Post your Centurion Ironman.. For the love of 80s paint jobs!
09-23-17, 12:19 PM
#3751
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Location: Los Angeles
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Gorgeous bike. 9000 wheelset and it will be perfecter.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
Last edited by Classtime; 09-23-17 at 03:42 PM. Reason: Add pic
09-23-17, 04:16 PM
#3752
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Absolutely do it.
Instant group tide conversation starter.
OEM tires were horrible, and that's being nice.
Instant group tide conversation starter.
OEM tires were horrible, and that's being nice.
Gorgeous bike. 9000 wheelset and it will be perfecter.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
09-23-17, 04:31 PM
#3753
Senior Member
Gorgeous bike. 9000 wheelset and it will be perfecter.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
09-23-17, 04:35 PM
#3754
Senior Member
This may irritate some, drop some pics off of older posts, but sometimes, ya gotta do....
I moved my Carbon-R to the dark side over last weekend, took about 4 hours, and only with a quiet determination to "just do it" did the endeavor complete itself. Wrenching with a cup of self-doubt on your shoulder tends to change the center of gravity, so to speak. I didn't feel really centered on the bike until I rode it.
OK, OK. texaspandj said "pics, already." Pics first, specs after. Ride report? Extremely good. Best this frame has presented itself to me, yet, and I'm certainly of a mind that only a wheel set upgrade may change that. (Discounting SRAM Red22 or one of the battery-powered systems...)
Not quite as striking as the previous version with more red and larger lettering on the wheels, but I'll deal with it. Perhaps less bike conversation at rest stops on large rides. So, we'll talk about women and drinking instead. Always a trade-off.
The cables are centered, the pic is just a bit off. I like them tight and right. Others prefer a bit more slack. I don't. The hoods are comfortable enough, and the cable routing is easier than previous "along the bar" STI's. The cables exit the shifter body side by side and stay that way.
Yes, I should have wiped it off. I ride it too much to keep it as clean as I should. I'll try to get better. I imagine I could save some weight with a lighter seat post. Good luck finding one in 25.0
I think the drivetrain looks decent with the black/polished mix, much like the frame's presentation. Several locals kept telling me "you gotta go 11-speed." I still don't think they're right, but I got a deal on the group and don't regret it. I'm now running 2 compact crankset bikes, and I've got no problem with them at all. The new FD arm system has me in "no noise, no trim" mode.
Prior to this build, I was fairly certain that the DA 7700 would always be the smoothest, lightest shifting STI system, followed closely by the DA 7800. I considered the "newer" routing to be one of the drawbacks to smoothness. The 9000 is "pick it and flick it," and just like the 7700, with what seems like a shorter paddle throw. Maybe it was just me, being satisfied.
1989/90 (Asian market) Centurion Carbon-R
56x56 Carbon tube/Alloy lugs. Aluminum fork.
Shimano 6400 headset. 3TTT quill 90mm stem. Nitto B115-420 bars.
Prologo Nack saddle w/carbon rails. 3TTT Fluted 25.0 seatpost.
Dura Ace 9000 compact crankset. Dura Ace 9000 FD and RD.
Dura Ace 9000 STI's Dura Ace 9000 11-28 cogs.
Dura Ace 9000 calipers. Shimano BB6700 bottom bracket.
SRAM PC X1 chain. Jagwire stainless cables/Jagwire Racer housing.
DT Swiss/Bontrager hubs with 2016 RXL hoops. Cont GP4000II 700x25 skins.
Fizik Microfiber wrap. Look Keo2Max Carbon/Ti pedals.
Runs a Garmin Edge 500 on an SRAM out-front mount.
Pearl Izumi bag, Ibera carbon fiber cage. Shimano cable stops.
Sans bag, 17.1 lbs. Sans bag, pedals, cage, GPS and mount, I figure 16.6-16.7 lbs.
I moved my Carbon-R to the dark side over last weekend, took about 4 hours, and only with a quiet determination to "just do it" did the endeavor complete itself. Wrenching with a cup of self-doubt on your shoulder tends to change the center of gravity, so to speak. I didn't feel really centered on the bike until I rode it.
