SDREAM X750S PAS Broken ? Gearing Problem ?

[Jel]

Hi, So I've had the X750S for a few days now and there are a lot of things I like about it but one things that's bugging the hell out of me (and I've contact support about it but haven't heard anything back) is I can't go faster than 20/21mph besides that its advertised to go 28mph with Pedal Assist. I can get to maybe 15mph with pedal assist in top gear and highest PAS setting but thats it. If I used the throttle I'll get to 20/21mph pretty easily but if I start to pedal I'm like road runner with my legs and there is no more power going to the back wheel.

Hope someone can give me some pointers

Cheers J

 

[Jel]

Okay so I sure everyone thinks I'm a massive noob to ebikes, which is 100% true. I have since discovered that 20mph is the limit in the U.S. for class 2.

1. How can eBike sellers say their bikes go more than 20mph even with peddle assist when they don't ?
2. Where can I get a Bluetooth Module for my display (VeloFox DM05) to access the advanced menu ?

Cheers J

 

[AHicks]

So it sounds like your big issue is you can't pedal any faster than about 15 mph in top gear, right?

That's about your gearing, which isn't that big a deal to change. First have a look at the number of teeth on the small gear on back, if it's already got an 11 tooth there, you're all the way home on that end. If it has a 13 or 14t, you can swap that cassette/freewheel out for one running an 11t. There's nothing smaller/faster than the 11t. That leaves the front gear. Look closely at how much room there is for a bigger gear there. The tight spot is usually the back side (rear) of the gear. If there's room, going bigger here can get you another couple miles an hour.

Regarding the assist being all done at 20 mph, I can't help. Not unless you want to get into changing out the controller, which gets into some pretty serious creativity/DIY skills. There are no direct bolt ins available. The payoff is there will now be no limit on how fast it will go. It will go as fast as the motor is able to go....

 

[Jel]

Hi AHicks,

Thanks for your responds. I was thinking of changing the cassette/freewheel which is currently 14t-28t (7 speed) and a 46t front sprocket. Is it common that bike manufactures to low gear their ebikes so they don't go faster ? Also why are they stating their bikes will go 28mph with peddle assist when they can't/don't ?

 

[AHicks]

Hi AHicks,

Thanks for your responds. I was thinking of changing the cassette/freewheel which is currently 14t-28t (7 speed) and a 46t front sprocket. Is it common that bike manufactures to low gear their ebikes so they don't go faster ? Also why are they stating their bikes will go 28mph with peddle assist when they can't/don't ?

You'd have to ask the advertising execs that question. What you have is a pretty common setup among all of the mfgs.

Dropping to an 11t on the freewheel will make a notable difference in how fast you can pedal it. The 46t in front would be cheaper and easier, but the room to do that can be a real "gotcha". I would look in front first and do that if possible. Check that result, then go to the 11t in back if it's still not fast enough for you.

 

[Jel]

Thanks again for your help AHicks, What size front sprocket do you suggest I start with ?

 

[AHicks]

Thanks again for your help AHicks, What size front sprocket do you suggest I start with ?

One that will fit? That's the big deal. If you have room for one with 4 more teeth than what's on there now, that's where I would start.

I have no idea of what you have on there now, or how much room you have (if any) to go bigger. Sorry I can't be more help.

 

[Jel]

It has a 46t front sprocket on now. I'm thinking of maybe a 52t ? But maybe 50t is a safer place to start.

 

[AHicks]

It has a 46t front sprocket on now. I'm thinking of maybe a 52t ? But maybe 50t is a safer place to start.

4 teeth should make a noticeable difference. If there's a lot of room though, I'd be tempted to go with the 52t.

 

[Jel]

So I fitted a 53t front sprocket/chainwheel and although I don't have to spin my legs as fast all it really does is reduce the wattage going to the motor but doesn't propel me faster.

I don't want to set any speed records I just want to keep up with the speed of traffic on the road I commute on which is a 25mph limit and I'm currently stuck at 20mph. My controller is a lsdzs controller and if someone can give me some pointers as to how to remove the limiter I would very much appreciate it.

Thanks in advance