7th gear chain skipping
 

After replacing a 32-12 Dnp freewheel with a 34-11 and upgrading the Shimano Tourney derailleur with an Altus I have a persistent but random small chain skip in 7th gear. The bike is a Lectric X Premium. The skipping only occurs about one time every one or two miles. Pedaling hard in 7th won’t induce it. In an effort to fix it I’ve replaced the chain, the derailleur hanger and swapped the Tourney derailleur back in. Using the Park Tools video, Ive repeatedly made every derailleur adjustment possible. Backing the B screw completely out helped reduce the skipping but didn’t eliminate it. I’m just now learning bicycle mechanics and sure could use som help sorting this out. TIA.

Did you install a locking designed for an 11 tooth cog? If you reused the old one from the old cassette that could cause skipping

Thanks but not sure what you mean by a locking? It’s a freewheel and not a cassette.

Check the chain. A tight link? You said you changed it but if you joined it with a riveter (vs a quick link) you may have left the riveted links binding a little which would show up first on the cog that requires the most link "bend". I drive the rivet through to its correct protrusion on the far side of the link which leaves a touch more rivet on the near side, then place the link over the middle position on the riveter where the far plate is not supported and press the rivet to equal to its neighbors on the near side, putting the play back into the links. Shop mechanics often simply flex the chain side to side to get that play back.

Thanks, but I used a quick link and have repeatedly checked the chain for tight links but there are none. I’m really at a loss and am wondering if the new freewheel might be defective. When I put the 32-13 freewheel back in the skipping stops. I’m also wondering if an 11 tooth 7th might be too small, but other XPremium owners have used a 34-11 without issue.

Then there is the RD adjustment nobody wants to check, hanger alignment.
Usually the symptoms are more pronounced, but it’s worth a check.

Barry

You've replaced the DR hanger, you've checked the chain, the wheel is obviously aligned in the frame, and you've adjusted the DR repeatedly, including the 'B' screw. I'll assume you also adjusted the 'H' screw to allow the chain to fully seat on the smaller cog. That actually happened to me once not that long ago. Does it not skip in the stand? I ask because you mentioned that putting power to it didn't induce it to happen more frequently. If you use that 11t as much as I do, you need to figure it out. Don't give up, there's a reason for the problem. Good luck

Being that you changed out the freewheel, do you know if this freewheel is intended to be used with e-bikes?

Even if it is, I see a lot of issues people are having with e-bikes that to me seems like they involve faster wear of parts that don't normally wear fast for non-e-bikes. And one of the bad habits I feel some or many e-bikers get into is accelerating in too high a ratio gear that causes more wear on those affected parts.

Sorry, I missed the freewheel part mainly because freewheels with 11 tooth small cogs are very rare
As well, 11 tooth cogs wear out very quickly if used most of the time

What is an RD adjustment? I’ve tried adjusting the barrel adjuster and the high and low limit screws. Thanks

How adjust hanger alignment? Does that imply the frame might be bent?

A properly aligned der hanger will allow the der cage to be "in plane" with the cogs, the two pulleys will be vertically in line with the cog that is in use. When the pulleys/cage is off line the chain can catch the cage plates, ride up and off the pulley teeth and/or the indexing (having the pulleys directly below the desired cog after each shift) can be off and this means the stupid chain thinks it is being told to try shifting.

After installing a new hanger one should confirm its alignment. Additionally one should check the der's range of movement WRT the cog set (with the limit screws).

Don't assume that the only place a chain can catch an adjacent sprocket is only at the back. Stuff can happen at the crankset too. Andy

Well, I have a "similar" problem - although the new chain skips when pedaling mildly - and it's due to the 7th cog of the freewheel being worn out.

The Wheel is held in the frame.
The Freewheel (or cassette) is attached to the wheel, and turns true with the wheel.
The RD (Rear Derailleur) is connected to the Frame by the Hanger (replaceable or not, it's still a hanger)

It is the job of the Hanger to hold the RD in the same plane as the wheel.
If the hanger is bent (and some are, even from new) then the RD cannot function correctly.

The Hanger Alignment Tool is a gauge and lever combined.
The gauge is used to check that the RD mounting bolt hole, is aligned to the wheels rim, within 1/8".