OK, OK. texaspandj said "pics, already." Pics first, specs after. Ride report? Extremely good. Best this frame has presented itself to me, yet, and I'm certainly of a mind that only a wheel set upgrade may change that. (Discounting SRAM Red22 or one of the battery-powered systems...)
Not quite as striking as the previous version with more red and larger lettering on the wheels, but I'll deal with it. Perhaps less bike conversation at rest stops on large rides. So, we'll talk about women and drinking instead. Always a trade-off.
The cables are centered, the pic is just a bit off. I like them tight and right. Others prefer a bit more slack. I don't. The hoods are comfortable enough, and the cable routing is easier than previous "along the bar" STI's. The cables exit the shifter body side by side and stay that way.
Yes, I should have wiped it off. I ride it too much to keep it as clean as I should. I'll try to get better. I imagine I could save some weight with a lighter seat post. Good luck finding one in 25.0
I think the drivetrain looks decent with the black/polished mix, much like the frame's presentation. Several locals kept telling me "you gotta go 11-speed." I still don't think they're right, but I got a deal on the group and don't regret it. I'm now running 2 compact crankset bikes, and I've got no problem with them at all. The new FD arm system has me in "no noise, no trim" mode.
Prior to this build, I was fairly certain that the DA 7700 would always be the smoothest, lightest shifting STI system, followed closely by the DA 7800. I considered the "newer" routing to be one of the drawbacks to smoothness. The 9000 is "pick it and flick it," and just like the 7700, with what seems like a shorter paddle throw. Maybe it was just me, being satisfied.
1989/90 (Asian market) Centurion Carbon-R
56x56 Carbon tube/Alloy lugs. Aluminum fork.
Shimano 6400 headset. 3TTT quill 90mm stem. Nitto B115-420 bars.
Prologo Nack saddle w/carbon rails. 3TTT Fluted 25.0 seatpost.
Dura Ace 9000 compact crankset. Dura Ace 9000 FD and RD.
Dura Ace 9000 STI's Dura Ace 9000 11-28 cogs.
Dura Ace 9000 calipers. Shimano BB6700 bottom bracket.
SRAM PC X1 chain. Jagwire stainless cables/Jagwire Racer housing.
DT Swiss/Bontrager hubs with 2016 RXL hoops. Cont GP4000II 700x25 skins.
Fizik Microfiber wrap. Look Keo2Max Carbon/Ti pedals.
Runs a Garmin Edge 500 on an SRAM out-front mount.
Pearl Izumi bag, Ibera carbon fiber cage. Shimano cable stops.
Sans bag, 17.1 lbs. Sans bag, pedals, cage, GPS and mount, I figure 16.6-16.7 lbs.
Outstanding, Mr. Tunes.
09-23-17, 05:46 PM
#3755
Junior Member
Join Date: Aug 2017
Location: Atlanta
Posts: 130
Bikes: '87 Centurion Ironman Expert, '88 Basso Loto, '89 Panasonic MC-5500, '92 Vitus 992
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Gorgeous bike. 9000 wheelset and it will be perfecter.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
My number one bike had 7900 for about 3 years. Got rid of it and went back to 7700 to be happier.
My club had a deal on new carbon bikes with 9000 and after a test ride, I almost went for it.
I was going to redo my cables, but now I think they are fine. I'm seriously considering riding this beauty in Eroica CA. Anyone know what bar tape this might be? I'm pretty sure it is original. It handled the re-installation wonderfully and feels great. I wish the tires handled 30 years of storage like this tape.
I think I had the original tape, too, but decided to trash it because of the shape it was in. My guess is some generic vinyl like the one you can find on eBay by searching for "vinyl bar tape" (I can't post links yet). It would be nice to know what it actually was, though.
09-23-17, 07:40 PM
#3756
aka: Dr. Cannondale
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Yet another lovely iteration of that carbon frame.
Me likey!
Me likey!
__________________
Hard at work in the Secret Underground Laboratory...
Hard at work in the Secret Underground Laboratory...
09-24-17, 08:18 AM
#3757
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This may irritate some, drop some pics off of older posts, but sometimes, ya gotta do....
