I started a thread a while ago about having problems with a QAD ultra rest hunter (i was having a problem with fletching contact on the bottom of the bottom two vanes, probably because of the nock point being too low.) i went to another bow place thats like 45 mins away and left happy and was sure everything was set to go...

so everything seams to be shooting alright when im shooting my whitetail 4560 carbon arrows with 2 inch vanes. (my draw weight is 55 pounds)

but then i have a few gold tip 5575 arrows left with 4 inch vanes and those were shooting maybe a foot higher...

could the stiffer spines arrows just shoot faster or something, or as i am kinda expecting, am i still getting contact with my 2 inch vane weaker spined arrows, but not with my 5575 arrows with 4 inch vanes???

i powder tested it at the archery shop and there was no contact but then i put the velvet stuff on the rest afterwards so i dk if i could have made it contact it again or what...any help is appreciated.

They aren't flexing as much so they hit higher, it's similiar to barrel harmonics...It has nothing to do with arrow speed...

Not losing as much KE since they are flexing less and flying straighter.

so would you say that it would be better to use the 5575 gold tips than to use the 4560s?

It might be a matter of different FOC and/or weight. In reality the spine is about the same for both arrows. They are both about a .400 spine. The markings (4560 and 5575) have very little correlation to the spine.