Towing with Prius C

Discussion in 'Prius c Accessories and Modifications' started by kevin1980, May 19, 2012.

  1. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Ahhhh.

    Tow Threads.
    You have to love them! :)

    I noticed that the OP hasn't been seen in these parts in almost 2 years.
    I hope that everything went well.

    The reason why I tend to buy base model new cars is that I like to keep them for a while - like 10+ years.
    I've just seen too many threads with people experimenting with gas, towing, intake mods, horsepower bolt-ons, and I've seen too many wrecked and neglected cars with pristine CARFAX histories to be comfortable buying one.

    Having said all of that, I don't think that it would damage a Prius to tow in the manner that the OP asked about, and there are some people out there that actually modify their suspension and brakes to allow for some diminutive towing capacity with Priuses.
    And yet....I'm always amazed when people say:
    "Heck.....MY Prius can pull that....EASY!!" without realizing that turning and stopping are pretty important too.
    One of the reasons that we're buried beneath tons and tons of DOT regulations is that Common Sense......isn't.
    The truly frightening thing is that there are actually people out there pulling large items at freeway speeds not realizing that they're endangering OTHER lives.
    Even MORE frightening is that some people DO know....and they just don't give a rats.

    I don't own a Prius. I just drive one every day.
    It's a fleet car for Big Phone.
    Don't ever buy a fleet car BTW....unless it's as cheap or cheaper than a salvage titled car.

    If I did own a Prius I wouldn't have any problem towing a small DOT approved garden trailer down to the big box store to get bulky, nasty, or even some heavy (**like a few HUNDRED....not thousand #) loads....and I'd like to think that I'd be honest with my Prius' next owner about it's history just as I am with all of the cars that I sell/trade. (Never trade! Always try to sell!)

    So.......
    Is it OK to tow with a Prius?
    If you have to ask......;)


    Be Safe!
     
    #41 ETC(SS), Apr 20, 2015
    Last edited: Apr 20, 2015
  2. PeterHaas

    PeterHaas Member

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    Curt Prius c hitches use three bolts per side, yet these are rated lower (1,000 pounds maximum trailer weight) than the others.

    Competitive Prius c hitches use two bolts per side, yet these are rated higher (2,000 pounds maximum trailer weight) than the Curt.

    Go figure!

    All are designed around the same principle, which is only the receiver shows ... a stye possibly pioneered by "Hidden Hitch", yet another manufacturer of towing products.

    The Curt Class 1 Trailer Hitch 112993 for Toyota Prius is what I ordered for my C1.

    The model number 11299 (no suffix digit) comes with no ball mount at all, just a 1-1/4" receiver (and a retainer pin and clip).

    The 112993 comes with a conventional (North American) ball mount, but with no ball. The ball mount is, of course, removable, and is also supplied with a retainer pin and clip. About $113 and change, delivered, from an eBay seller in Wisconsin, and which actually ships from Arizona.

    I believe other suffix digits, as in 112991 and 112992, are for the so-called "Euromount" versions of the basic Curt 11299 Prius c hitch.

    Confirmed: 112991 and 112992 ARE, indeed, for the two sizes of "Euromount" balls, which fit into the 1-1/4" receiver, just as the North American ball mount fits into the 1-1/4" receiver.

    Note: 1-7/8" "Euromount" is available separately as 45571 and 2" "Euromount is available separately as 45572, for those who started out with a 112993 complete ball mount hitch kit, and this ball mount is also available separately as 45501 (3/4" hole, and which accepts any ball with a 3/4" shank ... 1-1/2", 1-7/8" and 2").


    I have yet to master the Prius c trailer lighting issue.

    Presently, no one claims to manufacture a "plug and play" (T-connector style) cable kit for a Prius c, although some have claimed that a slightly modified T-connector kit intended for a Prius v will work in a Prius c.

    The Curt T-connector style Prius v cable kit requires DIRECT connection to the 12 volt auxiliary battery, and for which an enclosed (and insulated) fuse block is incorporated into the cable kit.

    Fortunately, the Prius c's auxiliary battery is located in roughly the same position as the Prius v's auxiliary battery.

    I am taking this issue one step at a time ... better to be safe, than sorry.
     
    #42 PeterHaas, May 6, 2015
    Last edited: May 8, 2015
  3. PeterHaas

    PeterHaas Member

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    The universal kit sources the trailer light power directly from the host car's rear lights.

    The T-connector kit sources the trailer light power from the car's battery, isolating the host car's rear lights using relays, and thereby protecting the host car's rear lights.
     
    #43 PeterHaas, May 7, 2015
    Last edited: May 7, 2015
    tgpii likes this.
  4. PeterHaas

    PeterHaas Member

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    A T-connector kit for the Prius c has recently been released by Curt.

    It is: "Curt T-Connector Wiring 56275 for Toyota Prius C", and is also available packaged with the hitch kit. According to Curt, it is applicable to 2012-2014, but I would expect that it is also applicable to 2015 (as is the hitch itself).

     
  5. tgpii

    tgpii Member

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    Thank you I been looking for one for a long time. I google it and see prices from $50 to $90. How much is a good price and how much should it run to install? Thanks for the information. How did you find it? I been looking for a while for one.
     
  6. tgpii

    tgpii Member

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    Google

    CURT Manufacturing - CURT T-Connector #56275
     
  7. PeterHaas

    PeterHaas Member

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    I found it quite by accident.

    I discovered that Curt had released a combined hitch + cable kit, and that these components incorporated the previously released hitch, 11299x, with the newly released T-connector. From that, I was able to deduce the order number of the cable alone (I already had the hitch kit, 112993, anyway).

    The lowest ePay price is in the $48 and change area, with the big trailer hitch companies charging a little more, but this application specific cable kit is, on the surface, a big improvement over the universal cable kit which was, and still is, available..

    The T-connector itself has some flaws, although it can be made to work.

    I will describe these flaws, in descending order of significance:

    1) the supplied (and factory crimped) ring connector is just plain wrong for this application: it appears to be intended for batteries with 3/8" (9.5mm) bolts, whereas the Prius c's battery has 1/4" (6.3mm) bolts; Curt does provide an alternate ring connector with the cable kit, but it appears to be intended for 1/2" (12.7mm) bolts, and there are no instructions provided for making the required adaptation (I guess Curt expects its installers to be experienced industrial engineers/electricians),

    2) the instructions for actually attaching the battery cable are incomplete if not entirely missing: you can, indeed, access the battery's ground terminal while following the supplied instructions, but the rear seat bottom must be removed to conveniently access the battery's positive terminal, and this is a much more involved process (the instructions for such seat removal are to be found in Toyota's Prius c Dismantling Guide, which can be found as a largish PDF on the 'Net; additionally, the battery wiring diagram shows the battery as being generically located in the engine compartment, whereas, as mentioned, it is actually located underneath the passenger seat,

    3) the installation instructions are hopelessly muddled by trying to reuse paragraphs 4 through 7 for two separate purposes: the passenger's side wiring which employs a three conductor tap cable, and the driver's side wiring, which employs a single conductor tap cable, these without specifically identifying what these cables are for, and why these are routed the way that these must be.

    Were I to do this all over again, I would not use the Curt hitch kit at all: I would use the Draw-Tite hitch kit, although it is more expensive; and I would use the Curt T-connector cable, as it comes the closest to meeting my expectations, although, unlike most end-users, I happen to own professional-grade "certi-crimp" crimping tools, so I can make the necessary and required cable kit modifications myself (yes, I am an electrical engineer, by undergraduate degree and professional employment).

    Why, you might ask, select the Draw-Tite hitch over the Curt?

    Well, Toyota appears to have changed the way it is manufacturing the rear bumper mount, so as to reinforce it by applying additional welds. This may apply to late 2014 and 2015 Prius cs, and not to 2012-early 2014 Prius cs ... I don't have enough information to comment, but I can clearly see that Draw-Tite apparently made an accommodation for such welds in its hitch, whereas Curt apparently did not.

    And, anyway, the Draw-Tite is rated 2,000 pounds with a 200 pound tongue weight, whereas the Curt, even with its six attachment bolts (to Draw-Tite's four bolts) is rated 1,000 pounds with a 150 pound tongue weight.

    Incidentally, the application specific Prius c cable kit has a release date of April 24, 2015, which is less than one month ago.

    Sorry if that is TMI ... again.
     
    #47 PeterHaas, May 16, 2015
    Last edited: May 17, 2015
  8. PeterHaas

    PeterHaas Member

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    The 1/4" ring connectors are in hand ... both blue (#16 to #14 AWG) and yellow (#12 to #10 AWG). I will be using the blue as I have confirmed that Curt used #14 AWG wire for the battery positive terminal connection.

    Also, four feet of "caterpillar" conformable grommet material, for use where new wiring passes through a hole conveniently provided by Toyota.

    All came from HSC in Santa Clara, California, one of the few remaining electronic surplus stores in Silicon Valley.

    As all wiring, or wiring adaptations to the Prius c, for towing, may be made using insulated crimp terminals, the "Horror Freight" tool,

    Ratcheting Crimping Tool

    is appropriate. Also Eclipse Lunar and Ideal, and possibly others.

    Forget about HF's (or any other's) el-cheapo crimping tool, such as

    8 In Four-Way Crimping Tool

    as tools of this type make poor crimps.