I moved my Carbon-R to the dark side over last weekend, took about 4 hours, and only with a quiet determination to "just do it" did the endeavor complete itself. Wrenching with a cup of self-doubt on your shoulder tends to change the center of gravity, so to speak. I didn't feel really centered on the bike until I rode it.
OK, OK. texaspandj said "pics, already." Pics first, specs after. Ride report? Extremely good. Best this frame has presented itself to me, yet, and I'm certainly of a mind that only a wheel set upgrade may change that. (Discounting SRAM Red22 or one of the battery-powered systems...)
Not quite as striking as the previous version with more red and larger lettering on the wheels, but I'll deal with it. Perhaps less bike conversation at rest stops on large rides. So, we'll talk about women and drinking instead. Always a trade-off.
The cables are centered, the pic is just a bit off. I like them tight and right. Others prefer a bit more slack. I don't. The hoods are comfortable enough, and the cable routing is easier than previous "along the bar" STI's. The cables exit the shifter body side by side and stay that way.
Yes, I should have wiped it off. I ride it too much to keep it as clean as I should. I'll try to get better. I imagine I could save some weight with a lighter seat post. Good luck finding one in 25.0
I think the drivetrain looks decent with the black/polished mix, much like the frame's presentation. Several locals kept telling me "you gotta go 11-speed." I still don't think they're right, but I got a deal on the group and don't regret it. I'm now running 2 compact crankset bikes, and I've got no problem with them at all. The new FD arm system has me in "no noise, no trim" mode.
Prior to this build, I was fairly certain that the DA 7700 would always be the smoothest, lightest shifting STI system, followed closely by the DA 7800. I considered the "newer" routing to be one of the drawbacks to smoothness. The 9000 is "pick it and flick it," and just like the 7700, with what seems like a shorter paddle throw. Maybe it was just me, being satisfied.
1989/90 (Asian market) Centurion Carbon-R
56x56 Carbon tube/Alloy lugs. Aluminum fork.
Shimano 6400 headset. 3TTT quill 90mm stem. Nitto B115-420 bars.
Prologo Nack saddle w/carbon rails. 3TTT Fluted 25.0 seatpost.
Dura Ace 9000 compact crankset. Dura Ace 9000 FD and RD.
Dura Ace 9000 STI's Dura Ace 9000 11-28 cogs.
Dura Ace 9000 calipers. Shimano BB6700 bottom bracket.
SRAM PC X1 chain. Jagwire stainless cables/Jagwire Racer housing.
DT Swiss/Bontrager hubs with 2016 RXL hoops. Cont GP4000II 700x25 skins.
Fizik Microfiber wrap. Look Keo2Max Carbon/Ti pedals.
Runs a Garmin Edge 500 on an SRAM out-front mount.
Pearl Izumi bag, Ibera carbon fiber cage. Shimano cable stops.
Sans bag, 17.1 lbs. Sans bag, pedals, cage, GPS and mount, I figure 16.6-16.7 lbs.
I moved my Carbon-R to the dark side over last weekend, took about 4 hours, and only with a quiet determination to "just do it" did the endeavor complete itself. Wrenching with a cup of self-doubt on your shoulder tends to change the center of gravity, so to speak. I didn't feel really centered on the bike until I rode it.
OK, OK. texaspandj said "pics, already." Pics first, specs after. Ride report? Extremely good. Best this frame has presented itself to me, yet, and I'm certainly of a mind that only a wheel set upgrade may change that. (Discounting SRAM Red22 or one of the battery-powered systems...)
Not quite as striking as the previous version with more red and larger lettering on the wheels, but I'll deal with it. Perhaps less bike conversation at rest stops on large rides. So, we'll talk about women and drinking instead. Always a trade-off.
The cables are centered, the pic is just a bit off. I like them tight and right. Others prefer a bit more slack. I don't. The hoods are comfortable enough, and the cable routing is easier than previous "along the bar" STI's. The cables exit the shifter body side by side and stay that way.
