Decoy top assist speed short changed

kylnman

Member
Jan 6, 2020
20
11
Virginia, USA
Been riding and loving my Decoy for a year now, although it has never delivered the 20mph assist speed limit allowed in the U.S., cutting off completely by 18.5 mph. I consulted YT about this over the year, again recently when upon riding 2 other Shimano E8000 motor equipped bikes by other brands that took you right to 20 mph before shutting off. Elliot at YT confirmed that all Decoys--and other Shimano 8000 e bikes--cut at 18.5. This may be true of Decoys, but my research has shown it is not true, at least in the case of Norco and Commencal. Not a deal killer, just disappointed that the Decoy is not optimized to the legal limit. Also raises the question, do the European Decoys comparably shut off at 13.5 mph? That would be a sad short change situation.
 

YokoOno

Member
May 5, 2020
141
92
Colorado
On the flip side, the battery lasts longer when 18.5 is the max :)

I believe the ST Unlocker app will increase that max speed, if you're so inclined. Personally, I'll take range over speed.
 

Sam233

Member
Jul 19, 2020
23
7
Germany
I prefer speed on downhill sections to get the right speed on some jumps. 15.5 mph (Germany) is not enough in some sections and the motor cut off is often hitting in the wrong moment
 

kylnman

Member
Jan 6, 2020
20
11
Virginia, USA
On the flip side, the battery lasts longer when 18.5 is the max :)

I believe the ST Unlocker app will increase that max speed, if you're so inclined. Personally, I'll take range over speed.
I think you miss my point: being short shrifted on max assist speed has nothing to do with range. I can choose to ride 2, 8, 12 mph. Or if my motor was properly optimized, 20mph. I’m fully aware how to conserve battery. Plus, If you’re riding at 18.5 mph all the time, you won’t get very far, and only 3% farther than me at 20, all things being equal.
 

YokoOno

Member
May 5, 2020
141
92
Colorado
I think you miss my point: being short shrifted on max assist speed has nothing to do with range. I can choose to ride 2, 8, 12 mph. Or if my motor was properly optimized, 20mph. I’m fully aware how to conserve battery. Plus, If you’re riding at 18.5 mph all the time, you won’t get very far, and only 3% farther than me at 20, all things being equal.

Nope. I didn't miss your point at all. I was being tongue-in-cheek. But, yes, upping max assist means drawing more battery, and so range is diminished.

Again, if you want more speed, look into the app.
 

jabberwocky

Member
Sep 9, 2019
14
16
Leesburg, VA
I think its true that most commercial motor systems are a bit conservative. My class 3 Yamaha (Giant) starts cutting off at ~26.5-27mph. My YT cuts out around 18.5mph.

I don't think its anything YT can do anything about. They are using stock Shimano motors running stock Shimano software. It doesn't personally bother me.
 

lamomie

Member
Jul 3, 2019
54
41
France
the problem is due to the value of the wheel circumference set in the decoy, Yt set a value of 2300 mm which is the circumference value of a wheel of 29 ", you have to set the correct value for a wheel of 27 , 5 "which is 2180 mm and you will have a correct speed limit
 

Lee Dove

Well-known member
Oct 12, 2018
301
269
Scotland
The speed is set by the Shimano SW , nothing different in the Decoy to other brands using this system. ST Unlocker changes it.
 

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