Ebike Noob here, I want to upgrade my 28" Crossbike into an ebike,

[Akologi]

Hey (not sure if this is the right forum to post this here but ill just start), so I want to upgrade my 28" crossbike (it uses hydraulic brakes)

Law and regulations here in Austria only allow me to use a 250 Watt Motor and a maximum speed of 25 km/h (anything else would be actually refered to as a scooter/pedelec here, requireing license plate, insurance, an actual Scooter helmet, not bicycle helmet etcetc..)

Now Since I am a total noob regarding ebikes(I did some minor DIY stuff on normal bicycles, but nothing regarding ebikes) and so far i have done some surface level research I do have lots of questions though...

I want it to be as cheap as possible but still reliant(obviously)
Pedal Assist is not even a must, I'd be already happy if i just manage to montage the motor, the battery and a little switch that accelerates the bicycle when pushed down(i'd mostly use it to accelerate or when going uphill, allthough the area i'll be cycling at is mostly flat)

Q1: as a roughly 100kg person are 250 Watts enough? I got the advice on reddit to buy a 48Volt Battery with a 20 AMP controller to over Volt the 250 Watt Motor.

Q2: I have looked up some cheap upgrade kits on Amazon for 200€(without battery), the issue i find in those kits is, they all have like these modified brake handles, which might become problematic because my Break handles can be also pushed up and down to switch gears. So obviously my worry is that the brake handles from that upgrade kit will most likely not be compatible with my bicycle.(hence why I just want a simple switch similar to e-scooters, I wonder if there'd be something available for purchase like that) No need for assisted pedaling etc. If anyone has an idea or suggestion feel free to post, otherwise i might have to switch out the entire Gear and brake thing for something more commonly used.

Q3: Are the cables&connections pretty much standardized? Like can i just buy the Motor from that one brand, connect it easily to a suitable battery from a different brand, with a different controller and Switch etc)?

Q4: Good websites, brands, suggestions etc would be nice, obviously cheap should it be. My budget would be around 500-600€ in total for this upgrade endeavour.

 

[Chalo]

250W (nominal, maybe 500W electrical) will work well-- as long as it isn't delivering that power at too high a speed. You should try to get a kit whose unloaded speed (wheel lifted off the ground) is not more than about 32 km/h, if you intend to abide by your local restrictions. That might mean using lower voltage and higher current than common systems, so you can get better performance at modest speeds, rather than optimizing for a speed range you're not allowed to use legally. Amps give you torque and volts give you operating speed, so higher voltage won't help get you what you're asking for (but more current will help).

It might be a little tricky to get a plug and play kit that does this, because the preponderance of the market for do-it-yourself conversion kits are configured to exceed EU legal power and speed limits.

You don't have to use switched brake levers just because they come with the kit. I never install them, because they add cables and points of failure without helping your ride in any way. If you can remember not to apply throttle and brake at the same time, then you won't be getting any value from them anyway.

Electrical connections aren't standardized in any way. The closest thing I've seen to standardization is the 9 pin Higo or Julet waterproof motor to controller plug which usually interchanges without problems. The small waterproof signal connectors from the same manufacturers are likely, but not certain, to work across different manufacturers and suppliers. Generic unsealed Chinese plugs and JST plugs are not likely to work together as received, even if they physically plug together.

I can't advise you about vendors who will ship to EU.

 

[Akologi]

250W (nominal, maybe 500W electrical) will work well-- as long as it isn't delivering that power at too high a speed. You should try to get a kit whose unloaded speed (wheel lifted off the ground) is not more than about 32 km/h, if you intend to abide by your local restrictions. That might mean using lower voltage and higher current than common systems, so you can get better performance at modest speeds, rather than optimizing for a speed range you're not allowed to use legally. Amps give you torque and volts give you operating speed, so higher voltage won't help get you what you're asking for (but more current will help).

Thank you for your response, regarding the kit, I thought a controller is able of regulating the speed. So I'd just buy a controller and set it up to a max speed of like 30km/h or something? maybe i have a wrong idea of the function of a controller.

 

[raylo32]

The controller apps and/or menus usually allow you to set and save speed limits. So, the motor assist will stop at that point. Crazy regulations you guys have... because on any downhill literally anyone can go way faster than 25km/hour even on a bike without a motor. A strong pedaler can go way faster than 25 km/hour on flat road without a motor. Do they also write tickets for that?

