blistovmhz
NAXJA Forum User
- Location
- Vancouver, BC
Very little in the way of discussion on this. I don't care that "it's a Jeep". That's a bogus excuse for poor engineering.
So my XJ's 5000lbs right now, sitting on 35x12.5's. I've no idea how that happened. The mass just crept up on me.
I've got a full size roof basket as well as a swing out tire carrier. Both look bad-ass as hell, but the basket is overkill for almost everything I ever do with it. The swing out carrier blocks my view (which only bothers me on the trail), increases my COG, and I land on the spare tire all the time on the trail even though it's centre line is pretty near half way up my rear window.
My COG is getting stupid, and the aerodynamics suck. With the roof basket and carrier removed, tire mounted inside, I go from 17mpg highway to around 23-24mpg. Yea, not a HUGE deal, but combined with the increased COG and hanging up on the tire, I think it's worth fixing.
The real question is, what's the most aerodynamic approach to the spare tire? I can move my 52" light bar above the front bumper, and my side lamps can all be moved either under the Jeep, or brought inside and mounted facing out the windows. I still need a roof rack with a full floor, but I can build something much lower profile and lighter.
Assuming a lower profile roof rack, what about the full size spare (that I'll probably never need but I'm paranoid and I often end up needing it for other peoples rigs). The carrier itself isn't as high as the roof, but it adds 60 or 70 lbs that's definitely above my roll axis, as well as puts an extra 150 - 170lbs on the ass end of my Jeep (which is already ass heavy). The aerodynamics of a spare on the back are horrible, and I almost suspect both my COG would be lowered as well as increasing aerodynamics by mounting the tire on the roof. Yea, you're moving the spare up higher, but you're also losing 70lbs of carrier from above the centre line.
What do ya'll think? Who's done both and actually got a feel for how it affected COG and aerodynamics?
P.S. No, there's no room inside the cab. In any situation where I may need my spare, I also need my tools, recovery gear, fluids, and usually camping gear.
So my XJ's 5000lbs right now, sitting on 35x12.5's. I've no idea how that happened. The mass just crept up on me.
I've got a full size roof basket as well as a swing out tire carrier. Both look bad-ass as hell, but the basket is overkill for almost everything I ever do with it. The swing out carrier blocks my view (which only bothers me on the trail), increases my COG, and I land on the spare tire all the time on the trail even though it's centre line is pretty near half way up my rear window.
My COG is getting stupid, and the aerodynamics suck. With the roof basket and carrier removed, tire mounted inside, I go from 17mpg highway to around 23-24mpg. Yea, not a HUGE deal, but combined with the increased COG and hanging up on the tire, I think it's worth fixing.
The real question is, what's the most aerodynamic approach to the spare tire? I can move my 52" light bar above the front bumper, and my side lamps can all be moved either under the Jeep, or brought inside and mounted facing out the windows. I still need a roof rack with a full floor, but I can build something much lower profile and lighter.
Assuming a lower profile roof rack, what about the full size spare (that I'll probably never need but I'm paranoid and I often end up needing it for other peoples rigs). The carrier itself isn't as high as the roof, but it adds 60 or 70 lbs that's definitely above my roll axis, as well as puts an extra 150 - 170lbs on the ass end of my Jeep (which is already ass heavy). The aerodynamics of a spare on the back are horrible, and I almost suspect both my COG would be lowered as well as increasing aerodynamics by mounting the tire on the roof. Yea, you're moving the spare up higher, but you're also losing 70lbs of carrier from above the centre line.
What do ya'll think? Who's done both and actually got a feel for how it affected COG and aerodynamics?
P.S. No, there's no room inside the cab. In any situation where I may need my spare, I also need my tools, recovery gear, fluids, and usually camping gear.