What if I said you’ve been using the wrong screwdriver for your bikes this entire time? Until Shimano started using hex-head screws on some of its derailleurs relatively recently, you needed a cross-head screwdriver to adjust your high and low limits.
You’d be forgiven for assuming Shimano limit screws have a Phillips head but, in reality, they’ve always been JIS (Japanese Industrial Standard), which require a subtly different screwdriver tip design for the best possible fit.
The subject of standards is a confusing and murky one, as it appears the JIS specification for screwdrivers has been absorbed into the current DIN 5260-ph (DIN is the Deutsches Institut für Normung or German Institute for Standardization). If you’re interested in geeking out on this subject, this article on motorcycle site webBikeWorld is worth a read.
In any case, Park Tool describes the DSD-2 as being “built to exceed JIS standards” and since it’s made specifically with limit screws in mind, you can be confident it’s going to fit.
One weird tip for limit screw lovin’Matthew Allen / Immediate Media
The flat blade DSD-4 is meant for limit screws with a full-width slot on the head, like those found on Campagnolo derailleurs.
Otherwise, large, flat-bladed screwdrivers don’t have many applications on bikes other than as a general purpose bodge-lever. Yes, I know you do that, we all do.
The depression in the end of the handles is perfectly machinedMatthew Allen / Immediate Media
The aluminium handles are pleasingly knurled and have two rubber ring sections for grip. A depression in the end gives you somewhere to rest a finger or thumb when you’re engaged in acts of fine adjustment.
Compared to the fat, rubbery handle of the SD-2, the new DSDs are slim and not at all soft. This makes them less suited to acts of vicious torque, but then they’re not really designed for that.
The DSD-2’s tip is subtly different from that of my (slightly abused) SD-2Matthew Allen / Immediate Media
It should go without saying that the DSD-2 fits Shimano limit screws really well. My trusty SD-2 was always my go-to for limit adjustments, but using it side-by-side with the DSD-2 makes me realise just how poor a fit it is.
The DSD-2 fits Shimano limit screws perfectlyMatthew Allen / Immediate Media
The DSD-2 slots into the screw head like a perfectly square peg into a perfectly square hole. Screw and screwdriver move as one, with none of the wiggling you get using a standard Phillips.
Do I need Park Tool’s new screwdrivers in my life?
The DSD-2 is fearsomely expensive for a screwdriver, but it’s very nicely put togetherMatthew Allen / Immediate Media
At £30 / $35, Park Tool’s new screwdrivers are a bit of a luxury and the flat blade DSD-4 is hard to justify over more affordable alternatives.
If a better cross-head for derailleurs is what you’re after, you can buy a Vessel ‘JIS’ screwdriver from Amazon.co.uk / Amazon.com for under £10 / $10.
All the same, the new Park Tool offerings are lovely objects that fit their intended usage perfectly. I’ve long been of the opinion that you’ll never regret buying good-quality tools, and I can’t imagine you’d feel much buyer’s remorse with these in your toolkit.