Chain skipping

[E-HP]

I'm having issues with my chain skipping on my TSDZ8 build. I was originally using the old 8 speed cassette, but although it ran well, I didn't have a chain line where I could use the full range. I replaced the cassette with a (cheap) Shimano 7 speed cassette, and a spacer. The setup worked really well, shifting smoothly for two days of riding. Way better than the old 8 speed cassette. Everything felt dialed in, then on the third day, the chain started skipping, in every gear. Adjusting the derailleur didn't help. My chain was about a link too long, so I shortened is. That helped slightly, but didn't get rid of the skipping. It's almost like the cassette or something is flexing, since it happens when everything looks perfectly aligned, in a gear with the straightest chain line. The chain has 300 miles on it. It's a cheap chain.
My plan is to replace the cassette with a better quality one, replace the aluminum freehub body with a steel version, and replace the chain with a better quality one. I'm replacing the freehub since the aluminum one is getting chewed up an I can tell it will just become more difficult to remove the cassette if I keep using it. Is there anything else I should be looking at?

 

[dgc]

I had a similar problem with a new e-bike build, first time I have had this problem. Firstly I thought there was a problem with the sprag clutch in the motor to the point where I switched it with a spare I had, no difference, next as I had the bike set up as a mullet 29"f 27.5" I thought as I did have a complete spare 29" rear wheel including the 9 speed cassette, rotor and tyre I'd switch the back wheels over so I would have a straight 29er. It seemed to be OK now, that lasted about two weeks and it was skipping / jumping again. What solved the problem in my case was to remove the Shimano Altus rear derailleur and fit a Sram X4 long cage rear derailleur complete with X5 trigger shifter. Mine is a 9 speed but the X4 suits it seems 7,8,9 cassettes but one doe's need a matching trigger shifter. I have always used Shimano Altus rear derailleurs but have an old bike with the Sram X4 gear on so thought I would try one on my new build and it worked, looking at the two derailleurs the X4 looks to align the chain better. The chain usually has a fair offset on it if you are bottom gear, but have not had one come off yet.

 

[fechter]

Usually it's not enough tension in the chain or not enough angle of wrap around the sprocket. Post a picture.

 

[E-HP]

Usually it's not enough tension in the chain or not enough angle of wrap around the sprocket. Post a picture.

I used the method of wrapping the chain on the large cog and from chainring and adding two links, which is what helped for a half a ride. My old XTR derailleur is pretty worn. I'm wondering if the spring tension is just too weak now. I have a cheap Shimano derailleur on my other bike and the spring feels a lot more stiff. I'll post a pic.

 

[Zambam]

What happens when the chain skips? Is it skipping on the teeth of the same gear or from gear to gear (e.g. jumps from 2 to 4 when it should be from 2 to 3)

I had a problem on my TSDZ2 where it jumps in and out of gear and sometimes skips a gear (2 to 4). Tried everything including adjust derailleur, checked chain length, chain stretch, lubed the chain, none of which helped. In the end, I bought a cheap derailleur hanger adjust gauge/tool from aliexpress, found the hanger slightly bent, straightened it with the tool and that fixed it.

 

[E-HP]

What happens when the chain skips? Is it skipping on the teeth of the same gear or from gear to gear(e.g. jumps from 2 to 4 when it should be from 2 to 3)

It seems like it's trying to jump gears, but hard to see exactly what it's doing. When it's still, it's perfectly aligned, but starts skipping when under power, both with the motor or just legs. If I stop, it still looks aligned.

 

[Zambam]

Everything looks aligned when I had the skips. Only the derailleur hanger tool can detect a bent hanger (unless you have eagle eyes). I bought this one which did the job https://www.aliexpress.us/item/3256...st_main.5.590b18024SbPq9&gatewayAdapt=glo2usa

Park Tools makes a nicer tool but I don't think it works 5 times better than the cheap tool.

edit: there's a trick to use a rear wheel as the derailleur hanger gauge/ tool but I didn't have the right wheel so had no choice but to buy.

more edit:
Unrelated to the skip. I also had problems with the chain jump off the chainring when I hit big pot holes. a narrow wide chain ring took care of it.

 

[Zambam]

Here's my post looking for help Who else has issues jumping in/out of gears on their mid drive rear cogs?

 

[dgc]

Yep, what doe's not help me is that I run a 9 speed 11 - 46 tooth cassette which I use climbing up and over grassed mounds in the local park and forest hence the X4 long cage derailleur, I found the Sram derailleur a bit more refined in the way it works is the best way to describe it. It doe's the job for me.

