so on my SS bike, the bottom bracket makes a creaking sound (kind of like an old wooden boat) whenever i start pedaling, and continues until i get up to about 15 mph. it seems to only happen when i put force on the left pedal.

i've recently converted this bike to a ss/fixed, andi made sure the chain had absolutely no slack when i installed the wheels. so, should i give the chain some slack? or is something else wrong with bottom bracket?

any help is appreciated, thanks much!

did you check the tightness/torque of the crank onto the bb (or the torque of the bb, if it's not the crank)? i don't think this is a chain issue. and given it's the left (non-drive) side, my hunch is that it's the crank.

crankset came on the frame which was given to me by a friend. checking the torque is a good idea since he claims the bike has been sitting around for a while. is there some sort of chart that explains how much torque i need to give it or is it universal for all cranks? i have an open model frame, nothing very special.

If you know the make/model of the crank you should be able to find the torque specs, assuming your talkingabout square taper i've heard 35ftlb(?) I don't use a torque wrench but many will tell you it is nesicary. could also be a lose lockring if its an adjustable bottom bracket

Yup, see link for fastener torque values:

https://www.parktool.com/repair/readhowto.asp?id=88

Sure it's the bottom bracket?

Nearly every time I've had pedaling-under-load creaking it was the stupid seatpost.

I second what Gene2308 posted. I've had the same experience with creaking.

Third. It's usually the seatpost. Remove it, clean it really well and put a light coat of grease on it then reinstall.

check cleats and pedals

The seat post is a good start. Another possibility is a little moisture in the BB. This will require removing the BB to check.

Take the pedals out, grease the threads, and put them back in, tight.

Also, read this: https://www.sheldonbrown.com/creaks.html

I had a similar creak and it turned out to be the Right Side -chainring side- Fixed Cup.
I tightened it w/a big Crescent wrench. This was an old, loose ball type square taper BB.
Cheers

You know i did get a new seat post recently! will try that first, although it'll have to wait a while since i blew one of my tires today (bead ripped off the rubber, taking the tube with it). Thanks for this recommendation.

thanks for the chart and the link MudPie and noglider.

ColKrenzer, are you saying you also though it was the left side, but it turned out to be a problem with the drive side?

You can't adequately tighten a fixed cup with a crescent wrench.

Well, it was one of those things - the squeeek - that just bothered me.
I checked the saddle & seatpost by swapping them with ones known to be quiet. Still squeeeked.
Took off the crankarm - left side, cleaned, greased, torqued back on. Still squeeeked.
Took off the right crankarm and chainrings, cleaned, greased and saw the bearing cup with the two flats on it. I have a 15" crescent wrench I hadn't used in a while and thought "why not"? I fitted the wrench on the two flats and probably applied 75lbs force x 1.25' = about 90ft/lb. The cup turned about 1/8 turn right away w/maybe 20ft/lb, then firmed up quite a bit. Altogether it turned a little less than 1/4 turn. That felt about right.
I put everything back together. NO MORE SQUEEEK even after almost a year. So I don't know, I'm just saying....
This bike is an old Colnago w/ a steel frame. I'd have let up on the torque sooner if it had been Aluminum.
I hope this helps in some way!
Cheers