Thule 528001 AcuTight Knob 1x, Black

After speaking to Thule, they told me this knob + the carbon frame adapter is made for transporting Carbon - which personally begs the question, why isn't there a bundle with the two together?Anyway, The knob itself does feel very tight when clamping - to the point you wouldn't want to use it on carbon but actually when you undo the knob again the pressure doesn't actually feel so bad & I tried it on a steel frame bike and found I could still force/move the bike around inside the clamp so it isn't really locking down as much as you'd expect for the tightness , but I'll admit it for someone that's new to carbon it does feel uncomfortable & no way i'd use it without the carbon adapter.Personally - I found the Thule Carbon Adapter is an absolute must, I would buy the Thule Carbon Adapter before the knob if I money was an issue - the adapter spreads the load more evenly across the clamping point - a test I did with standard knob & no carbon frame I clamped an empty deoderant can & found it easily left a dent in the can, with the adapter I went much harder and no dents so it definately works & safe to say without the adapter you are running serious risk of a pressure-point breaking the carbon if the jaws aren't perfectly aligned, but with the adapter things feel much safer, also the adapter is rubberised so extra grippy in the clamp.As for real world experience - I'm new to carbon and I'm suffering from serious carbon anxiety of my YT Jeffsy (Mountain Bike) & I'm not brave enough to tightening it upto the click point, just tightening it to a tight level with some common sense and I found after a 100 mile car trip yesterday the bike never moved an inch, where as before doing the same trip I could see the bike slowly wiggling its way loose from the clamp & needing to be clamped again at a service stop.TLDR Version:You *must* buy the Thule Carbon Adapter if your transporting Carbon.

My bikes arnt carbon frames but I wanted to be able to tighten them as much as possible to ensure they stay in place without over tightening. The torque limiter stops me worrying about damaging the carrier or the bike. Win win.

I bought this so I could attach a newly purchased carbon MTB to my Thule bike carrier. To replace the existing knob it use a clever little key that removes the entire locking barrel and installs it in the corresponding hole of the AcuTight Knob. After a bit of fiddling, I thought i’d test it on an aluminium frame first just to be safe. This is where I discovered you need to apply what seems to be an insane amount of pressure before it clicks off. Even with the Thule Frame Protector it feels like it would cause considerable damage to a carbon frame. Not only that, but unlike a torque wrench your still able to continue tightening it after the click. As I doubt Thule would offer to replace my frame if it broke I decided not to risk it on my pride and joy. I still use it to secure my aluminium frames nice and securely but unfortunately that sort of misses the point of buying it in the first place

If I had used this to secure my Nukeproof Mega caravan framed MTB bike to the rack. It would have crushed the frame before the torque element had clicked.Not fit for purpose, returned as such.

Replacement knob, easy to fit, exactly the same as the original.

I really like the idea of this, but in reality it just isn't fit for purpose. It allows for too much torque to be applied before "clicking" off. I tried it on my hand and it allowed so much force to be applied that it would have crunched a carbon fibre frame. Consider the Thule carbon frame protector instead.

Will be buying more of these for the remaining clamps on my Thule bike carrier. Feels good to know that the clamp is tight enough and secure and not worry about crushing your bike.

The Thule Torque Limiter 528 doesn't work. I have now tried three of these, none of them limited the torque in any way. There is a tiny little click you can barely hear which I guess indicates that the torque is sufficient. But if you continue turning the knob it will continue tightening until it crushes your carbon frame like a vice.I had assumed these would work like a torque wrench and stop tightening when the correct torque is reached, but that is not the case. Total rubbish.