Late 80's Shimano 600 SIS Conversion?
10-13-06, 12:05 AM
#1
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Late 80's Shimano 600 SIS Conversion?
I have found a new Schwinn Prologue from 1987. It has the complete Shimano 600 group on it with the indexing on the downtubes. It fits my wife perfect but she likes my brake lever shifting. Can I just buy a set of Sora 8speed shifters. Instead of clicking seven times for eight gears I'll just do six for the 7 speed it has on it. Has anyone done this? Does it work?
10-13-06, 06:33 AM
#2
Tiocfáidh ár Lá
I think Shimano 8, 9, and 10 speed cogs have the same spacing but the 7 - speed is diffferent so it won't work without getting a new 8 speed freewheel or new wheel with an 8 speed cassette.
I am not 100% sure on this, try asking questions like this in the mechanics forum, you'll get the right answer.
I am not 100% sure on this, try asking questions like this in the mechanics forum, you'll get the right answer.
10-13-06, 07:05 AM
#3
Unique Vintage Steel
first a question: does the rear wheel have a cassette or a freewheel?
now for a bit of information: 8sp and 7sp do have different cable throw, but its close. I mean really close. Right now I'm doing the opposite, 8sp cassette on 7sp shifters. It works fairly well with downtube shifters were I can give the lever a little tug one way or another to fidget with a messy shift or a ghost shift issue enough to quell it. With Sora brifters, you wouldn't be able to do that. Higher likelyhood of shifting issues and keeping the shifting smooth throughout the range.
If the bike has a freewheel, then you're likely locked into 7sp unless you get a new wheelset (or at least rear wheel). 7sp freewheel hubs have a spacing of 126mm. 8-10sp hubs have a spacing of 130mm. The extra 2mm from 7 to 8 is how they fit the extra cog into the wheel while maintaining a very simular spacing per gear.
If you want to go with STI shifting, and do it right where you or your wife won't be messing with it fairly often, I suggest matching shifters to gears. I'm currently waiting on a new pair of shifters to match my 8sp cassette myself because I'm fed up with the shifting problems. It has worked for me over the last 9months, but after a season of having to switch the downtubes over to friction shifting in the middle of a 100k ride to stay in the gear I want, I'm done.
So here's my suggestion: get an 8sp cassette (SRAM still makes some in road gearing), an inexpensive wheelset (Ultegra/Open Pro for about $200 or check ebay for cheaper), and the Sora shifters. The Shimano 600 group is a fantastic setup and the Schwinn Prologue should be a great ride.
now for a bit of information: 8sp and 7sp do have different cable throw, but its close. I mean really close. Right now I'm doing the opposite, 8sp cassette on 7sp shifters. It works fairly well with downtube shifters were I can give the lever a little tug one way or another to fidget with a messy shift or a ghost shift issue enough to quell it. With Sora brifters, you wouldn't be able to do that. Higher likelyhood of shifting issues and keeping the shifting smooth throughout the range.
If the bike has a freewheel, then you're likely locked into 7sp unless you get a new wheelset (or at least rear wheel). 7sp freewheel hubs have a spacing of 126mm. 8-10sp hubs have a spacing of 130mm. The extra 2mm from 7 to 8 is how they fit the extra cog into the wheel while maintaining a very simular spacing per gear.
If you want to go with STI shifting, and do it right where you or your wife won't be messing with it fairly often, I suggest matching shifters to gears. I'm currently waiting on a new pair of shifters to match my 8sp cassette myself because I'm fed up with the shifting problems. It has worked for me over the last 9months, but after a season of having to switch the downtubes over to friction shifting in the middle of a 100k ride to stay in the gear I want, I'm done.
So here's my suggestion: get an 8sp cassette (SRAM still makes some in road gearing), an inexpensive wheelset (Ultegra/Open Pro for about $200 or check ebay for cheaper), and the Sora shifters. The Shimano 600 group is a fantastic setup and the Schwinn Prologue should be a great ride.
10-13-06, 11:05 AM
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The Shimano 600 drivetrain in the 1987 to 1990 period was perfect "as is". Don't change a thing. If a rider spends twenty minutes in an empty parking lot or empty running track practicing, learning to use downtube shifters is very easy. And, the "feel" and precision of the Shimano 600 brake levers from that period puts today's STI brake levers to shame.
Other than new tires and a tune-up, a Shimano 600 level bike from the 80's is best when left as original as possible. You could spend a bunch of money on supposed "upgrades", but you will not end up with a better bike.
Other than new tires and a tune-up, a Shimano 600 level bike from the 80's is best when left as original as possible. You could spend a bunch of money on supposed "upgrades", but you will not end up with a better bike.
10-13-06, 11:13 AM
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8 Speed levers will shift 7 speed cassetes OK. The spacing is close, but not identical. 4.8mm c-c for 8s, 5.0 c-c for 7. The other thing you can do is run 8 cogs and 7 spacers from a 9s cassette (just drop the biggest cog and associated spacer) on the 7s cassette body, and use 9s shifters. I do this on my road bike.