Yes, I should have wiped it off. I ride it too much to keep it as clean as I should. I'll try to get better. I imagine I could save some weight with a lighter seat post. Good luck finding one in 25.0
I think the drivetrain looks decent with the black/polished mix, much like the frame's presentation. Several locals kept telling me "you gotta go 11-speed." I still don't think they're right, but I got a deal on the group and don't regret it. I'm now running 2 compact crankset bikes, and I've got no problem with them at all. The new FD arm system has me in "no noise, no trim" mode.
Prior to this build, I was fairly certain that the DA 7700 would always be the smoothest, lightest shifting STI system, followed closely by the DA 7800. I considered the "newer" routing to be one of the drawbacks to smoothness. The 9000 is "pick it and flick it," and just like the 7700, with what seems like a shorter paddle throw. Maybe it was just me, being satisfied.
1989/90 (Asian market) Centurion Carbon-R
56x56 Carbon tube/Alloy lugs. Aluminum fork.
Shimano 6400 headset. 3TTT quill 90mm stem. Nitto B115-420 bars.
Prologo Nack saddle w/carbon rails. 3TTT Fluted 25.0 seatpost.
Dura Ace 9000 compact crankset. Dura Ace 9000 FD and RD.
Dura Ace 9000 STI's Dura Ace 9000 11-28 cogs.
Dura Ace 9000 calipers. Shimano BB6700 bottom bracket.
SRAM PC X1 chain. Jagwire stainless cables/Jagwire Racer housing.
DT Swiss/Bontrager hubs with 2016 RXL hoops. Cont GP4000II 700x25 skins.
Fizik Microfiber wrap. Look Keo2Max Carbon/Ti pedals.
Runs a Garmin Edge 500 on an SRAM out-front mount.
Pearl Izumi bag, Ibera carbon fiber cage. Shimano cable stops.
Sans bag, 17.1 lbs. Sans bag, pedals, cage, GPS and mount, I figure 16.6-16.7 lbs.
09-24-17, 09:51 AM
#3758
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Kind words, and gratitude outward. Definitely one for Thunder Ridge and the Dare. Building this allows me to run my black '89 Expert with 53/39 and 11-24, for when it's Hammer Time.
09-26-17, 01:49 PM
#3759
Me duelen las nalgas
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@RobbieTunes , @texaspandj and other Ironfolk...
I mentioned recently I've been stumped by a draggy drivetrain on my '89 Ironman Expert with Suntour GPX group. To give an idea of how bad it is, when I try to kick the pedal backward to a good position for takeoff after a stop sign or traffic light, I have to physically push it into position with my foot. With my other two bikes I just flick the pedal back with a foot and it swings completely around easily. Not so with the Ironman.
After checking everything carefully I've narrowed it down to the internal spring tension in the rear derailer cage pivot.
A few things it's not:
It's definitely the rear derailer tension. Specifically the cage pivot tension, where it pivots down/up from the main derailer body.
I should have thought of this first, but the GPX rear derailer cage requires at least twice as much effort to pivot as the Shimano derailers on my other bikes (Altus and Exage). This is adding a lot of drag, pretty comparable to riding the brakes.
To clarify, I don't mean the swing tension for shifting gears -- it feels and works fine. And I don't mean the B-tension screw and spring tension pivot around the attachment to the dropout/hanger. Those are both fine.
Just to test, I did try adjusting the B-tension screw yesterday but, as expected, it had no effect on the drag. It just made shifting sloppy, since it was already set perfectly for both the original 13-24 Suntour and new 13-25 SunRace freewheels. So I reset the B-tension screw to the original position for snappy shifting.
But the spring tension where the cage pivots from the derailer body feels excessive -- I don't mean a little, I mean it's seriously dragging the entire drivetrain. It's not gummy, sticking, gritty, etc. It pivots smoothly. But it demands way too much force.
When I used my left hand to pivot the cage downward a bit it relieved a lot of the drag. Of course that added some slop to the chain and it's impossible to recreate actual riding tension using that method. But it confirmed my hunch that the internal spring tension is way too high.
Have you ever disassembled a GPX rear derailer to see whether that spring can be adjusted? I've seen diagrams for older Suntour derailers and there were notches for the spring tension.
