Be_original

Hey everyone, new member from Central FL. I purchased a 2017 Critical Cycles Harper. I enjoy the bike and use it to commute to work. There is one annoyance I have with the bike in the month that I have owned it: constant chain slack and rear cog/chain noise
I am pretty sure I figured out the slack. I have horizontal dropouts and was not tightening the rear axle nuts enough. The force of the pedal movement kept sliding the rear wheel forward hence the chain slack. I tighten the hell out of the nuts now and it seems to have worked.
The noise (clicking/binding) I assumed was from the chain being to tight or from dirt in the chain/rear cog/front sprocket. Eliminated all the above by adjusting the chain correctly at 1" of play with the wheel centered and clean the drivetrain every few days while keepin the chain lubricated. This made me look into "chain line".

Read Sheldon Browns chain line article.

Read this great article and my measurements come out to:
Front- 50.8mm
Rear- 42.1mm
I can clearly see the offset when I look down from either side. My question is, without buying new parts can I adjust either the front or rear to minimize the difference? Any suggestions are greatly appreciated. Thanks!

Solution and repairs on post 47

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JeremyLC

I'm pretty sure you can't. It sounds like Critical wasn't very careful in selecting a BB to go with the crankset.

scoho

Ugh, yeah, sounds like Critical blew it.

This is a long shot, and unlikely to be the entire cause of such a huge offset, but it's possible that an asymmetric bottom bracket was installed backwards. When you spin the cranks, do they have roughly the same chainstay clearance, or is one noticeably farther away than the other? Also, can you post top-down pics showing the crank-to-spindle interface?

edit: That was a dumb comment by me. The drive side is already sticking out too far, so my long shot theory about the asymmetric bb is more like a no shot.

SquidPuppet

I hope not, or the threads in his frame/BB shell are destroyed.

^^^ I will not disagree with you.

SquidPuppet

I'm thinking that "Wasn't very careful" might be a big understatement. It's wrong by 16mm . That's a whole lotta Oooops.

scoho

SquidPuppet

Touche.

Be_original

Guys thank you for youre replies. I measured 4 times thinking I may have measured wrong the first time due to the 8mm difference. I have not yet disassembled anything or really looked deeper into it. Im afraid if I bring the BB/crankset in it will definitely interfere with the frame. I may call Critical Cycles directly as it is under warranty and I see this causing damage down the line. This sucks, I am ready to ride again and just replaced the crap tires with some Continental Hardshells that I am eager to test out.

Be_original

Am I missing something here, how did you get a difference of 16mm? Its an 8mm difference front to back from my measurements right? Excuse my ignorance im new to this.

seau grateau

50-42=16, it's pretty basic math.

Be_original

....this is epic

seau grateau

Anyway, it's possible the cranks and/or bottom bracket weren't installed correctly. Calling them about it sounds like a good idea.

SquidPuppet

The bottom bracket spindle is 8mms too long on the drive side, correct? In order to shorten the drive side sufficiently you will need a spindle that is 16 total mms shorter. That will pull the drive side as well as the non drive side crank arms in by 8mms each.

Problem solved for under $20.00 if you have crank and BB tools. Measure the total length of your BB spindle and buy a replacement that is is a close to 16mm less as possible and you will be golden. They aren't available in every single length in 1mm increments, but you will be able to find one that will get you super close, if not right on 42.

Edit: Before replacing the BB, measure to be sure that your chain ring and the pedal end of the crank arms can come in 8mms without making contact with the chain stay.

Be_original

Squidpuppet thank you for the clarification. Makes sense now. I sent a message to Critical Cycles as they are closed and I could not reach them by phone. If they give me the run around I will most likely take your advice and run with it. Thanks again.

Gresp15C

Are there any washers or spacers between the hub and the frame? Don't know if it applies to your situation, but I just got done assembling a single speed wheel with an old coaster hub, and I set the chain line with those spacers, and then "dished" the wheel to re-center the rim. I think that I got within a couple mm.

