.
I have crashed my Niner Air 9 Carbon hard and not even thought twice about the bike.
I use it for CX training at a local park and stand on the top tube to stash my jacket in a tree.

There is stuff CF is not good at.
Don't put a rack on a CF.
Don't take a hammer or bat or hard object to CF.
Don't take a drill to CF.
Don't over or under torque bolts.

I am just amazed at the slow acceptance of CF frames.
When CF forks first came out there was a lot a questioning.
But now CF is the dominant rigid fork.
A fork takes a lot of stress from a lot of directions.
People think CF is too light to be strong.

I get engineers are misunderstood (and certainly under appreciated) but a simple one foot drop landing on the front wheel is going to put more stress on a top tube than your weight. The frame did not even flex in the picture.  I would not ride a frame I could not jump on.


What are the advantages and disadvantages of riding a smaller Mountain Bike frame?

With a smaller frame, you will need an appropriately longer handlebar stem in order to retain the cockpit length. This will affect handling of the bike: it will feel more "lively", which can be good in some cases (tight turns, difficult terrain) or bad (less stable) - in most cases.
A smaller frame will be marginally less reliable, and more prone to break, due to bigger stresses in its structure; longer stem and seat post mean bigger levers to exert force on the frame. But this should not be a significant effect.

As a rule of thumb, a 17" frame is an inch or two too small for your size. I would not recommend taking the smaller one without actually riding it for a couple of hours and making sure it's comfortable for you.


Look on the inside of the crankarms, where the pedal threads into the crankarm, if there is a socket for a hex wrench. Cheaper pedals don't and I'm guessing these don't.

Pedals require a narrow spanner, as indicated by Willeke, thus an ordinary adjustable wrench ... could work but probably won't. Google around for pedal spanners to see how the professional ones look like.

Lastly, I once again agree with Willeke to try and oil them in place. Even if you removed them, disassembling a pedal can be a challenging and tool-requiring business.


How to re-tension front derailleur cable

Agree with others here - cables stretch only slightly, requiring one or two clicks/half turns of whatever barrel adjuster, either typically next to the headtube, or for the rear also where the cable meets the derailleur body. More than that, implies the cable actually slipped because the nut clamping it at the derailleur wasn't tightened enough.
  These are not complex issues, and every cyclist should learn how to at least make these basic adjustments, on principle to be more self-reliant, and also to free yourself from constant, costly, inconvenient trips to the shop. That said, the shop that did all the work should definitely follow up on what appears to be related to their work. Cables can also not be seated fully in the frame points etc. so another possibility exists there.


2018 Tour De France - schedule with start times?

The Official Tour de France website has this information. Alas, it's unlinkable but:

Select "Route 2018" from the top menu bar.
Click the stage you're interested in.
Scroll down to just above the map, where you see "Sport Side"*.
Click "Time schedule".

Times are given in local time, which is CEST (GMT+2).

* The TdF website has always had somewhat idiosyncratic English. I don't know why they don't just get a native speaker to write their English content.


I suspect it is one end of a pump holder. It holds one end of a pump. If my suspicion is true, there should be at the other end of the rack something to hold the other end of the pump. You compress the pump against a spring in the pump to attach it to the rack. This works only for pumps having a spring.
Presumably the pump that came with the bike (if it was an accessory sold bundled with the bike) has long ago gone missing. You may not be able to find a replacement pump of exact the same length.


Switching from a mountain bike to a road bike

You will find the differences are significant.

When you say a road bike, we understand a bike with drop handlebars. Drop bars give you a very different riding position compared to an MTB. Some people need time to adjust to the new position, and can have problems with weak or tired neck muscles.

An alternative would be a hybrid style of bike, with flat handlebars. This would be much closer to the riding position you are used to.

The thinner, smaller, slick tires will provide two more differences.

One is much less cushioning, so you'll feel bumps more. The other is they'll be much faster. So you'll ride faster and feel any bumps in the road more.

As a consequence, some people get sore hands or wrists.

The other main difference is how light the bike is. On any medium quality bike (or better) you'll feel like you suddenly got on an F1 bike :-)

When switching to road cycling, make sure you have well padded gloves to absorb road vibration. And the bigger the change in riding position from your MTB, the more gradually you should make the change. Keep the MTB and ride the new bike for a few days, then switch back. If you start feeling sore then give the new bike a break for a day or two.

It may sound like I'm talking road bikes down, but as a road-only cyclist I am keen for you to get the best out of the change. You'll quickly discover that each kind of cycling has it's own different pleasures.


Are BMX threaded headsets and other threaded headsets interchangeable?

No, they're not interchangeable. BMX 1" threaded headsets have an outer cup diameter of 32.7mm - they wouldn't fit in a standard road frame. Standard (ISO) threaded headsets have an outer cup diameter of 30.2mm - they'd fit loosely in a BMX frame.

Sheldon Brown's Bicycle Headset Dimension Cribsheet is a useful reference for headset interchangeability.


My bike won't shift out of 7th gear in the back

Assuming you did not have a fall and it was working well in the recent past and it does shift but not correctly then you just have to adjust the tension on the cables. What you are describing seems normal some adjustments on your bike are due after some use. If adjustments cannot fix I would then check the cable condition and derailleur function.

The cables needs to have a certain strech so it can move the derailleur far enough to reach all gears. And yes it is also not suprising that the strech changes when a rider is on the bike, your weight and motion streches the frame and cables and they may behave differently especially if not well tuned or are too old. You more likely just have to adjust - again, unless something out of the ordinary occured which is not mentioned.

Most bikes have a fine adjuster which can adjust the tension by just turning a knob (barrel adjuster) without tools even while you are on the road. If this is not enough just adjust the cable tension with tools. Then try all your gears to make sure all shift fine.

If your rear does not shift at all then this is an indication that your cables are getting stopped or impeded somewhere when the rider is on the bike. Run visually the cables from your shifter up to your rear derailleur and find where their movement seems impeded (especially if you have rear suspension have someone sit on the bike when you do that). For example some cable guides or ferrules may have been worn out on one end and when someone sits the cable runs through that part and gets impeded by the wear. If you cannot find the wear run full new cable set (should be fairly inexpensive).


Shimano 105 R7000 drivetrain makes crackling sound

It sounds like your derailleur indexing is bad. The 'crackle' is the chain trying to climb the shift ramps on the next largest sprocket then falling off.

It may be that your derailleur indexing is badly adjusted. You can run through a rear derailleur adjustment process and see if this fixes the problem.

You should also check that your derailleur is aligned properly. The derailleur hanger can get bent so that the derailleur cage is not longer parallel to the rear wheel. If you pick rear wheel of the bike up and look down the line of the chain you can see if the cage is grossly out of alignment if it is not parallel to the chainrings. A bike repair shop can check and re-align the hanger.

