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Giant Talon AKM128H build

jbell

🧲 New user
Joined
Oct 13, 2025
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8
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usa
Q128H Giant Talon build:

Goals:
1. As invisible as possible. I ride with a gravel group of almost all non-ebikes. Ebikes are seen kinda as cheating or a crutch by the competitive riders in the group. I have an ab/back injury where I can't bend over in a cycling posture, so upright and ebike is a must. However, a painfully obvious ebike, that flies up hills with zero effort catches more than sideward glances... Exposed batteries and obvious motors and wires, as well as motor noise are dead give aways. Aka, it has to look like a bike, and ride like a bike, and be welcome on bike/class1 areas.
2. 50+ mile gravel events with enough battery to spare so on 20mph windy days, and 10%-18% gravel hills, I don't run out. (yes I run ebike/non-competitive class)
3. Gears to be able to accomplish lake trails, and easy single track when not with the gravel group.
Equipment:
1. Giant Talon 2, 50mm stem + 50mm handlebar, 38T chainring, 11-42 Shimano 5100 cassette,5120m derailure, 1x11 shifter, 180mm brakes to clear motor, Ride1Up turris torque arms/plates, PakRak mini commuter bag.
2. AKM Q128HCST 36v201rpm motor,48v bag battery,25Amp 36/48v KT controller,TF01 Display,12PAS sensor, Pair of 48v10.5ah 13S3P battery in 4x10, not 3x13 configuration, plus a 2:1 battery combiner/balancer.

Configuration:
1. Rated versions of this motor yield 2800rpm core speed, so I wanted to keep rotor speed under that when overvolting to 48v. On 29" mtb tires, 23mph is 2800rpm core, so the display max speed is set to 23mph.
2. Motor is rated at 800w, I set display/controller to 50% to limit PAS 5 to 800watts (measured) and increased PAS C14 setting to high for a measured at the battery 150/250/370/540/800watts using constant current (simulated torque sensor mode) I weigh 250lbs, and run 9.2 wh/mile pas1, and 11.2 wh/mile pas2.
3. At 38chainring/11cassette on 29" tires my max cadence is about 23-24mph, motor is limited to 23mph, competitive riders in gravel group run 22mph.... aka, I can 'just' keep up and everything (me and the motor) runs out of gas at 23.
4. PAS kicks in in 1/2 pedal revolution, so no 'false starts' on the motor, no brake or shifter interrupters, as I find I don't need them. The motor shuts down quick enough and I have plenty of hydraulic brakes. I rarely am in anything other than PAS1 or 2. (pas3/4 for steep hills for a minute or so if needed)

Why did I build it:
1. I have a ride1up Turris, with an akm angle geared 125RX motor that is supposed rated at 90nm/1000watts/20amps. It is HEAVY and rides heavy, and sucks going uphill. (but the motor IS quiet) I have added eRuban Plus 27.5x2.6 tires, 1x11 shimano drivetrain, and 48v relay for extra bag battery. The only way I make it up steep kansas hills is PAS9 at 1000w generating mainly heat using 46chainring/36cassette to try to keep above 6mph where the motor gives me something. If I go down to 46/42, I'm so slow I get even less from the motor... I typically strain my knees climbing these hills with the pedal effort needed, and then the back pain.....
2. I typically ride around 14.5 or more wh/mile on the Turris at same route - same pedal effort of the giant that is 11.2wh/mile. Aka, the akm128h is much more efficient at the speeds/roads that I ride, so it takes less battery for a 50+ mile ride.
3. without bag, the giant is 40lbs. It is a breeze to load on the bike rack. It rides light, It feels light, going uphill the motor is running high enough rpm it's still giving useful output, so it climbs light. The turris is pushing 60lbs with integrated battery.... it's heavy all the time. I can climb lake trails/single track/18% grades on the giant and all I do is shift down and keep going, I never have to put in the excessive pedal effort that the Turris requires.

Things left to do:
1. Better internal cable routing / better controller mounting / eRuban plus tires. (yes those tires are the best thing I've ever seen on an ebike)
2. Colorado mountains / big events....
 

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Very nice stealth build!

Consider not suspending your battery from the seat tube:
- it will cause your bike to wag in a way that adds uncertainty when cornering
- in the worst cases with a heavy battery, the seat tube or frame can shear

I'd personally go with a regular chainstay mounted rack since there's going to be less motion. And drop it's height as much as possible because mounting behind the seat has a bad center of gravity to begin with.
 
Very nice stealth build!

