Belt size going from 13 teeth pully to 16 teeth pully

i have a qustion i have a pully on 59 teeth and a pully with 13 teeth i am running 330mm 66 teeth belt now

if I change the 13 teeth pully with a 16 teeth pully what belt size do I need

add 15mm for the 3 extra teeth on the motor pulley. It’s 5mm per tooth if you’re running an HTD-5M belt.

I know you’re running a 5M because 66 times 5 is 330. See how that works? You’ll need a 345mm belt.


thank u I was thinking it was simple and just add 3 teeth but better safe then sorry longhair boy is king : DDDDD


Looks like my favorite site has them in 12 and 15mm widths.

12mm width:

15mm width:

I dont want to sound like an idiot, but are you 100% sure about that? It just doesnt make sense to me since you are not using whole pulley but just a part of it :slight_smile:

I put the similar values (not exactly the same) in belt length calc and it doesnt add 15mm to the length by adding 3 teeth of smaller pulley :slight_smile:

What u said just doent make sense to me :wink:

For 16 teeth:

For 13 teeth:

EDIT: not saying 335 mm is the right way OK? EDIT2: I have filled in wrong values of the bigger pulley…it is wrong example but with the correct idea

1 Like

He needs 3 more teeth on his belt because he added three more on his motor pulley. Unless, of course, he wants to slide his motor back toward his wheels and use the same exact belt he had to begin with. OR slide it less back and use a belt with only 2 more teeth… and so on.

Adding three teeth adds 15mm because…


… HTD-5M says so.

Yep it does :slight_smile:

However it does add extra milimeters on the motor pulley, NOT BELT LENGTH…but you are not using whole motor pulley to transfer the power…just like 6 or 7 teeth of it :slight_smile:

1 Like

I am not sure if that may be the cause of the problem but in the pictures you dont have the same center to center distance while LHB is talking about not moving the motor so it may be where the difference in length is from

Yep I know, but it doesnt matter, I will ad the correct once, since the centre distance is like 62 mm :slight_smile:

For Martin directly: Mám ti to vyvětlit česky, ať jim to tu přetlumočíš, protože ve vysvětlování v angličtině trochu pokulhávám :smiley:

1 Like

Haha no skus :smiley: inak asi sme jedini co tu su zo Slovenka/Ceska mam taky pocit :smiley:

Nejsme, jen se k tomu ostatní nehlásí :smiley: a asi jsme nejaktivnější :slight_smile:

1 Like

Oh ok. Feel free to be wrong in your own language. As long as you’re not wrong in mine.


Ok, I will try to make a sketch to explain everything :slight_smile: If not I will explain it to Martin and he will translate to you :slight_smile:

While you’re at it, you can have him explain why a 330mm 5M belt had exactly 66 teeth to begin with. It could be a coincidence, after all.


Alright I am by no means a mechanic and while what @longhairedboy is saying makes sense to me, you add 3 teeth to the pulley you should add the same amount of teeth to the belt but I got curious and put the numbers to some calculator first link on google search and the results are above. I am not sure what to make of this, I just thought I would give my results on the subject.

1 Like

THank you <3

Ok, I will try words one more time :slight_smile:

Just part of the motor pulley is “in mesh”…while your motor is pulling you, about 6 teeth from a 15 teeth pulley are used in a moment (can be incrased by idlers, size…) what does it mean? That when you increase the motor pulley, you are increasing just the length of the part of the motor pulley, that is in contact with the belt…that is the reason why <3

Not whole perimeter of the motor pulley is in contact with the belt, just think about it :slight_smile: Which part of the belt are you lengthening? just the part that is in contact with motor pulley, the parts of the belt between wheel and motor pulley are still the same :slight_smile:

For my beloved Slovak brother

Jenom část řemenice motoru je v danou chvíli používaná na přenos síly, asi tak 6 nebo 7 zubů, zbytek v tu chvíli není použitý, myslím tu část, která je v danou chvíli v kontaktu s řemenem…takže když zvětšíš řemenici o 15mm obvodu, ve skutečnosti neprodlužuješ řemen o 15 mm ale jen o jejich podíl :slight_smile:

There was a train headed towards Munich at 6pm. Another train was headed to your face at 7:30am. How many penguins will be eaten by a polar bear in the time it takes a laden swallow to traverse England?

This may not work so well on motor pulleys because things break down when the size decreases but it totally works when adding teeth to the wheel pulley, which isn’t relevant here, so i’ll shut up.

1 Like

Where is the problem…Which part dont you understand? My English or the explanation? It works with both motor and wheel pulley, but I must admit that it is more important when you change motor pulley…

1 Like

@longhairedboy the point he’s making is that you’re only actually meshing with half of the teeth at a time, so if you were to add, say, two more teeth to one pulley, the belt would only be meshing with one additional tooth.

1 Like