Physics of breaking crosses

[ChanterRacquet]

Many on here state that those who play with top spin break the mains because the mains notch as they slide against the crosses. No argument, makes sense.

They then claim, by extension, if you are breaking crosses first, you must be hitting flat. But that’s an extrapolation that isn’t necessarily physically justifiable. If you truly hit nothing but flat, I’m imagining that you’d get a 50/50 split of breaking mains and crosses.

So, without explaining why mains break with top spin and then assuming you can just flip the coin over and equate flat hitting with crosses breaking, what physical explanation would justify the claim that ALWAYS breaking crosses first is indicative of flat hitting?

My claim is that always breaking MULTIFILAMENT crosses first is also indicative of top spin, the mains notching while the crosses are fraying are both a consequence of mains sliding over crosses and it’s a race to see which gives first. If you hit hard, you’ll notch faster and the mains break first. If you hit less hard, fraying of the crosses takes them out first. I am willing to bet this also correlates with how long a full bed of multi lasts for various top spin players. FB multi lasts you 1 hour, hell yeah you broke through those mains, you’re hitting the crap out of the ball. 2 weeks (with lots of playing), yeah you wore right through those crosses hitting top spin as the mains slide over those filaments over and over again. Of course with poly, you’re unlikely to break the crosses because they wear down and flatten as opposed to breaking tiny strands, but the mains are still notching so you always break the mains first with poly.

 

[Humbi_HTX]

...but the mains are still notching so you always break the mains first with poly.

Unless you find a hybrid combinations of strings where the main is more durable against friction than the cross, and just how stiff the string is does not really gives you an answer.

 

[ChanterRacquet]

Yeah, hybrids can give you all sorts of scenarios.

 

[Steve Huff]

Same string mains and crosses with equal angles of deflection (not necessarily the reference tension being equal), it would make sense that the cross would break 1st on hard hit balls due to their shorter length (less length to stretch before breaking).

 

[ChanterRacquet]

Same string mains and crosses with equal angles of deflection (not necessarily the reference tension being equal), it would make sense that the cross would break 1st on hard hit balls due to their shorter length (less length to stretch before breaking).

Unfortunately, we very much see that the hardest hitters among us consistently notch through and break the mains first, in spite of their longer of string length. That notching is a result of the string response to the ball, one of if not the most important consideration. Additionally, each intersection is going to limit the effectiveness of string length in absorbing impact forces, I would think.

 

[Kevo]

I've broken crosses only on string hybrids where the cross was just the weaker string. I think there could be some strings where the fraying of the crosses might make them break first, but I suspect that would happen mostly in cases where the movement of the mains is rather limited so that the main is applying all it's wear to a small section of the cross. Typically I would expect harder hitters to cause the main to slide against a larger section of the cross so the wear on the cross would be spread over a larger section of string.

I could imagine there are different potential scenarios depending on the particulars of the situation.

 

[ChanterRacquet]

Excellent points.

I’m just tired of hearing “you break crosses first so you hit flat.”

That statement is wrong in so many contexts, including some that involve hitting with top spin. There are so many variables.

 

[Steve Huff]

Unfortunately, we very much see that the hardest hitters among us consistently notch through and break the mains first, in spite of their longer of string length. That notching is a result of the string response to the ball, one of if not the most important consideration. Additionally, each intersection is going to limit the effectiveness of string length in absorbing impact forces, I would think.

He just wanted an explanation of how crosses could break first. That's just one. There are many reasons why the main would break 1st also.

 

[ChanterRacquet]

He just wanted an explanation of how crosses could break first. That's just one. There are many reasons why the main would break 1st also.

Who is “he”? I’m the OP.

 

[Irvin]

I’m just tired of hearing “you break crosses first so you hit flat.”

I see crosses fray and break more often in full bed multi string jobs. The reason is simple, the ball slides over the cross string on one side and the main strings slide over the cross on the other side. The main string will tend to deflect at the ball is hit. With a poly / SG hybrid you will see the SG actually worn flat from rubbing on both sided. Many times Ive seen SG crosses look as flat as a ribbon from the string to string and string to ball rubbing.

Hitting harder and / or with more spin just makes a string break faster.

EDIT: Use poly / gut or gut / poly and you almost always break the gut first.