Replacing BB/crank on '88 Centurion Ironman Expert... bunch of (dumb) questions
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Replacing BB/crank on '88 Centurion Ironman Expert... bunch of (dumb) questions
I would like to replace the BB and crankset on a stock 88 Centurion Ironman Dave Scott. The BB size is 68-113, the crank is 52/39, and the cassette is 7-speed. All components are Shimano 105. I took the BB apart and it is completely worn with pitting and scarring on the spindle. I'm guessing the hubs probably need replacement too.
Since it seems all components these days are 9 or 10 speed, will they work with my bike? For instance, I was looking at replacing the crank with a Shimano FC-5700-S paired with an appropriate BB, however it says it requires a 10 speed chain. Will it still work with a 7 or 8 speed chain?
I am replacing the rims with Velocity "Deep V" rims, so I figure it's a good time to swap out the hubs. Will any 126mm modern hub work with the 7-speed cassette? I would like to keep it so I don't have to replace the shifters too. Plus I don't ever need more than that. I barely shift as it is since it's so flat where I live.
I'm trying to keep my budget under $400. I have done some bike maintenance before but this is the first time I have replaced parts and it is confusing since bike components have changed so much in the last 20+ years. Please give me any recommendations you have that will allow me to upgrade the aforementioned parts (bb, crank, hubs), without getting stuff that is too "cheap" -- I would like to stay with replacements that are at least as good as the original 105 gear.
Thanks,
Ben
Since it seems all components these days are 9 or 10 speed, will they work with my bike? For instance, I was looking at replacing the crank with a Shimano FC-5700-S paired with an appropriate BB, however it says it requires a 10 speed chain. Will it still work with a 7 or 8 speed chain?
I am replacing the rims with Velocity "Deep V" rims, so I figure it's a good time to swap out the hubs. Will any 126mm modern hub work with the 7-speed cassette? I would like to keep it so I don't have to replace the shifters too. Plus I don't ever need more than that. I barely shift as it is since it's so flat where I live.
I'm trying to keep my budget under $400. I have done some bike maintenance before but this is the first time I have replaced parts and it is confusing since bike components have changed so much in the last 20+ years. Please give me any recommendations you have that will allow me to upgrade the aforementioned parts (bb, crank, hubs), without getting stuff that is too "cheap" -- I would like to stay with replacements that are at least as good as the original 105 gear.
Thanks,
Ben
#2
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I would like to replace the BB and crankset on a stock 88 Centurion Ironman Dave Scott. The BB size is 68-113, the crank is 52/39, and the cassette is 7-speed. All components are Shimano 105. I took the BB apart and it is completely worn with pitting and scarring on the spindle. I'm guessing the hubs probably need replacement too.
Since it seems all components these days are 9 or 10 speed, will they work with my bike? For instance, I was looking at replacing the crank with a Shimano FC-5700-S paired with an appropriate BB, however it says it requires a 10 speed chain. Will it still work with a 7 or 8 speed chain?
I am replacing the rims with Velocity "Deep V" rims, so I figure it's a good time to swap out the hubs. Will any 126mm modern hub work with the 7-speed cassette? I would like to keep it so I don't have to replace the shifters too. Plus I don't ever need more than that. I barely shift as it is since it's so flat where I live.
I'm trying to keep my budget under $400. I have done some bike maintenance before but this is the first time I have replaced parts and it is confusing since bike components have changed so much in the last 20+ years. Please give me any recommendations you have that will allow me to upgrade the aforementioned parts (bb, crank, hubs), without getting stuff that is too "cheap" -- I would like to stay with replacements that are at least as good as the original 105 gear.
Thanks,
Ben
Thanks,
Ben
#3
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Just get on eBay and buy the same stuff already on the bike. Tons of new, used, NOS and in between show up constantly. I have several 126mm bikes and the conversion to modern is a PITA getting everything lined up and then there is the thing of these so called 20 speed 10 speeds and index shifting and brifters and all of that. The "many" speed bikes just don't seem to friction shift very cleanly like the six speed cluster do/did.
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Is a replacement BB like this any good? I can't imagine quality for only $8 but maybe I'm wrong?
https://cgi.ebay.com/Shimano-BB-LP28-...item5888484bae
It also seems like some of these newer BBs have plastic cups (is this the right term?) on one side. Is this an issue? I'd rather pay for metal. Hell, I'll pay $40-70 for a BB if it's gonna last.
https://cgi.ebay.com/Shimano-BB-LP28-...item5888484bae
It also seems like some of these newer BBs have plastic cups (is this the right term?) on one side. Is this an issue? I'd rather pay for metal. Hell, I'll pay $40-70 for a BB if it's gonna last.
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This one looks better, no? And likely what I need?
https://cgi.ebay.com/IRD-QB-55-JIS-Sq...3#ht_500wt_928
https://cgi.ebay.com/IRD-QB-55-JIS-Sq...3#ht_500wt_928
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Throw a un-54 in there, replace $5 worth of bearings in the hubs, $10 worth of cones if needed - good to go
https://bicyclewarehouse.com/product/...te=google_base
https://bicyclewarehouse.com/product/...te=google_base
#7
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The plastic cup square taper bottom brackets are fine. I've used them for a lot of miles on my own bikes and seen them last just as long on others' bikes. All you do differently is use a lower torque on the plastic cup side. There are better square taper bottom brackets out there if you want to spend more:
https://www.universalcycles.com/shopp...8&category=268
You need a JIS taper (not Campy) for your cranks.
Either of the bottom brackets you linked to will work fine too.
https://www.universalcycles.com/shopp...8&category=268
You need a JIS taper (not Campy) for your cranks.
Either of the bottom brackets you linked to will work fine too.