    The H-F ratcheting frame can be used with other dies (not available from H-F), but HSC can assist you there. They even have straight F-Crimp dies and the ultra-rare right-angle "flag type" F-Crimp dies.

    I now have in-house everything I need with which to complete the hitch and wiring kits on my Prius c.
     
  9. priusCpilot

    priusCpilot Active Member

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    As I mentioned I took a Curt Prius V Harness and re soldered it to work on the C PIP.

    I looked at all the hitches and the Torklift Eco was the best built one hands down.

    Curt mounts 6 points but that doesn't mean it can tow more since it's rated for 1000lbs.
     
  10. PeterHaas

    PeterHaas Member

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    Agreed, and designing and building it for 2,000/200 pounds, but rating it for 1,000/150 pounds is a marketing decision, not an engineering decision.

    The truly P'n'P wiring kit is now available from Curt as its 56275. This item was released only 27 days ago, and I would presume it took several days to reach distributor stock, and several more days to reach retailer stock.

    Curt hitches appear to be shipped from the manufacturer. Curt wiring kits appear to be shipped from the retailer.
     
  11. PeterHaas

    PeterHaas Member

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    I have requested and have received the EcoHitch instruction manual for their hitch for the Prius c.

    The design concept of the EcoHitch is completely different from competitive products (Curt, DrawTite, etcetera).

    Whereas the competitive hitches employ what I would term a conventional mounting means (end mounting, with all bolts torqued to the hitch manufacturer's specifications, usually 25 ft-lbs), the EcoHitch employs what I would term an unconventional mounting means (side mounting, with two very long bolts penetrating the frame members and tightened only finger tight plus two additional turns, thereby forming a "pin connected" system about which the hitch assembly is free to rotate, plus two additional, shorter bolts, which are attached at two additional points, and are tightened to 25 ft-lbs, thereby forming a secondary system about which the hitch is prevented from rotating.

    At this point one has to decide whether a conventional or an unconventional hitch mounting means is acceptable, and whether a 1-1/4" receiver or a 2" receiver is desired.

    If a 2" receiver is desired, then EcoHitch appears to be the only option.

    If a 1-1/4" receiver is desired, then EcoHitch or any of the others are options.

    I am an electrical engineer (although I completed coursework in structural engineering, including computer modeling of structures), not a structural engineer. I cannot state with legal certainty which ... conventional or unconventional ... is best. However, it is my non-legal opinion that six (Curt) or four (Curt competitors, except for EcoHitch), all bolts torqued to 25 ft-lbs, is intuitively a superior, and possibly a safer system, than two (EcoHitch), both torqued to 25 ft-lbs, plus two about which the entire hitch is free to rotate should one or both of the other two bolts fail.

    I already have the complete Curt hitch kit in hand, and I am going to proceed with that option, which is fine as a 1-1/4" receiver is my choice for my Prius c.

    My Hyundai Santa Fe AWD SUV is equipped with a DrawTite hitch with a 2" receiver, with three bolts per side, and that has proved to be a good choice for that vehicle and its application.
     
    #51 PeterHaas, May 21, 2015
    Last edited: May 21, 2015
  12. priusCpilot

    priusCpilot Active Member

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    I'm going to throw this out there and make my point.

    Here is a curt 4 bolt hitch for a F-150.

    Trailer Hitch for 2012 Ford F-150 - Curt C14002

    This 4 bolt hitch can pull 10,000 lbs - 12,000lbs

    Take a look at those bolts!

    It is rated over 12 times more then there Prius C 6 bolt hitch from curt but yet the C is only rated to 1,000lbs by curt.

    The hitch also employes a similar bolt through the frame mount like an eco hitch.

    Aside from this. If you have both the eco and curt hitch and examined them like I did. *

    *(I ordered a curt then found out about eco hitch after)

    You would see the difference in weld quality and size. You would also see based on observation the difference in gauge thickness with the eco begin thicker around the flange and beam

    I believe this is where the crucial difference is between curt vs eco. The larger welds and thicker base.

    Take a look at Draw-Tite. It mounts like the curt front mount bolts but with 2 less bolts and is rated higher then the Curt in tow capacity.

    The front mount I would say is worse due to the fact that you will be loading/unloading those bolts 1000+ times. This may cause loosening or stretching. When you have the bolt going laterally into the frame like the F-150 Curt hitch and eco. The risk would be far less with the higher loads. This might be why curt gave it the 1,000lbs rating.

    Also when I spoke with Torklift. About going past 2000lbs, they don't recommended it of coarse, but they told me the hitch was tested to 3500lbs. Like I said that does not mean its OK to pass it the 2000lbs mark but I may hit 2200lbs or so if I get a small travel trailer.

