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-   -   Help deciding crankshaft setup (https://www.bikeforums.net/singlespeed-fixed-gear/1239021-help-deciding-crankshaft-setup.html)

lancelegstrong 09-17-21 08:49 PM

Help deciding crankshaft setup
 
Need some advice as I am fairly new to this,


So basically i am getting a lot of clunking/clicking that seems to be coming from my crankshaft area, i've taken a look and discovered that my (FSA) chainring doesn't attach properly to my (dura-ace 7400?) crankset, all of the bolts are fully tightened all the way but here is still play in 4 out of the 5 of them.

Im guessing this would be the main culprit for the noises coming from that area but i have a sneaking suspicion there might be some bearing wear as well because it seems like i can feel some clunking coming from my left pedal too not just the crankset side (hard to say for sure though, only going by feel)


Luckily, either way i already want to upgrade my chainring to a 44T size (the fsa is 42T currently) so i was looking at finding a duraace chainring to match and then hopefully getting a better fit with the bolts to secure and clicking coming from there.

Looking at durace chainrings, unfortunately seems like the cheapest i could get one shipped to Australia for is around $90-$100 AUD, then i would mostly likely need new bolts ($25 AUD) and chainring bolt tool ($10AUD) to get the job done, then if i'm still getting clicking i will have to take a look at the bottom bracket and possibly do work on that, i'm not sure what the bottom bracket is but i don't think its anything good so might just replace bearings or might do a whole upgrade?


Basically i don't know what to do in terms of upgrading all the parts or just buying a whole new crankset considering the price of even doing the chainring isn't going to be exactly budget. Is the durace i've got worth keeping and getting what i need to fix the problem or should i just sell what i have, get what i can for the crankset/chainring separately and then buying something else? I know durace seem to have a decent reputation but i really don't know enough to make an informed decision.


For reference, I am currently freewheeling, use the bike for commuting mostly and also recreational riding and exercise, take it to the nearby velodromes fairly frequently for exercise etc. I don't need to be breaking any speed records but i would like something nice and smooth to ride with at least which i feel quite far from atm. Doesnt need to be top tier but something decent that wont break the bank...


Let me know what you think, i'll attach some pics, cheers!

lancelegstrong 09-17-21 08:50 PM

2 Attachment(s)
Pics

TejanoTrackie 09-17-21 10:04 PM

By "crankshaft" do you mean bottom bracket ? Your second photo seems to show the left side bottom bracket cup not fully seated in the frame. As to your chainring bolts being loose, that could certainly cause noise. Perhaps you just need shorter bolts so they will tighten fully. Did you originally have an inner chainring that you removed to make it a single speed, and reused the original bolts ? Your Dura Ace crank arms are probably not the cause of the noise, so replacing them will not solve the problem. They are top quality, so I would not replace them.

lancelegstrong 09-17-21 10:17 PM


Originally Posted by TejanoTrackie (Post 22235135)
By "crankshaft" do you mean bottom bracket ? Your second photo seems to show the left side bottom bracket cup not fully seated in the frame. As to your chainring bolts being loose, that could certainly cause noise. Perhaps you just need shorter bolts so they will tighten fully. Did you originally have an inner chainring that you removed to make it a single speed, and reused the original bolts ? Your Dura Ace crank arms are probably not the cause of the noise, so replacing them will not solve the problem. They are top quality, so I would not replace them.

Ohh sorry i meant to say crankset not crankshaft (getting my car and bike parts mixed up haha), but yeah the noise is coming from that area, just not sure where exaclty, hard to pinpoint so could be bottom bracket, could be crankset

I didn't realise about the bracket cup not being correctly seated, i will have to take a look at it and see if i can fix it. Perhaps thats also part of the problem?

I receive the bike as it is currently so not sure about the history, i'm assuming that whoever but the chainring on maybe used FSA bolts instead of durace ones so thats why they don't clamp properly, or the FSA chainring is just a bit thinner than the durace ones are so theres a gap in between? Im hoping with the correct (durace) chainring on the crankset it'll fix the problem though.

So you think definitely keep the durace and just replace the parts as needed?

Cheers

Rolla 09-18-21 12:07 AM

Replace the chainring with any 44T unit that has the same BCD measurement (distance between the bolts) and 3/32" tooth width. It doesn't have to be Dura Ace or anything expensive. When you do that, get shorter fixing bolts that will fully secure the chainring to the crank spider. I've seen perfectly tight bottom brackets with a few threads showing outside of the bottom bracket shell, but if yours is loose it can definitely contribute to noise, so be sure to check it. The left (non-drive) side is right-hand threaded, and the drive side is reverse, btw.

And note that a bigger chainring will use up more chain, so the rear wheel will need to move forward unless you get a longer chain to accommodate for it.

lancelegstrong 09-18-21 01:43 AM


Originally Posted by Rolla (Post 22235189)
Replace the chainring with any 44T unit that has the same BCD measurement (distance between the bolts) and 3/32" tooth width. It doesn't have to be Dura Ace or anything expensive. When you do that, get shorter fixing bolts that will fully secure the chainring to the crank spider. I've seen perfectly tight bottom brackets with a few threads showing outside of the bottom bracket shell, but if yours is loose it can definitely contribute to noise, so be sure to check it. The left (non-drive) side is right-hand threaded, and the drive side is reverse, btw.

And note that a bigger chainring will use up more chain, so the rear wheel will need to move forward unless you get a longer chain to accommodate for it.

Thanks for the info, turns out i made a mistake and my crankset is 7402 not 7400 but i'm pretty sure the measurements are the same anyway?
I've literally been looking all day for a chainring to match and i managed to find one on ebay that is a Dura Ace SG-X 10 Speed 44T Chainring
Would it be compatible? I tried to google some info about the sg-x that it is advertised as but couldn't come up with anything, looks like it might work?
Also not sure about the 3/32" tooth width, i might have to message to ask because it doesn't look like it specifies that either. Is that the standard measurement for single speeds?

Cheers

Rolla 09-18-21 09:18 AM


Originally Posted by lancelegstrong (Post 22235213)
Thanks for the info, turns out i made a mistake and my crankset is 7402 not 7400 but i'm pretty sure the measurements are the same anyway?
I've literally been looking all day for a chainring to match and i managed to find one on ebay that is a Dura Ace SG-X 10 Speed 44T Chainring
Would it be compatible? I tried to google some info about the sg-x that it is advertised as but couldn't come up with anything, looks like it might work?
Also not sure about the 3/32" tooth width, i might have to message to ask because it doesn't look like it specifies that either. Is that the standard measurement for single speeds?

Cheers

Any 44T chainring with the same BCD will work with that crankset.

The 3/32" width is one of two standards, the other being 1/8". A lot of dedicated singlespeeds and BMX bikes use 1/8", but geared drivetrains typically don't. The only issue is that a 3/32" chain won't work on a 1/8" chainring or cog, but a 1/8" chain will work on both 1/8" and 3/32" rings and cogs. It's extremely likely that your chainring and cog are 3/32". I only mentioned it because you might have to get a longer chain when you increase the tooth count on the chainring, and it's best to match the chain width with that of the other components.

lancelegstrong 09-18-21 09:46 PM

Okay makes sense, hopefully the chain fits otherwise ill just have to grab another i guess. Went ahead and ordered the chainring so just have to wait now.

Thanks for the help brother appreciate it!


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