Another possibility is that the chain is catching in one of the jockey wheels in the cage. If you hold the rear wheel off the ground and pedal manually you should be able to see this easily.


i used a secondhand e bike kit but i cant get it to work

Can the connector on the motor be connected only in one orientation? (Is there a notch of some sort to prevent you from connecting it incorrectly?)

It looks like this connector is used for both the motor phase wires (3 of them) and hall sensor wires (5 of them). If you connect these incorrectly you risk damaging the hall sensors and the motor coils won't work correctly or won't work at all.

There are controller testers available online for example on AliExpress. They are quite cheap (approx 15 euro IIRC) and are perfect for your situation
 You can test the workings of the throttle
 Test your hall sensor and motor coils. Test the phase wire output of the controller etc. Makes it a lot easier to test.
-------

Link:
https://nl.aliexpress.com/item/4000327577472.html?spm=a2g0o.productlist.0.0.aabf53e5ZgR3Xv&algo_pvid=f085ff01-8b80-48f2-bb35-60c9350f4f92&algo_expid=f085ff01-8b80-48f2-bb35-60c9350f4f92-3&btsid=0b0a187b15824111666037870e2379&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

You can use a multi meter to test the continuity of your motor coils (test two of the three phase wires relative to each other and check if they have continuity, if they don't one or more of your coils are burnt out).

Some controllers have both a connection for throttle and a connection for pedal assist sensor. Check if you have both and which you are using (can be checked by checking the wire colors and comparing with similar looking controllers online (most likely on Aliexpress, they often include some information on what wires do what)).

If you have both a fore mentioned connectors you could try connecting your throttle to the currently unused connector and seeing if this works.

Most controllers have a wire which you have to connect to either the battery positive or battery negative in order for the controller to turn on. In my experience this wire is usually a thin red wire. To which side of the battery you have to connect it for the controller to turn on differs from controller to controller. Check if this wire Is present and if it is check if it is connected. It is often called a 'power lock' wire.

Most controllers have an output for connecting a light or alarm which outputs a low voltage DC such as 12V DC. If this is present on your controller you can measure if there is a voltage across this wire/connector and if there is you know your controller is in fact turned on.

You can disconnect your throttle and on the connector (the side that is connected to the controller) connect the red wire with the non-black wire (usually there is a red wire for 5V, black wire for GND and one more wire which is the signal wire). When you connect the red wire with signal wire it's as if you're giving full throttle. If you connect these wires and the motor turns you know your issue is in the throttle (throttle is faulty).

Check if your controller has wires to connect the brakes (some e-bike brakes have switches in them in order to signal to the controller that you are braking). These switches are called ' brake cutoff sensors' (among other names) and usually stop power to the motor when you activate them by braking. Some of these switches are normally open and some are normally closed ('normally closed' meaning the switch is closed/circuit is closed when the brake lever is not pressed and the switch/circuit is open when the brake lever is pressed).
If you have a controller which works with 'normally open' switches and you've got a short somewhere in your brake sensor wires (causing the controller to think that you're pressing the brake lever) the motor will not have any power from the controller since it will think you are braking..
or if you have a controller which works with normally closed switches and you do not connect anything to these brake sensor wires it will be as if you're constantly braking (but keep in mind this type of switch is much less common in these types of brake sensors if even available at all).

Possible steps you could take to try and find the problem:

1)

Check if battery outputs voltage and if so if voltage is high enough (above nominal voltage of battery pack or at least above approx 3 volt per cell in series (you'll have 10 cells in series for a 36v nominal battery pack).

2)

Check if the controller receives power from the battery, either by measuring voltage at the bullet connectors or by poking a hole in the insulation with your multi meter prongs (in the battery plus and min wires leading up to the controller.

3)

Check if (if present) the output for the light/alarm has a voltage output (for example 12V DC or 6V DC. If it does you know the controller is turned on. If it doesn't check the 'power lock' wire, if it is connected properly, if it is damaged anywhere.

4)

Disconnect throttle and short red and non-black (signal) wire of throttle connector (controller side). If motor spins when these are connected your throttle is faulty.

5)

Connect 'learning wires' if available. these are usually two wires of the same color on the controller with 2 individual plugs (one male one female) which fit together. when you connect them together the wheel should start spinning. If this does happen (if the wheel indeed spins) you know your controller is turned on, battery isn't the issue, phase wires aren't causing your issue.

6)

Check if motor connector can be connected in multiple ways and if so if it is connected properly (especially the 3 phase wires, the hall sensor wires can be left disconnected for now for this troubleshooting stage).

Try some or all of these things and keep track of the results. Add your findings to your question and let me know when you've done so and I'll try and help you troubleshoot. It's a lot easier when I've got some info to work with :)
Good luck!


Price difference between buying a bike in Europe (Austria) vs USA?

I would be in favor of waiting until you move. There is the possible problem of needing service work under warranty and the nearest dealer being some distance away. You must also factor in the shipping cost  along with the expense of disassembly and reassembly if you can't do it yourself. There is also no better way to start a good relationship with your local shop than by buying two bikes. The other advantage is being able to check out the terrain and see what type of bike you need.


Who has right of way at a staggered crossroad

Yes, this is a tricky situation. I think this section of the highway code should cover it, but is very light on details like this.

I think there are two ways to interpret the situation:

1. As two T-junctions a small distance apart, with you turning left and then right.

In this case it's a fairly clear cut - see rule 180. You've turned left, already on the main road and have priority over vehicles trying to join your lane, including ones turning right out of the road you're about to take.

2. As a normal crossroads, with you going straight on, the other car turning right.

For case 1, from Internet discussions like this from Yahoo and this from the RAC there seems to be little consensus on this. Many say that the traffic going straight on has priority, but then add that you have to give way to traffic coming from the right (as you would on a roundabout), which seems contradictory.

My opinion

I think this needs official clarification, but in practice it would seem sensible to interpret it like rule 170: "watch out for pedestrians crossing a road into which you are turning. If they have started to cross they have priority, so give way".

When at a give way line, all vehicles must give way to others not crossing the give way line. So if you arrived at the junction and there was no other traffic coming, of course you would start to cross. Being a bike you're usually slower than a car, so a car which later arrives opposite you at their give-way line should give way to all traffic already on the junction or the other road.

Furthermore, from the look of it this is a box-junction, so the car must not proceed until its exit is clear. In the image below the green car attempting to turn right is in a very similar situation to the one you mention.

If you both arrived at the give-way line at the same moment, then given the above image, you might still have the priority (de jure), but it's not obvious and my instinct is to let the faster vehicle go first.

As others have mentioned, us cyclists have to be careful as collisions are usually more serious for us. Whenever cars do show you consideration, always give them a wave or nod of thanks, even if you have priority.


Tiagra lever extremely stiff on new bike

As mentioned in comments you should take the bike back to the store and get them to fix it. I wouldn't even attempt a repair because disassembling anything introduces the possibility the store will decide you caused the problem.

However, initial steps for diagnosing the problem if you want to:

I think it's highly unlikely the that cable routing is the problem because the cable would hang up on both up and downshifts.

