Deda's Parabolica Due clip-on bars are an excellent solution if you want to add an aero position to your bike for whatever reason. They're well made, light and reasonably cheap.
The Parabolica due bars have three main pieces. There's the extension itself, a hollow alloy tube with an S-bend that has a maximum extension from the bars of 290mm and is designed to work with bar-end shifters, if you're going full TT. The extension is attached to your cockpit via an alloy clamp, which is nicely made with smooth edges that should be kind to carbon bars. A steel armrest bolts on to that, and there's a grid of holes for you to fine-tune your arm position. You also get a self-adhesive velcro strip for each side to attach the arm pad. The pads themselves are fairly deep and very comfortable.
I primarily used the Parabolica Due bars as an extra position on an audax setup. That's very useful when you're rolling along the flat, especially into a headwind.
The S-bend bars allow a number of holds. With the middle of your forearm on the pad you can grip the bend, or if you slide your arms forward so you're almost resting on your elbows you can get a bit lower and grab the ends of the bars. There are a couple of positions in between too.
I found the lowest position the best, although I'd like to see end plugs included with the bars to use if you're not fitting shifters, as that would make them more comfortable to hold. If you wanted a bit of extra comfort (and grip) you could always wrap them with bar tape and use the plugs from that.
The Dedas sit above the bars but they're not particularly high and you'll likely be able to get an acceptable aero position on a road bike if you have a couple of spacers below the stem you can swap out.
If you're contemplating a few time trials in the summer and you're not going to go the whole hog and buy a TT bike, fitting clip-on bars (and using them) is the single most effective change you can make to your bike, and an easy one too. The Dedas would be a good choice for that: they're cheap (less than £50 online) and they feel well made and sturdy in use. If the Due curve doesn't suit they're also available in Uno (a single bend at the end) and Zero (completely straight) configurations.
Well made aero extensions that are easy to fit, light and comfortable
road.cc test report
Make and model: Deda Elementi Parabolica Due Clip On Bars
Size tested: n/a
Tell us some more about the technical aspects of the product?
Two curves ('S' bend) offering several hand positions
Clamp to fit 31.6mm handlebar
Weight about 378 grams
Max length 290mm
Tell us how the product performed overall when used for its designed purpose
Very well, a range of positions from a single bar.
Tell us what you particularly liked about the product
Well made, light, easy to fit.
Tell us what you particularly disliked about the product
Shame you don't get end plugs.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
About the tester
Age: 42 Height: 189cm Weight: 91kg
I usually ride: whatever I'm testing... My best bike is: Kinesis Tripster ATR
I've been riding for: Over 20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: road racing, commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mtb, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.