 

[marvin78]

I want it to be as cheap as possible but still reliant(obviously)
Pedal Assist is not even a must, I'd be already happy if i just manage to montage the motor, the battery and a little switch that accelerates the bicycle when pushed down(i'd mostly use it to accelerate or when going uphill, allthough the area i'll be cycling at is mostly flat)

I'd say a tsdz2 kit is as cheap as any cheap hub motor laced to a rim already.

Q2: I have looked up some cheap upgrade kits on Amazon for 200€(without battery), the issue i find in those kits is, they all have like these modified brake handles, which might become problematic because my Break handles can be also pushed up and down to switch gears. So obviously my worry is that the brake handles from that upgrade kit will most likely not be compatible with my bicycle.(hence why I just want a simple switch similar to e-scooters, I wonder if there'd be something available for purchase like that) No need for assisted pedaling etc. If anyone has an idea or suggestion feel free to post, otherwise i might have to switch out the entire Gear and brake thing for something more commonly used.

Those all in one handles are a nightmare to ride in rough terrain, and I never liked it when I combined many things in one since now if one function breaks.. I need to replace it all. Anyway, as Raylo32 said you don't need brake sensors if you know to stop pedaling when you grab your brakes ( with a torque based setup especially, not a cadence sensor activated hub motor where there can be much more harmful delay in power delivery ).

Q3: Are the cables&connections pretty much standardized? Like can i just buy the Motor from that one brand, connect it easily to a suitable battery from a different brand, with a different controller and Switch etc)?

Q4: Good websites, brands, suggestions etc would be nice, obviously cheap should it be. My budget would be around 500-600€ in total for this upgrade endeavour.

PSPower -> Tongsheng TSDZ2 Torque sensor mid motor Kits

Motor is +-250 and battery can be had for about the same ( depending on what you want.. ). edit: also, 'motor' is a kit, controller is integrated and it comes with a display of your choice.

There is a lot of info on these things on this forum, I know maybe 1% of it all and am trying to not only learn something new each day but also not forget it again the next. Either way, these motors are well known and you can get a lot of help with issues with them.

Electric bicycle ebike Battery Hailong G70 G56 21700 18650 Cells Pack 48V 36V 17.5AH 15AH 20AH 12.5AH Bicycle Lithium ebike Battery Lithium fits1000W

Electric bicycle ebike Battery Hailong G70 G56 21700 18650 Cells Pack 48V 36V 17.5AH 15AH 20AH 12.5AH Bicycle Lithium ebike Battery Lithium fits1000W

www.pswpower.com

If you order them at the same time and leave them a note they will make sure both battery and tsdz2 come with the same connectors ( standard bullet connectors though, I like my xt60's so I swapped them ).

 

[999zip999]

Add up the prices before buying. Make a box the size of the battery and controller to how you will fit them. This way you are not surprised when it comes.
Plus I have looking and seeing great deals on new e-bikes out the door . So you can have two bikes. On case a flat or problems. They got overstock

 

[Chalo]

Thank you for your response, regarding the kit, I thought a controller is able of regulating the speed. So I'd just buy a controller and set it up to a max speed of like 30km/h or something? maybe i have a wrong idea of the function of a controller.

If you don't care about complying with all the restrictions, but only with speed limiting, then my earlier advice doesn't apply. In that case, get a 500-750W kit that has a display, and limit it with settings to 25 Km/h.

But if you want to be fully in compliance, it's a little more difficult to squeeze out enough performance for a big rider. That's why you'll want the motor to give its best output and efficiency at low speed. The slower the top speed at a fixed power, the harder the motor can push at low speed. So you want the motor when unrestricted to turn just fast enough to reach 25 Km/h (usually 10% to 20% faster unloaded than your desired road speed), so that its best power and efficiency are in a speed range you are allowed to travel. That's why optimizing a 250W system is a more delicate balancing act that takes more attention to detail.

 

[Akologi]

If you don't care about complying with all the restrictions, but only with speed limiting, then my earlier advice doesn't apply. In that case, get a 500-750W kit that has a display, and limit it with settings to 25 Km/h.

