SUNRACE SP570 EXTENDED LINK REAR DERAILLEUR HANGER EXTENDER
The Sunrace SP570 extended link is a neatly machined hanger, designed primarily, to increase the clearance between the rear mech and cassette. Situations where the mech runs too close to the largest sprocket(s).
Fitment won’t magically permit the use of a 11-42 cassette, with a road mech. However, it may extend the mech’s capacity by a few teeth. For example, permitting a mech with 28tooth capacity, to play nicely with a 32tooth cassette. So long as the overall gear capacity (chain wrap) doesn’t exceed the rear mech’s.
Pros: Nicely made, low weight does the job.
Cons: Will not massively increase gear range.
Both hanger and bolt are made from CNC machined 7075 aluminium alloy. The hanger is black anodized, with laser-etched graphics, and has a drop of 2.25cm. Nothing exotic but standards of machining and finish, are reassuringly good. Aluminium bolts are not only lighter but softer, so easier to machine than steel.
There’s also some suggestion that this might be engineered to shear i.e. breaking away to protect the mech and frame end, in the event of a nasty spill. Not something I’ll be putting to the test, mind. Describing something as “Universal fit” is begging for contradiction. However, ours fitted my Univega and a road frame hailing from 1991, perfectly.
My mile munching rough stuff tourer’s Microshift M45 rear mech was singing its swan song. It’d served faultlessly for nigh on 6 years, through some very harsh winters, and certainly didn’t owe me anything. After some deliberation, I recalled being given a Microshift Centos 10spd mech and brifters, some years back.
The short arm mech’s maximum capacity is 27teeth and I wanted to pair ours with a 28tooth sprocket. Low enough for my everyday riding and frankly, what I had “in stock.” I’m a firm believer in the “use what you got” philosophy. Well, to a point and so long as it’s right for the task. A quick rummage through the spares’ drawer produced the components in question, new gear and brake inner wires and chain (albeit a 9speed).
So, having stripped the Univega of bar wrap, existing 9spd brifters and rear mech, we were ready to go. A quick lick of grease on the SP570 extender bracket and Centos hanger threads, I bolted them to my Univega’s Ritchey hanger. 9 speed 11-28 Sram cassette exchanged for 10 speed 11-28 Tiagra, it was time to wire everything up.
Now, we should point out that mixing n’ matching parts is not necessarily something we’d advocate, and you do so, at your own risk/frustration.
Being as the build had been a 1x9 setup for a couple of years, I figured I’d get away with retaining a 9spd ring and chain. A dry run confirmed the chain’s additional .5mm girth was not going to foul the derailleurs cage. Cables connected, handlebar wrap reinstated, all behaved impeccably on the stand, save for a quick turn, or two of the derailleur’s limit screw and barrel adjuster.
Well, crucially everything has played nicely together in the past 500 mixed terrain miles and the Sun Race SP570 mech extender has played its role perfectly and without incident. The Centos group has also behaved impeccably with my tourer’s a la carte transmission.
Other than adjusting the derailleur’s cable tension after the first 50 miles, shifts have been slick, and precise with no hesitancy under load. With a 42-tooth front ring and 11-28 cassette, the Centos mech has never felt over-stretched. The shorter arm also offers the system a little additional ground clearance, which is welcome when hustling along disused railway lines, forest trails etc.
£9.99 is considerably cheaper than a rear mech turning cannibal on itself and indeed, permitted me to use one in my “stash” rather than buying a replacement. Provided you have calculated maximum capacities, it could be the solution to many rider’s needs.
Playing devil’s advocate, visually similar homages are availa from online auction sites, for a third of the price. However, there’s little comeback should one fail. At the other Extreme, Wolf Tooth Components Roadlink comes in at $21.95. It’s made in the US, from 6061 and employs a stainless steel, CNC machined bolt. Those of you seeking to extend a long cage Shimano derailleur’s capacity (so they’ll accommodate 40-42 tooth sprockets) might be better served by Lindarets Goat.
Provided you’ve done your calculations correctly, and everything’s correctly setup, the Sun Race M570 mech extender will do exactly what it says on the packaging. There are cheaper options, and more expensive alternatives. Whether these are better value, will depend on your perspective and component worth.