Bottom Bracket Lug - common crack location?
02-25-23, 12:42 PM
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Bottom Bracket Lug - common crack location?
1989 Panasonic Mountain Cat
NDS chainstay at the bottom bracket.
Is this a location anyone has seen develop a crack?
I’ve had 2 TIG welded frames crack in this area. One a 25ish year old RockHopper. The other a couple of year old Gunnar CrossHair I had purchased new. Gunnar repaired at no cost to me.
This Panasonic I bought last year to use as my dirty road camper/tourer for 2023. While cleaning and frame savering I noticed this hair line on the lug that won’t scrape off. My thumb nail will catch on it.
When I flex the rear triangle it does not look too change. I suppose I could remove the paint….
So now what? Ride and keep an eye on it? Try to convince my wife I should buy an even older StumpJumper for sale an hour away for $500?
Contract Assenmacher to replace the lug? He’s not painting last time I checked, so I’ll have to rattle can it after….
Thanks.
In the wild this fall….
PS - this frame is spaced 130 mm for rear hub. As received it had a 130mm wheel installed. I upgraded to a different set and changed the hub to 130. White Industries has spacers to do that. They are great to work with.
NDS chainstay at the bottom bracket.
Is this a location anyone has seen develop a crack?
I’ve had 2 TIG welded frames crack in this area. One a 25ish year old RockHopper. The other a couple of year old Gunnar CrossHair I had purchased new. Gunnar repaired at no cost to me.
This Panasonic I bought last year to use as my dirty road camper/tourer for 2023. While cleaning and frame savering I noticed this hair line on the lug that won’t scrape off. My thumb nail will catch on it.
When I flex the rear triangle it does not look too change. I suppose I could remove the paint….
So now what? Ride and keep an eye on it? Try to convince my wife I should buy an even older StumpJumper for sale an hour away for $500?
Contract Assenmacher to replace the lug? He’s not painting last time I checked, so I’ll have to rattle can it after….
Thanks.
In the wild this fall….
PS - this frame is spaced 130 mm for rear hub. As received it had a 130mm wheel installed. I upgraded to a different set and changed the hub to 130. White Industries has spacers to do that. They are great to work with.
Last edited by mrv; 02-25-23 at 12:47 PM.
02-25-23, 12:52 PM
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Not a framebuilder but I'd guess replacing the bottom bracket is probably harder than building a frame from scratch. Now I have broken chainstays (behind the bridge; not at the BB. The bike rode OK with the broken chainstay. So if I were you, I;d just ride it and keep an eye on the crack. (If it does go, you will have that bridge keeping things together, at least for a while so I don't think you have anything to fear unless big time descents are in your future.)
Now,if this were at the front end of the bike, I'd take a much keener interest in that crack, mark the ends and watch carefully for growth.
Now,if this were at the front end of the bike, I'd take a much keener interest in that crack, mark the ends and watch carefully for growth.
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02-25-23, 01:20 PM
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Not a framebuilder but I'd guess replacing the bottom bracket is probably harder than building a frame from scratch. Now I have broken chainstays (behind the bridge; not at the BB. The bike rode OK with the broken chainstay. So if I were you, I;d just ride it and keep an eye on the crack. (If it does go, you will have that bridge keeping things together, at least for a while so I don't think you have anything to fear unless big time descents are in your future.)
Now,if this were at the front end of the bike, I'd take a much keener interest in that crack, mark the ends and watch carefully for growth.
Now,if this were at the front end of the bike, I'd take a much keener interest in that crack, mark the ends and watch carefully for growth.
I do have a couple of far-ish from home treks planned for the late summer - Katy Trail in Missouri, and some rail-trail stuff a few hours away in Michigan. Worst case I'm pulling out a credit card at a bike shop near the Katy trail. Or my wife comes and picks me up and we make a mini-vacation of it.
Keeping an eye on it is my first thought. When I had BB-cracks before, the shifting went wonky first. Neither time was I far from home though.
02-25-23, 01:29 PM
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Your crack is on the non-drive side so even if it fails, your gears ought to work pretty well.
Those big Lower Mitten climbs - I lived at the summit of Ann Arbor' s mountain for two years. In those days I was superman and could make that massive ascent on my 42-17 fix gear.
Those big Lower Mitten climbs - I lived at the summit of Ann Arbor' s mountain for two years. In those days I was superman and could make that massive ascent on my 42-17 fix gear.
02-25-23, 01:30 PM
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ouch: $250 for a BB replacement: https://www.assenmachers.com/about/2...rame-pg171.htm
- not a lot for a repair - just a lot when I can get a beautiful refurbed Peugeot Orient Express for $500 - and I think it's the exact same frame!
- not a lot for a repair - just a lot when I can get a beautiful refurbed Peugeot Orient Express for $500 - and I think it's the exact same frame!
02-25-23, 07:04 PM
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1- The scratch doesn't look like the typical cracks that happen to a lugged BB, much more like a simple scratch from a sharp pointed something. So I suggest riding the bike and just keep an eye on this to be sure.
2- Replacing a BB shell is a big effort and one that many builders won't seek out. Replacing BB shell on a French frame? - Bike Forums Is a thread on this that just happens to be current.
3- I sold Panasonics for a bunch of years back in the day. Perhaps one of the better production bikes WRT joining quality and consistency that I have handled. Andy
4- $250 is what I would consider a low price for a shell replacement. I suspect Matt A isn't doing this to make "real" money... Andy
2- Replacing a BB shell is a big effort and one that many builders won't seek out. Replacing BB shell on a French frame? - Bike Forums Is a thread on this that just happens to be current.
3- I sold Panasonics for a bunch of years back in the day. Perhaps one of the better production bikes WRT joining quality and consistency that I have handled. Andy
4- $250 is what I would consider a low price for a shell replacement. I suspect Matt A isn't doing this to make "real" money... Andy
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02-25-23, 07:52 PM
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Originally Posted by Andrew R Stewart;[url=tel:22812490
22812490[/url]]1- The scratch doesn't look like the typical cracks that happen to a lugged BB, much more like a simple scratch from a sharp pointed something. So I suggest riding the bike and just keep an eye on this to be sure.
2- Replacing a BB shell is a big effort and one that many builders won't seek out. Replacing BB shell on a French frame? - Bike Forums Is a thread on this that just happens to be current.
3- I sold Panasonics for a bunch of years back in the day. Perhaps one of the better production bikes WRT joining quality and consistency that I have handled. Andy
4- $250 is what I would consider a low price for a shell replacement. I suspect Matt A isn't doing this to make "real" money... Andy
2- Replacing a BB shell is a big effort and one that many builders won't seek out. Replacing BB shell on a French frame? - Bike Forums Is a thread on this that just happens to be current.
3- I sold Panasonics for a bunch of years back in the day. Perhaps one of the better production bikes WRT joining quality and consistency that I have handled. Andy
4- $250 is what I would consider a low price for a shell replacement. I suspect Matt A isn't doing this to make "real" money... Andy
02-25-23, 08:05 PM
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I am 88.5% sure that is not a crack, just a scratch.
The Beatles weigh in:
"Rocky said, Doc it's only a scratch"
"Speaking words of wisdom — Let it be"
Mark B
The Beatles weigh in:
"Rocky said, Doc it's only a scratch"
"Speaking words of wisdom — Let it be"
Mark B
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02-26-23, 05:18 PM
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02-27-23, 05:21 AM
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Cracks almost always happen at the transitions from one tube to another. Something probably got stuck in the wheel and pushed into the bb shell and scratched the paint.
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