But if you want to be fully in compliance, it's a little more difficult to squeeze out enough performance for a big rider. That's why you'll want the motor to give its best output and efficiency at low speed. The slower the top speed at a fixed power, the harder the motor can push at low speed. So you want the motor when unrestricted to turn just fast enough to reach 25 Km/h (usually 10% to 20% faster unloaded than your desired road speed), so that its best power and efficiency are in a speed range you are allowed to travel. That's why optimizing a 250W system is a more delicate balancing act that takes more attention to detail.

I'm really tempted to not comply and I'm certain with how easy it is to get stuff on amazon that accelerates your bike up to 50km/h that theres lots of people in vienna who do not comply(controls are not that common in my city, but its known they already did speedchecks of ebike cyclists and I'm planning to cycle alot on a daily basis so it'd be a matter of when and not if I'd get caught). The other issue is, if I'd have an accident where lets say a car or a person is involved, I can get into alot of troubles with a tuned ebike. As my Ebike would be classified as a scooter/pedelec, I'd face fines of things like not having a scooter helmet, no license plate, insurances would just jump off because they can, fines for driving a "tuned" ebike. Not to mention possible injuries I'd have to pay for because the insurance would drop out. Soo yeah in the worst case i could end up in prison and financially ruined.

And yeah the regulations are insane. Theres lots of cyclists that go faster than 25 km/h here.

 

[marvin78]

Tsdz2(b) has custom firmware which allows switching to 'street legal mode' with a button press..

I mean, I been told.. still waiting till my cable comes in and my cooling kit... should be this week.

Voila, mr copper, no really it only outputs 250w and doesn't give assistance above 25km/h, just take a ride on it

As to the legalities, if you're getting technical: a> afaik also in Austria they can impound your vehicle if they find it doesn't adhere to street legal rules and you were caught using it in this manner on public street ( no 'street legal mode' will save you if the motor cop had to pull a stripe to catch up to you, they will tear everything down and proof you're not street legal ). b> if insurance finds out your vehicle is not street legal, they can refuse to pay out.

Not sure about being able to register a faster ebike as scooter in Austria, can you? Here, only 'speed pedelecs' can get a license plate, as they have 'type approval' for use on public roads in that matter, Conversions would never be allowed to be given a license without getting them checked at the dmv perhaps?

Anyway, the main thing imo is: behave! Don't be an idiot! Don't try to be cool! Don't draw attention and most people would be fine..

I been checked 3 times on my actually street legal 250 rear hub... which runs 40km/h+ with a 48v battery Read rating laser etched in the motor and I was good to go without a speed check ( hehe ). That guy just has it in for me, I doubt most have the same experience, as long as you behave and don't drive like you got an illegally fast not street legal contraption.

 

[raylo32]

I would tell the copper to wait right there while I get my pedal road bike and ride past him at 40-45kph. Then ask him how much sense it makes for an e-bike to be limited to 25. LOL. I honestly don't understand the different treatment.

 

[marvin78]

I would tell the copper to wait right there while I get my pedal road bike and ride past him at 40-45kph. Then ask him how much sense it makes for an e-bike to be limited to 25. LOL. I honestly don't understand the different treatment.

Its has to do with the 25km/h moped class. If they allow 'powered bikes' to be faster, they can't make money of registrations and insurance of mopeds since no one would use one.

Since those mopeds are loosing their protected status ( helmet mandatory, no longer allowed on bike paths ) it makes even less sense since they are now treated like 45km/h mopeds who are just slower..

Either way, the main issue with this is that to much is up to the coppers having had a nice coffee and donut, or if his wife didn't give him his cuddles the night before.

If they just left everything under 45 open, I had no issues with that.

As to your point, ask your legislator if they keep statistics involving road cyclists? 9/10 the answer is no. But they can tell you about the times something 'evil' was involved, but forget all those other serious accidents ( where it wasn't tin cans ) it was the speed of the cyclist himself.. and we never regulate that.

I heard in France they actually have a law which limits the speed for cyclists in cities. Here, bicycles are explicitly left out of the regulations, and thus have unregulated speeds.

That being said, there are few people capable of reaching a sustained 40km/h for prolonged time. No, don't tell me you a pro rider and that it is easy, even if you are it doesn't mean anything. Heck most roadies in their lycra are happy to get a 30km/h trip average. And I was struggling HARD to stay above 20, just below 25, on my mtb on the road. On average. But I can peak much higher, it's just not sustainable.