 

[dgc]

Zambam, eyes are getting old, do fancy the alignment tool, one frame I have did need a large pair of adjustables on the hanger.

 

[Chalo]

7sp and 8sp spacing is similar, but not matching. 5mm gear to gear for 7sp, 4.8mm for 8sp. They'll work, kinda, but not well.

 

[BiggKidd]

It often seems to me derailers need a little more chain tension than they have.

 

[E-HP]

Thanks all. New derailleur on the way.

 

[fechter]

I recall once having an issue where it wanted to jump back and forth between gears which was annoying. I don't remember exactly what I did to fix it though. I think it was a problem with the shifter or the cable got too dirty.

 

[E-HP]

I went out for a short ride yesterday and noticed that in the lower 3 gears, I didn't have skipping. Actually in 3rd gear it skipped a couple of times. Any higher gears and the skipping. I'm leaning toward chain tension issue due to worn out springs in the old derailleur. While I was out, the new derailleur and cassette arrived. Springs are definitely stiffer on the new one. Even though the derailleur will probably fix things, the SRAM cassette looks like it's made so much better than the bottom of the line Shimano, that I don't want to return it lol.

 

[Zambam]

Mine didn't skip on all gears also, only between certain ones (do not remember exactly which 3). If your new derailleur still skips, check and adjust the derailleur hanger. It is made of very soft metal (just checked, mine is aluminum, erroneously thought it was steel). Does not take much of a bang to bend it.

 

[ZeroEm]

I went out for a short ride yesterday and noticed that in the lower 3 gears, I didn't have skipping. Actually in 3rd gear it skipped a couple of times. Any higher gears and the skipping. I'm leaning toward chain tension issue due to worn out springs in the old derailleur. While I was out, the new derailleur and cassette arrived. Springs are definitely stiffer on the new one. Even though the derailleur will probably fix things, the SRAM cassette looks like it's made so much better than the bottom of the line Shimano, that I don't want to return it lol.

Just wondering, can you buy springs or is it even worth it with the rest being worn out also?

 

[dgc]

Looks like one can buy spare tension springs for certain Shimano derailleurs typically for about $5, is it worth it, where I looked it said "more stock due".

 

[ZeroEm]

Was just wondering if the bearings would be wore and pivot points also. bet my trike is due for a new derailleur, somethings are out of mind until they cause trouble.

 

[E-HP]

I put the new derailleur and cassette on today. It was still skipping, but then I noticed that the cassette has some play in it. I needed to add another 1mm spacer. After than, it ran so smoothly, until it skipped. Ugh. Upon closer inspection, I noticed my chain looked beat up. Very beat up for 300 or so miles. It looks like the skipping under power bent the outer plates, so they're bulging outwards. Even when the derailleur is aligned, those plates rub or almost rub against and catch on the next cog and cause the skipping. At least that's my theory. I'll swap out the chain this afternoon. Crossing my fingers.

 

[slaphappygamer]

I needed to add another 1mm spacer

I had a similar issue with my derailleur. I just could never get the gears indexed properly. I found my hanger was bent and I was also missing some washers, on the axle, between the dropout and cassette. Shifting was MUCH better after realigning the derailleur hanger AND using a 2mm washer, instead of 4mm of washers. Now I can use all gears even the largest cog, which I couldn’t use due to the 2mm added width. Such a delicate device.

 

[E-HP]

Swapping to a new chain fixed it! I’m glad I noticed the damage, but it was only obvious when I looked closely. Charging my battery to take a longer test ride.

EDIT: Success, for now!! 15 miles with plenty of shifting with no skipping. I really felt great to ride. I can't seem to find my calipers, but when I do, I'll post a pic of the damaged plates with some measurements.

 

[dgc]

My usual chain wear check is to take a 12" ruler and measure the chain length over 12"'s you will find that the chain pins will align. if not the chain has stretched, I have always used a good quality e-bike chain like a KMC E9 9 speed E-Bike chain or a Sram Powerlink chain.

 

[raylo32]

Did you replace the chain when you replaced the cassette? A stretched chain will skip like this on cogs that don't match its wear pattern.

 

[dgc]

Yep, change the chain and cassette as the 11t sprocket along with the next 3 or 4 sprockets tend to take a beating, not helped if the chain is on the soft side and stretches.