As for the wheel sliding in the slot, there's supposed to be something like serrated washers or similar in there, to prevent that from happening. Are they present?

SquidPuppet

How far from the chain stay (frame) are the teeth of your chain ring and the pedal end of the crank arms? I ask because it's possible that they designed the frame (chain stay size, shape, bend, and angle) poorly and used a WAY too long BB spindle as a band-aid solution. A chain line that is off by a couple mms aint the end of the world. But 8mms is going to cause it to be noisy and rough as you have discovered. It might even cause premature wear on the sprockets and chain.

79pmooney

Yes, if the BB spindle is symmetrical. No if it asymmetrical. The Shimano cartridge BBS I've use are symmetrical. All the Sugino BB spindles I've paid any attention to were not. Back in the day, very few BB spindles were symmetrical. I never ran across one untl I started using the Shimano cartridges.

I am not a fan symmetry except on very narrow cranksets with just one ring as my knees like the smallest Q-factor I can get. I like near paint scraping left cranks.

Ben

SquidPuppet

His rear chain line is a perfect 42. The obvious, and substantial problem is at the crank.

Good call on the serrated washers. Or buy some track nuts.

Brian25

Measuring the crank and cog outset is all dependent on that the bb shell is perfectly square. I suggest that you sideline the chain, take an 18" metal straight edge and place it on the chain ring and see if it lines up with the rear cog in a straight plain.

andr0id

I'm not convinced you're measuring correctly. That's a track frame with a flip/flop track hub so it's 120mm rear. I don't see how it could be as far off as you think it is.

Your measurements need to be from the exact center of the bike to the center of the chain ring and cog.

For the chain ring, measure from the center of the seat post to the middle of the chain on the ring.

For the back, it's a bit trickier. You can measure from the inside of the right dropout to the center of the cog and then subtract that from 60mm. (Measure your inside dropouts and verify it is 120mm)

Take a photo looking straight down on the chain from the top and post it.

Be_original

There are what appears to be collars and washers on either side of the rear axle. There ARE serrated washers I just wasn't tightening the nuts being afraif I would damage the frame. I tighten them down now and they held up fine the last 3 days I rode. Thanks for the input.

Be_original

I am out of town until Friday the 4th, I will post pictures when I get back. I will post an update on what Critical tells me.

Brian25 and andr0id I will take the measurements again when I get back and take pictures.

Gresp15C

Good point. On my bike, I was going with "try to make it work with whatever I found in my parts bin." Hardly a standard of decency.

SquidPuppet

That won't matter. If the BB shell is "off" then the chain stays are as well. Since they are connected to the shell, they will run perpendicular to the shell and not affect the measurements, or the alignment of the chain ring and rear sprocket. Plus, if the shell isn't in square and the chain stays are running off to the left (which would be the case) his bike would be pulling hard to one side while riding.

Edit: Unless you mean that the BB shell isn't square to the top tube, but the rear triangle is attached equally crooked but reversed to make up for it. Yeah, that would roll straight but have a nasty chain issue.

1. He can see the alignment issue when he rifle sights the chain. If he can see it, it's bad.
2. He has all the symptoms. Noise and binding feeling.
3. He took the time to read Sheldon Brown and used his methods to measure.

I'd bet his numbers are right on.

Be_original

Received an email from Critical cycles:

Zach
Wed, 08/02/17 9:16 pm

Hi Jose

Thank you for reaching out to us. Is there any issues while pedaling when the popping happens? I just want to be sure if it is noise or causing riding issues. IT may be a defective freewheel. If I could have a shipping address now to get a warranty order started it would be greatly appreciated. I hope to hear back soon.

Thank you
Critical Cycles


My response:

Zach,

There seems to be resistance while pedaling, I am assuming from the angle the chain is at. The noise happens only while pedaling not when coasting or freewheeling. The noise is more significant at the rear cog but the worst measurement of the 2 seems to come from the front sprocket/BB area.