shelbyfv

Remember, OP said in the first post that he had no problems until he replaced the chain.

Psimet2001 

Doesn't matter. Hanger is bent.

It's the root cause of so many issues it's disgusting. It's a long video I have planned for the youtube channel when I get some time this winter.

DaveSSS 

When I tipped over and bent my RD hanger, it made more noise on some of the sprockets and didn't want to stay on one of them, but that is not chain skip. I knew what caused the problem and realigned the hanger as soon as I got home.

Chain skip is the chain staying on the desired sprocket, but failing to transfer power under a heavy pedaling pressure, by going over the top of the teeth. It may not show up until you pedal standing with those sprockets. It nearly always occurs when a new chain is installed on worn sprockets and the skipping only occurs on a few of the most-worn cogs. Another thing you will find is that a slightly used chain, with only a few hundred miles of use on it will work just fine on those worn sprockets. The worn sprockets will NOT shorten the chain life.

danallen

NEW STATUS: 70 miles on the new chain. Drive train performance has stabilized, in the sense it is consistent and the problem is isolated to two cogs running on the small chain ring. I have marked up the picture I put up a few days ago, showing the affected cogs and the fact that the width of the teeth on those cogs are narrower than the teeth on the other cogs.




I did not clean the cassette when I put the new chain on. Cassette is ready for cleaning, no doubt about that.

That big paint chip was like that when the bike got to me. The seller told me the bike was serviced at the same time I bought it. The bike was shipped by the seller's LBS. When I got the bike, I took it to a LBS and everything was declared ok.

In addition to the large paint chip on the hanger, there are dozens of paint chips knocked off the seat stays and chain stays. I don't have any information about what caused them. I am putting up more pictures after posting these comments.


How can you tell?

I am sure I could be mistaken, but it looks to me as if the hanger on this bike cannot bend. It seems as if it would break the frame before bending. I could not figure out how to get a good picture of the hanger that would show whether it is bent. However, a portion of the hanger is detachable. I removed that piece, placed it on a flat surface. I don't see bending in this part.



This what is left of the hanger when that piece is removed





Thank you for mentioning that.

I bet you are 100% right about this.

The tape is velcro, holding a battery pack for lights I run on the rear spokes.








Here in Houston, drivers are particularly hostile toward bicycles. I ride a lot at night. Running unusual bright lights seems to buy a bit of deference from the cars.

What are we looking at?

Now that you can post photos, OP, maybe you'd like to post a couple more showing us more of the bike?[/QUOTE]







This description of chain skip is exactly what I have going on here. I don't know whether the hanger is a factor or not.

Based on the fact that more cogs were affected when I first put the chain on than are affected now, it appears possible that the chain is breaking into the cassette.

Psimet2001 

Hanger is bent. How can I tell? Because I have been doing this longer than I care to admit. You can't tell by looking at the hanger on a table. It has nothing to do with any of that and "bent" is a misnomer. It is an industry expression for the hanger is not in plane with the cassette. It can happen a billion ways. To align it you need a hanger alignment tool - there are many that are made. They aren't usually very cheap so just wing it by a shop and have them align it.

Or you can keep posting on the internet without having it fixed. Call it snarky if you want but honestly I am just kind of over a lot of forum people (not you) with little to no actual experience troubleshooting random people's bikes in all sorts of situations like all of the tons of hours I have done neutral race support who then think they someone know a different solution. This isn't rocket science. Align the hanger.

DaveSSS 

The way to test the cassette for wear is to put an older chain back on and see if the skipping goes away. If it does, it may mean that the cassette is worn out.

A RD hanger can certainly bend. I bent mine just recently, after a minor tip-over. I have the same style of hanger on my LOOK frame. I always recheck my RD hanger alignment, any time I have a shifting issue, just to be sure. A hanger alignment tool is well worth the money. Taking the hanger off the bike is meaningless. It's what the alignment tool tells you that matters. https://www.parktool.com/blog/repair...nger-alignment

02Giant 

Put the bike back together and visually see if the jockey wheels are in the same plane as the cogs on the cassette. Look at it from behind and slightly above the cassette.

Succhia Ruota

I think this is definitely an overlooked issue for most riders. When I finally figured out how easily the hanger can bend, I bought my own alignment tool.

I have the Park Tool one, which I would recommend to anyone – but it's not cheap. For me, the price is well worth eliminating alignment as a contributing factor.

I have no idea about the quality of this one, but it looks like it may be a good deal for anyone that may be interested.

superdex

whatever you do, please don't think you have to use a new DA cassette. If you replace it, replace with a 105 or Ultegra instead.

danallen

The bike is stable now, in the sense that its performance with the new chain is not changing and the bike rideable. I cannot pedal hard on the 2nd and third cogs especially on the smaller chain ring.

So it is a new cassette for me. I see a used dura ace 7900 with the gearing I like (12-27) in much better condition than mine for $60 including shipping. Considering that four of the cogs are titanium, thus more durable, plus the benefits of the trick shifting, seems like a good buy to me. I am going to upgrade the rear derrailler too.

At this point it seems straight forward, the jumping gears are visibly more worn than the others. It is very flat where I live. The jumping happens with the small chain ring a lot more than the big one, maybe the chain ring is worn too, I will have to take a look.

I didn't know chains wear out as fast as they do. I figured tires would wear out sooner but I guess it is normal get a few thousand miles on tires and less than half that for a chain. I also did not know how running the chain too long costs you gears too.....

