Short answer: most clip-on aerobars fit a round 31.8mm handlebar, clamping either side of the stem, so they suit most standard aluminium and carbon road bars. They often will not fit aero, flat-topped or one-piece integrated handlebars, which have no round section to clamp to. Before buying, check your bar's diameter and shape, whether its maker allows clip-ons on a carbon bar, and that there is room for the clamps between the stem and your brake levers.
Clip-on aerobars are the cheapest way to get a faster, lower position for triathlons, time trials and long solo rides, without buying a triathlon bike. Most fitting problems come down to the handlebar, not the aerobar. This guide explains what has to match, how to handle integrated and aero cockpits, and how to set the position up once they are on.
- The five-point fit check
- Handlebar diameter and shape
- Integrated and aero handlebars
- Carbon handlebars
- Extensions, risers and armrests
- The aerobars we stock
- Setting up your position
- FAQ
- Getting help
The five-point fit check
| Check | What to look for |
|---|---|
| Clamp diameter | Most clip-ons are made for 31.8mm bars. Some are also offered for 35mm bars. Older bars at 26mm need a shim or a different clamp. |
| Round clamping area | The bar needs a round section either side of the stem, usually a few centimetres wide, where the clamps sit. |
| Carbon approval | On a carbon bar, check the handlebar maker allows clip-on aerobars, and follow its torque limit. |
| Space for cables and mounts | Brake and gear cables, a computer mount and a light must still fit around the clamps. |
| Your position | The armrests must sit at a height and width you can hold, which may mean risers or spacers. |
Handlebar diameter and shape
Almost all current road handlebars are 31.8mm at the centre, where the stem clamps, and stay round for some distance either side. That round section is where clip-ons attach. Deda lists its bars as 31.7mm, which fits the same clamps. Some bars, mainly from Deda and some aero designs, are 35mm at the centre, and need clamps made for 35mm.
The width of round bar available matters as much as the diameter. Many bars flatten or start to sweep forward just a few centimetres out from the stem, especially compact and aero road bars. Measure the round section on each side before buying. Our handlebar and stem sizing guide explains how to measure your bar.
Integrated and aero handlebars
Many modern aero road bikes use a one-piece handlebar and stem, or a flat-topped aero bar. These usually have no round section to clamp to, so standard clip-ons will not fit. The options are:
- A brand-specific aerobar mount, where the bike or cockpit maker offers one. Check with the maker or ask us.
- A manufacturer adapter kit, such as the Deda Jet 2 adapter kit for the Colnago TT1, which is made for one specific cockpit.
- Swapping to a conventional stem and round handlebar for triathlon season, if your frame's steerer and cable routing allow it. This is often the simplest route on an older aero bike.
Do not clamp aerobars to the flat, wing-shaped part of an aero bar. It is not designed for that load, and the clamps will not hold securely.
Carbon handlebars
Many carbon road handlebars accept clip-ons, but not all do, and leaning on extensions puts a different load through the bar than your hands on the tops. Before fitting:
- Check the handlebar maker's guidance on clip-on aerobars. Some carbon bars do not allow them.
- Use a torque wrench and stay at or below the lower of the two limits, the aerobar's and the handlebar's. Our torque specification guide lists typical values.
- Use carbon assembly paste on the clamping area, so the clamps grip at a lower torque.
- Check the clamp edges are smooth and not digging into the bar.
Extensions, risers and armrests
- Extensions are the bars you hold. Most use a standard 22.2mm diameter, so you can change shape later. J-bend extensions angle the hands upwards, S-bend and ski-bend shapes keep the hands lower or flatter.
- Risers lift the armrests and extensions together. Most riders on a road bike need some rise to reach a sustainable position. Zipp's riser kit for the Vuka Clip adds up to 50mm in steps.
- Armrests should support your forearms just behind the elbow. Width and tilt adjustment help comfort. The Profile Design armrest wedge kit adds tilt to third-party brackets that lack it.
- Shifting from the extensions is possible on compatible Di2 systems with a wired remote, such as the Shimano Dura-Ace Di2 SW-R9160. Some extensions, such as the Deda Jet 2 Evo, route wires internally and suit electronic groupsets only.