Also, if you have time, could you compare this derailer tension on your bikes just to compare? Even if your Ironmen have Shimano derailers the tension should be reasonable. I'm not sure how scientific my method is -- just flicking the pedal backward -- but it seems like the pedal/crank should spin more than half a rotation before dragging to a stop.
Thanks for any suggestions!
I mentioned recently I've been stumped by a draggy drivetrain on my '89 Ironman Expert with Suntour GPX group. To give an idea of how bad it is, when I try to kick the pedal backward to a good position for takeoff after a stop sign or traffic light, I have to physically push it into position with my foot. With my other two bikes I just flick the pedal back with a foot and it swings completely around easily. Not so with the Ironman.
After checking everything carefully I've narrowed it down to the internal spring tension in the rear derailer cage pivot.
A few things it's not:
- It's definitely not the chain. Tried two new chains. They're fine. I added a couple of links to one -- only a slight improvement.
- It's not chain suck. The chainrings are virtually unused, other than wear from riding since June.
- It's not the rear hub. It was already spinning freely. Just to be sure I cleaned, regreased and retensioned the cones/bearings last night.
- It's not the brakes dragging.
- It's not the tires rubbing.
- It's not the freewheel. Same problem with both the original Suntour 13-24 and new SunRace 13-25.
It's definitely the rear derailer tension. Specifically the cage pivot tension, where it pivots down/up from the main derailer body.
I should have thought of this first, but the GPX rear derailer cage requires at least twice as much effort to pivot as the Shimano derailers on my other bikes (Altus and Exage). This is adding a lot of drag, pretty comparable to riding the brakes.
To clarify, I don't mean the swing tension for shifting gears -- it feels and works fine. And I don't mean the B-tension screw and spring tension pivot around the attachment to the dropout/hanger. Those are both fine.
Just to test, I did try adjusting the B-tension screw yesterday but, as expected, it had no effect on the drag. It just made shifting sloppy, since it was already set perfectly for both the original 13-24 Suntour and new 13-25 SunRace freewheels. So I reset the B-tension screw to the original position for snappy shifting.
But the spring tension where the cage pivots from the derailer body feels excessive -- I don't mean a little, I mean it's seriously dragging the entire drivetrain. It's not gummy, sticking, gritty, etc. It pivots smoothly. But it demands way too much force.
When I used my left hand to pivot the cage downward a bit it relieved a lot of the drag. Of course that added some slop to the chain and it's impossible to recreate actual riding tension using that method. But it confirmed my hunch that the internal spring tension is way too high.
Have you ever disassembled a GPX rear derailer to see whether that spring can be adjusted? I've seen diagrams for older Suntour derailers and there were notches for the spring tension.
Also, if you have time, could you compare this derailer tension on your bikes just to compare? Even if your Ironmen have Shimano derailers the tension should be reasonable. I'm not sure how scientific my method is -- just flicking the pedal backward -- but it seems like the pedal/crank should spin more than half a rotation before dragging to a stop.
Thanks for any suggestions!
09-26-17, 04:09 PM
#3760
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Wow. It should easily move. All that's there for is to take up chain slack. I have two GPX RD's sitting here. I'll check them. I've never had that issue. In this case, it could have been disassembled, and turned "one too many" before insertion back into the body. I've done that with tricolor, and realized it before I mounted it.
09-26-17, 04:13 PM
#3761
working on my sandal tan
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You say it pivots smoothly, but I wonder if it would still move freer if opened up, cleaned, and lubed. RJ The Bike Guy has a good video on doing this to a Shimano RD, might be similar for the SunTour.
How is the RD alignment? I've noticed extra drag from the pulleys when the hanger was not well-aligned, but being 7-speed it still shifted alright.
How is the RD alignment? I've noticed extra drag from the pulleys when the hanger was not well-aligned, but being 7-speed it still shifted alright.
09-26-17, 04:35 PM
#3762
Me duelen las nalgas
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Wow. It should easily move. All that's there for is to take up chain slack. I have two GPX RD's sitting here. I'll check them. I've never had that issue. In this case, it could have been disassembled, and turned "one too many" before insertion back into the body. I've done that with tricolor, and realized it before I mounted it.