You can easily determine if the shifter or derailleur is the problem. Detach the cable from the derailleur, work the shifter. If downshifting is now free the dearilleur was the problem. If still stiff it's the shifter.

You can also attempt to manually move the derailleur from the smallest sprocket to the largest while holding the rear wheel off the ground and pedaling (you need a work-stand or a friend to do this, or possibly put the bike upside down on something that will not scratch the saddle or hoods). Be careful not to catch your fingers in the chain.


There's a couple points being covered here.
Classical cup and cone hubs use standard axles (M9, M10, 3/8" etc) that flex under compression from the QR. The cones are getting a little closer to one another.
Once you get into hubs that don't use standard QR axles, most of them are much stiffer and have little or none of the same effect. Almost all higher end hubs from recent years are like this. Even Shimano, who still uses cup and cone, use nonstandard axles on most of their nicer hubs and have for a long time now. You can adjust those to have some play and test how the bearing responds in the bike. Most of the time you won't be able to make the play go away or even change appreciably with force from a quick release, meaning you should adjust it to have no play off the bike.
Your second question is one of those topics that bike people might say whatever about but is more properly the domain of bearing engineers, but I'll try. Hub designs that aren't like you describe are then by necessity trying to play the game of having the shoulder to shoulder distance on the axle be exactly the same distance as the bore to bore distance on the shell. If they fail at this by too much you get excess preload. A lot of hub designs do work this way, but not all. Some designs eschew this by allowing the outer race on or both bearings to not actually be bottomed in the bore. BMX three-piece crank cartridge BB bearings for American shells are a poster child for this, although a lot of people don't realize it. Those shells are made with zero uniformity or precision of the exact face to face dimension, yet the BB kits come with a tubular spacer that's machined to be a certain length. The trick they are playing is that when you press it all together, one or both bearings unseat themselves in their cup. It works by the cartridges being overbuilt enough to handle being loaded this way without premature wear.


Any chance of identifying this tandem. (S/N T9012 737) Could be other numbers under cable guide. Manufactured around 1990 I think

According to this thread Bob is correct. His bike is a Gary Fisher Gemini. The tandem in the thread is a good match for Bob's bike.

From the thread

  I ran into a former Fisher employee at NAHBS this last weekend and was asking him about the tandem. All he could tell me was that the early ones were made in Mexico and weren't very well made. I suspect that yours and mine are later, Asian made bikes as mine, at least, seems reasonably well made. I'm still trying to figure out who designed it and decided to use the "uptube". I suspect that was the cheapest, easiest way to build it. Ritchey still uses the uptube design in their tandem, though Santana insists it makes no sense. At least it gives you a place to put a water bottle. The placement of the stoker seat tube cage won't allow the use of larger modern bottles. We use a clamp-on handlebar mount for the second stoker bottle. -- fxsvelo

later

  Serial number on mine is 19012-0707. It has (mostly) Shimano DX components; the catalog scans I've been able to find show Suntour XC on the 91-93 models. So maybe mine's an '89. Guess it doesn't matter too much!  -- rcschafer

I suspect he's wrong about the serial number based on the picture in the original question - it's probably T9012-0707

According to the Fisher catalogs for 1989 and 1990 the Gemini had a Shimano Deore II drivetrain. The Gemini was first sold in 1989, the last year was 1993. Fisher started using a Suntour derailleurs and a Sugino crankset in 1991.
Seems like Bob has a 1989 or 1990 model.


Is my six-year old touring bike worth repairing?

As LBS mechanic, I also would recommend to repair - the cost is sufficient. Your bike will be almost as new.
So if it's a bike that worth repair (like mikes mentioned), and your tires and derailleurs are in good condition yet, go for it.
If you know that you should replace tires or derailleurs soon, better is to buy a new one with all parts new and a warranty.

Edit: if you will anyway buy a new bike soon, you should consider whether you want to do all this repair, or a part of it will be enough.


In the end, it seems I had a badly applied patch that was leaking.

I dipped the tube in water (again) and there were small air bubbles coming from the edge of the patch, maybe one per second. I tore off the patch and installed a new one.

It leaked more when I rode the bike, likely due to the extra weight. When I wasn't riding it, the air loss was much slower which lead me to think that it had fixed itself. Also, my pressure checks were inaccurate, done with fingers only, which can't really tell the difference between 40 PSI (the minimum) and 75.


If the model numbers are the same, they will be the same parts built to the same specs. Of course, there are production line variations.

If there are slight variations in the model numbers, they may be the same or they may be slightly different (typically slightly cheaper) to prevent exact comparison to the regular part as Daniel R. Hicks said in a comment. This is because a manufacturer can do a large order for a part specific to OEMs which may be branded some way or slightly cheaper to them or not come with certain accessories or warranties which the manufacturer sources from other manufacturers (which can cut some costs, and possibly increase or decrease quality).

This ability to do bulk purchasing is the primary way that complete bikes are cheaper (they're buying 10s of thousands of cranksets or whatever without retail packaging or manuals or stuff, when you're buying 1 in a nice box with a warranty pamphlet and installation instructions and stuff, along with a markup for the shop). Naturally, its convenient to give the OEM and Retail versions different model numbers to keep things straight (for example, the OEM version's warranty is typically through the complete bike manufacturer, not the part manufacturer and may be shorter than the retail version, and it keeps stock easy to keep track of). This can be substantial - If you walk into Radio Shack for lets say a LM741 op amp, they'll charge you at least $1.50 for one of them (they don't do bulk discounts). My usual retailer for these type of parts, Digi-Key, sells the same part (possibly made by a different manufacturer, but I know to be of essentially same quality) for $0.70 each without the retail packaging (just cardboard boxes filled with foam and the chips in them) if I buy just one at  a time, and for $0.28 each if i buy in lots of 1000 or more. Thats around 19% of the price I would have paid at Radio Shack, for a bit different packaging and just getting it in bulk from a wholesaler (certainly, digi-key is marking this up as well. If I were a huge company, I could probably skip them and go straight to Texas Instruments or whatever, and order my 1 million op amps at an even lower rate!). The complete bikes also often ship essentially assembled correctly, so you further save money on the total cost of the bike by not having to pay as much time for a tech at the LBS to do things. This is known as "economies of scale". [To drive the point home: As Kibbee points out in a comment, this is why the "losing money" articles news sites often run on electronics are faulty - the sum of the costs of parts to a consumer whose only buying a few of each part will be higher than the cost of the device, but when you're buying large quantities of each part, the sum of the costs will be significantly less. Those articles do make for great click-bait though!]

