So about 15 months ago I bought a road bike (aluminium frame) with a threaded bottom bracket (Shimano BB-RS500) and while they were setting up the bike at the shop, they realised the bottom bracket was put on reverse sided (left cup on right side and vice versa), then they removed it and installed it the correct way (right cup on right and left cup on left side). I asked them if that would be a problem and they said it would not. This was about 15 months ago.

Two weeks I took my bike to get serviced and I mentioned a clicking sound from bb to my mechanic (different shop and mechanic) he said he will take a look at it. When I picked up my bike, he said the right cup was way too tight to remove. So that initial reverse installation was already bothering me from day one and since I heard this tightness it started to bother me even more.

My question is if I manage to uninstall that bottom bracket, what damage may be beneath it, like would the threads on the bb be damaged or the threads in my frame would be damaged, and would replacing that initially reverse installed then correctly installed bottom bracket solve all possible problems (including that clicking sound)? What would you suggest me to do? Should I just leave it as it is or should I replace the bottom bracket (I wanted to upgrade my bb too because it came as a lower model than what was written on the product page, I'm a little perfectionist).

Thanks for your help in advance.

How did they switch the BSA cups? One side is reverse threads so without permanently damaging the shell this would be impossible. If the original shop did actually do this than they owe you a fix. The BB shell and the BB cups will probably both be trashed. Take it back to the original shop you bought it from and go from there.

Same question. "Installing" a cup on the wrong side seems like it would totally bung up the threads in the BB. Steel cups in an aluminum frame means the cups would act like a tap and rethread the aluminum BB. And it would take a LOT of force to do it. And then installing the cups correctly would rethread the BB again. This makes no sense. I think the OP misunderstood what the bike shop was saying.

To get a right handed cup to tighten in a left handed thread or vice versa you can re-tap the frame or use a big impact driver. That's assuming the parts are in spec - it won't be so hard to turn a wrong-handed cup in an already stripped thread but it won't stay tight. In either of these cases the thread in the frame is damaged, and the tight side has probably either been forced in and jammed because of thread damage or glued in because they thought it would loosen otherwise.

aluminum BB, aluminum frame... the threads will be roached on the frame and BB just about equally. IF the right cup was"too tight", it would have to be improperly threaded since the threads were already bunged up by the first incorrect install and it would also look ruined on the OUTSIDE of the cup. you never said a thing about that factor.

too many odd things mentioned or overlooked.... like the fact that you rode it messed up for over a YEAR, out of alignment and dragging badly......
putting a BB cup into opposite threads ends with the cup NOT fully installed, and it doesn't line up correctly.
installing a Hollowtech 2 crank into it would be nearly impossible, and the crank wouldn't turn well, if at all.

i've run across this a couple of times, but with steel frame and aluminum BB, or an aluminum frame and steel 5 piece BB. I've seen ONE steel/steel case of backward insy=tall..that bike went away to be made into a really cheap washing machine and two walmart steel rims.
neither one turned well.. one was WAY too loose, regarding adjustment, and the other one displayed drag,was a hassle, but came apart... the steel/steel didn't turn at all since the caged bearings got crushed, then rusted too.... i saved the ashtabula valentine crank.

either the first "shop" screwed up then lied about their mistake, and the second shop is also lying,,
,,,,, or you're the one lying.

i'm leaning towards option #2.

just my opinion.

using a BB tap set will POSSIBLY get things sorted out, or could leave too little thread to properly seat the new BB you will need to buy and try to install.

and there's a small chance that shop #1 bought you a year of riding by re-installing one cup with some evil green Bearing Retainer Locktite.... in that case, heat is your friend, but not at all friendly to paint..
Good Luck

I had this done to me once, but the frame was Italian, so both sides had right-handed threading.

I assume yours is too, or you would not have a useable frame. (The BB cups can't be BSA -- even the right-threaded one won't work as it is a different diameter and pitch.)

When I finally got around to correcting it 25 years later, I remember it was an ordeal to get the fixed cup off, but the frame and threads are fine.

.
...I think there's some information missing. Sealed unit BB assemblies come in an assortment of varieties. Some have aluminum cups (not really "cups", but are commonly references as such). Some ogf them have nylon/plastic cups. The purpose of these is not, as in the old style of cup and cone, to serve as a race for bearings, but to simply hold the sealed unit assembly in position. Thus nylon/plastic will work for this. The nylon ones don't usually wreck the threading in the shell. They are soft, and generally conform to whatever they discover inside by way of threading. And as already mentioned, there are a few bicycles still made to the Italian standard, with RH threading on both sides.

I don't know if this is your circumstance. Really, without disassembly and inspection, there's no way to know what's going on with your bicycle at this point.

I wouldn't panic yet, there are some fixes. But it doesn't sound like you're in a position to employ them by yourself. If you're asking whether the guys who sold you that bike screwed you, maybe or maybe not. Depends on what your threading looks like, and the whole situation as you describe it is rather mysterious to me.

It isn't a mystery. He says it is a BB-RS500:



What I don't understand is how you turn an aluminum cup with reverse threads into an aluminum frame with standard thread, and vice versa. That's impressive work.

That is impressive work. I had no idea this was even possible, even if you were intentionally trying to trash the frame.

​​​.

...still seems mysterious to me. I am easily mystified.

If the frame was originally English or French thread, the BB shell can be reamed and tapped with Italian thread. If the shell was originally Italian thread, a threadless cartridge can be used to mount a crankset.

If it is Italian, the thread isn't damaged.

A few posts ago I was going to say that we didn't even know the shell's threading spec. I tried to look up the spec options of a BB-RS5000 and only found Eng/BSA versions. So I didn't post.

One more thread where we all speculate, and the OP hasn't (yet) followed up with more info. Andy

https://blueskycycling.com/products/...bottom-bracket
RS500B is a BSA, RS500I is Italian.

If it was, and I guess from that comment, assuming the shell is too, why would they care if they’d put them in the wrong sides? Are they not identical in that case?

IF, if, if- Not all cartridge BBs have the axle centered WRT the frame centerline (usually called "symmetrical"). So if an Itl, threaded Bb was installed backwards the resulting chainline might not align as intended. But there would be no thread damage as in cross threading. Do know that because the drive side BB cup wants to unthread on it's own (epicyclic forces) some mechanics will apply a thread locker to that cup and if a strong version of this was used that cup would likely require far more force to loosen than usual. Andy

Well, one side is labeled differently than the other. Which is how this started.

+1. I noticed when searching for the RS500 all that turned up appeared to be BSA so went to the Shimano site and it lists it as available in 68 & 70mm shell widths but doesn't note BSA or ITA so to the uninformed (maybe the OP) there is no obvious difference in threading. Could explain this whole thread. SHIMANO TIAGRA Threaded Bottom Bracket 68/70 mm shell width | SHIMANO BIKE-US We need to hear back from the OP to find out which he actually has.

Heat should help.

With all the other things that cause clicks and noises that we think is the BB, I wouldn't say that the OP's noise issue is only due to the BB being installed wrong and subsequently corrected. Might still be totally unrelated. The issue of not being able to get the cup removed might be and stand a good chance as being related to the original faulty installation.

The cracking noise may possibly be a cracked ball in a pedal bearing as they rotate once per BB revolution.I know this thread is old but I was just searching for answers to my BB problem and thought of this possibility. What happened in the end, did it ever get sorted ?

Trevor