PeopleAreIdiots

From how you described it, it sounds like you may be noticing that your chainring isnt perfectly round. From what I understand, even aftermarket chainrings arent perfectly round and you so will notice a certain variation in chain tension throughout a full pedal stroke. That said, I dont think this should really pose a significant issue to your ride quality (with stock parts or upgraded ones) as long as you have the correct chain tension.

Now, I cant really tell based on the info in your post but if your chain is too tight, it will feel really sluggish to pedal, almost like a brake is rubbing on the rear wheel or something, at least for part of the pedal stroke.

If the chain is too loose, it might wobble around a bit and you ride and you will notice a bit of slack in each pedal stroke. It will feel like you have to turn the cranks a few degrees before they actually engage and start turning the rear wheel...(jeez sorry, thats kindof hard to explain so maybe somebody else can help me out).

Before you go out and buy whole new drivetrain, I'd check to make sure your chain is tensioned properly. (Seems like the mechanics you showed it too should have been able to help you with that though )

However, if you do still want to upgrade, thats cool too. Im just not sure that will totally fix your problem. For reference, heres what I did to upgrade my cranks on my fuji track. These parts are good if you ask me, pretty easy on the wallet and durable as hell. I'm still using them on my current bike 2 years later, no issues.

Crankset
Cog
Bottom bracket
Chain
Lock ring

just fyi, the crankset and bottom bracket I linked must be used together. Everything else is just what I have for your reference, you can choose whatever you want.

seau grateau

You could try the Sheldon Brown method for centering the chainring, might help even it out a little: https://www.sheldonbrown.com/no-dera...html#centering

I'm assuming the "wobble" your talking about is coming from chain slack, in which case you do want to have a little bit of that throughout the rotation so that your drivetrain isn't binding at any point.

Bigpond

dan.

From what I can tell, the "wobble" seems to be a result of the fact that partway through the pedal stroke the chainring is further towards the front wheel, and the other way through the stroke it's a bit further towards the rear cog. There may be a bit of play in the left/right dimension as well, but it's less noticeable. The result is that the chain jumps up and down throughout the strokes, going from being tight to hanging down a bit more. I'm sure it's not a huge deal, but it would be nice to even it out if possible.

PeopleAreIdiots

Flip your bike upside down so its resting on the saddle and handlebars. Turn the cranks really slowly and observe the chain tension.

Does the chain still do this bouncing thing when you rotate the cranks really slowly? If so then yeah you probably do have a significant issue with drivetrain; somethings definitely loose or off center. If not then Im thinking your chain under-tensioned.

You should only have like 1/2 to 3/4 in of up/down play in your chain. Normally there's a spot in the crank rotation where the chain is at its tightest (due to imperfect chainring shape) but this shouldn't be significant to notice unless your chain is too lose or too tight. As long as you make sure to set your chain tension in the crank position where the chain is stretched its tightest, then you should be good to go. A good rule of thumb is that with proper chain tension your chain should not sag at all (that can cause wobbling); it should be as tight as you can make it while still being able to rotate it freely (test this by spinning the rear wheel by hand and seing how long it takes to stop rotating. It should go for a good long while. You should be able to tell if there is too much tension in the chain as the wheel will slow down and stop turning after only a short time.)

the only other thing im thinking is this
In my experience with the fuji track, I once accidentally loosened axle nuts on the rear hub to the point where there was some side to side play in the axle. That felt really weird and wobbly to ride but it was a quick fix once I realized what was going on. Maybe give that a check perhaps.

REDMASTA

it's normal. my fuji track was the same. variances in parts and what not.

even if you go replacing the entire drive train the tight/loose chain you're noticing will most likely remain to some degree.

questions about this "issue" and how tight should chain be get asked frequently.

dan.

Yeah, it's quite visible. I'm bothered enough by it that I'm going to ride it into my LBS to see if they can diagnose. Will report back on what I find...

PeopleAreIdiots

hmm...
Yeah sounds like you do have something wierd going on.

I took a look at my stock cranks and bottom bracket that came with my fuji and I did notice that the cranks seemed not to seat very securely on the bottom bracket spindle until I really gorilla-fisted them into place. Makes me wonder if your drive side crank is not seated properly...?

In that case your best option may indeed be an upgrade.

keep us posted!

Philasteve

Do you actually feel anything while pedaling the bike? Not sure what crankset comes on the Fuji but I've been on a set of Andel's for years now that came with my bike. They aren't exactly high quality and are not perfect, but they're good enough for me. Probably the next thing I'm upgrading though, it's been like 7 or 8 years.

dan.

So an update

Went to the LBS, and turns out my crank arm is deformed! Puts pressure on the chainring which deforms it.

Do I feel anything while pedaling? I don't have much to compare it to, but I think that it's probably "fine". At the same time, it does sort of bother me, and I'm thinking I have two options.

1. See if Fuji will cover this under warranty since it's a brand new bike
2. Dunk by getting a new crankset

I'm wondering if there's a good crank for option 2. which would be a sensible upgrade I can actually feel without dropping a super high-end crank on a low-end bike. Initially I was looking at the Sugino Messenger as PeopleAreIdiots mentioned, but I have to buy a new bottom bracket, and apparently some folks have trouble setting up a good chainline?

Anyone have experience with the Sram S300? Comes with the bottom bracket included for roughly the same price as the messenger, and seems to get pretty positive reviews. Is this overkill on the track?

seau grateau

Try warranty first.

PeopleAreIdiots

Yeah warranty sounds like a good idea to start off with. Even if you do end up upgrading down the line, its nice to hang on to functional old parts. I just started building up my old fuji track frame into a beater/lockup bike with some of the old stock parts.

As for the sugino rd2/messenger crankset, as I understand it, the RD2 cranks are actually a originally road crank. Even with the 103mm bb the chainline is like 45mm. So its a bit further out than the track standard of ~42mm (I think). In practice I never noticed an issue.

I ended up resolving the chainline issue once and for all Here but I dont think my solution would work on most hubs. Had I done more research at the time, I may have gone a different route with the crankset, probably something with a more track specific 144bcd. That said though, I still recommend RD2s for the money. Ive heard good things about the andel cranksets too.

dan.

Welp, warranty did not come through

I'm pretty sure I'm going to overhaul the drivetrain at this point. So far I've heard good things about the Sram S300 and of course the Andel standard track. Seems that both add up to ~120-130 when the BB is factored in which feels like the sweet-spot for my budget, given this is going on a really basic frame.

Has anyone here had experience with both cranks? I think I understand the technical tradeoffs (in terms of specs) between the two cranks (BCD, width, BB compatibility), but I'm more interested in the actual roundness, quality, chainline, and feel of them out of the box.

thanks and happy friday all!