It actually amazes me that chains are the most efficient for what they do... I dunno, they look complicated,


HANGER
Now that I watched some videos and learned the piece I took off the bike is the hanger.... I thought the part still on the bike is the hanger. I can see it will be a miracle if mine is straight. Then I found the alignment tool is $50-$180 depending.

fyi, chain rings are 50-34. Outer chain ring is a wreck. Looks like shark teeth. Cassette is 12-27.


You guys helped me a lot, going from no clue to some idea of what is going on. Thank you very much.

shelbyfv

You cannot tell by looking at it if a cassette is too worn to work well with your new chain. You cannot tell by looking.... Check your hanger, buy a new cassette (any group) and move on.

DaveSSS 

Ti cogs wear much faster than steel. Their only advantage is weight savings. Buy a cheaper Ultegra or 105 cassette to get the best bang for the buck.

danallen

I get it now this is a routine problem. I also believe that you cannot tell if a cassette is worn out by looking at it, unless it super worn, way too late to notice, as I think it is on some of my cogs.

I had a road bike I got for $20, for getting around at college. I did took that bike apart, repacked bearings, out of curiosity and to make sure everything was ok. I used that bike from 1980-1982. Rode all over Boston on it.

I went 36 years without riding a bike after that. Two years ago, I took my son's Trek 2100 for a spin. I could not believe how fast it went, so I got this bike. I am starting to feel decently oriented. I do all the maintenance and this was the first actual problem. I needed so help and I got all I needed right here in this thread. I am taking the bike to the shop to have the hanger alignment checked. I putting on a old but less worn dura ace cassette than the one I have. The cassette after that, if I am still running 10-speed, I think is going to be Ultegra 6700 if they are still available.

danallen

Wow, I totally did not know that titanium has a weakness with regard to wear in metal to metal contact of moving parts. When I read your comment I thought you were wrong but NO, I was wrong and you are 100% correct.


I already ordered the titanium. I am looking forward to the experience of running them. Next time, I am going to get a new Ultegra cassette and see what difference I can notice. Weight difference around 60 grams. Considering the fact velcro batteries to my hubs to run lights on my wheels, I doubt the 2.5 ounces extra in the cassette will be noticeable.

That main reason I went for the titanium was the longer wear I thought they provided. doi.


Thank you for the tip.

danallen

I know what you mean. There are plenty of times I want to just tell people how things are and spare the nicities.
I am going to let the LBS show me what the find checking my hanger a few times. Then I probably will buy the Park tool you mentioned. Immediate buy: chain wear measuring tool.


Hummm,...........that offer on the tool you posted looks too good to pass up.

danallen

NEW CASSETTE IS ON THE BIKE

Now that I have the topic somewhat sorted out, my big mistake once this problem developed was springing $50 for a used Dura Ace cassette, on the grounds it is a lot less worn than mine and the idea it would provide better shifting.

Since my shifters and deraillers are Ultegra 6700s (10-speed with 50x34 chain rings, I would have had ideal shifting with a new Ultegra 6700 or 6770 10-speed cassette. That shifts the same as the 10-speed Dura Ace but it would have been brand spanking new for the same price as the used Dura Ace. The extra weight would not matter enough to justify extra cost for Dura Ace, just like people said in here. I also wish I insisted on a Shimano chain to go with the shimano components instead of the SRAM chain. I know the SRAM is compatible, but still. Now I know.

I just put the replacement cassette on the bike, about to take it for a spin.

LBS for hanger alignment tomorrow morning.

danallen

The results of running the bike with the replacement cassette are so dramatic, I was compelled to make a brief video explaining what I discovered. Video is 1 minute thirteen seconds.

Racing Dan

Just so you know. A 4700 tiagra cassette or a 105 would have been just fine. As long as it shimano 10 speed. Imo you are better off replacing cheaper parts more often.

Rocket-Sauce 

Yes. Pros use Ultegra and 105 cassettes. Even in the Tour.

danallen

OK, but in the event that someday I am contending for the podium in the Tour, I am reserving the right to consider upgrading to higher end gear is provided by a sponsor, so I don't have to pay for it.

To me, that is just prudent.

bampilot06

I am pretty much in the same boat as you were at the beginning of this thread. 20 year old bike I bought used in Oct with unknown mileage. Started skipping in December, tried to fix it myself and made it worse. LBS was able to tune it, and I put a new chain on. Put about 600 miles on the new chain and now it’s starting to skip pretty back or certain cogs. Need to replace the cassette as well, but plan on replacing the whole group set when I can afford too.

Glad you were able to fix yours.

Cyclist0108

Did you get the derailleur hanger aligned?

@Psimet2001 is almost certainly right about this.

jadocs

So does it still skip on the two cogs you identified previously? To me, your old cassette did not look like it needed replacing and that it was probably a hanger & indexing issue.

Atlas Shrugged

To summarize after 48 posts and counting.
1. Replace chain with any mid-range and up 10speed chain.
If still skipping
2. Check hanger alignment.
If still skipping
3. Replace the cassette with a new mid-range and up 10-speed Shimano compatible cassette.
If still skipping.
4. Take to a competent LBS and have them get you out of this mess because obviously buying a well-used bicycle might not have been a good call.

Rogerogeroge

Well, you could summarize one poster's view as:
1. HANGER IS BENT!!! It's the root cause of all evil and mis-shifting setups!!!