Jonathon94

My bike is starting to have issues I do not know how to fix. Whenever I pedal hard (such as standing up and pedaling on some of the higher gears) it doesn't work right. It's hard to explain, but it's like the feeling you get when you are cycling up hill and shift gears while still pedaling.

LarDasse74

like the chain slips on the gears under load?

Sometimes this is a wear issue, sometimes it is a problem with the gears being mal-adjusted, sometimes it happens when you put a new chain on a bike with worn cogs.

FBinNY 

What you're describing can be one of two different things, each with different possible causes.

1- the chain slips forward, but the bike doesn't change gear, most likely a worn chain or sprockets or usually both.
2- the chain slips off to (usually) a smaller rear sprocket, most likely a derailleur adjustment of some kind.

Since the likely causes are so different, take the time to note what is happening. It's easiest if you look back and note which sprocket the chain is on before and after the slippage.

Jonathon94

I would guess this is the issue. I would assume wear is the issue. I have no idea when or if it was last maintained. Would replacing the chain and cog fix it?

Jonathon94

It doesn't change gears, it stays on the same gear. So I guess I need to get a new sprocket and chain?

ThermionicScott 

Well, maybe. Start with a new chain if yours is old, and see what that does before buying anything else. Side-view pics of the cassette and chainrings might help.

FBinNY 

Start by measuring your chain for stretch (wear). There are lots of tutorials about this available, so I'll spare my fingers. If your chain isn't worn, then it likely isn't the problem, and replacing it may not help.

My rule of diagnostic and repair is that I spend no money replacing stuff until I've confirmed (or nearly so) that they are the cause of the problem.

Jonathon94

https://imgur.com/a/BhiDm#0

Here are some photos I took that should hopefully help identify the issue. I don't see what could be wrong but maybe you guys do.

Bill Kapaun

I think the first thing I'd do on THAT chain is check for stiff links.

FBinNY 

Probably good advice. Looking at the condition of the sprockets, there's a good chance that the chain isn't overly worn, so replacing it may not be necessary. If the bike hasn't been ridden for a while, rust may be binding a link or two (or three), and all that may be needed is lubrication and working some links free again.

Jonathon94

I ride it daily and it has just now started acting up. About two weeks ago I put some motor oil on the chain.

Bill Kapaun

Which doesn't mean a thing. The chain may have been bent sideways by some mechanical means.
IF you aren't willing to actually check out something that is FREE to do, why should we bother trying to help?

Jonathon94

Woah wait a minute, FBinNY mentioned "If the bike hasn't been ridden for a while, rust may be binding a link or two (or three), and all that may be needed is lubrication" that was the point of what I wrote.

FBinNY 

What I'm saying, and said a few times, and what Bill is also saying is spend the time to do a thorough diagnosis of what's happening and the likely cause before spending dough "fixing" what may not be wrong at all.

Earlier, I suggested that you read about chain stretch, and measure your chain to rule that in or out (or maybe borderline). Looking at the photo, I doubt that the chain is worn, but an actual measurement trumps a guess based on a photo. Also, lubing doesn't rule out the stiff link possibility that Bill mentioned. This is especially likely if the slippage happens with a regular frequency roughly every 2-3 turns of the crank.

Another possibility that can cause exactly the slippage you report is a derailleur adjusted so the upper pulley is too close to the sprockets.

So my advice, and that of Bill remains the same. Observe and analyze what's happening before throwing money at the problem.

Jonathon94

Alright then Thank you

cny-bikeman

FB is dead on, and beyond not throwing money/parts at the bike it also applies to throwing solutions at the problem by trying out random things to see if that fixes it. Doing so not only often prolongs resolution but also does nothing to help you with the next time a problem occurs. One needs to adopt a logical approach to each problem, rather than relying on "it might be ____," or "I had the same problem one time and it was ___."

Take for example the issue of stiff/bent links. Stiff links would only announce themselves when engaging or disengaging with the chainwheel, rear cogs or the pulleys. When they are first developing it's sensible to assume they would only show up under low pedal pressure. In fact one of the most common ways to locate a stiff link is to pedal the drivetrain backwards (with almost no pressure on the chain) and look for "jumps" in the pulley assembly. In addition the chain takes several revolutions of the cranks (number of links divided by chainwheel teeth) to traverse the drivetrain, so there would be a rhythm to the sound/feel of a stiff link problem, and that rhythm would change depending on which chainwheel is engaged,.

