I can't say I would have considered the t-tops shattering a possibility, but if the load was heavy enough, and enough front to rear torsional stress was placed on them, then I suppose it could possibly be an issue.

However, the part of the t-top that the racks are connected to are rather sturdy, and of course a well designed and properly used rear tow bar support rod should eliminiate the majority of stress on them.

I also would want to consider the weight of the canoe, etc.

If it was not exceptionally heavy, and a good rear support bar was used, I would think it quite viable to carry a conoe.

But you will have to determine what you think is a safe amount to carry.

I have only used my Thules for carrying skiis, so not much of a weight load, but I never heard or felt any significant torsional noise from carrying a coulpe sets of skis and driving at high freeway speeds either

(80+ mph at times).

I have also considered installing a luggage carry-all on the Thules, and would not have worried excessively about having it up there full of luggage being buffeted by strong winds, but I never have done it yet, mainly because I don't want to give up use of the t-tops for a really long period in good weather.

So, I'm afraid there is no real easy answer for you.

You will just have to decide what you think is a safe weight to carry on them.

Remember, the main danger would probably just be if you did not have the canoe stabilized from front to rear.

That is where longitudinal torsion would come into play and possibly cause an issue.

If a good rear support bar is used

, and is quite solid then you will have eiminated most of your worry.
