Stupid ? Of the Month (a perpetual thread!)

[HPL]

I should have done this open-ended thread with my first stupid question as I'm sure there will be more.

I recently tore apart a BB due to having excessive (in my opinion) play and hearing a slight knock when pedaling; not feeling it though when pedalling or when manually spun w/o chain. It showed no signs of wear, pitting, scoring etc.on cups, spindle, or balls; no rust anywhere. Grease looked almost as if it was just repacked (last done by a shop), not dirty or dried out.

I cleaned, replaced balls, repacked, and adjusted feeling no play on NDS, but some play on drive side even though tightening it more made it start to bind and turn less freely. I took it for a test ride and sure enough the original sympton remained but less so.

I know that replacing the BB entirely will solve the issue (I'd use a cartridge instead of loose ball bearing type if replacing).

My stupid questions for the month:
Since I assume there must be more wear on the drive side, will simply reversing the spindle (it's symmetrical) "even out" the wear and allow me the better adjust it? Can I just replace the drive side cup and keep everything else as before? Can I tighten it up more with everything as it presently sits and "break it in"?
Easiest and quickest is to tighten up more and see what happens, but not really liking that thought and it would not be much more involved to flip the spindle and see what happens. I don't have a spare cup or BB; need to remove to check spindle length. The BB is from a 1st gen. Shimano 105 groupset with who knows how many miles on it (I'm not original owner & have put a good 3000+ miles on it myself with one prior servicing upon receiving bike) so not much too lose if I damage it beyond further use.
What would the best starting point between the 3 options other than complete replacement?

Feel welcome to berate me if my thinking is foolish.

Thanks!!

 

[vtwinvince]

There are no stupid questions. Regarding old school, loose bearing BB's, I mix and match and do a lot of unorthodox things to get them to work. For instance, on my Benotto the BB has a Campy cup, a Gipiemme cup and a Shimano axle, but it works. I would try flipping your axle and see.

 

[Nothin-fancy]

I would flip the axle. But you can get a cheap cartridge BB and find out if it's the BB.

I have a bike that was doing the same thing but it was adjusting perfectly fine but had a clunking-ish sound when pedaling. I changed it out to a cartridge BB and it still clunked. I've figured out that it's coming from my chainrings because they are 6/7 speed and I'm running a Campagnolo 9 speed chain and it's just a smidge to narrow for the chainrings and it's clunking on the shift ramps. So just saying that a random noise may be something else that's surprising. But it seems like you've narrowed it down.

 

[HPL]

@vtwinvince Thanks. I need to pull it out to measure anyways (something I should have done during the overhaul just in case).
I would use another cup, but only have Italian threaded ones, but I found a Chorus cartridge BB in my stuff with 1.37"x24 threads/102.5mm and should have Chorus cranks since can't use 105 JIS taper cranks on the Chorus spindle.

@Nothin-fancy Glad you mentioned the chainring. Large one definitely has noticeable wear so changing that out if I keep the same set up (small ring is fine, neither has ramps or pins). The Chorus crankset has good rings, but 52t versus the 53t I run with now.

 

[jim haseltine]

Back when I worked in the trade alloy cotterless cranks were starting to appear on utility bikes and we had a lot of customers complain of knocking or clicking when they rode - especially, for some reason, on Falcon bikes. The cure was a tiny drop of oil on the pedal threads and lightly wiped off before tightening them - ever since then I've never fitted pedals dry.

 

[HPL]

Back when I worked in the trade alloy cotterless cranks were starting to appear on utility bikes and we had a lot of customers complain of knocking or clicking when they rode - especially, for some reason, on Falcon bikes. The cure was a tiny drop of oil on the pedal threads and lightly wiped off before tightening them - ever since then I've never fitted pedals dry.

I always put some grease on the threads to prevent galvanic corrosion and general rusting. I did a pedal swap just for giggles though I did not suspect that issue.

One time while out of town (away from tools and parts) I experienced an odd knock that seemed cyclical (no pun!) while pedalling. I had a shop pull the BB and service (I physically inspected when they removed it; nothing wrong, old grease was excellent) and test ride. The tech said it was good (rode it with street shoes on Look pedals!). I immediately got on it and under load it still knocked. I had just cleaned enitre drivetrain meticulously prior to my departing my home, but after a couple rides I got caught in severe rain and knock occurred after that. When riding back from shop I found a pair of pedals to swap and knock still occurred even after BB service & pedal swap. Because rain caused debris/grit to get on my recently cleaned drivetrain I again cleaned and lubed chain and all cogs. Voila! Problem solved.
I made sure to do that on my present bike with the BB overhaul, but it did not solve it and BB play could be the only culprit.

Worked on car today, and now will do the spindle flip on the bike. I should know in an hour if I need a new part. I don't think my Chorus BB is long enough though I have plenty of ring to frame clearance with present set up. I think chainline will not be as optimal. Still might check for the heck of it just to see where chainline sits.

 

[HPL]

After removal of spindle to flip it, I could definitely see slightly different wear at the races with more on the drive side; not much but still not even on both races.
Upon flipping and readjusting I definitely got a tighter tolerance, but when I installed the drive side crank it seemed to be ever so slightly loose even after proper tightening. I removed it and re-oriented it 90° and it appeared to be better, but at this point I assume that it is also part of the issue.

I went on a short (12 mile) and fairly hard (18 mph avg) test ride and could still discern the same noise at the same spot in the pedal stroke, but less so than after initial overhaul. I am assuming that the crank arm might be part of the issue. I could definitely see chainline variation at normal pedalling load when in highest gears, though not enough to necessitate trimming front mech upon each rear shift change.

At this point I am going to ride it for another 1000 miles or so which will get me through the fall/winter seasons before replacing entire front drive, or earlier if problem becomes worse. I think 40 years is pretty good for original cranks. Upon measuring the spindle I think it had been replaced with a longer one (it measured 115.5mm) similar to what I have used on a triple ring set. There is plenty of inner ring clearance even using the installed 48t small ring (it was used as the outer ring when I first got the bike, removed OE 40t Biopace ring and use a 53t large ring at present; all round rings). I think the original 1st gen. Shimano 105 spindle was 110 to 112mm, but not positive. Present spindle is marked "MTBS609" with no Shimano branding. Is that a mountain bike spindle? I only have the 102.5mm Chorus BB as an onhand replacement, but bringing in the "small" ring 6.5mm/.25" is too close so needing to get a new BB if keeping same 53t/48t.

Any recommendations for a cartridge BB and 130 BCD crankset (willing to go 135 BCD since I have new 54t ring; running a 5 spd corncob 14-18t and at times 14-28t when in hill country).
Thanks!

Edit: chainline presently sits midway between the 15t and 16t cogs, or inline with 15t cog with chain on the large ring.

 

[ChromeChainstay]

did you check the chainring bolts

 

[HPL]

@ChromeChainstay I did; removed rings for cleaning, and polished up the cranks a bit. Bolts were tight upon removal; and also after 30 miles of test rides. Thanks for the heads up though; it has happened before. We learn through experience!

 

[ChromeChainstay]

i've had pedals click also cleats