Summery: When I bought my 2005 Parker Fly Mojo I wanted to put on heavy (.012″) strings. But there was a problem. The tuner posts weren’t long enough to accommodate larger strings. It took some sleuthing to figure out the solution. In the end I replaced the tuners.
Here is the video of me changing them out.
Warning: Putting heavier strings on your guitar will increase the tension on the neck and tremolo system. Don’t be cavalier about it. You can damage your guitar. Make sure your guitar can accommodate the string gauge. Call the manufacturer. Check the manual. Check the user forums. I remember putting heavy strings on an acoustic and permanently resetting the neck in a bad way.
Parker necks are wood with a carbon and glass fiber exoskeleton. They are supposed to be strong.
Parker supports tremolo springs (actually on Parkers it’s a plate used in compression) for .011″ (medium) strings. I reasoned heavy strings tuned a step flat would have the same tension. Then I used an on-line string tension calculator to get an estimate.
I used this calculator. It’s nice. It sums strings for a total tension, accounts for wound strings, allows different string scales and alternate tunings. According to this calculator a set of medium strings tuned to E with a 25.5″ scale is about 126lbs of tension. A set of heavy strings tuned to D is 129lbs of tension. About the same so should be fine.
The problem with my current tuners: The part of the tuner that goes through the headstock is called the post. It has to be at least long enough for the hole in the tuner to poke out the other end of the headstock and receive your string. As you can see here the hole for the low E string is slightly recessed beneath the bushing and washer. You can thread a string so long as it’s not too thick.
On the end of the headstock everything seemed fine. First I thought the posts were different heights. They weren’t. So I measured the headstock thickness and found a 1/32″ variance. That explained it.
I was confused about this at first. But after a bit of sleuthing I think I figured it out. I called Roger over at Sperzel (the stock tuners on my Parker are Sperzel Trim-Loks). He said pre-2000 the Parkers shipped with a shorter post height tuner. My guess is this Parker left the factory with the old hardware.
I started surfing about for replacement tuners. The only site that actually listed some useful specs on the post height was stewmac.com. They had 3 different post heights listed for some sets of Trim-Loks. I only wanted to order once so I called Roger again. He told me to order from Carvin. Carvin’s inline set was the right height for my Parker. I suspect most of what’s out there is the right size for my Parker but no one seems to list any meaningful specs.The measurement I have from the bottom of the post (where it presses against the headstock) to the bottom of the hole is about 25/32″. But good luck finding that listed anywhere.
Just an FYI, the Sperzel Trim-Loks fit heavy strings fine. The largest of mine is .052″ or .05245″ as this AccuRemote micrometer shows (for $50 I like this tool). I can’t vouch for larger strings fitting the tuner holes.
Removing/Installing: Remove your strings. Use a 11mm socket to unscrew the bushing. Be careful not the strip the bushing. There isn’t much to grab. You may need to push and wiggle the tuner out a bit. These tuner have a pin that keeps them from rotating on the back of the headstock. Some pins have a snug fit. There is a video at the top of this post where I swap them out.
Other Important things: Changing the tuners to put heavy strings on is just the beginning. Now I have to adjust the tremolo to balance out the new string tension. On a Parker this requires getting a new spring (actually more like a compression plate). I’ll also need to check out the relief and see if I need to adjust the truss rod. Another post…