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#1
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Upgrade Bike Boom Model
I have an Atala Grand Prix from 1973. It is like the following chart
except the to be replaced rder is original Valentino, and the fder is now a Suntour Cyclone GT. http://www.classicrendezvous.com/Ita...ala_advert.htm All I'm really looking to do is have a tech spread the frame to 126, and put in the 7-speed Shimano 14-34 freewheel on the existing hub, and put in a wide range (Tourney) rder and a new chain. Seems to me this might be $70 in delivered parts, and the labor to install, re-dish wheel, etc. Is there much reason not to get the SunRace 7-speed downtube shifters and go to indexed? What else if required? My weight is 245lbs, is going to 7 speed maybe too much for the wheel? It is alloy 36 hub and has a piece of a yellow label that can't be read. |
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#3
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Donald Gillies wrote:
writes: I don't think the grand prix is a fabulous frameset, so $70 will not be repaid in much additional value added to your bike. I have two suggestions. The only value I expect is better gear spacing and a gear for hills. But I was wondering about indexing if it only cost $30-35 more. 1. A tourney should work as long as it has its own derailleur hanger. The derailleur hanger length was changed by shimano since the 1970's so as to make shimano's stuff not work with campagnolo hangers. A campy hanger i think puts the derailleur too close to the larger sprockets. Sheldon (Harris) sells Tourney RD with an adapter claw 2. Why not consider just getting a cyclone GT rear derailleur? They are available on ebay every week for $10-$20, they are one of the best bargains in derailleurs, imho, and they are one of the best shifting and lightest derailleurs of 1970's and 1980's. Will it take the 34 gear? The tourney w/claw is $20 from Harris. I really need lower than 42x28. Also, the jump from 24 to 20 is too much for me now. I'm up to an hour ride at 10.5 mph, so I'm in the 24 most of the time and want the 22 of the seven speed. Does the sunrace freewheel have the proper spacing for indexed operation? It's an important consideration. I think it should be 5 mm between cogs to index, but to be sure, check out the freewheel chart at http://www.sheldonbrown.com/k7.html. It is the Sunrace shifters that were a question. The Shimano 14-28 freewheel is no problem. I think that a 126mm axle should probably be o.k. as long as there isnt vibration in the drivetrain (can you guess that i broke an axle last month, my first in 30 years of riding, from my shimano derailleur on a huret dropout hitting the 34T sprocket?) It's my only drop bar bike, and I figure the change would help me through a year or two until I get a new bike. |
#4
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On 20 Sep 2005 13:34:09 -0700, wrote:
I have an Atala Grand Prix from 1973. It is like the following chart except the to be replaced rder is original Valentino, and the fder is now a Suntour Cyclone GT. http://www.classicrendezvous.com/Ita...ala_advert.htm All I'm really looking to do is have a tech spread the frame to 126, and put in the 7-speed Shimano 14-34 freewheel on the existing hub, and put in a wide range (Tourney) rder and a new chain. Seems to me this might be $70 in delivered parts, and the labor to install, re-dish wheel, etc. Is there much reason not to get the SunRace 7-speed downtube shifters and go to indexed? What else if required? My weight is 245lbs, is going to 7 speed maybe too much for the wheel? It is alloy 36 hub and has a piece of a yellow label that can't be read. At 245 lbs, rider weight could be a problem with a hollow axle; to reduce the probability of failure, I would go with a solid rear axle in the 7sp setup. Otherwise, I see no significant issues in what you propose. -- Typoes are a feature, not a bug. Some gardening required to reply via email. Words processed in a facility that contains nuts. |
#5
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Hi...
well as somebody said before... that atala isnt nothing out of this world anyways... all the changes are posible to do... follow the recomendations people is doing to u... The only thing i never liked was indexed shifters.. thats for lazy people hehehe... well i think going in retrofriction will help a lot more just in case the frame is not in straight line u know... it'll be easier to adjuts the RD using friction than using the shifters in indexed mode... hope u have the custom to drive a manual car, if u know what i mean... Good luck. Noname ps: r u sure u want to spend like 150 in parts and stuff? u can get a whole new bike like for 300 at ebay u know. |
#6
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#7
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wrote:
2. Why not consider just getting a cyclone GT rear derailleur? They are available on ebay every week for $10-$20, they are one of the best bargains in derailleurs, imho, and they are one of the best shifting and lightest derailleurs of 1970's and 1980's. Will it take the 34 gear? Yes, it will. The Cyclone GT is a fabulous derailleur, and shifts even better with modern chains and cogs. But it certainly won't index... Does the sunrace freewheel have the proper spacing for indexed operation? It's an important consideration. I think it should be 5 mm between cogs to index, but to be sure, check out the freewheel chart at http://www.sheldonbrown.com/k7.html. It is the Sunrace shifters that were a question. The Shimano 14-28 freewheel is no problem. I have (or rather, my girlfriend has) a similar bike with a Shimano derailleur on an adapter claw, and I could never really get the SunRace shifters to index properly. I ended up unscrewing them from the clamp and replacing them with a pair of Shimano 7-speed shifters, which work just fine. IMHO the SunRace shifters are crappy shifters on a very nice downtube clamp. They also don't have a non-index mode. So, I guess, off to eBay or your local dumpster for a set of Exage, RX100, 105SC, or whatever shifters - they're all good! |
#8
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On Thu, 22 Sep 2005 11:03:47 +0200, Herve Henry wrote:
PS: indexing is apparently difficult to set up and it is not so useful. And you base this statement on what experience? From my somewhat limited, but actual experience, i find both of the above to be wrong. Life is Good! Jeff |
#9
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On 2005-09-21, Donald Gillies wrote:
I don't think the grand prix is a fabulous frameset, so $70 will not be repaid in much additional value added to your bike. I have an Atala Grand Prix of similar vintage, and you're right -- the frame is nothing at all special. It does make a nice fixed gear bike, though: http://www.os2.dhs.org/~john/atala.jpg Be aware that the frame was designed for 27" tires and plenty of fender clearance, so you'll need drop bolts to put 700C wheels and/or modern brakes on it. -- John ) |
#10
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Suntour VGT and Suntour Cyclone use the same pulley cage and have the
same stroke. http://www.yellowjersey.org/stour80a.html Suntour VGT-Luxe / Cyclone capacity is 36T Suntour VGT-Luxe / Cyclone max cog is 32T definitely. some say the VGT-Luxe can do 34T, others say cyclone tops out at 32T. http://groups.google.com/groups?hl=e...GT&qt_s=Search Suntour Cyclone MKII can handle 34T http://groups.google.com/group/rec.b...f612a5e4cdeae4 - Don "Suntour Lover" Gillies San Diego, CA |
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