Freewheel Problems

[creativepart]

I think that maybe I found the issue for my chain skipping in 9th gear only... and it's not the freewheel. Well, it is sort of. Here's what I know think is the issue.

CHAIN LINE - The new freewheel is taller, or more likely the motor and freewheel together are farther out from the center of the bike. This makes the chainline in 9th gear too out of plane. And this is why the 8th gear and other gears work perfectly. 8th gear is almost a perfectly straight chainline with the front chainring.

I'm not at all sure how to move the chainring outward to help the gearline in 9th gear. Or could it be a chain length issue? I know the new chain is a little long. I told the bike shop I was thinking of getting a 48 to 50T chainring so the shop tech left the chain long and told me to size it later.

Here's a photo from behind. You can see the chain in 9th gear and how far out of true the chainline is.

 

[JES2020]

I think that maybe I found the issue for my chain skipping in 9th gear only... and it's not the freewheel. Well, it is sort of. Here's what I know think is the issue.

CHAIN LINE - The new freewheel is taller, or more likely the motor and freewheel together are farther out from the center of the bike. This makes the chainline in 9th gear too out of plane. And this is why the 8th gear and other gears work perfectly. 8th gear is almost a perfectly straight chainline with the front chainring.

I'm not at all sure how to move the chainring outward to help the gearline in 9th gear. Or could it be a chain length issue? I know the new chain is a little long. I told the bike shop I was thinking of getting a 48 to 50T chainring so the shop tech left the chain long and told me to size it later.

Here's a photo from behind. You can see the chain in 9th gear and how far out of true the chainline is.

View attachment 80903

Meh, Mine looks like that too.

 

[creativepart]

Thank for that prospective @JES2020. Maybe it's not that. But I plan on taking a look at that chainring to see if it can be mounted differently.

I worked on derailleur limit adjustments yesterday. Something I noticed, when adjusting the chain for 9th gear the limit screw is backed off of the derailleur body. When it just touches the derailleur that is as far "out" as the derailleur will go. If I screw in the H limit screw even just a tad it starts moving the chain "in" and the chain will start to climb up to the 8th gear.

When I was taught how to adjust the H limit screw I was taught to go past the smooth setting for the chain in the 9th gear - moving the chain out too far - and then just come back "in" a tad until the chain ran quietly. But it's not possible to do that as the H limit screw will lose contact with the derailleur body and the chain cannot be moved farther "out." At all.

I haven't had any crashes or reason to doubt the hanger or wonder about a bent derailleur - but nonetheless I suppose I can't ignore those things either.

After more Limit screw adjustments yesterday the chain still skips in 9th gear - but importantly not constantly in every pedal rotation. So, perhaps I'm getting closer to a solution.

 

[creativepart]

Another day another round of checking and trying different approaches. First I check the derailleur hanger and found it a little bit bent. Probably not enough to cause an issue. But test it and attempt to straighten it I did anyway. Then, since I knew my chain was too long and it had dropped twice recently, I resized the chain by 2-links.

After this work I re-indexed the gears and took it for a test drive. Slip, slip and slip. No change.

I stopped by a Specialized bike shop last Saturday and spoke to the tech there. He was keep to give it a go so I"ll take the bike into him this week if possible. I live ~40 miles from the nearest bike shop. I don't want to do the drop it off and wait for them to get too it. I'd rather get a set time to bring it in when they can get to it right away not 7 to 10 days later.

 

[JES2020]

Another day another round of checking and trying different approaches. First I check the derailleur hanger and found it a little bit bent. Probably not enough to cause an issue. But test it and attempt to straighten it I did anyway. Then, since I knew my chain was too long and it had dropped twice recently, I resized the chain by 2-links.

After this work I re-indexed the gears and took it for a test drive. Slip, slip and slip. No change.

