Zipp SL Bar and SL145 Stem

September 6, 2009 by  
Filed under Machine

SL SS bar.smA few years ago I got to spend a few months riding Zipp’s Contour SL bar. It was the first carbon fiber handlebar I had ridden that weighed less than 200 grams and one of the more comfortable wing bars I’ve tried to date. It was stiffer than single-malt Scotch straight from the bottle.

Since then, I haven’t encountered many truly sub-200g bars. Lots of companies advertise that their super-light Ultrabar X weighs less than your conscience, but a simple fact distinguishes reality from marketing hype: mold. Well, the plural: molds.

Most companies producing bars in the 200-250g range are doing so because they produce all the bars in halves, trim the sections to length and then bond them to the clamp section. Three pieces. The extra weight comes from the overlapped carbon in the bonded areas.

All sub-200g road bike handlebars have in common monocoque construction. The key to producing one is machining a mold for each size and each bend. Given that carbon fiber handlebars start in cost around $250 and run upwards of $500, each new mold can run a few thousand dollars to cut, a company has to sell a shipping container’s worth of bars to recoup the development cost and turn a profit.

To achieve its low weight the Zipp engineers had to resort to what may seem like a bit of old tech. To combine ultra-low weight and race-worthy stiffness the engineers had to employ a round bar profile throughout its length—no cable grooves, no wing shape. The wing shape adds about 20g. My test bar weighed all of 177g.

zipp_bar_dropsWith the SL bar, the company’s lightest offering, riders can choose from four widths (38, 40, 42 and 44cm c-c) and three different bends (traditional, ergo and compact). That’s 12 molds total. It’s a significant commiment to fit and comfort at the high end of the market.

My review bar was the 42cm compact (or as they call it, short and shallow). No matter what you call it, the compact bend, when compared to more traditional bars, reduces both reach and drop, usually in the range of a half to a full centimeter. While I’ve heard some riders deride the compact bar for making your drop position as the same as your bar top position, anyone who has compromised flexibility (rhymes with 40th birthday) can appreciate three usable hand positions. Unless you are still racing, comfort rates more highly than aerodynamics, and three usable positions is a winner.

This was my first experience with a compact bend and the big thing I noticed was how easy it was to ride in the drop position after having spent time on the hoods. The short drop from the hoods to the drops is easy to manage four hours into a ride when my hamstrings start to tighten up.

What I found most unusual about the short and shallow drop was the bend of the drop. The traditional bend is a bar that has fallen out of favor with product managers, but not with pros. No less than Lance Armstrong still runs a traditional bend bar on his bike. I prefer the ergo bend, but found the short and shallow to be a most unusual compromise. The bar bend isn’t as tight as a traditional, but because it doesn’t flatten out the way an ergo bend does, you don’t turn your wrist when in the drops. On the off-chance you may not have noticed, when using a traditional bend bar, your hands don’t bend at the wrist when using the drops, but when using an ergo bend, you hands bend sharply at the wrist. Anyone who has ever had carpal tunnel syndrome can tell you ongoing road shock makes ergo bars hell due to the wrist bend.

It took me a few weeks to get accustomed to the different bend. It seemed to reduce the reach to the levers a bit (I couldn’t figure out a decent way to measure this) and gave me a very comfortable position for descending. Under hard sprinting the bar felt unusually stiff, if not the stiffest bar I’ve used, then easily in the top three.

I assume the SL stands for Super Light. If so, mission accomplished. Price-wise, the bar sits squarely in the middle of the price range of carbon bars at $375. So the tally is: very light (lightest?), very stiff (stiffest?) and not most expensive. I like those numbers.

A few words about the SL145 stem: I’ve used a few different carbon fiber stems that have a certain amount of flex. While I don’t mind vertical flex in a stem due to the comfort it can bring, I never notice flex in that plane. What I notice is twist when I grab the levers and stand up. Years ago I had a very light, very trick titanium quill stem that twisted like Chubby Checker.

The Zipp SL145 doesn’t twist. At all. I’ve ridden it in the 120 and 130mm lengths and couldn’t detect any change in flexibility. Zipp reports the stem is made from 50 different pieces of carbon fiber in order to achieve its combination of stiffness and low weight (my 120mm weighed 152g). It retails for a cool $200.

My only criticism of the stem is the face place. I live near the ocean and occasionally I encounter an aluminum part with what is in my view substandard plating. I’ve ridden this two copies of this stem and despite judicious cleaning, my time near the beach has caused the face plate to corrode and the plating to flake off with fewer than six months of riding. For 90 percent of the country, this won’t be an issue, but those of us who live near salt air will find this phenomenon frustrating. Zipp needs to offer either replacement face plates or—better yet—they need to improve the plating on the face plate.

Taken as a whole, the SL bar and SL145 stem are truly exceptional. Light enough to keep climbers happy, stiff enough to keep the sprinters jazzed and with enough fit choices to satisfy the fussiest fit, they are a formidable combination, an inarguable choice for any rider determined to find the optimal combination of fit, comfort, stiffness and weight without having to pay top dollar.

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