Changing RadMini gear ratios

[cayjak]

I didn't measure the thickness of the rear shoulder on the DNP freewheel. I should have done that while I had it off. I think it was approximately the same thickness as the spacer ring, which means the DNP freewheel (without the spacer) should end up with the sprockets in about the same position as the original freewheel. So I agree, the derailleur should work...

It is very possible that I am missing some adjustment technique, or doing something wrong. I am a novice at this derailleur stuff...learning by "trial and error". The inexpensive derailleur on the RadMini only has 3 adjustment points that I can find: the H and L screws, and the barrel adjuster on the cable. If I back both H and L screws out all the way, the derailleur still won't move far enough inboard to fully seat on the biggest sprocket. I agree - it should have enough total range of travel, because it worked with the original freewheel with the same sprocket spacing. I'll keep playing with it, and reading online to further my knowledge of the subject, and see if I can figure it out.

Just thought of something else I can try. I'll drop the chain completely off the freewheel, then see if the derailleur has enough total travel to line up with all 7 sprockets. I'll report back on my results.

 

[Nova Haibike]

It is very possible that I am missing some adjustment technique, or doing something wrong. I am a novice at this derailleur stuff...learning by "trial and error".

How to Adjust a Rear Derailleur by Park Tool

 

[cayjak]

OK, good news (for me, anyway) - I got all my gears back! My shifting problem was totally due to my messing with the derailleur without knowing what I was doing. I went back to the beginning, and followed the excellent Park Tool tutorial linked by Nova Haibike above (Thank You!) This got everything back where it was supposed to be, and now my RadMini shifts through all 7 gears without a problem.

The thing I did really wrong was I tried to tighten the tension on the gear shift cable, and actually ended up making it too loose. Then it didn't have enough tension to pull the derailleur all the way over to the biggest sprocket, even with the barrel adjuster screwed all the way out. That's why it wouldn't shift to 1st gear. Once I corrected that (self induced) error, then things went much smoother.

I still have one concern about how the derailleur is working. It is quiet in all 7 gears when pedaling, but if I try to back pedal in either 1st or 7th gear, it makes a "clicking" noise and sometimes "auto shifts" to the adjacent sprocket without me moving the shift selector. Is that normal? In all the other gears, I can back pedal without any problem.

I am still happy I removed the spacer ring from under the freewheel (see earlier posts). I think leaving the spacer out positions the DNP freewheel closer to where the original freewheel was set, and makes for a straighter chain line especially in high (7th) gear.

 

[Nova Haibike]

I still have one concern about how the derailleur is working. It is quiet in all 7 gears when pedaling, but if I try to back pedal in either 1st or 7th gear, it makes a "clicking" noise and sometimes "auto shifts" to tne adjacent sprocket without me moving the shift selector. Is that normal? In all the other gears, I can back pedal without any problem.

It is a chain line issue. The chain can only be perfectly straight in one gear. The crank's chainring should be mostly inline with one of the middle cogs, but when you shift to the inner or outermost cog, the chain deviates from straight. When you pedal forward, the derailleur guide pulleys puts the chain straight with the cog, but when you pedal backwards, there is nothing to guide the chain onto the freewheel's cogs. This lack of guidance can lead to the "auto-shifting" you are experiencing. Which is why I tell people not to backpedal; it serves no purpose and can cause problems.

 

[cayjak]

OK, Thanks! Simple solution: don't back pedal. I can do that. My other eBike has a Nexus 3-speed internal gear hub, which of course doesn't care if I back pedal. Guess I have gotten into bad habits. I don't ever back pedal when shifting...just when I'm coasting down the street where I don't need to pedal. So, I just need to eliminate that unnecessary behavior.

Still VERY happy with the DNP freewheel! Makes the RadMini much nicer to ride when you actually have a little resistance to your pedaling!

 

[cayjak]

Another update. After a couple weeks of riding almost every day, the DNP freewheel continues to function perfectly. Shifting is still smooth in all gears. I am finding the ratio selection works great for my riding style, which is "recreational/light exercise". I.E I don't commute on the bike - I just ride it for fun in good weather. At my normal riding speed of around 10-15 mph I am staying mostly in 4th and 5th gear with PAS 1 or PAS 2 selected. This combo works great on our mostly flat TX roads. I have enough pedal resistance to get some exercise without working too much. If I want to really push it hard, 6th and 7th gear are still available with the higher PAS settings.

SO, all in all I am 100% satisfied with the DNP freewheel upgrade. IMO, this range of rear gears should be standard equipment on this bike.

 

[TonyBlonie]

I did almost exactly what you did Cayjak and I am happy as well. The only change I did was I didn't quite cut my tool completely in two. I cut all the way through one side and most of the way through the other with just a small uncut part in the middle. I then used a flat blade screw driver to pry open the gap to get it over the wire. I then pinched the tool back together with pliers and it fit well. I noticed on my Rad Rover that the low gear is 34 tooth and a big step up from #2. I see DNP also offers a 11-30 set which would be closer to the stock granny gear. All the other tooth counts are the same as the 11-28. I rarely used gear

1 before so losing a little torque will not be a problem. That is what the peddle assist is for! Thanks for the guidance!

 

[kamakazi17]

Just bought a radmini. Is there a way to remove the freewheel without the specialized tool? Try to do little cutting as possible.

 

[cayjak]

If you don't want to buy the tool and perform the required surgery, then take the wheel off the bike and carry it to your local bike shop (LBS). They may be able to get the freewheel off using some brute force technique. They may also bugger up the inside of the freewheel, but if you are not going to reuse it, then it doesn't really matter.

