It seems to me these two types are very close in spine given the same length and point weight. Am I correct?
According to my chart the 2018 is 65# and the 2117 is 78# so they are not really very close...
2117 on my spine chart is 81#s and 65# for 2018s.Anyway they arent very close.
2018 - 68#
2117 - 77#
Calculated spine and verified by measurement.
To get aluminum spine divide 31.5 by the listed deflection.
For 2018: 31.5/.464 = 67.9#
For 2117: 31.5/.407 = 77.4#
2115 shafts are close to 2018s......just lighter.
2117's are about 80# spine and are a tad larger in diameter so they are not what I would call close to 2018's. A closer spine would be 2020's...Van