Bicycles

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Re: Bicycles

Postby Alan » Mon Aug 26, 2019 11:48 pm

I needed help from a bike shop mechanic to get the fixed cup of the bottom bracket removed. The previous owner had not put any grease, lube, or anti-seize on the threads so it had seized.

The headset is a little bit of an odd one, the Stronglight B10, that has a plastic cup and roller bearings instead of ball bearings. They seem to have significantly more friction even when cleaned and lubricated than ball bearings, can't say I'm a fan. But it's probably not a big enough deal to replace it.

So, the next step is to get this thing sanded and powder coated. It'll probably be a few weeks before we have time to visit a shop and pick out a color and finish, etc.
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Re: Bicycles

Postby Alan » Thu Sep 05, 2019 9:39 pm

Facebook Marketplace is a shitshow. On Monday, Maggie had to work so I had to come up with someplace to take the kids. I've been keeping an eye out for good deals on Marketplace and Craigslist since all I have for Maggie's bike is the frame and fork. Well, I came across a listing for an unspectacular road bike that had reasonable components (9-speed Tiagra rear derailleur, Sora front derailleur, shifters, and brakes), stock wheels, priced at $100. I would probably have to spend 2-3 times that to buy all the components individually so I contacted the seller, who lives in Oceanside (about 35 min north with no traffic). We agreed on a 10 am pickup time on Monday, and I figured afterward I'd take the kids to the playground or the beach. Well, after I let her know at 9:15 am I was leaving and asked her for the address to pick up the bike, I never heard from her again. I decided to drive up there anyway since there was a playground right next to the beach up there so the kids had fun, but I was kind of pissed.

Anyway, last night right before going to bed, I found this listed for $100 from a seller in Encinitas (about 20 min north of us):
Chorus group.jpg
Chorus group.jpg (152.98 KiB) Viewed 32 times


An 11-speed Campgnolo Chorus groupset, which is the prior generation, but which is cross-compatible with 11-speed Shimano groups. Brand new 11-speed Chorus groupsets sell for $1000-1100, and similar used groupsets on eBay sell for $600+, depending on whether brakes, cassette, or chain are included. They were not for the set I bought, but still, $100 is an incredible price. I contacted the seller right away, and was the first to do so. I drove up there during my lunch break and there was a guy there trying to talk the seller into selling it to him instead for a higher price. But the seller (who is clearly pretty wealthy, was trying to get rid of all his extra bike components because he was moving to Switzerland, and had two bikes in his garage that were easily $10k+) had decided that he had made an agreement with me and sold it to me for the $100.

Even if the groupset turns out to be broken (doesn't seem like it) I feel like it was worth the $100.

I'll probably throw the shifters and derailleurs onto my Ridley, and move my Shimano 105 shifters and derailleurs onto either Maggie's current bike or onto the Trek I'm building for her. She currently has 10-speed Tiagra components on her Scott so the 105's would be an upgrade for her. I might stick the Chorus crankset (it's a 46/34) onto my Trek, since I'm planning to put bigger tires on it and take it off-road, and put the Centaur crankset onto Maggie's Trek.
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Re: Bicycles

Postby Alan » Thu Sep 05, 2019 10:10 pm

The Chorus crankset is 172.5 mm, as are the Centaur and my 105 cranks. Maggie's used to a 165 mm so mine may be a bit too long for her. But she can probably try it out.
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Re: Bicycles

Postby quantus » Fri Sep 06, 2019 7:39 pm

Alan wrote:The Chorus crankset is 172.5 mm, as are the Centaur and my 105 cranks. Maggie's used to a 165 mm so mine may be a bit too long for her. But she can probably try it out.

Does the increase in length mean she lowers her seat a few inches to compensate and when tilting the bike the pedals will hit the road quicker when the crank is vertical? How would changing crank length affect cadence or power? Now that I'm thinking about this, it makes me wonder what the crank lengths are on our tandem. I assume they're both the same. I wonder if LM would adjust to a lower cadence to match mine if she ended up having more torque because of a longer crank. I like a slower cadence at a higher gear, but LM complains it hurts her knees to push as hard on the pedals :-\ Part of the reason I don't like a higher cadence is that I feel like the bike starts to be bouncy because I hit some harmonic or maybe I just don't know how to pedal right :-p
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Re: Bicycles

Postby Alan » Sat Sep 07, 2019 12:13 am

Crank length affects your fit in two ways: one you need to adjust the height of your saddle so that your leg has the right amount of extension at the bottom of your pedal stroke and two you need to adjust how fore/aft the saddle is so that the front of your knee is directly above the pedal (using a plum bob) at 3 o’clock (for the left pedal, or 9 o’clock For the right pedal). Particularly for the latter factor that can lead to knee pain if you aren’t lined up properly. Otherwise it mostly is a matter of how sensitive you are to changes.

A low cadence does mean more torque per pedal stroke and can contribute to knee pain. Generally it’s recommended to have a cadence between 80-100. If you feel like you’re bouncing around it probably an issue with neuromuscular coordination, ie your muscles are not activating in the proper sequence because you’re not used to that cadence. You can change what cadence you feel most comfortable at by adjusting it gradually, like increasing 5 rpm and staying there until it feels comfortable (over the course of multiple days or even weeks).
Last edited by Alan on Sat Sep 07, 2019 1:51 am, edited 1 time in total.
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Re: Bicycles

Postby Alan » Sat Sep 07, 2019 12:24 am

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