I stopped by a Specialized bike shop last Saturday and spoke to the tech there. He was keep to give it a go so I"ll take the bike into him this week if possible. I live ~40 miles from the nearest bike shop. I don't want to do the drop it off and wait for them to get too it. I'd rather get a set time to bring it in when they can get to it right away not 7 to 10 days later.

Good thinking!
Let us know what they come up with.

 

[Sierratim]

Is the hub motor width greater than the original wheel hub width?

 

[creativepart]

Is the hub motor width greater than the original wheel hub width?

Not sure. It still fits in 135mm dropout... barely. The freewheel is about 6 mm taller than the cassette. I haven’t measured the overall width.

 

[Sierratim]

Not sure. It still fits in 135mm dropout... barely. The freewheel is about 6 mm taller than the cassette. I haven’t measured the overall width.

I've done a couple of these DIY hub motor conversions. My experience is that the hub motor is often wider that many standard rear wheel hubs, but still fits in the drops by eliminating fairly common spacers. As I inferred in my earlier post #4 this may limit this hub motor to something less than 9 speed.

Comparing the hub motor width to the original wheel hub should give you the insight into its compatibility with a 9 speed setup. If the bub motor is wider you may need to go with an 8 speed setup.

 

[creativepart]

I've done a couple of these DIY hub motor conversions. My experience is that the hub motor is often wider that many standard rear wheel hubs, but still fits in the drops by eliminating fairly common spacers. As I inferred in my earlier post #4 this may limit this hub motor to something less than 9 speed.

Comparing the hub motor width to the original wheel hub should give you the insight into its compatibility with a 9 speed setup. If the bub motor is wider you may need to go with an 8 speed setup.

I've been looking at this and I've found used 8-speed Shimano XT RD and MicroShift for not much money at all.

The only real issue with the number of gears is running PAS 2 or 3 and wanting my pedaling to play a roll. Another route may be that bigger chainring I had thought about previously.

 

[creativepart]

Comparing the hub motor width to the original wheel hub should give you the insight into its compatibility with a 9 speed setup. If the bub motor is wider you may need to go with an 8 speed setup.

I attempted a rough measurement of this today. It's difficult to do accurately. I measured from the center of the hub of the original wheel to the outside of the 9th gear on the cassette and then the same for the motor hub and freewheel. The hub motor/freewheel combined are about 20mm wider than the original wheel/cassette.

I say "about" because I'd have to take everything apart to get more accurate measurement. Which I may do for my own edification.

When I couldn't get the rear derailleur to adjust any farther outboard with the H limit screw, even if I removed it completely, I think I can see the issue.

 

[creativepart]

I've ordered a DNP 8-speed freewheel. And to make the gears index appropriately I ordered an 8-speed micro shifter as well. Both will be here tomorrow (Sun 3/14). So, we'll see if this solves my problem.

The current Sunrace freewheel has a 13T low gear and I'm currently not able to use it at all. So, hopefully, the new 8-speed DNP will work as designed and it has an 11T low gear to boot. So, better for an eBike all the way around.

Honestly, 6-gears would be plenty with a rear hub eBike. I use a few gears but don't need 8 or 9, that's for sure.

Depending on how his goes I may revisit my plan to go to a 50T or 52T chainring up front. I currently have a 44T chainring. I'll need a whole new crankset - probably including a new BB.

 

[creativepart]

FIXED!
The new DNP 8-speed freewheel and Shimano 8-speed shifter has completely fixed the issue.

I figured the 8-speed freewheel would be shorter over all. But the 8-speed DNP and the 9-speend Sunrace were pretty much the same height.

My rear derailleur is a Shimano 9-speed Alivio but after doing research I found that 7-8-9 RDs all work the same and it's the shifter that does the gear indexing. So, I bought a Shimano Tourney 8-speed. It was easy to index and works OK.

I reused the original cable housings because it's internally routed. I find that the thumb upshift works fine at the der but the thumb lever doesn't spring back without some help. I may need some new cable housings.

