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location Minnesota, USA
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visits member for 2 years, 10 months
seen 4 hours ago

Old, tired, crazy.


Apr
7
comment Why and how much is riding big-chainring-frong small-cog-rear a negative practice?
(And if he's in that same gear uphill doing 20km/h then he's definitely pedaling too slowly.)
Apr
7
comment Riding bicycle without using seat
I recall a broad race in mountainous conditions about 20 years back where somehow one of the riders had her seat disassemble itself midway through the ride. So she rode a 20-30 mile stage standing up, until the next rest stop when the seat was replaced by her crew. Did pretty well, IIRC. (But I can ride all of about 20 feet standing.)
Apr
7
comment Why and how much is riding big-chainring-frong small-cog-rear a negative practice?
(But 60 RPM is the absolute minimum for that level of effort -- he should be striving for 80 or so.)
Apr
7
comment Why and how much is riding big-chainring-frong small-cog-rear a negative practice?
@Kibbee - I worked through the math, but definitely it wasn't a robust computation. 30 km/h = 8.33 m/s. A 700c is around 4.4 m in circumference, so a little less than 2 rps. Divide by 4 for the gear ratio and you get about 0.5 rps or 30 rpm. (Oops, I figured the circumference wrong -- it's only half that, so closer to 4 rps and 60 rpm.)
Apr
7
comment Why and how much is riding big-chainring-frong small-cog-rear a negative practice?
But I work out his RPM to about 28 -- far too slow. He's gonna blow out his knees and cause other injuries.
Apr
7
comment Why and how much is riding big-chainring-frong small-cog-rear a negative practice?
(Though it should be noted that 44/11 is not a terribly high gear ratio -- it's the top end of my tourer, and that's not an aggressive bike. Not that I spend much time in that gear, except downhill.)
Apr
7
comment Why and how much is riding big-chainring-frong small-cog-rear a negative practice?
What is the rider's cadence? He should be maintaining at least 60 rpm. If not he's apt to blow out his knees.
Apr
7
comment Is it possible to ride 18km everyday for a beginner?
The distance is not so great that butt soreness should be a significant issue.
Apr
7
comment Obtaining the optimum chain line
I think it's too hard to figure out all the variables, especially just based on description. But note that if you have adjustable cups you can usually offset the cups about 2mm one direction or the other.
Apr
7
comment Obtaining the optimum chain line
OK, I didn't pick that up. Then "optimum" is obviously where front and rear cogs are exactly in line. But note that the setup can easily handle 5mm or so of offset without noticeable problems.
Apr
7
comment Obtaining the optimum chain line
`Taint no such thing as an "optimum" chainline for any derailleur-style setup. You just strive for it to be not as bad is it might be.
Apr
7
revised Do I have too much chafer strip showing after fixing a puncture?
added 350 characters in body
Apr
7
comment new tires for schwinn phocus 700C
Use belted tires. I've only had two punctures since I switched to Kevlar belted tires many years back. Prior to that had about one a week. And inflate to at least the sidewall max pressure.
Apr
7
answered Do I have too much chafer strip showing after fixing a puncture?
Apr
7
comment How do you install a bicycle pedal without a wrench?
If the pedal fell off then something's wrong -- either it was not threaded in correctly in first place (did someone force a left-hand pedal into the right arm, eg?) or the bearings have gone bad in the pedal. (And note that if it was the entire crank arm that fell off (which is much more common) then the crank arm and possibly the spindle end are very likely damaged and in need of replacement.)
Apr
7
comment Do I have too much chafer strip showing after fixing a puncture?
The rib on the sidewall of the tire, near the rim, should be a consistent distance from the rim edge all the way around. If that is the case, and the tire is the proper size for the rim, then the tire is properly mounted. If the rib seems to waver up and down relative to the rim more than a mm or so then there is a problem.
Apr
7
comment What does vulcanizing solution in patch kits consist of? Can I buy it?
I would guess that the adhesive used for EPDM roofing is similar, and you can buy that in 5-gallon buckets. But as others have said, the stuff dries out so fast (once opened), you don't usually want to buy large amounts (unless you are repairing bikes for a living or or exceedingly unlucky with punctures).
Apr
6
comment Is it possible to ride 18km everyday for a beginner?
@Mohebifar - If the route is really that steep you need a bike with low enough gears, but other than that (and not wanting anything too heavy or poorly fit) the bike won't make much difference. On longer rides you'd be more concerned about the quality of the seat, style of handlebars, etc, but these aren't so important for a ride that will only be on the order of a half-hour long.
Apr
6
answered Is it possible to ride 18km everyday for a beginner?
Apr
6
comment Extra screw after removing front wheel (plus enclosed hub brakes)
That appears to be a bolt for fastening a fender stay to the fender.