You say it pivots smoothly, but I wonder if it would still move freer if opened up, cleaned, and lubed. RJ The Bike Guy has a good video on doing this to a Shimano RD, might be similar for the SunTour.
How is the RD alignment? I've noticed extra drag from the pulleys when the hanger was not well-aligned, but being 7-speed it still shifted alright.
How is the RD alignment? I've noticed extra drag from the pulleys when the hanger was not well-aligned, but being 7-speed it still shifted alright.
Alignment seems okay. I've eyeballed it every which way. It's straighter than my comfort hybrid/errand bike's Altus derailer, which is bent because I've crashed a couple of times. But that derailer still shifts well (well... good enough for an errand bike with twisty grip slopshifters
), and there's no excessive drag.I'm heading over to the LBS to pick up a tool. I'll check their used bikes to see if they have a similar older road bike derailer to compare spring tension.
09-26-17, 06:29 PM
#3763
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Canklecat,
I had a same vintage SunTour XCM (09/89) where the cage was bound tight and would not rotate without force. Spring tension was adjusted via four mounting holes, two on the cage plate and two on the inside of the lower pivot casting. This gives four spring tension combinations. I'm assuming the GPX uses the same basic design.
Disassembly is different from Shimano. The cage releases from the lower pivot housing only at one particular point of rotation. This because the lower pivot housing has a small internal protrusion that locks into an undercut on the shaft of the cage. The pivot shaft flange next the undercut has a relief flat cut at one point, so that when the relief flat and protrusion are in alignment, the cage will be released from the lower pivot casting.
In the case of my XCM, the the pivot shaft also has a flat where it is swaged onto the cage. This relief is almost diametrically opposite the relief to release the cage. Consequently, aligning the relief on the swaged end of the shaft with the bottom of the lower pivot housing will align the protrusion and pivot shaft relief flat to release the cage. Once this is done, you use different combinations of spring anchor holes to vary the tension. While apart, clean, deburr and lubricate the shaft and housing.
It's kind of hard to explain, so here are pictures. Hopefully, they help. Oh yes, don't forget to remove the rotation stop screw first.
I had a same vintage SunTour XCM (09/89) where the cage was bound tight and would not rotate without force. Spring tension was adjusted via four mounting holes, two on the cage plate and two on the inside of the lower pivot casting. This gives four spring tension combinations. I'm assuming the GPX uses the same basic design.
Disassembly is different from Shimano. The cage releases from the lower pivot housing only at one particular point of rotation. This because the lower pivot housing has a small internal protrusion that locks into an undercut on the shaft of the cage. The pivot shaft flange next the undercut has a relief flat cut at one point, so that when the relief flat and protrusion are in alignment, the cage will be released from the lower pivot casting.
In the case of my XCM, the the pivot shaft also has a flat where it is swaged onto the cage. This relief is almost diametrically opposite the relief to release the cage. Consequently, aligning the relief on the swaged end of the shaft with the bottom of the lower pivot housing will align the protrusion and pivot shaft relief flat to release the cage. Once this is done, you use different combinations of spring anchor holes to vary the tension. While apart, clean, deburr and lubricate the shaft and housing.
It's kind of hard to explain, so here are pictures. Hopefully, they help. Oh yes, don't forget to remove the rotation stop screw first.
Last edited by T-Mar; 09-26-17 at 07:06 PM.
09-26-17, 07:07 PM
#3764
Me duelen las nalgas
Join Date: Aug 2015
Location: Texas
Posts: 13,513
Bikes: Centurion Ironman, Trek 5900, Univega Via Carisma, Globe Carmel
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Excellent info! Thanks so much, @T-Mar, much appreciated -- especially the clear photos and instructions.
Looking forward to tackling this project and seeing the results. Sure feels like riding with a constant light drag on the wheel, kinda like running a bottle generator or dragging brake pad.
Looking forward to tackling this project and seeing the results. Sure feels like riding with a constant light drag on the wheel, kinda like running a bottle generator or dragging brake pad.