    In the end this is my opinion only and anyone can do what ever they want to do.
     
    #52 priusCpilot, May 22, 2015
    Last edited: May 22, 2015
  13. priusCpilot

    priusCpilot Active Member

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    Glad to hear about the PIP harness. It took a while!
     
  14. PeterHaas

    PeterHaas Member

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    And mine is only mine.


    As I said earlier, were I to do it all over again, I would not select the Curt hitch.

    However, the Curt plug and play wiring kit is excellent, and can be made to work by the rather simple substitution of a 1/4" ring connector for the supplied 3/8" ring connector, for the 12 volt battery connection.

    No need, now, to modify a Prius v wiring kit.
     
  15. PeterHaas

    PeterHaas Member

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    My personal recommendation for routing and installing the connection to the 12 volt battery is to make sure the red molded housing for the trailer lamp fuse (10 amp) is next to the 12 volt battery, but towards the outside right side of that battery, so that the fuse may be accessed and examined simply by removing the single panel on the right-hand side of the passenger seat bottom (three push/turn fasteners). There is more than enough wire provided in the wiring kit.
     
  16. priusCpilot

    priusCpilot Active Member

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    So the size of the 12v on the PiP harness isn't correct ?

    One issue I had was the wiring seemed to obstruct the batter vent path and I heard the batter fan running high after install. I went back and made sure the wiring was all the way along the side going the same path as the factor harness and cleaned up the install and it worked. Battery went back to normal.
     
  17. PeterHaas

    PeterHaas Member

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    My comment was solely limited to the Prius c and the purpose-built Curt wiring (released by Curt only 28 days ago, BTW), and not adaptations of other Prius wiring (the Prius v, specifically) to the Prius c.

    The Prius c has a different 12 volt battery than the others, and at least in my example, a 2014, it has 1/4" dia. bolts which clamp to the battery's terminals. And, my Prius c is a One.

    It is indeed possible that earlier Prius cs, and higher trim levels of the 2014 Prius c use a different battery, and for which the supplied 3/8" terminal might be correct.
     
  18. PeterHaas

    PeterHaas Member

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    Here is the perhaps critical difference:

    What we have been referring to as "front mount" is really an "end mount" (the hitch is mounted on the end of the underlying structure).

    The mounting bolts, therefore, are always in tension, which is certainly appropriate for a Class 10.9-rated fastener.

    The few manufacturers which are using the alternative mount are placing the mounting bolts in shear, not in tension.

    The example cited of the F150 Ford is perhaps a poor example, as the holes (actually slots) into which the shear bolts are installed are way, way oversize, with respect to the cross section of the supplied bolts themselves, and the manufacturer's installation video shows the application of several "fender washers", and some "spacers" to take up the difference between the slot size and the bolt size ... a curious "make good" ... whereas I would expect and require a proper adaptation, using a machined spacer.

    Following up on my forthcoming Curt installation, I earlier noted that Toyota appears to have applied reinforcing welds to the bumper attachment members. These welds, four of these, are "proud" of the surface against which the Curt hitch is expected and required to be attached.

    In order to avoid crushing these reinforcing welds, by the installation of the Curt hitch, I estimate that three 5/16" ID (0.328" to 0.344" actual ID) "fender washers" be applied between the Curt hitch and the underlying structure, probably 1-1/4" OD. Such 5/16" "fender washers" (really, these are oversized OD flat washers with a standard ID hole) are available at most ACE Hardware stores.

    I made a template of the Curt mounting flange using heavy hard stock, and checked it against my 2014-1/2 Prius c One's frame, and which confirms the above observations.
     
  19. PeterHaas

    PeterHaas Member

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    Make that two or three "fender washers", and depending upon the height of the reinforcing welds, which appear to be hand-made, hence varying, somewhat, in height.

    I made a thickness gage block with which to estimate the required bolt length and this turned up the interesting result that the Curt-supplied "10.9" bolts are just long enough to show three threads protruding past the end of the "weld nuts" (three threads is the absolute minimum, according to accepted practice, but more than three is certainly OK).

    So, the Curt-supplied bolts are only long enough for installation according to Curt's instructions, and are not long enough for my suggested application of a spacer with which to accommodate the reinforcing welds, which welds may not have been present when Curt finalized its product.

    M8-1.25 x 30 are the dimensions of the Curt-supplied bolts. I would suggest at least 35mm, but better yet would be 40mm, when using spacers as I have suggested.

    Alas, ACE Hardware does not stock "10.9" fasteners, but Orchard Supply Hardware does, in both 35 and 40mm lengths.
     
    #59 PeterHaas, May 30, 2015
    Last edited: May 30, 2015
  20. priusCpilot

    priusCpilot Active Member

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