A couple of months ago I bought 2 Cube Hybrids and my wife and I are absolutely delighted with them. I also got a tow bar installed on my car and bought a Thule 925 rack (expensive, but the only model I could find which would take the weight of both bikes.) It all works brilliantly. However, later in the year we are off to France with the whole rig and I'm a little worried about protecting the bikes while steaming down the Autoroutes in possible pouring rain. Is there any way of covering the bikes efficiently and legally? There's a standard two-bike rain cover in Halfords which is marked 'Not for use on bike racks'. Why? I can see it would have to be secured against ballooning but apart from that, there's only the question of rear visibility which is taken care of by wing mirrors. So ......

A couple of months ago I bought 2 Cube Hybrids and my wife and I are absolutely delighted with them. I also got a tow bar installed on my car and bought a Thule 925 rack (expensive, but the only model I could find which would take the weight of both bikes.) It all works brilliantly. However, later in the year we are off to France with the whole rig and I'm a little worried about protecting the bikes while steaming down the Autoroutes in possible pouring rain. Is there any way of covering the bikes efficiently and legally? There's a standard two-bike rain cover in Halfords which is marked 'Not for use on bike racks'. Why? I can see it would have to be secured against ballooning but apart from that, there's only the question of rear visibility which is taken care of by wing mirrors. So ......

 

I suspect the reason why Halfords might have put that warning on was to protect themselves. The wind whipping around the back of the car can reach hurricane speeds and could rip open the rain cover. Image the consequences of that flying off behind and alighting on the windscreen of a following car.

 

Why not just remove the battery and the intuvia panel and cover the elecrical contacts with a piece of duct tape. The battery should be removed, and stored in the boot, while traveling for the safety reason. The catches are not designed for heavy vibration and the consequences of 3 kg bricks airborne unpleasant. .. and at 500£ each expensive.

I wonder if the Halfords warning refers to roof racks?

Another unexpected consequence of a bike rack at high speed is that oil or grease can be sucked or blown out of non sealed bearings.

I used to regularly do four hundred mile trips on fast roads and found thick grease was best for staying put.

I also used to cover the sensitive parts and handlebars, remove seats and cover the seat stay hole so moisture didn't get down to the bottom bracket.

I hadn't any electrics to worry about in those days so as Danidl says you would need to cover those parts as well.

I think a full cover might have a lot of wind resistance in the turbulent air behind the car, just try putting your hand out of the side window whilst doing 70mph!

Dave.

Thanks everyone for your help. For the record, I never for a moment intended to leave the batteries and computers on board while carrying the bikes! Gaffer tape over the electrical contacts sounds the best compromise.

I had a similar issue and posted on an mtb forum. I though the best suggestion was to buy a roll of industrial cling film and cocoon the whole bike. It is cheap (about £4 on fleabay) and will last for ages? Some gaffer tape can be a pain to remove?

Thanks for the suggestion - I'll investigate!

I wonder if the Halfords warning refers to roof racks?

 

The airflow over the roof of the car will be faster than the car speed, but not as fast as the air rushing back in to the void behind the car. The car creates a vacuum behind it and the air has to flow back in.it is also very turbulent flow..

Can you imagine what the wind resistance would be on a covered bike at motorway speeds. If the cover doesn't get ripped to shreds, I can imagine your bikes ending up horizontal. Even if it stayed in place, it would knock your mpg down by about 40%.

 

Not so much of a problem if you have a van or motorhome with a flat back.