 

[raylo32]

We have bicycle speed limits here is places, and in the places they exist they usually make sense. Bike paths, boardwalks, C&O towpath. But to have different limits for 2 nearly identical form factor vehicles in the same driving location and conditions makes no sense to me, especially since the range you are talking about the vehicle speed capabilities are essentially the same. Also makes no sense to limit power for the ebike to a level such that the other can go faster under human power.

Sorry: I will drop this line about regulation and let the OP have his thread back!!

I heard in France they actually have a law which limits the speed for cyclists in cities. Here, bicycles are explicitly left out of the regulations, and thus have unregulated speeds.

 

[Chalo]

And yeah the regulations are insane. Theres lots of cyclists that go faster than 25 km/h here.

There's nothing limiting your ability to legally go faster than that if it's your pedal power. So that's fair in my opinion. What's not fair is letting motorists go so much faster than that without regard for their effect on others' safety and quality of life.

I do violate my local restrictions on allowable power, but not speed (at least not very often).

 

[marvin78]

Law and regulations here in Austria only allow me to use a 250 Watt Motor and a maximum speed of 25 km/h

Sorry: I will drop this line about regulation and let the OP have his thread back!!

We are not deviating so much are we

Pretty sure OP also does not enjoy his legislation. But indeed, maybe just limit it to what might work within his legislation.

I do violate my local restrictions on allowable power, but not speed (at least not very often).

I have never seen an ebike on the dyno like they use for mopeds. But, I have seen bikes being checked for 'markers' like a hub motor twice as big as the brake rotor and a 72v battery. Thing is, all 250w motors actually run much higher peaks, especially under heavy load. If they did dyno all commercially available '250w' motors I don't know how many would actually still be allowed under current broken legislation.

There's nothing limiting your ability to legally go faster than that if it's your pedal power. So that's fair in my opinion. What's not fair is letting motorists go so much faster than that without regard for their effect on others' safety and quality of life.

I .... actually, let's give OP his thread back

 

[Akologi]

Its alright, its an interesting discussion. And I do agree with that post

Its has to do with the 25km/h moped class. If they allow 'powered bikes' to be faster, they can't make money of registrations and insurance of mopeds since no one would use one.

Since those mopeds are loosing their protected status ( helmet mandatory, no longer allowed on bike paths ) it makes even less sense since they are now treated like 45km/h mopeds who are just slower..

Either way, the main issue with this is that to much is up to the coppers having had a nice coffee and donut, or if his wife didn't give him his cuddles the night before.

If they just left everything under 45 open, I had no issues with that.

As to your point, ask your legislator if they keep statistics involving road cyclists? 9/10 the answer is no. But they can tell you about the times something 'evil' was involved, but forget all those other serious accidents ( where it wasn't tin cans ) it was the speed of the cyclist himself.. and we never regulate that.

I heard in France they actually have a law which limits the speed for cyclists in cities. Here, bicycles are explicitly left out of the regulations, and thus have unregulated speeds.

That being said, there are few people capable of reaching a sustained 40km/h for prolonged time. No, don't tell me you a pro rider and that it is easy, even if you are it doesn't mean anything. Heck most roadies in their lycra are happy to get a 30km/h trip average. And I was struggling HARD to stay above 20, just below 25, on my mtb on the road. On average. But I can peak much higher, it's just not sustainable.

They could just add 2 Speed limitations. 45km/h and above needs a license plate. For certain areas/bikelanes or at bike&Pedestrian mixed zones(they exist in austria) they are limited to 25km/h. If you want to go faster you are obliged to drive on the street. I mean lots of bikelanes are basically on the side of street, just seperated through ground markings. Also it is already allowed to cycle on the street in vienna and even take the entire lane if there is no bikelane(Even if you slow down everyone behind you, allthough you can be sure car drivers won't take it nicely and ettique is you stay as right as possible so they can overtake if the opportunity presents itself, also there are just super busy streets where you'd be suicidal to try and cycle on lol).

So in a sense increasing the Speed limit and letting cyclists drive on the street would probably even increase traffic flow since cyclist would be less of an obstacle if they can go up to 45km/h.
Maybe make it mandatory that ppl have a drivers license or sth but thats it. I feel like i'd be even more in danger cycling slowly on some streets lol.