To quote Surly on this: "Can I get the same stem/crankarm/saddle/handlebar as the one that came on my Surly complete bike?"
"No, we don't offer most of the stock parts that come on our complete bikes. These parts are sourced from the manufacturer directly and aren't usually available for purchase, but in most cases you can get something darn close or even better from your LBS"

(Surly is owned by QBP, so they can source a lot of stuff from QBP at a very good rate, which can bring down costs at little to no quality penalties versus using other manufacturer's parts, and can do custom runs for similar products that would be sourced from QBP without accessories or fan fare)

Remember that a lot of bicycling things on part quality is in people's heads. If I took a Deore derailleur and made it to say it was a Tourney derailleur and people saw it, a lot of people would say it performed inherently worse than one that I hadn't scratched out the decal on. Also, there is variance in manufacturing and riding conditions, so sometimes you get a part which lasts longer than others in the same batch or model or comparable models. It would be near impossible to get a statistically significant sample telling you that aftermarket parts are different than the parts with the exact same model number supplied to bike manufacturers (I highly doubt it exists). Also, when someone pays for something, they often believe it to be better than the "free" thing (there was a Newsweek article about 6 years ago talking about how colleges priced themselves higher so people would believe them to be better). We see this all the time with other products in our lives, such as badge-engineered cars among other things. Finally, remember that a lot of people replace things as they break, when typically the parts aren't running well anyway, lowering the perceived quality versus the replacement, even if they are the same part.

There is a practice, commonly used in the electronics industry, known as "binning", where parts are tested, and higher performing parts are often branded differently than lower performing parts and sold at a higher price (and when there are more higher performing parts than necessary, they are often branded as lower quality parts. Overclockers in PC's, for example, often take make use of this for unlocking cores and extra performance and what not). However, it doesn't really make sense to do a binning for lower quality and higher quality things in the same model number and sell the lower quality ones to bike manufacturers - the parts in a bicycle are simple enough from a machining standpoint typically that they can be made amazingly consistent, so the variations aren't great, and this just adds complexity to the supply line as well as opens up the manufacturer to possible litigation.

If they are different models, then sure there can be differences in quality (you may fit a cheaper part for something not very important or a wear item or something that people aren't used to noticing (as noted in one of the comments) like a cassette or saddle (which is hard to choose due to personal preferences) or pedals (often thrown out for some clipless system on more expensive bikes) when build the complete bike, knowing that this will bring your costs down and the rider is going to replace anyway with something better once it wears out). You can save some money this way (and certainly, this is substantial for bicycles which are cheaper).

In any case, I wouldn't lose any sleep over it and would just ride things until they need replacing. Then just pickup whatever looks good and move on with your life.


Balance of leg muscle usage while riding out of the saddle

I suspect your glutes are working harder than you think. Because they're big muscles, and cycling (seated) uses quite a lot of their range, but excludes the extremes, they'll be late to fatigue. This is even more the case if you do a lot of squats or leg press.
That's not to say that you can't recruit them more. When I get out of the saddle for climbs, which I don't do very much, I tend to be overgeared. That certainly seems to make them work harder; it also makes the quads work harder, but not by as much.
I reckon - and you'd have to test this - that a lower torso position while standing would help. That would suggest hoods, but with your arms bent and taking some weight on your triceps - just a little to steady you at certain points in the stroke - the vast majority still needs to go through your pedals, even more when climbing steeply. It's also going to be more aero than a more upright position in sprints. I assume standing while using the drops isn't an option. I sometimes do for short rough patches but it doesn't really work for long, for neck and wrist (brake) angles. Or maybe it would work for you.
You sound almost like you're over--using your calves. If that's true when seated and not just out of the saddle, there may be some room for tweaking.


Will panaracer 27.5x3.5 tires on Velocity Blunt 35 rims fit on a Medium Surly Karate Monkey Frame?

Yes.

http://surlybikes.com/gallery/karate_monkey/karate_monkey_b
It took me a while to confirm that these were indeed the panaracer fat b nimbles due to the low resolution of the image. However, it's definitely a panaracer, and there are only so many models that size. Like BEVR1337 said, I may have some issues if using a front derailleur, it looks like this should clear the frame fine. Rims appear to be velocity duallys which are a bit wider than the blunts, so if it is a good fit with these rims, the narrower blunt 35s should be totally fine.


Mechanical Ultegra's R8000 right-mech cable failure

This problem happens enough across the board with all recent STIs, especially on heavily ridden bikes, that there may be an element to it where the bends the cable is being subjected to is the real problem and there's some inevitability to it. But it's happening to you especially often. Here are some possible reasons:

You shift a lot.
The fancy nosed plastic Shimano ferrule isn't being used at the shifter.
Friction elsewhere in the line, like from overly tight routing or any of the other causes for it that contemporary road bikes sometimes create, is causing you to need to be more forceful with the shifter, causing the first bit of cable to see higher loads on it.
The cables have been getting installed in a manner that kinks them near the head. Then when combined with the tight bends that are inherent to this shifter, some strands are experiencing heightened fatigue and breaking prematurely.

Kinking the cable on this shifter during replacement is a fairly easy mistake to make, especially if you're not unwrapping the bars. The easy way to install the cable is to feed the whole thing through first until the end is resting in its seat, and then feed the whole thing back the other way, then into the tip of the ferrule. The trouble is if the ferrule is rigidly taped down and in place, it's easy to create a kink in the cable just ahead of it, especially with the nosed ferrules that one really should be using. The way to avoid this is feed the first part of the cable in and back the other way, but not pull it all the way through, and use a pick or small flathead screwdriver to guide it into the ferrule. Then gently push it through the housing bit by bit, and only seat the cable head in the shifter when it's all the way through and you can pull it into place without any of it getting bunched up and then kinking. Failure to do this is a way to cause the cable to break at the shifter.


Can I fit a compact cassette with a long cage derailleur?

Unlikely to cause any problems. A long cage R7000 (Shadow type) is rated for 28-34t cassettes. The short cage is rated for 25-30t, so going from 32t to 30t or 28t would be fine.
Expect to need to make normal adjustments for the new cassette, but it should work fine.
Of course it depends which precise RD you have, and since you didn't say I can't be 100% certain.


Shimano Hydraulic Disc Brakes vs Tektro Hydraulic Disc Brakes

It all depends on what you are looking for.  Both the Tektro HD-M285 and the Shimano M315 are considered entry-level hydraulic brakes (despite the fact the M315s are over twice the cost), so if your current setup works for you, I wouldn't change it.

If you were looking to upgrade your brakes, I would go with the Deore (M6000) or SLX model (M7000).  At that point you are going to get quite a few additional features.  For instance, the M7000 has tool-free reach adjustment along with a few other weight savings and some minor increased performance upgrades (better pistons for instance).

The nice thing about getting into this upper range is you can easily swap individual components with the higher Shimano ranges.

Personally I would save up for the M7000s.


Do the benefits of clipless pedals out weigh any danger they may pose the rider?