09-29-17, 12:59 AM
#3765
Full Member
Im really excited to be in the MV club.
I had no luck finding a local score so I pulled the online auction trigger. Hope it's as nice as it looks when it arrives!
I can't post a pic because I have less than 10 posts. booo!
I had no luck finding a local score so I pulled the online auction trigger. Hope it's as nice as it looks when it arrives!
I can't post a pic because I have less than 10 posts. booo!
09-29-17, 06:34 AM
#3766
Senior Member
There's magic in those MVs.
Looking forward to your pics.
Keeping it original?
09-29-17, 07:27 AM
#3767
Full Member
09-29-17, 08:27 AM
#3768
Senior Member
09-29-17, 09:09 AM
#3769
Senior Member
Here's mine.
This same pic is on my tablet but so much clearer and detailed. It really brings out the Beauty of my Miami Vice. For some reason I can't post it so I posted it somewhere else then here and the gorgeousness was lost in transmission. It's a shame cause it's Awesome. Oh well maybe use original pic as a screen saver.
This same pic is on my tablet but so much clearer and detailed. It really brings out the Beauty of my Miami Vice. For some reason I can't post it so I posted it somewhere else then here and the gorgeousness was lost in transmission. It's a shame cause it's Awesome. Oh well maybe use original pic as a screen saver.
Last edited by texaspandj; 09-29-17 at 09:33 AM.
09-29-17, 12:33 PM
#3770
Full Member
I'm guessing someone just swapped out the wheels at some point. once I have the bike here, I'll have a better plan on what I need to return to stock.
Yours looks great!
09-29-17, 02:05 PM
#3771
Senior Member
I think I've aquired three bikes thru ebay, I could barely stand the wait.
I checked my stash it turns out I have a pair of wolber GTX hoops, wolber super alpine with 600 hubs from a master Ironman and wolber super alpine with 105 hubs from a Miami Vice.
I checked my stash it turns out I have a pair of wolber GTX hoops, wolber super alpine with 600 hubs from a master Ironman and wolber super alpine with 105 hubs from a Miami Vice.
09-29-17, 03:06 PM
#3772
Me duelen las nalgas
Join Date: Aug 2015
Location: Texas
Posts: 13,513
Bikes: Centurion Ironman, Trek 5900, Univega Via Carisma, Globe Carmel
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I tackled that drivetrain a couple of days ago. (Summary: There's unusually high felt drag in the drivetrain on my '89 Ironman Expert, which I traced to excessive tension in the rear derailleur. It's much higher than any felt drag in my hybrids or new bikes I've examined in the LBS. It's effectively robbing me of more power than any combination of tires, wheels, or other minor equipment issues.)
Over the past couple of weeks I've swapped in a SunRace 13-25 freewheel to replace the original 13-24 Suntour. I liked the spacing better with the new SunRace freewheel and original 42/52 chainrings.
Then I added a couple more links (1") to the chain, which reduced some tension and helped a bit.
And Wednesday I replaced the original 42T chainring with a new Vuelta SE Plus 39T (snagged it new for only $7 through an Amazon Warehouse sale -- it was listed as damaged packaging but to me it was indistinguishable from new). The smaller chainring makes the slightly-larger-than-stock 25 cog more effective for steep climbs, but I'm not sure I like the overall gear spacing. We'll see how it goes after a few more rides.
And the chain tension is reduced with the smaller chain ring, although now I'll need to pay closer attention to downshifting to avoid dropping the chain. Happened once on my first ride.
Disassembled the Suntour GPX rear derailleur. There was a combination of old dried grease and fresh so I cleaned it out and regreased it with Phil's green goo. It pivots slightly more smoothly but there's still a bit of the drag I described.
There are no alternate spring retention holes so it's not adjustable as-is. The cage pivot arm has a place where another hole could be finished, but it wouldn't solve the problem -- the hole would be in the wrong place and would overtighten the spring. I'd need to drill a second hole. But I'll wait and ride the bike awhile to evaluate the other drivetrain changes.