The aerobars we stock
| Aerobar | Type | Fits | Price |
|---|---|---|---|
| Controltech Falcon TRI | Clip-on, alloy J-bend | 31.8mm round bars | ā¹8,690 |
| Deda Parabolica Due | Clip-on, S-bend, with risers | Compatible round bars; UCI approved | ā¹12,999 |
| Profile Design Sonic Ergo 39a | Clip-on, highly adjustable armrests | Round bars | ā¹16,490 |
| Deda Parabolica Pro | Clip-on, most adjustable Deda system | Compatible round bars, or TT base bars with the supplied plates | ā¹25,299 |
| Zipp Vuka Alumina Evo extensions | Extensions only | Zipp Vuka Clip, Vuka Aero and other 22.2mm systems | ā¹4,690 |
| Zipp Vuka Alumina base bar | TT base bar | 31.8mm stems; pairs with Vuka Clip and most clip-ons | ā¹6,590 |
| Deda Jet 2 Evo | Carbon extensions for TT base bars | Compatible base bars; electronic shifting only | ā¹67,900 |
| Zipp Vuka Aero carbon | Complete TT cockpit | 31.8mm stems | ā¹74,990 |
Prices are indicative and move with exchange rates and import duty. See all aerobars.
Setting up your position
- Start high and short. Fit enough risers that you can hold the position for 20 minutes without neck or back strain. Lower it in small steps as you adapt.
- Elbows under shoulders. Set the armrests so your upper arm is roughly vertical, with the pads supporting your forearms just behind the elbow.
- Narrow, not pinched. Armrests about shoulder width or slightly narrower are a good start. Too narrow makes steering twitchy.
- Consider the saddle. On a road bike, riders often move the saddle slightly forward to open the hip angle in the aero position. Our seatpost and setback guide explains the options.
- Practise on quiet roads. Steering from the extensions is slower and your hands are away from the brakes. Never ride on the extensions in a group.
A bike fit is the quickest way to a fast position you can hold for a whole bike leg. Our triathlon and TT bike guide explains when a dedicated tri bike becomes worth it.
FAQ
Will clip-on aerobars fit my road bike?
Clip-on aerobars fit most road bikes with a standard round 31.8mm handlebar, clamping to the round section either side of the stem, but they usually will not fit one-piece integrated cockpits or flat aero handlebars with no round clamping area, and some carbon handlebars are not approved for them. Check your bar's diameter, shape and maker's guidance first. Send us a photo if unsure.
Can you put clip-on aerobars on a carbon handlebar?
Often yes, but only if the handlebar maker approves clip-on aerobars for that model, because extensions load the bar differently from your hands, so check its guidance, use carbon assembly paste on the clamping area and tighten the clamps with a torque wrench to the lower of the aerobar and handlebar limits, then recheck them after the first ride. Never overtighten. Some carbon bars prohibit clip-ons.
Are clip-on aerobars allowed in triathlons and group rides?
Clip-on aerobars are allowed in most non-drafting triathlons and time trials, where most Indian triathletes race, but draft-legal races ban them or limit them to short bars that stay within the brake levers, and you should never ride on the extensions in a group ride or bunch, because your hands are away from the brakes and steering is slower. Check your race rules first. Ride the extensions alone.
Do clip-on aerobars make you faster?
Yes, for most riders clip-on aerobars are one of the biggest speed gains per rupee in cycling, because tucking your arms and narrowing your shoulders cuts the frontal area that causes most of your wind resistance, which on flat roads can save more time than an expensive aero frame or deep wheels, provided you can hold the position comfortably. Comfort decides the gain. Start high, then lower gradually.
What is the difference between clip-on aerobars and a TT base bar?
Clip-on aerobars attach to the handlebar you already have, so you keep your normal drop bars, brake levers and shifters, while a TT base bar replaces the handlebar with a flat or bull-horn bar designed for time trial bikes, with brake levers at the ends and extensions mounted on top for the most aerodynamic, adjustable cockpit. Clip-ons suit road bikes. Base bars suit tri bikes.
Getting help
Send us a photo of your handlebar and stem, or your bike model, and we will tell you which aerobars fit. Ask TBA Guide, and we will check it for you.