Terminology is important here. Pedal Clips (refer here) are straps that tighten around the shoe. Clipless, such as SPD have a cleat - refer here
Toe clips are not common these days - but still used by some (touring and fixed hub bikes) more niche applications. I assume you are talking about SPD style clipless pedals, but the following discussion does not really change if you are using clips. I do not believe they are dangerous. However, there is a learning curve - it's similar to asking "Is learning to ride  a bike dangerous", in that you will get exactly the same answer. Do it in the right locations and take appropriate precautions, expect a few skinned knees and at very worst, a broken bone. Do it in the wrong location at the wrong time, at worst - death.
What precautions - learn to use them in the same place you would teach a person to ride a bike. Avoid heavy traffic - no point falling under a B-Train - and mountain trails with large cliffs along side the track until proficient (Unless you are wearing a parachute) . i.e. Use common sense. Practice clipping and unclipping - and don't venture too far from your safe area until you can do both without looking down (If you look down at you feet, you will fall off). Then - practice "emergecy exits" - Not needed so much for onroad riding, but MTBing, you often need to unclip without expecting it. Eventually you will be able to unclip at any time, without thinking about it.
Don't use mix the use of toe clips and clipless pedals - it will end in tears, as the exit methods used for of each is completely incompatible with exiting the other.
Where not use them - anytime a fast, unhindered separation between the bike and rider is likely to be needed - BMX, Downhill MTB and Trials riding come to mind. In some XC riding, it is advisable not to clip for some sections - depending on the riders confidence and competence, however most of the time an XC rider will be clipped in.
Some riders prefer flats - especially MTB - there is nothing wrong with that - don't feel forced into using clipless pedals.
Edit:
Updated in response to comments.
In response to you photo and attached picture - not an entirely unexpected outcome of a novice to SPDs riding rocky ground, as might be expected putting a novice bike rider on same ground.  Unfortunately you now have an additional couple of problems to overcome if you decide to go with SPD's. You will have a mental aversion to them, and to rocky ground - that needs work but is relatively easy to overcome compared to the other - If you go with SPD's your wife will be certain you are mad - nothing you do will change her mind on that....
I suggest not using beginner clips  - they will install a false sense of security "I'm on beginner clips, I can un-clip easily....".
However, there is absolutely nothing wrong with flats.....


I'm assuming you have rim brakes, since you are asking about wear and aligning brakes.

Winter riding will wear out everything faster. The rims are going to be wet and dirty for most of the time, and the same goes for transmission. It might be a good idea to use any old equipment you don't care about as winter parts. The exception is that better hubs have better sealing. 5000 km isn't that much for rims, by the way.
Unless the rims are exact same width (or the rotor is aligned exactly the same) you'll have to adjust brakes every time you switch wheels. Possibly the derailleur too.
New cassette on worn chain will be noisy, wear out the cassette fast and skip if the chain is worn badly enough.


What crankset/chainrings on 1990's cyclocross

Crank Set Types
Lots of different crank sets and chain rings were being used on cyclocross bikes in the mid 1990s. Some factors that influenced the parts selection process:

Price
Availability
Performance characteristics
Personal preference

I don't know of any cyclocross specific crank sets.
To aid you in finding period appropriate parts and using Shimano as an example of one maker here is a link to a Shimano parts timeline.
Here is a link to a collection of Shimano catalogues from 1984 to 1997.

Number of Chain Rings
People used single, double, and triple chainrings
Here's a 1988 (it's a little older than the 90s but it's an example) Alan bike posted on bikeforums.net with a single chain ring:

Here's a Cicli B Cyclocross from the early 1990s that was sold on steel-vintage.com with a triple.

Gearing
According to Wikipedia

  Gearing is typically lower, with most common setups using a 46-36 (110mm BCD) or 48-38 (130mm BCD) chainring combination with a 12-25 to 12-30 cassette. Some riders opt to use a single chainring in the front (typically a 40-42 tooth chainring) while retaining multiple sprockets in the rear cassette.

Since cyclocross is such an open ended sport it might be best to go with the gearing that fits your riding style.


What does MSL stand for with Rocky Mountain carbon bikes?

Race Super Light and Marathon Super Light


Do cartridge BB's have both ends removeable?

Most of the standard square taper bottom brackets on the market (e.g. Shimano BB-UN54/BB-UN55) have one cup permanently attached to the bottom bracket (usually drive side) and the other one removable.

However, some manufacturers make ones with both sides removable (e.g. Phil Wood) and some other variations on installation (notably threadless ones like the Velo Orange Grand Cru Universal).


Can I replace my bicycle's dynamo with batteries?

Yes, a battery holder and switch from radio shack would accomplish this. Most dynamos are 6vac and can be replaced with 4xAAs or the 5vdc from a USB pack. You can ignore the issue about polarity as the dyno lights that I've worked are either incandescent and don't care or are LED but have built in blocking diodes and don't care.

Whether you would want to do this is another issue. I've gone the opposite direction and put a dynohub in my commuting bike.

Note: if you are handy with a soldering iron and multimeter, you can remove the diodes/rectifier (and likely super cap) from the LED lights and have them run in straight DC. You'd gain brightness especially when your batteries are running low because you would no longer have the voltage drop of the diodes or rectifiers, but you would need to check polarity and make sure you aren't drawing too much current.


Where should the brake calipers grasp the rotor?

Some amount of unworn upper lip on the rotor is normal. For example, when you try to measure a round-edged rotor with a caliper, usually it doesn't work from the outside edge because there's some kind of lip there. The entire brake pad surface should be contacting rotor - in other words, there shouldn't normally be any lip getting worn into the pad. If there were, that would be your real sign that the pad isn't making full contact. But because it can't be totally perfect, it follows that the rotor is wear the unworn spot is going to show up. This one does look a little more extreme than normal, but I think it's fine.
The first thing I would do if I suspected a problem is check firsthand that the mount is actually to spec, since it's pretty simple. Use a caliper or even a pocket rule and poke a skewer through the axle without the QR nut to give you an easy spot to measure the center of the axle. Here are the dimensions. If it's not that then it may be a peculiarity of how this rotor is getting along with this brake and adapter. In my experience, even though it's not supposed to matter, you can save yourself some grief by mismatching adapter/caliper/rotor as little as possible, and you've got a different brand for each here. I do tend to be willing to put in Shimano rotors on anything. (Just to be clear, mismatches shouldn't matter and usually don't.) I think part of what may actually be going on here is the pad type used by the HYRD is just a little taller than most or all of the SRAM/Avid pads and it's making it look like the rotor wear is going further than normal into the large cut-out section of the rotor.
Up to 2-3mm or so should be fine if you want to try this. I would feel like I was doing something wrong if I stacked them up any more than that in a shop setting. I don't really think it's worth messing with upon further consideration.

Edit: Substantively changed this answer after thinking it through a bit more.


More careful buffing - the ribs stop the sandpaper/scratcher from getting into the butyl rubber and exposing raw rubber, so the vulcanising agent can't work so good.

You don't need to buff the ribs off completely, but scratching up beside the ribs helps a lot.