You do not need the split tool to install the new freewheel. Just spin it on by hand and reinstall the wheel on the bike. The first time you go for a ride, the action of pedaling the bike will tighten it up.

 

[Trail Cruiser]

Took the bike out for a ride with the new freewheel, and was REALLY pleased! I had to make a couple tiny little adjustments in the derailleur positioning for 6th and 7th gears. After that, shifts were smooth and quiet through all gears. The top half of the gear range is now MUCH more useful. Before, I would spin out at about 19-20 mph in 7th gear, and the pedaling was basically useless in PAS 3-4-5. After the mod, I can continue to pedal with some resistance all the way up to just under 25 mph in 7th gear & PAS 5. I am now actually helping the motor in the top gears, instead of just being along for the ride. I believe this upgrade will make the RadMini much more enjoyable to ride, plus providing me with more exercise, which is a good thing.

Bottom line: I highly recommend the DNP 11-28T freewheel.

I looked at your new 53T chain ring and DNP 11-28T 7speed freewheel in relation to the 20 inch wheels and 4 inch tires. That gearing is about perfect. You have a comfortable 80 rpm cadence at 25 mph.

In my case with my Magnum Metro+ project, I geared down (instead of gear up) to have 80 rpm cadence at 24-25 mph and closer spacing cogs.
https://electricbikereview.com/forums/threads/project-magnum-metro.24328/

 

[kamakazi17]

If you don't want to buy the tool and perform the required surgery, then take the wheel off the bike and carry it to your local bike shop (LBS). They may be able to get the freewheel off using some brute force technique. They may also bugger up the inside of the freewheel, but if you are not going to reuse it, then it doesn't really matter.

You do not need the split tool to install the new freewheel. Just spin it on by hand and reinstall the wheel on the bike. The first time you go for a ride, the action of pedaling the bike will tighten it up.

Hi Cayjak,

Would this method work? Would this ruin the freewheel mechanism?

 

[cayjak]

That procedure might work, but since I didn't try it, I don't know for sure. This is what I was calling a "brute force technique" in my reply above. I prefer, when possible, to use the correct tool for a given job so you don't tear things up, but that's just me.

Looking back at my photos in Reply #9 and Reply #12, it looks like the Shimano freewheel that came on my bike does have the same type of "dimpled" lock ring as shown in the video. Using the punch to remove the lock ring should work. I don't know if the whole set of gears will come off in one piece...if they do, then a pipe wrench should work to remove the center "core" of the freewheel.

If you don't care about saving the original freewheel for reuse, then all I can say is "Give it a try". Let us know the result!

 

[BPINE]

Very nice write up thanks for spending the time. Probably answering my own question but will ask anyway, I can't seem to find the freewheel in a better brand the DNP gets terrible reviews I sure would like to have a Shamino which seems to be cheaper as well.

 

[kamakazi17]

That procedure might work, but since I didn't try it, I don't know for sure. This is what I was calling a "brute force technique" in my reply above. I prefer, when possible, to use the correct tool for a given job so you don't tear things up, but that's just me.

Looking back at my photos in Reply #9 and Reply #12, it looks like the Shimano freewheel that came on my bike does have the same type of "dimpled" lock ring as shown in the video. Using the punch to remove the lock ring should work. I don't know if the whole set of gears will come off in one piece...if they do, then a pipe wrench should work to remove the center "core" of the freewheel.

If you don't care about saving the original freewheel for reuse, then all I can say is "Give it a try". Let us know the result!

Will definitely try once I get my Radmini. I'll document it for you guys who are on the fence to go the 'ghetto method'

 

[harryS]

Shimano quit making 11T freewheels. It was probably too expensive to make while keeping their standards for reliability.

Cayjak says his normal speed is 10-15 mph. So are mine when my wife and I ride our 20" folders. In pedal assist 1/2, we're not puting much force on the drive train with a hub motor, so I think we will be fine.

I do believe the bad reviews, but the people that give those reviews are likely fast riders who wear out chains in six months. Sure, a DNP ought to blow up with that kind of riding.

 

[BPINE]

I am going to give it a try, I ordered the 32-11 because I am putting it on a Rover.

 

[BPINE]

Made the swap today, I had to use the hillbilly method of removal it was way to tight for the split removal tool. I barley got it off with a very large pair of channel locks. Other than the tool not working out it went very smooth, I removed the space and it gets every gear with no problem. The gearing is much better I think this is going to do the trick.

 

[cayjak]

Surprising that the split tool would not fit. My removal tool was a snug fit in the DNP freewheel before I cut it in half, and a easy drop-in fit after the surgery. It also fit fine in the Shimano (after the cut).

But, as long as you got the swap done, it's all good! Enjoy your (improved) ride.

 

[BPINE]

Surprising that the split tool would not fit. My removal tool was a snug fit in the DNP freewheel before I cut it in half, and a easy drop-in fit after the surgery. It also fit fine in the Shimano (after the cut).

But, as long as you got the swap done, it's all good! Enjoy your (improved) ride.

The tool fit but the sprocket was so tight it deformed before it would loosen.

 

[kamakazi17]

Made the swap today, I had to use the hillbilly method of removal it was way to tight for the split removal tool. I barley got it off with a very large pair of channel locks. Other than the tool not working out it went very smooth, I removed the space and it gets every gear with no problem. The gearing is much better I think this is going to do the trick.

Did you happen to document the process with photos?