Review first purchase and quick questions

Hey first post, thanks for any help!

Background:
Light weight, speed 25 mph (with additional top end room)
Occasional light off road, but mostly flat street under 10 mile range and with enough capacity for a couple trips between charges
Steel hardtail frame (enormous triangle), 26" wheels, disc brakes, derailleur or single speed (I have parts for both)
I have tools to strip and build up a bike frame which I've done once

Shopping cart:
10T MAC rear cassette on 26" DM24 rim, torque arms
CA3 with torque sensor BB, hydraulic sensor, short throttle
em3ev small triangle 50v 17.7Ah 14S6P 30Q
em3ev 12fet controller

Questions:
The controller and battery combo looks high for the geared MAC, with a correctly setup CA3 is that enough to keep the motor from melting/ clutch from breaking? em3ev pairs this controller with the DD Crystalyte

Have I crossed the line where I should just go DD? Crystalyte TC3065 TC3080? From what I've read off street should be DD or mid anyways...

It looks like with the TC30 series I still have options to try freewheel rear derailleur/ single speed, or single speed and front derailleur, or just single speed?

Can I still use a torque sensor BB with the Crystalyte? are they still useful at higher power levels?

I'm unsure how these motors affect chain line, can I keep my current spindle length of 114mm?

Baterries and controller are good for both DD or geared motors. With the CA you can optimize settings for any. PAS can be used with any motor too.

Both solutions have their own advantages. The geared motor is lighter and does coast freely, while the DD motor can be fed higher power, can regen and has less moving parts that can fail.

For the low speed and light weight that you plan, the geared motor is not a bad idea. If you think about future upgrade for higher speed and power, the DD hub might be a better choice.

Unless you are extremely heavy, with that much power you are not really going to need very many gears.

MadRhino said:

For the low speed and light weight that you plan, the geared motor is not a bad idea. If you think about future upgrade for higher speed and power, the DD hub might be a better choice.

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Thanks makes sense.

LewTwo said:

Unless you are extremely heavy, with that much power you are not really going to need very many gears.

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Sure, I was trying to keep them in the plan because they seem common in a lot of builds, but I don't mind going without.

It looks like the TC3065 is slower but higher torque than the TC3080? I see it listed here but this page is not laid out very well.

That is a myth. Motors are wound for a volt/speed ratio. A slow motor only turns slower for a given voltage. This is to let you match wheel size and voltage for desired speed.

Torque is another story. If you have slow and fast windings of the same motor, the quick way to know if one can produce more torque, is to put them on the scale to see if one is heavier. It could be the fast or the slow winding, but not a significant difference anyway.

The best torque improvement is a smaller diameter wheel.

Cool so any idea what speed differences will be between the TC3065 and TC3080 with a 26" wheel and 50v?

Edit: I did find this,
TC3080 is 9.9 Kv
TC3065 is 8.6 KV

So between the two I should get a slower speed out of the 3065 right?

Yep. kv is the back EMF factor.
A motor that is 8.6 Kv will need to spin 8.6 RPM to produce 1v and, by approximative extrapolation, it will spin 430 RPM at 50v when there is no load to slow it down.

Just to throw a monkey wrench at ya, you can do lots of dirt riding on the mac. What you can't do with the mac, is have a small motorcycle for dirt. ( meaning running 2000-3000w)

And you have to keep the jumping down, mostly in the form of not landing jumps with the throttle on, which is hard on the internal freewheel. Not hard to land the jump, then get back on throttle.

If you plan to ride dirt at speeds you'd pedal, 15-25 mph, and pedal up the hills, there is no reason you can't run the mac on dirt. It will be lighter resulting in a better handling bike, and use your battery less fast.

On the other hand, street, where handling is less important, is were I mostly run DD motors. Because I tow trailers, street is where I have the most need for the big power DD motor. For others, the many stops on street rides makes the mac a better choice, for a less loaded bike.

But,, I do have a 2000w DD motor dirt bike too. I don't need it, but its fun. I limit its speed to 30 mph with a slow rpm motor, because I don't like crashing any faster than that.

What a slower rpm motor gets you is a lower speed when the motor reaches decent efficiency. Typically a slower motor will stop making so much heat at about 12 mph, while a very fast motor will need at least 15 mph rpm when they are used in 26 inch bike wheels. What works for many, is aim for a max speed about 5 mph more than you plan to cruise, since you will only have max speed at the start, and as voltage in your battery drops, you will lose that extra 5 mph later in the ride.

As MR said, for more torque, go for more motor, in that same type. The heavier DD motors will have the most torque, simply because you can run thousands of watts more power, through that much more copper.

But if you want the most torque from 1000w, then the geared motors rule. Which is why they can make a good dirt ride, light, and torquey for the wattage they run. But not a small motorcycle, if that is what you'd like.

Easy to change motors later, no wheel choice is set in stone like your battery choice is. Cheap to change motors later.

dogman dan said:

But if you want the most torque from 1000w, then the geared motors rule. Which is why they can make a good dirt ride, light, and torquey for the wattage they run. But not a small motorcycle, if that is what you'd like.

Easy to change motors later, no wheel choice is set in stone like your battery choice is. Cheap to change motors later.

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That clears up a lot thanks. I'm sure the geared mac is a better fit for me. There were just a few posts I read that made it sound like I'd be replacing clutches and gears unless if I did anything besides ride in a straight line :wink: