Motor choice?

[Casimirrx]

Im starting with an AMYET S8 frame

16S6P 60V setup using 96 EVE 40PL 21700 cells (4000mAh, 70A)
Alternatively depending on the advice here, 72V would be 100 cells in a 20S5P configuration.

2 × FarDriver Mini 12 controllers with Bluetooth (TY72V80A).

Dual-controller Grin shunt with Cycle Analyst.

The goal of this post is deciding between dual QS 159.8 motors, dual QS 205 V3 5T (front and rear), or a mixed setup with a QS 159.8 in the front and a 205 in the rear. What I’m really after is a bike that can snap through corners—hit one, flick it, and set up for the next. Top speed is nice, but it’s secondary to off-the-line thrust and strong 1/8-mile performance.


On paper, dual 205s seem like the obvious choice. But there’s a tradeoff with all that weight on the front fork. The 159.8 is significantly lighter, so while I may give up some torque, I could gain handling. Conversely, running dual 159.8s shifts things the other way—a lighter rear end, even though the magnets are larger.

The real complication I think is mixing two different size motors. I’m not sure how manageable that will be in real-world use with the dual FarDrivers.

I’m not locked into these motor choices yet, so if there’s a combination I’m overlooking that better fits my goal, I’m open to suggestions.”

 

[larsb]

Off the line thrust, corner taking and front motors don't mix well on a bike, even a hotrodded "250w" motor can spin out if you've got a bit of current. Had a "250W" geared Q100 motor in the front at 1500W, that was too much for the grip sometimes (wet, gravel, starts etc)

With your goals I'd look at just a larger rear motor. Can't recommend one though, I'm running low power these days.

 

[bananu7]

The goal of this post is deciding between dual QS 159.8 motors, dual QS 205 V3 5T (front and rear), or a mixed setup with a QS 159.8 in the front and a 205 in the rear.

Why aren't you considering a single rear motor?

 

[E-HP]

Wrong frame for your goals. In order to launch the bike, you need to get as much of your body weight forward to keep from flipping over immediately. Those tall handlebars make that impossible, and the short wheelbase makes it worse. I try to get at least my chest or more over the handlebars at launch, but enough over the rear to maintain traction. It’s tricky. That bike, with that upright riding position, is made for leisurely riding.

 

[Alex12345]

Im starting with an AMYET S8 frame

16S6P 60V setup using 96 EVE 40PL 21700 cells (4000mAh, 70A)
Alternatively depending on the advice here, 72V would be 100 cells in a 20S5P configuration.

2 × FarDriver Mini 12 controllers with Bluetooth (TY72V80A).

Dual-controller Grin shunt with Cycle Analyst.

The goal of this post is deciding between dual QS 159.8 motors, dual QS 205 V3 5T (front and rear), or a mixed setup with a QS 159.8 in the front and a 205 in the rear. What I’m really after is a bike that can snap through corners—hit one, flick it, and set up for the next. Top speed is nice, but it’s secondary to off-the-line thrust and strong 1/8-mile performance.


On paper, dual 205s seem like the obvious choice. But there’s a tradeoff with all that weight on the front fork. The 159.8 is significantly lighter, so while I may give up some torque, I could gain handling. Conversely, running dual 159.8s shifts things the other way—a lighter rear end, even though the magnets are larger.

The real complication I think is mixing two different size motors. I’m not sure how manageable that will be in real-world use with the dual FarDrivers.

I’m not locked into these motor choices yet, so if there’s a combination I’m overlooking that better fits my goal, I’m open to suggestions.”

Do they even make a front hub version of QS159.8? It's normally designed for 175mm+ dropouts. I'm running it in the rear and yeah it's light but still it's 7kg so that would probably affect maneuverability to some extent if put in the front.

The good news is if you do manage to put it in the front, it will probably not skid as much as a geared hub would due to higher weight and lower torque, and you could probably tune the phase amps down for the front to limit spin outs.

 

[Casimirrx]

Do they even make a front hub version of QS159.8? It's normally designed for 175mm+ dropouts. I'm running it in the rear and yeah it's light but still it's 7kg so that would probably affect maneuverability to some extent if put in the front.

The good news is if you do manage to put it in the front, it will probably not skid as much as a geared hub would due to higher weight and lower torque, and you could probably tune the phase amps down for the front to limit spin outs.

You dear sir are whats known as a Party Pooper...Your quite right. I had assumed since they plug it for ebikes at 48V it would have a drop out that makes sense but all i can find are 175 or 190 so you settled that question by default and crushed dreams (sob) I ll try to move on.

 

[Casimirrx]

Wrong frame for your goals. In order to launch the bike, you need to get as much of your body weight forward to keep from flipping over immediately. Those tall handlebars make that impossible, and the short wheelbase makes it worse. I try to get at least my chest or more over the handlebars at launch, but enough over the rear to maintain traction. It’s tricky. That bike, with that upright riding position, is made for leisurely riding.

I already switched the handlebars to a flat surron style. Have you worked with a Cycle analyst? you can control the front trottle so that i begins milliseconds before the rear pullling the bike forward before the rear end has a chance to pull up. Its awesome.

Why aren't you considering a single rear motor?

After expericaning dual motors i will never go back to one single in the rear. Okay maybe i would do a Bonnell MX but the primaryvf reason i dont do single is FUN! Dual motors is the most fun i can have with my clothes on but i dont get out much.

 

[bananu7]

Okay maybe i would do a Bonnell MX but the primaryvf reason i dont do single is FUN

Interesting how different people view fun differently. I was going at the fact that your two planned motors don't really have all that much power, all things considered, i.e. you can pull much more from a proper single (especially mid mounted) motor than from two hub motors, but I guess there's some added value from the front drive.

 

[scianiac]

After expericaning dual motors i will never go back to one single in the rear. Okay maybe i would do a Bonnell MX but the primaryvf reason i dont do single is FUN! Dual motors is the most fun i can have with my clothes on but i dont get out much.

Having to wrangle an unstable bike back from almost dumping you because you spun the front wheel is not my kind of fun.

Also a 205 in the front you are just not going to be able to even use most of the power it has, may be the case for the smaller motor too. It will mostly just be dead weight. IDK maybe with sticky enough tires and just loading as much weight on the front as you can but I don't see it.