 

[marvin78]

Since you left the discussion open I'm happy to continue it as it is quite interesting, but since we're deviating so much from the topic I'll put it in spoilers as not to flood the topic for those not interested in it.

Spoiler: eternal traffic law discussions and safety considerations

While there are people who would perhaps be absolutely fine mixing with cars when going 45, I don't think that's the solution. The 'proper' solution imho makes me very unpopular with those who need to plan and pay for public infrastructure, but you have to keep cyclists apart from cars. And, in addition to that, there are studies which correlate safety and perceived safety is included in that consideration, for the average cyclist it feels threatening to share a dedicated cycling lane with traffic going almost twice as fast as they are. Average cyclists also include children and the elderly, and people who just aren't busy 'exercising' but just being out and about.

Roads don't only have speed limits on the upper side, you can't drive on the highway at half the 70mph limit because a larger differential in speeds cause dangerous situations since our brain on average isn't fighter pilot grade and has issues instantly judging speeds of multiple moving objects. So it makes assumptions, especially in the first few moments.

So not only do you need infrastructure which separates high energy tin cans from humans on bikes without crumble zone's as to prevent death from the surplus of energy in an impact, you should also have the same separation in high and low speed personal transport ( since you can use bike lines also for commercial activities, especially looking forward when lots of inner cities want to limit car traffic and deliveries using 'other means' will only increase ).

Maybe it's because people already claim I live in 'utopia', with an excellent cycling network, that I see the 'only solution' doubling that infrastructure. I mean, it's nothing else as stating that dedicated road lanes for heavy traffic so they don't constantly mix with normal cars, increases safety. And those do exist, do they not?

I'm afraid that letting road cyclists mix with cars at 45km/h we will see a sharp increase not only in amount of accidents ( even if all cyclists knew how to behave at those speeds, and they don't, those drivers aren't used to meatbags mixing with their tin cans ) but mostly in the severity of them due to the high energy impacts when heavy tin cans collide with human bodies.

Human bodies do not do well in collision tests with heavier denser objects. The amount of energy increases exponentially when you're being hit by a moving tin can as opposed to another heavy dense but static object like a wall or tree, and if you mix meat bags with tin cans in environments where this energy becomes substantial enough, each time you force a cyclist to cross a potential path of travel of a tin can you should imho be potentially liable for negligence claims.

Back to the bike, where are you at in your considerations? Hub, mid drive? Heck yesterday I found myself looking for modern friction drives and even those seem to be way more available then I thought they'd be.

 

[Akologi]

Since you left the discussion open I'm happy to continue it as it is quite interesting, but since we're deviating so much from the topic I'll put it in spoilers as not to flood the topic for those not interested in it.

Spoiler: eternal traffic law discussions and safety considerations

While there are people who would perhaps be absolutely fine mixing with cars when going 45, I don't think that's the solution. The 'proper' solution imho makes me very unpopular with those who need to plan and pay for public infrastructure, but you have to keep cyclists apart from cars. And, in addition to that, there are studies which correlate safety and perceived safety is included in that consideration, for the average cyclist it feels threatening to share a dedicated cycling lane with traffic going almost twice as fast as they are. Average cyclists also include children and the elderly, and people who just aren't busy 'exercising' but just being out and about.

Roads don't only have speed limits on the upper side, you can't drive on the highway at half the 70mph limit because a larger differential in speeds cause dangerous situations since our brain on average isn't fighter pilot grade and has issues instantly judging speeds of multiple moving objects. So it makes assumptions, especially in the first few moments.

So not only do you need infrastructure which separates high energy tin cans from humans on bikes without crumble zone's as to prevent death from the surplus of energy in an impact, you should also have the same separation in high and low speed personal transport ( since you can use bike lines also for commercial activities, especially looking forward when lots of inner cities want to limit car traffic and deliveries using 'other means' will only increase ).

Maybe it's because people already claim I live in 'utopia', with an excellent cycling network, that I see the 'only solution' doubling that infrastructure. I mean, it's nothing else as stating that dedicated road lanes for heavy traffic so they don't constantly mix with normal cars, increases safety. And those do exist, do they not?

I'm afraid that letting road cyclists mix with cars at 45km/h we will see a sharp increase not only in amount of accidents ( even if all cyclists knew how to behave at those speeds, and they don't, those drivers aren't used to meatbags mixing with their tin cans ) but mostly in the severity of them due to the high energy impacts when heavy tin cans collide with human bodies.

