One small nit to pick: 108" is actually 1/4 wave on 11m not 102".
Using a 102" whip alone won't work well because it's too short.
If you look at it with an SWR meter. you'll see that--especially with 1/4 wavelength antennas--the antenna has the bandwidth to be acceptable at either length (6" vs. total length is a very small percentage). I've had flat SWR both with and without the spring, no tuning needed on the length of the radiator.