My local bike store charges ~$25 if you have the RD already removed and don't expect them to realign/adjust the RD settings

After a couple store visits I purchased the tool, which made my cycling buddies very happy!

Barry

I have no clue about a washer behind the freewheel or if it even plays a part in any of this, but I found this thread on your brand of e-bike...

https://electricbikereview.com/forum...eewheel.39763/

John

So it's the 11-34t freewheel then. I suggest you use the 11-34t freewheel a bunch more. Sometimes it just takes some breaking in to smooth the rough edges. Unfortunately the quality for these 7s freewheels are not the best currently. They take some breaking in.

Thanks to all who replied here. After trying again to adjust the skipping problem away, even replaced the chain and freewheel, I posted the following on the Lectric Facebook X Premium group: 7th gear skipping has been driving me crazy for 1300 miles. In an effort to solve it I have upgraded the derailleur to an Altus, installed a new DR hanger, shortened the chain, three times replaced the freewheel and replaced the chain 2x. I have given up trying to get 7th gear with a 34-11t freewheel to work. Though with that freewheel, I did manage to get the skipping reduced to one small skip every 5 to 20 twenty miles. So damn random! This was somewhat acceptable but still annoying. Yesterday, after putting around 600 miles on the 34-11t freewheel and chain, I swapped in an OEM 32-12t freewheel that Lectric sent me under warranty along with a new KMC E8 chain. Am hoping that it will solve the problem but I am not that confident it will. After installing it yesterday I went for a 36 mile ride and had one small 7th gear skip at the 21 mile mark. I readjusted the H limit screw, 1/2 turn, to move the chain slightly outboard from the wheel and it didn't skip again. Will be doing a longer ride today to see what happens. Here are some things I learned trying to figure this out: 1. When I first put the 34-11t freewheel on it skipped in 7th gear once every mile or two. I discovered that the derailleur hanger was slightly bent. After replacing it with a new hanger ( I had straightened the old one 2x previously) the skipping only occurred, as stated above, 1x every 5 to 20 miles. I rode like this for around 400 miles until I removed that freewheel yesterday. 2. Shortening the chain helped but did not eliminate the problem. I used the Park Tools Easy/Hard chain sizing video. With a 34t freewheel the chain was 124 links and with a 32T freewheel its now 122 links. 3. Backing the B screw out moves the upper jockey wheel of the derailleur up toward the sprocket which puts more chain on the 7th gear sprocket. This helps but also does not solve the problem. If you do this you must reset the H limit screw and reindex the derailleur. 4. Using a 32-13t freewheel seems to solve the problem. I used one for about 400 miles and the chain never skipped in 7th gear. However I was unhappy with the cadence in 7th gear so I tried again a 34-11t freewheel with the results described above. 4. There is a whole school of thought among the DIY community that says to avoid 11 and even 12t 7th gear on a mid drive motor, there is just too much torque and the chain will skip in 7th gear. 5. Stay out of PAS 4 and 5 in 7th gear with an 11 or 12t 7th. There is just too much torque and you will quickly wear out the freewheel and the chain. If, like me, you are not a bike mechanic and you've never had a mid-drive ebike, it takes a good while to really learn how to ride the bike in a manner that preserves the drive train. Am hoping the OEM freewheel I put on yesterday will solve the issue but, like I said, I've already had one small skip. If anyone with more knowledge than me has any suggestions, I'm all ears.

Which gears do you normally use when you start off from a stop?

3rd - 5th depending on the circumstance.

Assuming first gear is the biggest tooth count cog that gives you the lowest ratio. And considering it probably only has 7 gears on the rear with big steps in ratio between each gear, then starting in 3rd might be reasonable. But starting out in 5th gear is probably putting a lot of wear and tear on the cogs, chain and motor that wasn't intended.

With electric motors it's more like a steam engine. You just smoothly surge ahead and all seems well when it's not really. That's why steam locomotives had an Engineer. Because he knew how much torque could be put on the various parts of the locomotive. And the engineer carefully controlled the amount of steam being let into the cylinders as the train accelerated and for any other times.

If you were doing this with a gasoline engine or entirely with your own legs, you'd be aware of the stress because the gasoline engine would be bucking or stalling out and your legs would be groaning with pain well before you put too much force on the gear train. Unless perhaps you are built like a professional sprinter. But you probably aren't, but the e-bike lets you ride like one.