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-   -   Bottom bracket question (https://www.bikeforums.net/bicycle-mechanics/1273704-bottom-bracket-question.html)

cemark 05-30-23 12:47 PM

Bottom bracket question
 
I dont know how this happened but when i was changing my seatpost i saw some corrosion in the seat tube all the way down to the bottom bracket area. I did some research and found a good solution that almost worked perfect. I cleaned the rust with steel wool but at the bottom bracket area the two sides of the down tube made it impossible to clean. I put some before and after picture. It looks much cleaner but i couldnt clean it all because of the shape of the bottom bracket area. I dont know whats exactly called that part. Is there a practical solution for it? Does it still look bad and may cause a problem in the future?

Also when i was cleaning i removed the bottom bracket and realized that one part of the bottom bracket which is the middle cylinder is missing. Probably bicycle mechanic didnt put it and i just realized it. Should i be worried and order a new bottom bracket or that specific part or can i still use the bicycle as it is. I never had a problem with the bicycle using like this but i just wanted to make sure.
https://cimg0.ibsrv.net/gimg/bikefor...13d9d7917c.png

https://cimg1.ibsrv.net/gimg/bikefor...111178f0d2.jpg
After
https://cimg3.ibsrv.net/gimg/bikefor...722225d856.jpg
After 2
https://cimg5.ibsrv.net/gimg/bikefor...38fd17ca16.jpg
Before
https://cimg4.ibsrv.net/gimg/bikefor...ec5910b1ca.jpg
Before 1

mpetry912 05-30-23 06:12 PM

so you're scrubbing all that "rust" and letting the residue cascade down into the bottom bracket ?

isn't Cannondale aluminum ? does aluminum rust ?

what am I missing here ?

/markp

soyabean 05-30-23 06:25 PM

I don't think the OP realizes that there are dozens of types of bottom brackets, and the one in diagram is a popular sealed unit, which may not apply to the OP.

"middle cylinder is missing" means it isn't a sealed unit, and just a crown race bearing type found on most big box store bikes.

Seat tube "corrosion" isn't an issue and safe to leave as-is. A well lubed seatpost is all it takes.

The OP did all this for nothing, and sure caused more damage by inadvertently honing out the seat tube to a possibly larger diameter.

This is why exists Local Bike Shops.

They are there to help.

maddog34 05-30-23 06:36 PM


Originally Posted by mpetry912 (Post 22907522)
so you're scrubbing all that "rust" and letting the residue cascade down into the bottom bracket ?

isn't Cannondale aluminum ? does aluminum rust ?

what am I missing here ?

/markp

you're assuming that cemark only owns one bike.

Look at the thickness of the seat tube.. that's not an aluminum frame.

maddog34 05-30-23 06:46 PM


Originally Posted by soyabean (Post 22907535)
I don't think the OP realizes that there are dozens of types of bottom brackets, and the one in diagram is a popular sealed unit, which may not apply to the OP.

"middle cylinder is missing" means it isn't a sealed unit, and just a crown race bearing type found on most big box store bikes.

Seat tube "corrosion" isn't an issue and safe to leave as-is. A well lubed seatpost is all it takes.

The OP did all this for nothing, and sure caused more damage by inadvertently honing out the seat tube to a possibly larger diameter.

This is why exists Local Bike Shops.

They are there to help.

the term "crown race" refers only to a part of a Headset.

and many cup and cone BB assemblies come with a removable plastic tube to help prevent garbage and water from easily entering the BB bearings... whether it's "missing" or not has yet to be determined.

To Cemark... nice job cleaning up the bike's tubes ! there are products meant to coat the insides of frame tubes to limit further rusting... here's an article on the process.. there are others, i'm certain. https://surlybikes.com/info_hole/spe...ur_steel_frame

If the Rust has popped through the tubes in ANY AREA, the frame is not even close to "safe" and don't waste another minute on it, ok? just find another frame or project with less rust..

so far, it appears the frame is worth saving.. wha brand and model?

soyabean 05-30-23 06:52 PM

1 Attachment(s)

Originally Posted by maddog34 (Post 22907560)
the term "crown race" refers only to a part of a Headset.

and many cup and cone BB assemblies come with a removable tube to help prevent garbage and water from easily entering the BB bearings... whether it's "missing" or not has yet to be determined.

Nope.

Crown encased bearings were popular since the 90s and still used today in many new big box store bikes. We call them that because it looks like a royalty's crown.