Also, over-size the area that you cover when you spread agent.  Those orange edges should be stuck down firmly.

Another help is to use a larger patch in these areas, but it means more buffing because more surface area.  You can also rotate your patch 90 degrees to cover the length of the ribs more.

Also make sure to wait 5-10 minutes after applying vulcanising agent, before pressing the patch on.  Then press patch firmly.  I use a roller the width of two coins, but a large round coin works fine too.


Suitable upright bar brake lever for old caliper brake

Yep, 'reach' is how long the brake calipers are, and an indication of whether the brake pads will hit the rim properly.

'Pull' is basically how spongy your brake levers will feel.  If this is not matched properly to the brake calipers, you could end up with jerky brakes that are very on-or-off and liable to catapult you over the handlebars, or ones that are just too soft for the job.  Some manufacturers (modern ones?) specify which brake levers to use with their calipers, but inevitably they recommend their own ones.  This doesn't mean that others won't work well, but that might be more a matter of trial and error and reading around.

I'm about to rebuild my front end (new brakes, new levers) and my best advice is buy from a website (or shop) that has a decent returns policy!


Should I get wider tyres/tires for my tour if I'm not going to go off-road?

I have seen fully-loaded tourists ride successfully with lightweight racing bikes (of years ago) on what were then called 7/8" tires (which is 22.2mm).  I've also seen them lay their bikes down in the parking lot at lunch and have the tires explode.  (Don't ask me what mechanism was involved, but it happened at least 3 times in a week among a group of maybe 20 on the lightweight bikes, among a larger group of about 200.)

As a commuter/tourist I favor wider tires (I currently ride 35s), for the slightly smoother ride, better handling on rough pavement, less frequent airing up, and better weight-carrying ability.

But the main question in your case is whether the tires can simply carry the weight, at full pressure, without compressing too much.  Load up your bike (with dummy weights if necessary), sit on it (or have a friend of the same weight do so), and see how the tires look.


What are the original components to a 1953 Schwinn Paramount?

The Schwinn Paramount was a special machine, as Sheldon Brown describes. I cannot tell you what components it had, because it seems that they were custom built to order only.

Maybe the people at the Schwinn Paramount Registry can help more.

Looks like it's valuable. Look after it.


If you want to upgrade gradually you need to follow the compatibility of the groupsets.

If your Tiagra groupset is the 4600 series of 2012, the 10 speed components should be compatible with other Shimano 10 speed road components, so you can use Dura Ace 7800 and 7900, Ultegra 6600 and 6700, and "105" 5600 and 5700.

The amount of cable pull per gear is different between Shimano 10sp road and Shimano 10sp mtb. SRAM 10sp doesn't use the same cable pull as Shimano 10sp road or mtb.


Is it possible to rebuild a a steel bike frame (to make it lighter) by welding aluminum tubes

I would not.  Instead I'd strongly recommend you look at buying the bike you want rather than chopping up a working vintage bike.  At best you'll come out with something worse than a replacement aluminium road bike, and perhaps slightly better or worse than the bike with which you started.

A used 2000's bike would be a far better bike than some chopped-up monster, and then you have N+1.

Steel and aluminium are dissimilar metals and welding is not possible. You'd be looking at brazing them. If you expected to weld them, then perhaps this is beyond your welding skill level.

If you are paying someone commercially to do the welding, then they will braze or silver solder the work.  Check for what their workmanship guarantee is as well.

You will have to paint the whole frame properly afterwards too, the steel parts need protection.


Triple crank, extra click while downshifting

Some shifters have an extra click that is used to 'trim' the front derailleur as the chain moves across the cassette.  This is to eliminate the noise of the chain gently rubbing the plates of the FD.

This data sheet for an Ultegra 6700 shifter has a section to explain this feature:
https://si.shimano.com/pdfs/si/SI-6SC0A-002-ENG.pdf


Different greases hold up varyingly well in different applications, depending on levels of dust, water, temperature, etc.

Park Tool Polylube PPL-1/2 are your basic bicycle greases -- they hold up well under most people's riding conditions (including repelling water enough; others like Phil Wood or Park Tool HPG-1 might be more water repelling). Depending on the conditions, you may end up repacking a bit more often than others, but its not really all that big of a deal, so long as the grease is doing its job (which for most people, it will just fine; if you're riding in -50 C, you might want to pick something else).

At the end of the day, note that many people are using just regular old multipurpose grease from the auto shop (that red stuff Valvoline sells for less than 5 bucks a pound) or marine grease and are doing alright (it's significantly more viscous than bicycle greases so not ideal; however, note that even a tube of Park Tool PPL-1 will last you quite a while, so the cost savings aren't immense for the home mechanic ). So, don't lose sleep over this.


I also have a folding bike with a 3-speed hub (Shimano Nexus 3). My bike has a chain protection cover in the front chainring, so I find it harder to follow those other suggestions. I usually prefer to put the chain over the front sprocket in the first place.

The chain is also as tight as I can, but sometimes it happens that it falls over. I have noticed this happens when pedaling on a more irregular road or over bumps, so I just stop pedaling for a moment or go slower.

This trick is pretty easy and fast:

Grab the chain and put it over the rear sprocket (assuming it is already over the top of the front sprocket).
Because the chain is tight, probably, it will only be possible to move it over one or two teeth -- no problem.
Let the bike go backwards a little bit. The rear sprocket will spin together with the wheel and it will pull the chain over the sprocket.


Why is the British version of "tire" is "tyre"?

Is there a reason they call diaper nappys? or elevators lifts? It's the queen's English. It differs from us american folk.

In British English both spellings are correct, but both words mean
totally different things.
In all of the English speaking world, the word tire when used as a
verb means to become exhausted/sleepy.
In Britain and many other Commonwealth nations, the word tyre is a
noun, it's the word we use for the outer rubber part of a vehicle
wheel.  For example, a bicycle tyre, or a car tyre.  In the USA the
word tyre is spelt tire.
Here are a couple of examples of British English usage: Since the
onset of her illness, she tires very easily. I find that I tire quite
easily these days. The car tyres need to be replaced. The bicycle tyre
has a puncture.
In American English, all of the sentences above would use the spelling
"tire".

Source
This may or may not be a question for the English language and Usage stack though.


I just bought a frame off this kid in my neighborhood but don't know who makes it?

This one is the closest I could find. It has similar head tube and seat tube cut outs. It's titanium though. Is yours titanium? This is the current, steel version. As far as I can tell, this frame is identical, with the same brake bosses on the wrong side of the seat stays. Also has cable stops in the same place for the rear brake. Seat tube clamp is under the seat stays as well, which is another uncommon similarity.

If this isn't the same frame, your frame is almost definitely manufactured by Eastern. The cut-outs on the seat tube and head tube are very common on their bikes, and many of their models seem to have a similar brake placement. The frame I linked to is the only one I could find that had the exact same head tube cut-out.  All the rest had a logo cut out of the head tube.


