Forum Discussion

mlts22's avatar
mlts22
Explorer
Dec 31, 2014

Move spare to top of TC, stick an Onan genset in the space?

This seems to be a question about something that nobody seems to have done with a pickup.

Has anyone moved their spare tire, taken a genset (a PowerTech for diesels, an Onan for gassers), mounted it in the spare tire's space, teed it into their gas tank, piped the exhaust out the side, then had a circuit breaker and receptacle mounted in the truck bed?

This is something very common done on class "B" vans -- the generator gets put between the rear pumpkin and the hitch, teed to the fuel tank (which the vehicle manufacturer authorizes), and exhausted out the sides. This is also done with class "C" pickup upfits. Since the genset is under those vehicles and breathes at the bottom, air cooling isn't an issue, just as it isn't an issue with the vans.

I did some quick napkin calculations, and most gensets would fit where a truck's spare tire would be with room to spare... why don't more TC owners do this? It would be a decently effective way to have power available in a safe manner, and a diesel generator can run hundreds of hours on the top 3/4 of a tank (proper installation would have the genset cut off at the 1/4 mark for safety reasons.)

I just wonder why this doesn't seem to be done. It is definitely possible, but I just never see it in the truck/TC ecosystem.
Truck Campers
  • sabconsulting's avatar
    sabconsulting
    Explorer
    Jan 01, 2015
    A spare wheel and tire is a fair bit of extra weight on your roof even once you have managed to get up there. It would be especially bad if you drove off road or on dirt roads as it bounces side to side putting stress on the camper structure as it acts as an inverted pendulum.

    Steve.
  • Buzzcut1's avatar
    Buzzcut1
    Nomad II
    Jan 01, 2015
    well you could put the generator there and put the tire on a front mounted hitch rack. much easier than hauling it into the air
  • midnightsadie's avatar
    midnightsadie
    Explorer II
    Jan 01, 2015
    tire on thin roof bouncing down the road is a disaster waiting to happen, some day it,ll be on the kitchen table.
  • Raften's avatar
    Raften
    Explorer
    Dec 31, 2014
    In my old decrepit state I have a hard time just getting a spare on the studs. I would need a anti gravity device to get one on a roof. I don't think I have ever seen a spare on on a RV roof.
  • Bedlam's avatar
    Bedlam
    Moderator
    Dec 31, 2014
    Some negative thoughts:
    1. Service access
    2. Protection from road debris
    3. Off-road protection from terrain
    4. Hauling a tire up and down off the TC roof or blocking the radiator
    5. If you take the TC off the truck and leave, you take away the power

    Some positive thoughts:
    1. Weight is closer the axle than typically on a TC
    2. Sound would be more surrounded under the truck
    3. You would have household power available anywhere you take the truck
  • tony_lee's avatar
    tony_lee
    Explorer
    Dec 31, 2014
    Lots of motorhomes have their generator mounted in the guts of the vehicle and have it on slides to get at it for servicing so I guess something could be arranged for servicing. I can get at the dipstick and water filler in the airstream onan but anything else requires it to be dropped. The small onans don't have a dipstick so oil level could be checked from underneath with a bit of modification.

    The tyre on top of the camper would be more problematic. Not light to get up there and nowhere to put it if you do. Hatches and solar panels take up all the roof space on the bigfoot and I can't even stick the second unmounted spare tyre up there. It sits in the crewcab.

    I know someone who made up a winch to get a large spare on top of his motorhome. Had a flat and decided to short-cut the process by throwing the spare off the roof. Didn't land as flat as he intended and bounced over the guard rail never to be seen again.

    "and a diesel generator can run hundreds of hours on the top 3/4 of a tank (proper installation would have the genset cut off at the 1/4 mark for safety reasons.)"
    Hard to believe I know, but several times I have been tearing my hair out trying to get the generator to start only to eventually wake up that the main fuel tank was only 1/4 full. Doh!!!
  • arto_wa's avatar
    arto_wa
    Explorer
    Dec 31, 2014
    mlts22 wrote:
    This seems to be a question about something that nobody seems to have done with a pickup.

    Has anyone moved their spare tire, taken a genset (a PowerTech for diesels, an Onan for gassers), mounted it in the spare tire's space, teed it into their gas tank, piped the exhaust out the side, then had a circuit breaker and receptacle mounted in the truck bed?

    This is something very common done on class "B" vans -- the generator gets put between the rear pumpkin and the hitch, teed to the fuel tank (which the vehicle manufacturer authorizes), and exhausted out the sides. This is also done with class "C" pickup upfits. Since the genset is under those vehicles and breathes at the bottom, air cooling isn't an issue, just as it isn't an issue with the vans.

    I did some quick napkin calculations, and most gensets would fit where a truck's spare tire would be with room to spare... why don't more TC owners do this? It would be a decently effective way to have power available in a safe manner, and a diesel generator can run hundreds of hours on the top 3/4 of a tank (proper installation would have the genset cut off at the 1/4 mark for safety reasons.)

    I just wonder why this doesn't seem to be done. It is definitely possible, but I just never see it in the truck/TC ecosystem.




    Sure you could mount one there but how would you service it there?

    I hope the class "B" vans have easy generator access panel from the side (as the built in Onan in my camper has), but I think that would be a bit of a challenge if the generator was mounted in the pickup's spare tire space?

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