Likewise, I have never see big box store bikes with any removable tube. That surely adds manufacturing costs.

smd4 05-30-23 07:08 PM

Those are “caged” bearings. And they definitely aren’t “races.” The “crown race” is part of a headset.

maddog34 05-30-23 07:12 PM


Originally Posted by soyabean (Post 22907567)
Nope.

Crown encased bearings were popular since the 90s and still used today in many new big box store bikes. We call them that because it looks like a royalty's crown.

Likewise, I have never see big box store bikes with any removable tube. That surely adds manufacturing costs.

the bearings you pictured are commonly known as "Caged bearings". and your timeline is horridly truncated, demonstrating a basic lack of experience

just curious, where are you getting the idea that the bike is a "box store" bike?

dedhed 05-30-23 07:37 PM


Originally Posted by soyabean (Post 22907567)
Nope. We call them that because it looks like a royalty's crown.

And we call them "caged" as well as most of the industry.

​​​​​​https://www.google.com/search?q=cage...hrome&ie=UTF-8

Andrew R Stewart 05-30-23 08:04 PM

Retainer ring of balls is another reference for the caged balls. Crown race as in fork crown. Never heard of a retainer/cage being called a crown but I do see the resemblance. "sealed" can mean the bearing unit only or the entire BB assembly. Andy

cemark 05-30-23 10:30 PM


Originally Posted by mpetry912 (Post 22907522)
so you're scrubbing all that "rust" and letting the residue cascade down into the bottom bracket ?

isn't Cannondale aluminum ? does aluminum rust ?

what am I missing here ?

/markp

I removed the bottom bracket and cleaned all the residue but there are still some leftover because i couldnt reach with a cloth to the corners that i tried to show in the pictures

bicycle frame is steel by the way

Russ Roth 05-30-23 10:43 PM


Originally Posted by cemark (Post 22907743)
I removed the bottom bracket and cleaned all the residue but there are still some leftover because i couldnt reach with a cloth to the corners that i tried to show in the pictures

bicycle frame is steel by the way

The area you can't reach is unimportant as is the part of the BB you may be missing. You've done a good job cleaning the seat tube, spritzing a little PB blaster down the tube to lightly coat the frame isn't the worst idea, not as good as JP Weigle's frame saver but good enough. Just remember to remove and spray from the top where the post is clamped, that should be liberally greased if using a steel or aluminum seat post or using carbon paste if a carbon post.
'

Bill Kapaun 05-30-23 10:59 PM


Originally Posted by soyabean (Post 22907567)
Nope.

Crown encased bearings were popular since the 90s and still used today in many new big box store bikes. We call them that because it looks like a royalty's crown.......

Who is this "we"?
It's certainly not "us".
Ignore list.

cemark 05-31-23 12:29 AM

I keep learning new stuff about cycling everyday when i have problems like this. I thought i did have a well lubed seatpost but i may have mistaken or somehow a little water penetrated into the seat tube.
This is a Salsa Vaya frameset. I bought all the parts individually and gave them all to my local bike shop. They provided the bottom bracket. So i didnt even know which bottom bracket they used.
I wanted to sell this bicycle and i wanted to have peace of mind after i sell it. I didnt want to give a damaged bicycle frameset to someone. Probably no one would ever check whats happening in the seattube with a flashlight.
I dont think i made the seat tube any larger. maybe 0.001cm wider. I just used a steel wool and polished those rusted area for 30 second. Still, hopefully didnt damage the frameset.

cemark 05-31-23 12:36 AM

Its Salsa Vaya and I have it only for 2 years. To me its worth saving as i have built it the covid times which was a pain in the a.. I had to wait months for parts that i had to order from all around the world.
I checked all the frameset and it looks completely new from outside, no rust whatsoever. I kept it inside all the time and covered possible contact points of the frame with thicker protective stickers.
Thanks for the link. I will definitely coat the insides of the tubes. I will either sell the it or keep it for a long time but either case i would like to keep it in a good condition.

cemark 05-31-23 12:42 AM

Thanks for the advise, i will look try to find a PB blaster or the frame saver. I live in Israel and it wont be so easy to find the JP Weigle's frame saver and they wont ship it here probably.
I did put the bottom bracket back to its place. Should i revome the cranckset and bottom bracket again before coating the seat tube?

Right now i am using aluminium seatpost buy i will buy a carbon seatpost. I will use carbon paste indeed.


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