If you feel no "tilt" on a flat road then there is probably nothing wrong.  A bike's steering geometry is designed as a compromise, using terms such as "rake", "head angle", and "trail".  A bike designed for agility will generally have a geometry that makes it turn downhill on a slope (if you let go of the handlebar), but a bike designed for stability (such as yours) will tend to turn uphill.  This tendency is amplified by the wider, lower pressure tires.

I doubt that there is anything wrong with the bike, unless this effect is very pronounced.

If you find the effect unsettling you might be able to reduce it by increasing your front tire pressure 20-30%.


What are the differences (and their practical implications) between a 29" mountain bike and a cyclocross bicycle?

There are a few very good answers on here already, however, I feel that a few pointers have been overlooked.
Height
I am not sure whether 29-ers suit all riders. Height comes into it, a 29-er imposes a high handlebar and heavier wheels than a 26" MTB. IMHO you need to be 6" or taller for the big wheel to make sense.
Standover height
The distance between you and the top tube is important on a MTB, regardless of your skill level. Most MTB's have a 'compact geometry' with big seat-post. Out the saddle it is useful to not have a 'five bar gate' between your legs, so, if you do go for the MTB, err on the smaller rather than the larger frame. You don't get this with CX bikes as a rule, although I would not be surprised if Giant do make one.
Brakes
Most 29-ers (if not all) come with disc brakes. CX bikes can come with discs but that is the exception rather than the rule. Disc brakes give much better stopping power, with little need for the rims to clean first. This gives you much better control.
History
Cyclo-cross pre-dates MTB-ing by some decades and the bikes for the sport evolved from road bikes. Meanwhile, the MTB evolved from a few Californians wanting to have fun, any notion of competition came along later. They were not tied down by UCI rules and UCI rules have always served to hinder rather than advance bicycle design. CX bikes are essentially a legacy product, for a 'formula' sport, not 'pure evolution'. They were not that popular before the mountain biking boom and have not been subsequently. Meanwhile, the separately evolved MTB is the 'weapon of choice' for many, many cyclists and CX ideas such as drop bars have not lasted long on MTB's (they have been tried by Johnny Tomac and Specialized did make a 'Rock-Combo' model with them, this was short lived). Wisdom of the crowds is that the MTB rocks off-road.
Suspension
For a long time I thought Suspension was a solution looking for a problem. However, there is suspension and there is suspension. A full suspension top end bike by the likes of Cannondale is amazing off road, you can roll over anything without losing speed or control. Cheap suspension is no good at all, i.e. the effort you get on a £300 MTB, perhaps useful for going up a kerb but that is about it. Modern, expensive full-suspension bikes are ridiculously light for how much is going on and a delight to ride. Well worth the investment, unless you are going XC with a bit of road to get to the trail in which case a hard-tail with front lockout is better for the ride as a whole.
Other uses
If you are a road-bike person then you probably carry nothing. Sometimes it is useful to have a bike you can carry stuff with. An MTB is really well suited to putting a rack on the back and carrying stuff. That may be just a trip to the shops or a long distance tour. Whatever your choice - CX or MTB, do look for those magical eyelets on the rear dropout for putting a rack on there. It may not be what you want to do now, but down the line it just might well be.


Your best bet is to find a good way of attaching it to the rear rack.  Anything attached to the main triangle much larger than a bottle is likely to cause interference with your legs.

One way you could attach it to the rear rack would be to buy some pannier hardware and make your own pannier for it.  Or possibly attach the hardware (zip ties?) to one of the tripod's legs, making it into its own pannier?

The other option is to strap it down to the rack deck.  A nice sturdy rack like the Surly ones (archive) should give you plenty of stability, using a couple bungees to tie it down.  I've hauled 3 foot long loads on my rack this way without any trouble.


Recommendation for lightweight pedals for use with SPD or without

Shimano make several models of pedals with SPD one side, and flat on the other. So they can be used with SPD shoes or normal shoes.
Options include:
PD-A530

These are designed for road/touring bikes, so are fairly slim, with a small metal platform. (Not to be confused with the PD-A520, which are one-sided SPD pedals, without a flat platform). Personally I use these, they work pretty well, with either SPD shoes or non-SPD shoes.
Weight: 383g (pair)
PD-T780

Designed for trekking or commuting bikes, they have a larger plastic platform. So they look a bit bulkier, but are not actually much heavier. They have reflectors built in, which is useful if that is a legal requirement where you are.
Weight: 392g (pair)
PD-M324

An older model, with a large metal platform, so a bit heavier. They have the option of adding reflectors or toeclips. Weight: 533g (pair)


What size mounting bolt does a Shimano SL-M7000-11 take (pic included)

From Shimano's Technical Documents website comes this exploded view of your right shifter. Typically on these drawings, Shimano will give the size and length of any fasteners highlighted in the drawing (see the "Clamp Bolt" listing--#8--in the linked schematic), however the entire base cover with it's screws is one part number and no information is given about the screws themselves. As has been typical of these kinds of shifters over the years and different models, the bottom cover utilizes two and even 3 different size screws in one unit.
Your missing screw is part of the assembly listed as #3 (of the referenced exploded view) and carries part number, Y06M98030, the  R.H. Base Cover Fixing Screw Unit. I googled, "Shimano part number Y06M98030" (without quotes in the search query), and this is the most relevant link that wasn't the same Shimano site I linked above. Still nothing about the size, but you can get a good look at the threads and the shoulder of it.  My final answer is that it's an M3 about 5mm long. Because of that shoulder, a matching fastener won't be easy to find in the local hardware store, but I wouldn't be put off trying an M3 socket head cap screw, short as I could get (though a Dremel with a cut wheel could customize a longer one) and seeing if that would be a satisfactory substitute.  Or, obviously, the part is for sale.


Campagnolo's system is to provide a tag,Certilogo, with new wheels which people can scan to confirm it is indeed authentic.

However, with a used wheel, there is no such tag. With carbon fiber, its incredibly easy for people to make very good counterfeits, so as Campagnolo says, if the wheel doesn't come with the tag, you should consider it being from uncertain origin (i.e. it could be fake).

You can also post pictures on forums to see if people can identify them by certain markings, mismatched aesthetics, features that shouldn't be there (brake tracks, for example, or wrong spoke pattern) and weigh them. For example, this thread gives some indicators of fake Campy wheels. It looks like this model is reasonably commonly faked, so keep your eyes wide open.


You will need to measure the thickness of your rotor to determine if it needs replacing, then check that against the manufacturer's recommendation for minimum thickness. I think your rotors look like Sram ones,  but I may be wrong, so I'll put the specs for other brands as well. Sram rotors should be replaced by the time they get worn down to 1.5mm thick. For Shimano rotors, it is 1.6mm. Magura recommends replacing at 1.7-1.8mm depending on the model of rotor. Hope have a limit of 1.4mm. Hayes should be replaced at 1.52mm.


How is cornering on the road different than cornering on dirt?