Human bodies do not do well in collision tests with heavier denser objects. The amount of energy increases exponentially when you're being hit by a moving tin can as opposed to another heavy dense but static object like a wall or tree, and if you mix meat bags with tin cans in environments where this energy becomes substantial enough, each time you force a cyclist to cross a potential path of travel of a tin can you should imho be potentially liable for negligence claims.

Back to the bike, where are you at in your considerations? Hub, mid drive? Heck yesterday I found myself looking for modern friction drives and even those seem to be way more available then I thought they'd be.

I ordered a frontwheel drive for roughly 250€ now. (includes a controller that limites speed to 25km/h a simple acceleration thumb switch and a lcd display). its basically exactly what i wanted, this way i dont have to remove the cassette for the motor one(which often had only 1 gear in most products i saw)and still have the gears if i decide to cycle without electricity. Battery will be ordered next month , till then i should have managed to at least install the motor lol.

 

[marvin78]

Could you link us the kit you ordered I'm curious what you might have picked up for that price. You're right about ease of install, front hub motor kits are usually the easiest drop in replacement. Even while I don't like the idea of getting power through my front wheel, it doesn't really matter when you're staying legal anyway.

 

[Akologi]

Could you link us the kit you ordered I'm curious what you might have picked up for that price. You're right about ease of install, front hub motor kits are usually the easiest drop in replacement. Even while I don't like the idea of getting power through my front wheel, it doesn't really matter when you're staying legal anyway.

Amazon.de

this one. Yose power brushless 250Watt 36v motor.

 

[marvin78]

Lots of good reviews, looks pretty simple ( though I really dig the silver enclosure normally all the cheap kits are black, or black and if you look long enough, black.

Will be interested in hearing the install process and after riding what you think of it.

 

[999zip999]

That will work as long as you put at least one torque arm to make sure the wheel don't fall off or spin. If it spins you'll rip the wires so that's a good insurance.
Could afford to run that at 36 volts giving your speed limitations as 36 volts would be cheaper. Remember bikes are always a compromise of this or a compromise of that can't have it all.
But I'm a speed freak I have 72 volts and go about 46 miles an hour with a cup holder for my beer.
I had a cop sitting up in the golf course I spotted him so I started pedaling like mad I looked at my speedometer I was going 46 miles an hour he saw me with his radar gun check the speed and point it back down at me and just let me go. Speed limit ??? What's that ???
I can only pedal on my back is fast as 30 miles an hour with the gearing.
That's where we come up with the term windmill. As as in your country windmill.

 

[Akologi]

46 miles an hour

tbh when i cycled downhill in the Mountains i reached speeds of 50km/h on my bicycle and I was already uncomfortable with that speed, but 46 mph(~75km/h).... nah I'm out thats wayy too dangerous for me lmao, I'd be scared of my bicycle falling apart or something. I'd rather get a Motorbike or an Ebike that designed for those speeds.

 

[marvin78]

When I was growing up, mopeds going about those speeds were quite the norm under the 'cool kids'. And those had drum brakes...

Good solid mtb frame with decent hydraulic disc brake setup can handle that speed. It's the other traffic which becomes a problem, or even colliding with dense immobile objects like sign posts or trees / walls.

I seen many entry level 'speed pedelecs' which were of way worse quality as even an entry level good mountain bike.

Remember, you can buy the same stuff they ride Hardline with.. and put an engine in it. Mid drive so you keep all your gearing and control, keep center of weight down and not in a wheel disrupting handling.

Ebike's designed to go fast are usually in essence mountainbike frames, given some mudguards and a rack.

 

[999zip999]

It's like a go-kart 4 inches off the ground 80 mph oh and faster. Haha
I'm thinking you made a pretty good choice for the options you have with the bike you have did I mention a torque arm or two ??? Important !!!
Could someone else help convince him. Lol

 

[marvin78]

~

Seems people want to make sure your fork will be strong enough. I don't think a legal motor would create enough torque to work it's way out of your dropouts but then again I know nothing so maybe you should listen to them. Probably could get away without a torque arm, my rear 250w hub doesn't have one ( and when overvolted run 50km/h unloaded so if he's staying stock... ). But again, I'm no authority.