Consider not suspending your battery from the seat tube:
- it will cause your bike to wag in a way that adds uncertainty when cornering
- in the worst cases with a heavy battery, the seat tube or frame can shear

I'd personally go with a regular chainstay mounted rack since there's going to be less motion. And drop it's height as much as possible because mounting behind the seat has a bad center of gravity to begin with.
thanks for the thoughts, but I'm good on the seat tube rack... no rideability concerns and I typically run a single 4lb battery, I only run the pair on 50+mile events. Other riders in the gravel group have several pounds of stuff in their bags, so I'm not out of line. This thing is just so dang much fun !!
 

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I have two Giant SL1 Toughroads and both came with an integrated rear rack. I pulled it off the old weekly rider but here is it still on the new one. Shouldn't be an issue picking one up either new or second hand. The mounting points will be there on your Talon as well, perhaps hidden under plastic plugs.

TR-RACK 01.jpg

TR-RACK 02.jpg

TR-RACK 03.jpg


I dug out the old rack and put it up against the holes in my 2016 era Talon-1 , perfect match.

t01.jpg

t2.jpg
 
I really can't believe that my seat post rack is the thing commenters are focusing on.... I must have done a bang up job if that's the biggest flaw seen. I've done over 1500 miles with 2 spare batteries in bag and the same seatpost rack on the Ride1Up, and am closing in on 400miles on the giant with zero issues. And yes, I know where the bolt-ons are for a standard rack, I just don't want one. The pakrak mini perfectly holds my batteries, tools, nutrition, the all important garmin 515, and space for a spare water bottle in the top laces. I even strap down a clothing layer if needed on variable temp days to the bag. Someday I may decide I need the fullsize pakrak commuter bag, but for now the mini works for my needs.

Do remember my primary goal of 'invisible'.... putting a battery in a place where no one expects helps that. I've had several savvy folks assume I somehow stuffed battery in the downtube, because they just write off the seat post bag as a battery location.

Now for anyone who really wants to use a hub on a giant talon, here is the detail that makes it truly possible, the Ride1Up Turris torque plate. The 15 degree plates on amazon are both the wrong angle AND the wrong length. The ride1up's fit perfect. A giant has a fairly shallow drop out, AND as you can see it's not flat. A couple washers plus the plate = perfectly secured hub.

IMG_7493.jpg
 
I've used the same seat post rack. They're very solid compared to others. I've since switched to a frame bag, but it felt fine even with an 11lb battery on a lighter road bike.
 
I really can't believe that my seat post rack is the thing commenters are focusing on.... I must have done a bang up job if that's the biggest flaw seen.
Well when looking at your post, everything seems normal and in check, except for that. We were not picking on you, we're simply pointing out some downsides to your design. One obvious benefit of the conventional factory design is a lower center of mass. All the mass of that pack is acting at seat level, swinging you back and forth, even when out of the seat, and bobbing up and down no doubt, all over rough terrain. Attaching it to the frame, lowering the weight more toward the ground, will give more stability, obviously.

But I understand your motivation, you are trying to deceive the other riders in the group. You won't, so why compromise?
Exposed batteries and obvious motors and wires, as well as motor noise are dead give always. Aka, it has to look like a bike, and ride like a bike, and be welcome on bike/class1 areas.
 
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But I understand your motivation, you are trying to deceive the other riders in the group. You won't, so why compromise?

Well.... I rode in a just for fun 'moonlight ride' with the Ride1Up bike where it was a closed to vehicles ride of several hundred. I know I heard more than one comment during the ride -- "they shouldn't let ebikes on this, this is just for cyclists...." etc...even though the rules for the event specifically stated non-throttle class 1 ebikes were welcome. aka, ebike push back from the 'true cyclists' is a thing, even in fun rides at night.... So, if I can pass the casual look test, then I get hassled less.

And I'm not bothered here by the questions, I just found it funny that I chose a motor from the way back machine, that seems to not be very popular, and yet that didn't cause any questions, but the seat post rack did.
 
Can't expect everyone to agree on everything, and posting will always draw naysayers. Some critics insult, and other strive to inform.
Your build is stealthy and beautiful. I can't see any wires!
That said, I'm in the frame mounted rear rack camp for non-rear suspension bikes. The physics just seems better, but that's just a guess.
Around here the #1 rule is do it your way, and you have done very well.
 
Finally got the wiring cleaned up.... cylindrical controller disguised as a bike pump is really nice.....

IMG_8039.jpeg
 
I love clean wiring
 

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