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REAR DERAILLEUR - ORIGINAL
Shimano Light Action L525 SS (Short Cage): Disraeli Gears info:
Maximum cog: 28 teeth
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REAR DERAILLEUR - NEW
Shimano Ultegra RD-6500-GS (Long Cage) [Shimano Tech Doc PDF]
[Total capacity 37T; Largest sprocket = 27T; Smallest sprocket = 11T; Front chainwheel tooth
difference = 22T]
http://www.disraeligears.co.uk/Site/Shimano_Ultegra_derailleur_%286500_GS%29.html
http://www.cambriabike.com/shopexd.asp?id=113672
Info on using it with 32T: https://groups.google.com/forum/#!msg/randon/HZWq4sLtBeM/5DqFWf9034wJ
(You have to adjust what is called the "b" screw in order to rotate the body of the derailleur back enough that the top pulley doesn't ride on the larger cassette sprockets. It isn't the best shifting experience I've ever had, but it works well enough). The Shimano Ultegra Rear Derailleur (RD-6600 GS) can handle a maximum 27t cog as the largest size rear cog, at least as stated by Shimano, however I have seen a 28t cog work. The minimum rear cog size is 11t, FYI. Maximum chainwrap capacity is 38t. " An important part of a rear derailleur's job is keeping the chain taut as you change gears. Chain-wrap capacity is a number that tells whether or not a derailleur will be able to do this on the drivetrain you plan to use it on. Calculate chain-wrap capacity with this formula: Chain-wrap capacity = (large chainring - small chainring) + (large rear cog - small rear cog). Example: 53/42 chainrings and a 12-23 cassette: (53 - 42 = 11) + (23 - 12 = 11) = 22-tooth chain-wrap capacity."
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Front Derailleur: Shimano FD-Z206 (Max ring difference = 18T; 28.6mm clamp; bottom pull) [VeloBase]
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CASSETTE - ORIGINAL
6 speed: 13 - 26
Possibilities:
With original derailleur, 28 is the maximum
Sheldon Brown: 6 Speed Freewheel; conversion to a 7-speed
Shimano 6 speed: 14-28
Shimano 7 Speed: http://sheldonbrown.com/k7-7.shtml; 11-28; 12-28; 13-28; 13-30; 13-34; 14-32]
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CASSETTE - NEW
Shimano 600 MF-6208 6 speed (14-32T) (14-17-20-24-28-32); 126mm threaded hub. [VeloBase 6208] [mid to late 1980s]
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CRANK
Shimano FC-MT60 crankset (triple) [VeloBase]
Crank arm 170mm
BCD = 110mm
Chainrings: 36/46 chainrings
Minimum chainring size: 33 (34)
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POSSIBILITIES FOR MODIFYING THE DRIVE TRAIN
Questions
(1) What is the minimum and maximum cog size? (Answer: The max is 28, given the current derailleur)
(2) What are the limits on the crank size?
(3) Can I convert to a 7 speed?
(4) What is a desirable gear inch range? (The Synapse is currently 32-120, and used to be 37-113. Rando is 25-104. I believe that 32-105 would be sufficient).
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VO Compact Double Crankset (34/48): $100: http://store.velo-orange.com/index.php/components/cranksets/vo-compact-double-crankset-34x48t.html
Proposed crankset: 34/46 (assume crank length: 170mm)
[Same cassette: 13-26, GI with 28 tires: 35-95]
[New cassette: 12-28; GI with 28 tires: 33-103]
[New cassette & LC derailleur: 12-30; GI with 28 tires: 31-104]
Crankset 34/50:
http://atlanta.craigslist.org/atl/bik/3430358611.html
http://atlanta.craigslist.org/nat/bik/3435981765.html
http://atlanta.craigslist.org/atl/bik/3467835242.html
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TIRES - POSSIBILITIES
28s or 32s
Shopping page: Tires
http://www.conti-online.com/www/bicycle_de_en/themes/city/hidden/topcontact/topcont_en.html
http://www.bikeradar.com/gear/category/components/tyres/road/product/review-continental-top-contact-33554
http://www.amazon.com/Continental-Road-Contact-REFLEX-Wirebead/dp/B001PPDA1A
http://www.conti-online.com/www/bicycle_de_en/themes/hidden/city/TopContact/topcontact_en.html
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GEAR INCH RANGE CHART
LOW END
LOW END
LOW END
HIGH END
* Currently have