I have a 6-string bass that's currently strung with daddario XL (32-45-65-80-100-130), but I have some Marcus Miller Fat Beams I want to put on it. The E and A strings are bumped up to 85 and 105 and the C is dropped to a 30. Will I need to adjust the neck? Normally it wouldn't be a big deal, but its a Pedulla and they require a special tool to adjust the truss rod, meaning I'd have to take it to my repair guy to get the neck adjusted. It's a hassle I'd rather not deal with if I don't have to.
I've made similar gauge changes on my 6-strings and never had to adjust the neck. YMMV, but that's been my experience.
Can't tell in advance. Every set of strings and every neck is different. If the neck is stiff and the strings are similar in tension, you may not need to adjust it - but you will need to re-intonate.
Hit up your local music store and find out if they have an autoharp tuning rod... they fit the Pedulla truss rod nut and are usually under $5.00. http://www.musiciansfriend.com/accessories/endust-autoharp-tuning-wrench Fishheadjoe