13T Drive Sprocket - Currie, eZip, iZip

[DrkAngel]

Oh golly, got the old sprocket off, new sprocket has two sides (obviously), one side has a taller lip than the other. Which side goes down!

Same way as the one you took off! :|

Forgot?

Didn't notice?

Whichever way aligns better with freewheel sprocket. 8)

 

[ChiefGeek]

Hey, you're the propagator of this mod, couldn't you just look at yours and tell me? I mean c'mon, "The same way as you took it off"? This is a new sprocket, so I never "took it off". :wink:

 

[DrkAngel]

Hey, you're the propagator of this mod, couldn't you just look at yours and tell me? I mean c'mon, "The same way as you took it off"? This is a new sprocket, so I never "took it off". :wink:

"Same way as the one you took off!"

Same as the sprocket you took off!
Sprocket you removed has the same "taller lip".

I flip it to however gives the best alignment ... I've modded 5 different eZips, 4 different ways.

 

[ChiefGeek]

I flip it to however gives the best alignment ... I've modded 5 different eZips, 4 different ways.

That was the million dollar question, "Which way (for best alignment) did you place the new sprocket on the motor?"

 

[DrkAngel]

I flip it to however gives the best alignment ... I've modded 5 different eZips, 4 different ways.

That was the million dollar question, "Which way (for best alignment) did you place the new sprocket on the motor?"

You have to look at the alignment ... with the sprocket on the shaft ... of your bike!

You could try, as I used ... by this picture, but different bikes might do better ... differently.

 

[d8veh]

I need a 9 tooth sprocket for my GNG, so if anybody wants to sell me one and send it to the UK, I can pay by Paypal.

 

[joedietz]

Hi Everyone,

I completed the 13T Drive Sprocket Mod on my 2013 Ezip Trailz today.

I am not a tinkerer by nature and don't really get into mechanics and stuff like that, so I was a little nervous to perform this mod. I kept thinking that I was going to break the bike somehow or mess something up. However, once I got into it, everything went pretty smoothly and it was a pretty easy install. Thanks to Drkangel for posting the instructions and for answering my questions. I took step by step pictures as I was installing the mod and I plan to put those together as a PDF and upload it to the site on this thread. It should be a good resource for other people trying to perform the mod.

I was really excited to perform this mod as I felt the factory top speed on the Trailz of 15-16 mph was just not adequate for me, especially since the legal limit for an ebike is 20 mph. I'm happy to report that after the mod my top speed is 20-21 mph. This is great! I can really hear the wind rushing past my ears! It's really a lot of fun to ride. Should cut my commute time down when I drive to and from work. I'm curious to see how it affects my range. Drkangel do you have any experience with testing the range of batteries before and after the 13T mod? Also, I took it for a 5 miles spin today after the mod and the motor felt really warm/hot. To be honest with you, I never felt the motor after a ride before I did the mod, so I'm not sure if this is normal. Is it?

Thanks!

 

[DrkAngel]

13T mod does put more strain on the motor = more heat + reduced range.
Sorry ... but you can't expect such a great performance increase without some downside.

Tips:
You don't need to constantly run at top speed.

Begin coasting well before any stop.

Keep tire pressure at maximum.

Pedal assist, especially, getting up to cruising speed and on hills.

Wind resistance becomes a major factor at 20 mph ... to the point that, while cruising on the level, a lowered seat-crouched position might reduce motor strain, use less battery, than an upright position with pedaling.

 

[joedietz]

Yeah, I don't mind the reduced range or the motor strain.....as long as it doesn't ruin the motor.

I've had some more trips with the mod bike and still satisfied with the results. On flat ground with light pedaling I get 20-21mph, with a slight downhill and light pedaling it pushes me up to 23-24mph. On original bike I was getting about 12 miles (full throttle, light pedaling) from the SLA battery (until it registered 1/2 power while idol) with a reduction in power at around 8-9 miles. With the mod I have a reduction in power around 7 miles and I'm guessing a total of 10 miles until it needs a recharge.

My problem is: I bought the bike to commute to work (with no gas, no pollution) but I didn't want to be sweaty when I got there. The bike was working great for that purpose. Now that I've put the mod on the bike I am so nervous that I am going to hurt the motor that I am pedaling much harder than I did before. Yeah I am getting to work quicker, but I arrive......sweaty.

 

[DrkAngel]

Yeah, I don't mind the reduced range or the motor strain.....as long as it doesn't ruin the motor.
...
Yeah I am getting to work quicker, but I arrive......sweaty.

Hit the PAS button.
Gently pedal and you will cruise at 16+mph.
No motor strain!
No sweat!

Give the throttle a bit of a twist for a little more speed?

But ... I've run a geared up eZip for 4,500 miles, mostly full throttle@19-20mph, w/25.9V Lithium, with no overheat damage.

So, as long as you assist getting up to speed and on hills ... I wouldn't worry about it ...

Oh!
For best SLA battery life, you should not deeply discharge or let set in a discharged condition!
Charge immediately after any, even partial, discharge!

See - SLA Disadvantages

 

[joedietz]

Here are the instructions for performing the 13T Drive Sprocket Modification.

 

[UNPETEABLE]

I need a 9 tooth sprocket for my GNG, so if anybody wants to sell me one and send it to the UK, I can pay by Paypal.

Try this site http://www.gngebike.com/

 

[DrkAngel]

Here are the instructions for performing the 13T Drive Sprocket Modification.

eZip Trailz 13T Drive Sprocket Modification

 

[micro23]

Anyone in the US have any 13T sprockets? I was going to order from the link provided but I figured I should check local first. Just got my bike today, really excited to test it this weekend.