First, let's answer the first to questions together, as they are closely related.

  Does one lean with the bike?

...and...

  Does the bike stay more upright?

Short answers are yes and yes in most cases.

To elaborate, let's take a look at what you're trying to achieve when cornering. I found this image recently and I think it does a great job of visualizing the basic physics of what's happening when you take a corner on a bike:

In a turn, whether you're leaning the bike, or your body, or both, that "local gravity" line is what's keeping you from highsiding or lowsiding. The center of gravity and that center line just moves depending on what you're leaning and how low you're getting.

Do a search for mountain bike cornering and a search for road bike cornering. Notice how centered the road riders are compared to the mountain bikers.
One of the big reasons for the "lean the bike" advice is to engage the more aggressive side knobs on a mountain bike tire. On a road bike this is not necessary.
With a mountain bike you spend a lot of time skirting the line of traction. You lose it and regain it often. Many of the techniques for cornering on a mountain bike are to keep you on the traction side of that line and to recover without crashing when you cross it. Many of these techniques aren't applicable on a road bike, where in most cases you either have traction or you've just crashed.

You'll also notice on the mountain bike cornering images that in big berms the riders are typically more centered over the bike, sharing the posture of the cornering roadies. That's because when traction isn't an issue being centered over the bike is the most balanced and stable way through a turn, and that's why you see road riders using that posture most of the time.

  Is the pressure more evenly spaced among both pedals?

No. The advice on weighting of the pedals and the bars stays the same. Drop the outside pedal and weight it primarily, weight the inside handlebar. Note that the primary reason that you're weighting the inside bar is to initiate countersteer.

  How can one get feedback when the (front) tire is about to loose traction?

If you've got everything weighted properly and you're lucky, the back will cut before the front does, at which point you've got a fraction of a second to stand the bike back up, or you crash. If the front goes first, you crash. A lot of knowing the limits of road bike tire traction comes from experience, and crashing.

  What does "dynamic" mean in this context?

There's a lot more movement of your body on and over the bike on a trail than on the road. The more technical the trail, the more this is true. The "lean the bike, not the body" advice is a good rule of thumb, but it is not a one size fits all solution for mountain biking. There are so many different types of turns in mountain biking- fast, slow, bermed, off-camber, uphill, downhill, steep, flat, loose, rocky hardpacked, etc, and nearly infinite combinations of each. Many categories of turns deserve their own questions for cornering technique.

  Is it customary to place the inside foot on the road in order to have three contact points and prevent tipping/sliding out?

Typically not during the turn. I've seen it done it the wet sometimes, but taking your foot out/off of the pedal during a turn will affect up your balance, especially on a road bike. Getting your foot out of pedal at the last minute is really hard, especially with road pedals.

  Is the weight of the rider evenly spaced (chin over stem, butt over seat)?

Somewhat dependent on slope/incline and speed, and whether you're on the hoods or in the drops, but largely yes, this is correct.

  Is standing up to gain additional "acrobatic" space i.e. freedom to more one's weight around rapidly ever used?

On a road bike, typically only for slow speed maneuvers. There are probably exceptions but I can't think of them at the moment.

  What about slippery pavement - water, snow, sand?

Sloooow dooown. The more treacherous the riding surface, the more upright you need to keep the bike and your body.


Trek 750 multitrack chainnsize and length?

Chains are highly standardized, but are specific to the number of sprockets in the rear cluster (because the spacing of those sprockets is narrower the more of them there are).

You simply need a chain marked as '6/7/8 speed' ('speed' here refers to number of sprockets in the rear cluster).

All chains are sold with more links than are needed. They are sized to each bicycle, cut to the proper length and joined.

Instructions for sizing, cutting and joining the chain are easy to find, but here's my favorite.

Buying a chain with a 'quick-link' type joining link is preferable as these are easier to join that those that use a joining pin that must be driven in with a chain tool.


The cassette really is worn.  It takes something of a trained eye to spot a too-worn cassette, and often when you switch to a new chain the cassette will skip worse than it did with the old, worn chain.
The chain is the wrong one for the cassette.  Chain/cassette compatibility is an area where there are no nice general rules -- you have to make sure that the chain you get is compatible with your specific cassette. This includes having the correct speed pairing (e.g. 8-speed chain for 8-speed cassette).
The chain was cut to the wrong length.  A chain is always delivered with 8-10 inches of extra chain.  You must shorten it to the appropriate length, using a "chain breaker".  Some people just wrap the chain around the largest sprockets and eyeball it, but if you haven't developed that skill the best thing to do is to lay old and new chain side-by-side and carefully match up links along the length so that there are the same number of links in the new chain as the old.  (Note that if you just match length the new chain will likely end up a couple of inches too long.)
The chain was threaded through the rear derailer incorrectly.  It's kind of hard to mess up on the front, but the threading through the rear derailer is not intuitive, and it's possible to muck it up.
The derailer is out of adjustment or has been bent somehow.


Differences between starting a road bike vs a mountain bike?

I ride a mountain bike and my feet have no issue hitting the ground and waiting
  until it's time to go again. That's not the case with the road bike, where I
  have to get out of the saddle when stopped.

You say you have to get out of the saddle when you stop the road bike. Is there a large difference is saddle height between your road and mountain bike? Are you staying sat on the saddle with a foot on the ground when stopping the MTB, but have to drop out of the saddle to get a foot down when stopping the road bike?

You should be able to reach the ground with your toes when sitting in the road bike saddle, without tilting the bike. You should be able to start sat in the saddle, one foot on the ground and the other on a pedal. Make sure you stop in an appropriate gear so  pushing down on the pedal gets you underway and able to lift the other foot of the ground.

Look at the saddle height on your road bike. It may be too high. Also your MTB saddle may be too low.


Can I Interchange Wheel Sizes On One Frame?

If you use disc brakes with same size rotors, you can put 26" wheels on a 27.5" bike.

In fact, you can put smaller wheels on any any frame, so you could put 24" wheels onto a 29er

You need to watch for the a few things - geometry is going to be affected, and you may get pedal strike as the bottom bracket is lowered. In the case of 26" and 27.5", the difference is small - 26" is ISO 559, 650B/27.5 is ISO 584 - diameter difference is 25mm, or 12mm radius(BB height).

You will need to watch the axles style and length for the wheels - an array of mostly incompatible new standards have come out in the last few years so you will need to ensure the wheel sets match the frame/fork


Irregular sounds on new 50mm wheels at speeds over 16mph

Generally speaking, the deeper the rim the more noise the wheel makes. A pronounced whooshing noise isn't unusual among deep dish wheels and disc wheels (as in the solid wheels, not the brakes) are even noisier. I had Cinelli and Hed discs when I raced and used to love the sound of them (the ride, not so much!)

I would personally be very nervous of the no brand Chinese carbon wheels, frames and parts being sold on eBay. I've been hearing some absolute horror stories from shops and race mechanics.