The new freewheel is a 11-34T and the old Sunrace was a 13-32T and with the highest gear not working I was only using the 8th gear which was 14T. Now, riding on the road in PAS 3 at 20 mph my pedaling keeps up with the motor. It's a big improvement.

Also, I don't think I'll be changing the crankset to a 50T chain ring. First I don't need it now and second I'm not sure there is room to clear the chainstays with that size of chain ring.

Thanks everyone for the help!

 

[JES2020]

FIXED!
The new DNP 8-speed freewheel and Shimano 8-speed shifter has completely fixed the issue.

I figured the 8-speed freewheel would be shorter over all. But the 8-speed DNP and the 9-speend Sunrace were pretty much the same height.

My rear derailleur is a Shimano 9-speed Alivio but after doing research I found that 7-8-9 RDs all work the same and it's the shifter that does the gear indexing. So, I bought a Shimano Tourney 8-speed. It was easy to index and works OK.

I reused the original cable housings because it's internally routed. I find that the thumb upshift works fine at the der but the thumb lever doesn't spring back without some help. I may need some new cable housings.

The new freewheel is a 11-34T and the old Sunrace was a 13-32T and with the highest gear not working I was only using the 8th gear which was 14T. Now, riding on the road in PAS 3 at 20 mph my pedaling keeps up with the motor. It's a big improvement.

Also, I don't think I'll be changing the crankset to a 50T chain ring. First I don't need it now and second I'm not sure there is room to clear the chainstays with that size of chain ring.

Thanks everyone for the help!

Am I missing something? Why not just NOT use the 9th gear on the old cassette?

 

[creativepart]

Am I missing something? Why not just NOT use the 9th gear on the old cassette?

I could have and did so for 350 miles of riding. But, as i said, the 8th gear on my 9-gear freewheel was 14T and it couldn't keep up with the motor. I wanted to be able to pedal and feel like my effort and the motor were what was moving me forward.

And, I'm sure there was some stubberness on my part to not accept a part that wasn't operating correctly. Many would just live with the problem. I felt a need to solve it.

 

[JES2020]

I could have and did so for 350 miles of riding. But, as i said, the 8th gear on my 9-gear freewheel was 14T and it couldn't keep up with the motor. I wanted to be able to pedal and feel like my effort and the motor were what was moving me forward.

And, I'm sure there was some stubberness on my part to not accept a part that wasn't operating correctly. Many would just live with the problem. I felt a need to solve it.

Ahh, that makes sense.
I have the same issue . I'm going to change a chain ring from 42t to 52t,
Then I expect I'll be able to help pedal at 30 mph, which is near my motor's top end, throttle only.
Wondering what my top speed will be then?

 

[creativepart]

I'm going to change a chain ring from 42t to 52t,

I looked at doing this too. I found that it was doubtful a 50T-52T chain ring would fit without contacting the chain stay. I used a Hybrid Bike for my electric build and it has a more MTB style frame. Road bikes can easily accommodate 50T chain rings due to thinner frames including chain stays.

I don't know for sure that it would not work on my bike- I didn't try it - but I was warned that it was likely an issue. Looking at my chain stay I can see there's not much extra room there with my current 44T chain ring.

 

[creativepart]

I reused the original cable housings because it's internally routed. I find that the thumb upshift works fine at the der but the thumb lever doesn't spring back without some help. I may need some new cable housings.

I posted that comment above stating that the upshift thumb lever was balky on my new shifter and that it might be a cable problem. Well, the internet to the rescue again. I did find a number of people had similar problems and lubed their cables, etc. But then fell upon a guy that fixed his shifter by simply loosening the handlebar clamp screw... and then 3 other people that agreed with that fix.

So, today I loosened the shifter clamp screw and BOOM! It was all fixed.

I had a short 13-mile ride today and it's so very nice having the shifter work instantaneously and having all of my gears available to call up when needed.