New horns - relay necessary or not.

[ZoneIII]

2015 R3T. I'm replacing the goofy "meep meep" horn that came on my R3T finally. I chose the P1AA 85114 Slim Line 400Hz + 500Hz set based on excellent reviews. I just received them today and tested them using my fully charged battery that isn't installed for the winter months but is being maintained on a Optimate 6. The horns are very loud and the manufacturer as well as some people who've installed them on their bikes say a relay isn't needed. The manufacture claims that each horn draws 2.7 amps but I tested them using my Fluke 28II meter and found that my set actually draws less current than claimed. My 500Hz horn draws 1.95 amps and the 400Hz horn draws 2.35 amps for a total of only 4.3 amps together. For reference, I tested the crappy OEM horn and it draws 1.5 amps.

I was not going to use a relay but the existing horn wires are very small gauge - I'm not sure what gauge - I'm guessing maybe 18 ga. (If anyone knows, that would be helpful.)

There's two other things I'm thinking about: One is that I'm aware that higher current draw through the horn switch can possibly burn the contacts over time (although how often do you use a horn?). The other thing is that the horn is on the same 15A circuit that the brake lights and turn signals are on so I don't want to blow that fuse, of course.

Has anyone installed the P1AA slimline set on a Rocket? If so, did you find you needed a relay. Do you think a relay is necessary or advisable? Of course, I rather not install the relay and wiring if it's not necessary. If you did install a relay, can you recommend a good horn relay kit. (I could just wire it up myself but a pre-made kit would be nice if I decide to go that way.)

Now I just have to figure out how to mount them but I think I have a solution for that. If anyone mounted this pair of horns on a R3T and could share a picture, that would be great.

Thanks in advance.

 

[leatal]

You will get the most volume from the horn by powering it directly off the battery through a relay. I passed the two OEM horn wires (I think 20 gauge) back from the original horn location to the rear of the bike. Then extended the wires to control a 40 amp relay and ran a wire from the battery to the relay to the add on horns. I am running a Triumph Thunderbird horn up front (in the original location) and a Denali air horn in front of the air filter box. The set up sounds like a train horn and will just about rupture your eardrums! In fact got to use it today. Had a young lady texting while driving (you know weaving from one edge of the lane to the other and not paying attention with her surroundings). She had her window down so I had to wake her up by pulling up along side and laying on the horn. She dropped her phone, locked up the brakes and I think Sh!t in her pants. I may not do that again as she almost wrecked her car in panic.

 

[ZoneIII]

Thanks, leatal. With your air horn, I would assume that you definitely need to run a relay because of the high current draw - plus the original horn. That compressor must draw a lot of current too. But the P1AA horns don't draw nearly that much current and the manufacturer and some people who are using those horns say they are running them without a relay and are experiencing no problems. But those are also different bikes. Here's a link to an excellent video on this subject:

But I'm still wondering if it is advisable to use a relay. Of course, you are correct that a direct battery connection would allow more current to flow but I would think that would be a problem mostly with horns (and compressors) that draw a lot of current. My current readings show that the P1AA horns would only draw 2.8 more amps than the original horn so I'm not sure that would be an issue. I would love to hear from someone who has installed these horns on their Rocket.

Hey! Thanks for letting me know that your original horn wire is 20 gauge. I think it's almost certain that that's what Triumph would use on the Rocket too since the horns are probably the same. Now that I think about it, the wires do look smaller than the 18 guage that i guessed. It's very useful to have that info because I can now look up how much current the wires can handle. Thanks much!

Edit: Just in case I decide to go with a relay, I looked for a pre-made relay/harness for dual horns. It turns out that they are hard to find. Some companies that made them no longer do. Most that are available are for only a single air horn. But I found one source for a harness for dual horns. Here's a link in case anyone else is thinking about getting one:

Stebel HF80 Wiring Harness

 

[Bernard Vinet]

2 cents worth. Use a 10 or 20 amp relay and drive without a worry in the back of your mind.

 

[ZoneIII]

2 cents worth. Use a 10 or 20 amp relay and drive without a worry in the back of your mind.

Bernard, That's kind of the way I'm leaning but, before doing that, I'd like to hear from someone who actually uses these horns on a Rocket. As you can see in the YT video linked above, that guy apparently had no problem and he mentions that other people he knows have no problem without a relay with this set of horns. And the manufacture insists that a relay isn't necessary. I compared the specs on these horns with other similar horns and these draw far less current than most - at least if the specs are correct. But, as I mentioned in my original post, my horns draw considerably less current than even the manufacture claims.

Even so, I'm inclined to go with the relay anyway for the reason you mention.

Thanks!

 

[ChrisACT]

I'd be very interested to see how you mount them. I bought similar PIAA horns but not the slimline ones. Buggers won't fit behind the headlights so I'll stick them on the car instead.

Still looking for a better option.

I don't want to mount them under the side covers like some people have done with air horns. I want loud horns behind the headlights where horns belong.

 

[ChrisACT]

Ahh, I see. Is yours an R3T? Mine is a 2006 standard so mounting horns may not work out the same anyway. Different headlights etc.

 

[ZoneIII]

Ahh, I see. Is yours an R3T? Mine is a 2006 standard so mounting horns may not work out the same anyway. Different headlights etc.

Yes, you would probably have a different setup.

 

[barbagris]

There is no way I would risk the stock wiring with a monster Horn load. Read the spec's. My Stebel Magums draw 6Amps each - 12A total. That is the same as two MAIN BEAMS.

 

[ChrisACT]

There is no way I would risk the stock wiring with a monster Horn load. Read the spec's. My Stebel Magums draw 6Amps each - 12A total. That is the same as two MAIN BEAMS.

The PIAA horns in question don't ever draw half that. I think mine were 5.4amps and these are the slimline version of those so may draw less but unlikely to be more.