This Zipp Service Course SL stem looks good, does its job without any fuss and features some high quality hardware - but at £90 it's a lot of money for an alloy unit.
The Service Course SL is forged from 7075 aluminium and it's available in eight lengths (70mm to 140mm) and two rises (+/-6° and +/-17°) so you should be able to get one fitted to your bike just so. There are two colourways too, although both of them are basically gloss black; ours had white etched logos and you can have black ones if you prefer stealth. That's (mental maths) 32 different versions.
Zipp claim a weight of 120g; ours (a 110mm stem with a 6° rise) was a touch heavier than that at 128g but that's still reasonably light. Certainly with the minimal front plate and open clamp to the rear there's not too much extraneous metal. The weight is reduced further by using Titanium bolts; they're a Torx T25 head which Zipp use for "precision torque readings and ease of adjustment". They're only easy to adjust if you remembered your Torx key though, so make sure your multitool has one: not all do. I'd suggest that keeping your bolt and stem threads clean is more important to an accurate torque reading than any difference between a T25 and a 4mm Allen head.
Fitting the Service Course SL stem was no faff at all and in use it performed faultlessly. You don't really notice a stem unless it's doing something badly, and the Zipp didn't put a foot wrong. It's plenty stiff enough to deal with handlebar wrestling on the climbs and sprints and it didn't creak or loosen. The finish is very good quality and it'll look just so on your shiny race bike.
It's ninety quid though. That's an awful lot for an alloy stem. It's pricier than other high-end units like the techy Thomson Elite X2 Road and the 100g Ritchey WCS C260, and more than twice as much as solid mid-range units like the Pro PLT, which will do the same job very well and doesn't weigh appreciably more. If you really wanted Titanium Torx bolts you could upgrade the lot for about a tenner.
Obviously if you wanted a carbon stem you could pay more – a LOT more, Zipp's own SL Speed unit costs three times what this one does – so in terms of the whole gamut of stems it's not ridiculously expensive. But if half the pro peloton is happy to stick with alloy you might as well save your cash for an upgrade elsewhere. If you think the Zipp will suit your particular steed, and you don't mind paying the asking price (you can have one for less than £70 online) then it certainly won't let you down.
Nice looking alloy stem that's finely crafted and performs very well, but still expensive for what it is.
road.cc test report
Make and model: Zipp Service Course SL stem
Size tested: 110mm
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Your stem has to resist flexing during sprints and accelerations, clamp securely to the fork and handlebar, and support your weight over significant impacts. It's a difficult job, but the Service Course® SL stem is still able to combine strength, stiffness and reliability at a weight of only 120 grams (100 mm).
The Service Course SL has high-strength, 3D-forged construction, 7075 series aluminum and titanium bolts to deliver an exceptional strength-to-weight ratio while allowing for smooth lines to complement the aesthetics of modern frames.
We make our Service Course SL stems in eight lengths (70 mm to 140 mm in 10 mm increments) and two angles ( /- 6 degrees and /- 17 degrees) to meet any rider's fitting needs.
We replaced the stainless steel bolts with titanium ones and use TORX® heads on all bolts for precision torque readings and ease of adjustment.
Every piece in the Service Course SL line is available in the standard gloss black with white logos, as well as a new Beyond Black color scheme with laser-etched black logos for a stealthy look.
Beautifully made and finished
Has resisted scuffs and knocks very well so far.
It's light, but not super-light.
About the most expensive alloy stem you can buy.
Tell us how the product performed overall when used for its designed purpose
Tell us what you particularly liked about the product
Looks good, performs its function very well.
Tell us what you particularly disliked about the product
Did you enjoy using the product? Yes.
Would you consider buying the product? No, I don't think I could justify it.
Would you recommend the product to a friend? Yes, for the right bike and pocket depth.
About the tester
I usually ride: whatever I'm testing... My best bike is: Genesis Equilibrium with SRAM Apex
I've been riding for: 10-20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: commuting, sportives, general fitness riding, fixed/singlespeed, mtb, Mountain Bike Bog Snorkelling, track