Getting a mountain bike secured safe and sound should be an easy and effortless task. Some systems require you to take off the front wheel, but that’s time spent not hitting the trails. “Rhino Rack’s Carrier is quick and easy to use … with a positive, lockable arm. [And you can keep] both wheels on the bike. The kit can be used with slim-shod roadies and gravel grinders or the wider MTBs and fat bikes.”
These car roof bars come with wordless (diagrams-only) fitting instructions that are difficult to comprehend and, in the case of a Peugeot 306 hatchback, specify the wrong assembly settings. The result is roof bars that cannot be fitted to the car or, at best, can be fitted only with extreme difficulty and at risk of damaging both the racks and the car body.
The most likely causes of excessive wobble at speed on a motorway are either that you have not placed the arm clamp sufficiently close to the chainring OR you have not tightened the clamp sufficiently. Having said that, there is a further cause where the clamp can slip UP the frame IF your frame gets thinner in that direction (eg My Cervelo S3 does precisely that). In that scenario you will need to put the arm clamp slightly further away from the chainrings at a thinner part of the frame.
Road tripping means you can bring pretty much anything — and you often do. Soon your trunk is full before you realize it. Then the back seat gets taken up, followed by the space at your feet. Next thing you know, you can’t even see out the rear-view mirror. That’s why a roof cargo box is a must-have for any sort of vehicular travel. Not only can it match your trunk’s storage capacity, but it's a secure place to stash dirty gear as well as snow-covered skis, snowboards, boots, and helmets.