New belt's teeth/grooves significantly different from old

[Deja_Vu]

So I'm in the process of replacing my belts and have gotten 2 in so far - timing and alternator belts. The new alternator belt has much smaller teeth than my current alternator belt. They are both labelled the same (Contitech AVX x 10 x 965 La), but the teeth on the old one (the one I took off my car) are much thicker and match the AC compressor and power steering belt. I asked Pelican about it and they said sometimes manufacturers have different teeth but the size and the width are really what matter. I pressed and said it was the same manufacturer but they didn't give a clear explanation. See attached image. Top is new, bottom is old. Am I ok to use this?

[AndrewBird]

The ribs don't do anything except make the belt a bit more flexible. It's fine to run it.

[Deja_Vu]

Ah OK. I was worried about slipping because of decreased surface area.

[AndrewBird]

The teeth don't actually touch the pulley, the angled sides do. There is a minor surface area difference there, but not a significant one.

[TobyB]

It's a v- belt, not a timing belt.

They didn't used to have ANY ridges for your enjoyment...

t

[15Michaeljoseph]

That belt is totally fine, different brands sometimes have different/updated designs.

[MR E30 325is]

Ah OK. I was worried about slipping because of decreased surface area.

Just for your future info, friction is not a function of surface area. In this case it is a function of tension.

[Deja_Vu]

Just for your future info, friction is not a function of surface area. In this case it is a function of tension.

Yeah I remember that from high school physics...but there is a reason RWD sports cars typically have thicker tires. Can't remember why though.

[MR E30 325is]

Yeah I remember that from high school physics...but there is a reason RWD sports cars typically have thicker tires. Can't remember why though.

It's a more complex idea, but the concept of friction being independent of surface area is still accurate. Mainly has to do with the irregularities in asphalt and how thinner tires react under loading compared to wider tires.

[TobyB]

the engine's too big.

Most rwd road course cars are the same all the way around...

t