Prius Towing Capability

I think I can answer that. Although I never really saw one of the plastic-melting Curt Hitches, I think it probably had a standard square cross-member all the way across. The new model has the square cross-member interrupted by a welded on flat section near the exhaust pipe end (attached photo shows how this part looks installed.)

Evidently the melting was caused because the earlier all-square cross member diverted the hot exhaust gas enough to overheat some of the plastic.

I've had the Curt hitch on for a year or so, haven't seen any problem yet. Of course the car is usually parked, so a year for the Parker is not as long as a year for somebody who racks up the mileage. It's had maybe 4000 miles since installation.

--Parker

 

Another *partial* answer from me.

If you're planning to tow, the CoastalTech hitch might not meet your needs:

That quote is about 2.5 years old, but from the pictures on CoastalTech's web site, it looks like it's still true.

Other than that, some people with the Coastal hitch seem happy with it, others say it's a bad design.

I seem to remember back when I was shopping for my hitch, the only options were the Coastal, the Curt, and U-Haul (which was said to be a Curt hitch with a different label on it.) Now a couple of other hitch manufacturers are marketing hitches for the Prius, but I bet almost no one on PriusChat has actual experience with the other two brands.

For what it's worth, I think all three of the "real" trailer hitch brands made for the Prius are probably about the same, and the CoastalTech is not a "real" trailer hitch. Would anyone who knows more about this care to comment?

--Parker

 

the coastaletech hitch works but flexes a huge amount. I'm almost tempted to pull it apart and re weld a few things.

 

This is from Toyota's web site in Australia and here it means it is not legal to tow anything with a Prius, even a roller-skate.

 

If you are interested in measuring the transaxle oil temperature, this is one of the earliest probes I put together:

The drain as well as the fill plug are identical in my NHW11 but given the aluminum case, an NHW20 fill plug modified like this would work just as well. The build is fairly straight forward:

• get a thermistor that fits in the plug recess
• use heat shrink to form insulating sleeves on both leads
• drill two small holes the same size as the sleeves
• fit the thermistor and trim heat shrink to extend just beyond holes
• mix quality structural epoxy, JB Weld, and but a dobb in plug recess
• insert thermistor (don't worry about JB Weld on leads)
• fill space around thermistor with JB Weld
• let sit, leads down, until JB Weld sets, at least 24 hours
• trim excess JB Weld from leads but try NOT to expose heat shrink

You'll then need a VOM and thermistor resistance curve. Run a Cat-anything ethernet wire from the filler plug area, laced through the engine compartment, down the fresh-air intake and through a small hole drilled through the cabin air filter. Install the plug, solder two leads, and use your cabin VOM to measure resistance to measure the temperature.

The transaxle has significant thermal mass so it takes about 20-30 minutes to reach a steady state value. I would recommend one trip without the load to understand the unloaded temperature and a second trip with the load:


As for transaxle temperatures under a tow load, it will look as if the vehicle is climbing a shallow grade. Mileage will suffer, primarily dependent upon aerodynamic drag above speeds of ~45 mph. IMHO, a speed of 55 mph will be safe with a rapid fall off as speeds increase.

GOOD LUCK!
Bob Wilson

 

Melting:
I got one of the first U-Haul hitches and had this problem. I caught it early and was able to remove a small portion of the rear spoiler and that allowed the exhaust to exit without heating the spoiler. (the portion removed is not viewable without being under the car) The new hitch does NOT have this problem.

Coastal Tech Hitch:
It is my opinion that this hitch is fundamentally defective as the receiver portion of the hitch and where it attaches to the frame creates a huge lever allowing small forces on the end of the receiver to be magnified causing distortion and failure of the coastal hitch. Plus I have seen some coastal hitches with significant rust, but have no rust on my hitch after 3 years and 140,000 miles. The coastal hitch can be modified if you need a 2" receiver, but you have to weld in a new support and re-coat the hitch.