The OP does not describe any type of rhythm to the roughness and stated the problem only occurs under high pedal pressure, so I would not consider looking at stiff links, certainly not right away. Rather he describes roughness (like shifting under pressure) in some (not all) gears. He also does not mention the gears "jumping," as often happens with a badly worn chain or cog. If we take that description at least initially as accurate the problem also cannot be only the chain, as that is the same in different gears.

He specifically identified some higher gears (cogs) which wear at a faster rate. Looking at the pics provided one can see that the 2nd and 3rd smallest cogs show significant wearing of the coating, whereas the smallest looks fairly unworn, which correlates well to the OP description of roughness in only some high gears. It appears to be a freewheel rather than cassette, and freewheel cogs, particularly for the first position, were very available for some time, so the smallest cog may even have been replaced. So the logical conclusion is that the problem is most likely cog wear that has not progressed to the point of skipping. In fact it's possible that the chain does not need replacement at all - further reason to measure it for wear rather than first replacing it.

Jonathon94

Thank you for typing this all up! I still have gotta measure my chain wear. But are you suggesting I need to replace the back freewheel/cassette (I am still new to some of the bike terms)

fietsbob

Scotty says "damn-it, Jim, I'm a mechanic , not a mind reader.'.

cny-bikeman

Yes, from what you describe it needs to be replaced. Feeling roughness under pressure has to be due to chain, rear cogs or chainrings or a combination. If it happens in only some rear gears the only variable is the cassette/freewheel. You can forget about obtaining/installing individual rear cogs - not worth discussing.

At this point I would suggest you take the bike to a shop and have them measure the wear (with a ruler - because chain wear guages are more convenient than accurate). Then have them assess the entire bike. My guess is that there are other items that need attention (the too-long rear derailleur housing indicates the bike has never seen a good mechanic). You need to know how much money you are or will be getting into before putting too much into the bike. The freewheel and chain replacement both require specific tools and a derailleur adjustment, and will run you in the $50 neighborhood.

As for terminology and general repair/maintenance information, Google is your friend, as are the sites Sheldonbrown.com and Parktool.com/blog. Forums are best for more specific needs. Just search for things like "bike diagram," "bike rear wheel parts," "cassettte vs. freewheel," or anything else you are curious about. Always look at several different sources, both videos and print (the latter usually being more complete). If you add Park or Sheldon to a search you will get the relevent pages in those sites.

billnuke1 

The bike appears to be an old Huffy Stalker. Not a high dollar bike. We don't know how big you are Jonathon94! These bikes are light duty new! If the problem showes when you standing up, you may just be over whelming the bike! The bike might be too small for you to ride sitting down to ride up inclines! Look at sites concerning bike fitting! Now might be a good time to upgrade your ride! This bike may have been a "good for now" ride and it is telling you to move on, move up! Consider your riding situation and look at better bikes that suit your progressed ride situation, style! A bike shop is not going to be very helpful with a bike like yours. Sorry. It could end up being a money pit! Just saying...

neurocop

OK, I read the answers so far and it seems your chain is not skipping, but what you feel is a lot of resistance when you "pedal hard." Looking at your bike (which has a basic Huffy-style steel (not even cottered, but bent) crank, I'd say your problem is high friction in the crank/BB mechanism. This kind of crank is never going to be as smooth and and efficient as a better designed crank. The best you can do (if you really want to keep this bike and not get another) is take it apart, clean it, replace and regrease the bearings and hope for better performance. I agree that stiff chain links can contribute to your bike's symptoms, so you should also try replacing/relubing the chain.

cny-bikeman

No, BB friction would not significantly increase in hard pedaling, nor would it be felt as roughness or in only some gears. Again, stiff links do not show up only when pedaling hard, and do not match the minimal sypmtoms the OP has given. The problem here is that we still do not have a complete description of the problem and are trying to diagnose a problem best detected by a test ride and hands-on inspection. I'm all for being self-sufficient - I have never had a bicycle I owned in a shop, even for a 30 day inspection - but what I see here tells me "Get thee to a mechanic!"