Also, the square section spring may have been overtorqued a bit already -- the diameter is slightly reduced at the end where it hooks into the cage pivot arm retention hole. Check the photos that illustrate this. I suppose a lower tension spring could be substituted. This was a common trick with gunsmithing to tune trigger pulls and actions on semi-autos, using either lighter or stiffer springs to suit the light target or heavier recoiling full loads.
There's also no alternate hole in the lower pivot housing. So really no way to reduce tension without modifying the derailleur.
Thanks again, @T-Mar, @RobbieTunes and other folks for tips and feedback.
Over the past couple of weeks I've swapped in a SunRace 13-25 freewheel to replace the original 13-24 Suntour. I liked the spacing better with the new SunRace freewheel and original 42/52 chainrings.
Then I added a couple more links (1") to the chain, which reduced some tension and helped a bit.
And Wednesday I replaced the original 42T chainring with a new Vuelta SE Plus 39T (snagged it new for only $7 through an Amazon Warehouse sale -- it was listed as damaged packaging but to me it was indistinguishable from new). The smaller chainring makes the slightly-larger-than-stock 25 cog more effective for steep climbs, but I'm not sure I like the overall gear spacing. We'll see how it goes after a few more rides.
And the chain tension is reduced with the smaller chain ring, although now I'll need to pay closer attention to downshifting to avoid dropping the chain. Happened once on my first ride.
Disassembled the Suntour GPX rear derailleur. There was a combination of old dried grease and fresh so I cleaned it out and regreased it with Phil's green goo. It pivots slightly more smoothly but there's still a bit of the drag I described.
There are no alternate spring retention holes so it's not adjustable as-is. The cage pivot arm has a place where another hole could be finished, but it wouldn't solve the problem -- the hole would be in the wrong place and would overtighten the spring. I'd need to drill a second hole. But I'll wait and ride the bike awhile to evaluate the other drivetrain changes.
Also, the square section spring may have been overtorqued a bit already -- the diameter is slightly reduced at the end where it hooks into the cage pivot arm retention hole. Check the photos that illustrate this. I suppose a lower tension spring could be substituted. This was a common trick with gunsmithing to tune trigger pulls and actions on semi-autos, using either lighter or stiffer springs to suit the light target or heavier recoiling full loads.
There's also no alternate hole in the lower pivot housing. So really no way to reduce tension without modifying the derailleur.
Thanks again, @T-Mar, @RobbieTunes and other folks for tips and feedback.
Last edited by canklecat; 09-29-17 at 03:17 PM.
09-29-17, 04:42 PM
#3774
Me duelen las nalgas
Join Date: Aug 2015
Location: Texas
Posts: 13,513
Bikes: Centurion Ironman, Trek 5900, Univega Via Carisma, Globe Carmel
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BTW, the LBS mechanics thought my bike's derailleur tension was typical for a road bike of that era. They showed me a few newer bikes that have almost zero drivetrain resistance because the derailleurs have few or no springs.
A few folks I see at local cycling group events ride classic bikes. So I'll have an opportunity to compare chaindrive feel and tension. Maybe I just need to get accustomed to it.
If this is typical of older road bikes I now have even more respect for folks my age who raced when they were younger. They were burning watts just to overcome drivetrain resistance that, nowadays, is next to nil. And mashing up hills in ridiculously tall gears. And here I've been complaining about a 42/24 combo not being good enough.
A few folks I see at local cycling group events ride classic bikes. So I'll have an opportunity to compare chaindrive feel and tension. Maybe I just need to get accustomed to it.
If this is typical of older road bikes I now have even more respect for folks my age who raced when they were younger. They were burning watts just to overcome drivetrain resistance that, nowadays, is next to nil. And mashing up hills in ridiculously tall gears. And here I've been complaining about a 42/24 combo not being good enough.
09-29-17, 05:18 PM
#3775
Junior Member
Join Date: Aug 2017
Location: Atlanta
Posts: 130
Bikes: '87 Centurion Ironman Expert, '88 Basso Loto, '89 Panasonic MC-5500, '92 Vitus 992
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You can post pics as a new member. You have to be looking at the full site (not mobile), and underneath where you type your reply, there's a "Manage Attachments" section where you can upload a pic.