Reach back to the late 1970s; the guitar world changed with the release of Van Halen’s first album. Driving that change was a very special guitar: Eddie Van Halen had assembled a Strat-style guitar from cheap parts, with a Fender-style vibrato bridge. But the real revolution? He had loaded the guitar with a single PAF-style humbucking pickup in the bridge position. Though he may or may not have been the first to install a humbucker in a Strat, after the first VH album hit turntables, many players were anxious to try it – the appeal of a Strat’s playability and its Strat-style vibrato bridge, combined with the thick, chunkier sound of a Les Paul, was very attractive.
But, perils awaited those brave enough to take a chisel or a router to their Strats – chiefly the differences in the bridge spacing between Gibson-style stop tailpieces/bridges and Fender vibrato bridges, and how the pickups are physically configured to match up with those bridge spacings.

The string spacing on most Gibson-style Tune-O-Matic bridges is 21?16” from the center of the high E string to the center of the low E string. To match this, most traditional humbucking pickups use pole pieces that measure approximately 1.90” to 2″ from the center of the high E pole piece to the center of the low E pole piece.
Traditional Fender tremolo bridges use 23?16” or 27?32” spacing from the center of the high E string to the center of the low E string. (Some newer models, particularly those made in Mexico, use 21?6” high E to low E string spacing.) For this reason, most single-coil pickups use around 2.07″ spacing from low E to high E.

So, those ’70s-era guitarists who boldly attempted to install humbucking pickups in their Fender tremolo-equipped guitars quickly found that the pole pieces of the pickup didn’t line up. Either the high E or the low E string typically was off enough to cause a drop in level and/or a change in the tone of that string. Eddie solved this problem by slanting the bridge pickup until one pole piece hit the high E and another hit the low E, with the pole pieces for the middle strings roughly lining up. Production guitars from Kramer and other manufacturers followed his lead, slanting the bridge humbuckers in their guitars as well.
Fortunately, “after-market” pickup manufacturers, including Seymour Duncan and DiMarzio, came up with a better solution. In the case of Duncan, the company offers most of their humbuckers as “Trembuckers,” which support bridge spacings that are wider than two inches. Likewise, DiMarzio offers “F-spaced” humbucking pickups that support the wider bridge spacings. With these pickups, there’s no need to slant the pickup if you install it in the bridge position of a guitar with a Fender-spaced bridge.
Problem solved!