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Jan
8
comment Weight of wheels vs. weight of tyres
I did answer the question -- here. And the answer is pretty authoritative, since I consulted with the folks at physics.stackexchange.com.
Jan
8
comment Weight of wheels vs. weight of tyres
Sigh. When you convert linear acceleration into angular acceleration you divide by radius. And despite your attempt to muddle it, the term "exponential" is not used, in either mathematics or general discourse, the way you want to use it.
Jan
8
comment Weight of wheels vs. weight of tyres
"Moment of inertia is a function of the square of the radius." But on a bicycle wheel, angular acceleration is inversely proportional to the radius. (And, contrary to what you believe, the term "exponential" does not apply to a simple squaring, but applies to a repeated application of a multiplier, where the number of applications is one axis.)
Jan
7
revised Safety guidelines for cycling in traffic
deleted 74 characters in body
Jan
7
comment Weight of wheels vs. weight of tyres
As has been shown elsewhere, an ounce of weight on the circumference of a wheel has exactly twice the effect on acceleration as an ounce of weight on the frame (and exactly the same effect as weight on the frame for climbing, etc). While perhaps this might be considered "significant", I have to feel is falls well short of "substantially greater".
Jan
7
comment What causes chain suck?
@AndreyT - Generally that's true. But you can experience chain suck with a reasonably good chain and cogs if the derailer tension is insufficient.
Jan
7
comment Any issues with yaktrax and flat pedals
Certainly getting your foot tangled is a danger. You'd have to study the particular cleats and the particular pedals together to determine how serious the danger is.
Jan
6
comment Lower back pain cause?
I've come to learn that age is a major factor. But fit/position is quite significant. I once had a bike that was a hair too big for me, especially in "reach", and changing to a smaller bike made a significant difference in both back discomfort and hand discomfort.
Jan
6
comment Weight of wheels vs. weight of tyres
I was referring to rolling resistance due to added weight. The four resistances a cyclist is concerned with are rolling resistance, climbing resistance, acceleration resistance, and wind resistance. To about 2 decimal places weight only affects climbing and (to a much lesser degree) acceleration.
Jan
6
comment Weight of wheels vs. weight of tyres
It should be noted that weight on the wheel circumference has exactly twice the effect as weight on the frame in terms of acceleration/deceleration, and exactly the same effect as weight the frame in terms of climbing effort. In general, weight anywhere has negligible effect on rolling resistance for a road bike (until the weight becomes a substantial fraction of rider weight).
Jan
6
comment Lighter bike slower than a heavier bike, possible reasons?
Looking at the pictures it appears that the tires on the Giant have larger lugs, which normally is bad for performance, but also they have a smoother centerline (though hard to tell for sure). The tires on the other bike appear to be lugged across the centerline and possibly be made of a softer rubber. A smooth centerline and hard rubber reduces rolling resistance.
Jan
6
comment Electronic shifters
I think the auto trimming is a feature that many will find interesting, especially those with 10-speed rears.
Jan
6
comment Weight of wheels vs. weight of tyres
410 grams is a little less than one pound, not really enough to notice unless you're a small rider on a lightweight bike. What does make a big difference is switching to tires with a relatively smooth tread and supple construction (though possibly with higher pressure), as this greatly reduces rolling resistance.
Jan
5
answered Is this a puncture protection thing?
Jan
5
comment Electronic shifters
When I looked at the Shimanos 2 years ago they were sexy, but only worth the price if you were a gear head. I'm guessing the price is coming down, though, to where they might be worth it, especially on a bike that is hard to rig otherwise. Or you can make your own -- a number of folks have done this.
Jan
5
comment 'Best' Gear inch to start with on a fixed gear? Moderatley hilly area
It's impossible to say. There is easily a 4:1 difference in strength between different riders, as well as a 4:1 difference in what one might call "moderately hilly". Your best bet is to borrow a multi-gear bike, find a gear that seems to work, and figure out it's gear inches.
Jan
5
comment Does valve stem diameter matter for my rims?
You should make an effort to get Schrader tubes if you have rims drilled for them. A Presta stem installed in a Schrader rims, without a grommet adapter, will tend to force its way through the hole and is apt to fail around the stem. Tubes of the proper type should be available from a well-equipped shop. (What size are they -- what are the numbers on the side of the tires?)
Jan
5
comment Any issues with wearing leg warmers over tights?
Just the obvious problems: Too warm, too tight, too restricting, the warmers not staying put well. You have to evaluate those on your own, with your specific tights, warmers, and riding conditions.
Jan
3
comment Are shimano FH-2200 hubs strong enough to use in a tubular wheel for CX racing?
Another issue with hub strength is the lacing pattern. Radial lacing places serious strains on the flanges and can cause them to fail, whereas it's just about impossible for a flange to fail if laced 3x.
Jan
2
comment Can I pedal my bicycle backwards to move it backwards?
A "fixie" is the most straight-forward way to move backwards. (If saying "straight-forward way to move backwards" even makes any sense.) That or a unicycle.