Also could someone link to the exact chain you are using for this mod? I see people linking the specs but does anyone have a go to bike shop online I could order a quality low price chain from?

"1/2" x 1/8" - single speed (410) chain

"15 - 2 T links - 30 tooth holes"

Is what I'm going to head to my local bike shop and ask for otherwise

 

[micro23]

Thanks to a member on here I got my sprocket in record time. I rode home on lunch and got to work right away. Unfortunately I simply could not get the old sprocket off. It's incredible how hard I was rocking it and it still would not come off. I have someone shooting over after work to give me and extra set of hands.

When you guys were able to get it off does it just pop off all at once or does it seem to come loose in a wiggle sort of fashion? I even put a flat head up against it and hit the flat head a few times trying to pop it off and it still would not come off.

 

[DrkAngel]

When you guys were able to get it off does it just pop off all at once or does it seem to come loose in a wiggle sort of fashion? I even put a flat head up against it and hit the flat head a few times trying to pop it off and it still would not come off.

Methods

2 screwdrivers
Pry on one side then other rock back and forth till slides off

Gear puller
I think copper pipe flaring tool has proper size half-ass gear puller

Oh ... don't forget to remove nut!

 

[micro23]

So I was able to get it off by putting a flat head on each side and having someone else apply even pressure with me. It popped right off no problem.

The next issue was that the pin was milled about a half a mm bigger then the 13 T sprocket. So it took a couple good whacks to get it on.

The speed improvement is incredible. It seems it's only 2-5 mph but man it sure makes a difference. My time cut down by three minutes, and my commute is almost the same as if I took the car now. The only downside is the bike needs 1 more gear! It seems like I just need a tiny bit more gear sometimes I cant even pedal because this baby is cruising so fast now

Here are real world times. The slower times are the exact run before the 13T mod. These are also based off Endomondo so they are not exact.

http://imgur.com/a/TlOWI

The only problem I have is that it looks like the chain is a little loose. I used the chain I was provided and it sure looked like it was correct. Does this look like it's hanging to loose? Whats the downside of a loose chain if it is?

http://imgur.com/a/2K1qa


Thanks to all the people in this thread that posted. This mod is really awesome and makes the bike damn fun to ride!

 

[DrkAngel]

Loose chain is better than tight but ...
looks like you need to use the adjustments to tighten it.

Page 11 of the Joedietz pdf.

 

[micro23]

Loose chain is better than tight but ...
looks like you need to use the adjustments to tighten it.

Page 11 of the Joedietz pdf.

I think you are right. I just checked and it looks like it might have slipped just a tiny bit. If I move it back a little I think it should be a little tighter.

Thanks!

Any ideas on how I can get the ability to pedal at full speed? If this thing is at full throttle I cant pedal my feet just float with almost 0 resistance. I would like to provide more pedal support at full speed. This mod is fantastic. Made it to work in 15 minutes again today. It's such a nice ride now.

 

[DrkAngel]

Loose chain is better than tight but ...
looks like you need to use the adjustments to tighten it.

Page 11 of the Joedietz pdf.

I think you are right. I just checked and it looks like it might have slipped just a tiny bit. If I move it back a little I think it should be a little tighter.

Thanks!

Any ideas on how I can get the ability to pedal at full speed? If this thing is at full throttle I cant pedal my feet just float with almost 0 resistance. I would like to provide more pedal support at full speed. This mod is fantastic. Made it to work in 15 minutes again today. It's such a nice ride now.

DNP Epoch 32-11T 7spd

 

[micro23]

Ok so that led me to this part.

http://www.amazon.com/DNP-Epoch-Freewheel-Nickel-Plated/dp/B005QCK9QW
$32.36 shipped.

I'm assuming thats a new set of gears. Is that the only part I will need? I think I'm going to take it to my bike shop and have them put that part on...

What would be the downsides of installing this?

DrkAngel. Thanks man. I really appreciate your help. Sorry for asking what seems to be really simple questions, I have never even owned a bike let alone work on them before and I'm trying to learn as well as I go along.

 

[DrkAngel]

DNP 32-11T 7spd is a great pedal assist enhancement for the eZips.
OEM 34-14Tis OK for the OEM 16mph speed, but when you upgrade the gearing, or voltage, you lose any comfortable assist from 20mph and up.
11T allows a comfortable 60 pedal rpm at 20mph and an aggressive 90rpm at 30mph.

Only downside is a wider gear spacing ... which I think is an improvement on a eaBike!

Note: requires a deeper removal tool but most LBS should have.

 

[micro23]

Just contacted my local shop and he said he would change the freewheel for $5. Thats a no brainer for me. I'm going to buy the part and head down there and see if he can tighten/tune anything else while I'm there. 32.36 shipped from amazon. I should have it soon!

Thanks again guys. Just hit over 100 miles on my bike in 2 weeks. Life changing.

 

[DrkAngel]

With my 25.9V LiPo, 13T mod pushes me along at 22mph+ ...
Too hard on my 25.9V 25.92Ah laptop LiPo?
20 mph "legal" is better?
PAS mode works OK at ~16mph but don't like the surges and 3 second power after stopping pedaling.
I tried a 22.2V variation ,,, but too whimpy!

So decided to pull the 13T motor sprocket and try an 11T.
Should give me ~20mph and 118% low end torque.
See - 11T sprocket and 1st Thoughts

 

[micro23]

Well I just got my DNP Epoch Freewheel 7spd 11-32 Nickel Plated and it cut another 2 minutes off my time. I think I'm officially done. Any more speed or mods and I think it would become a little unsafe.

Here is a screenshot of my final stats. 13 minutes flat on the dot and this is only my first ride. I think I can get this to 12 minutes. The same amount of time it takes in my car. I couldn't be any more pleased.