UKH

I'm after some opinions on roof carriers.  I've a 29er trail bike and MrsD has a similar 27.5" bike (both Alu frame) which we want to be able to put on the car roof.  We already have square section roof rack bars so just looking for recommendations and/or gotchas for compatible carriers. 

Initial response would be to just go for something like the basic Thule Freeride

Cheers

I feel the bike is more stable when clamped by forks. Downside is you have to have the wheel in the car, and thru-axles make things more complicated

Thule Thruride looks good, but it's pricey 

Thule Proride, it is so much easier getting the bike up on the roof with the support arm already erected and ready to "catch" the down tube with  clamp open on one side.

Avoid any carrier that you need take the wheels of for because this will wear out the dropouts on an aluminium alloy frame.

For the road bikes I do have fork carriers which I like, but I'd rather keep the muddier and bulky MTB wheels out the car.  So I think I'd prefer a frame carrier in this case.

Thanks, I'll take a look at those.  Price might ultimately sway me to the lower cost ones though...

I got some Cruz roof carriers from www.roofbox.co.uk, they are a fraction of the price of some other ones, I have been using regularly for over a year and have not had any problems so far.

Interesting - really interested in hearing other opinions on frame vs fork mounts. Putting the wheel in the car is a bit of a pain, but the bike feels more secure

In my mind the fact that the road bike has a 'delicate' carbon frame was what tipped me towards fork carriers for the road bike, but I think the thought of one or two bulky MTB wheels in the car makes that decision a bit different !

Thule pro ride can be got as a Multi pack buy, making it a bit cheaper, thule are good in as  much as spares are readily available if straps fittings etc are lost. and they are very conveniant with the catch for the down tube, something to Bare in mind your wife may not be as brawny as yourself and overhead fiddling whilst trying to get a bike in a cheaper rack may not be appreciated hence the pro ride.

+1. 

Can be fitted to square bars, (I bought a cheap Cruz version of the aero bars as it wasn't much dearer and is neater).

Only issue is might be a bit difficult to load/unload the bikes without a step if you're a shortarse with an SUV or tall car.

I'm not a shortarse but this:

https://www.amazon.co.uk/Draoer-19260-Heavy-Folding-Stool/dp/B007UZ81WW/

is permanently resident in my Yeti, tucked neatly behind the rear seats.

(Other, cheaper folding step stools are available.  I prefer to err on the side of robustness if I'm going to trust my weight - plus that of whatever I might be trying to manhandle on to the roof of the car - to it.)

Oh, and another vote here for the Thule ProRide.  (Handy tip: it's easy to disassemble and reassemble them the "other way round", so that you can have eg two bikes both facing forwards but accessed from opposite sides of the car.  I don't know if it's covered in the instructions but I see so many people driving around with bikes back-to-front, or with the downtube clamp on the outside of the bike, that I assume this feature is not well known.)

Is a tow ball rack completely out of consideration?

Much easier for MTBs

And cheaper on a ferry/tunnel, you aren't going to knock them off accidentally at one of those height restricted carparks MTB areas love to have, plus the mud doesn't go all over your car on the way home.

If a roof system is the only option, then I would consider if you'll ever get or carry a carbon bike - in which case you will need to fork mount or (horror of horrors) use one of those upside down mounts rather than the more common frame clampers. Fork mounters are also easier to load (at least for me)

You don't have to... you can get wheel mounts for the front wheel:

e.g. https://www.evanscycles.com/saris-track-rack-wheel-holder-EV189508?lsft=esv...

Love my Thule Fork loaders they've been looking after my bikes and car for nearly 15 years now and no sign of wear & tear... previous cheapo clampers didn't last any where near as well or give as much confidence.

10, 15 and 20mm Thru axle fork adapters are about £10 for a pair on ebay (cheaper if you know someone with a lathe)

We have thule prorides. Cant compare to any others but they are robust and very easy to use. Just pull up the arm. The frame slots in and then just rachet the clamps to grip the tube. To release the clamps simply press a button. Almost certainly the best roof option.