OBA?
Q There are many options of onboard air: CO2 tanks, electric, and compressor types. I have a TJ and don’t need more add-ons than necessary for room and weight. What would be a good choice? I know there must be many options on your Ultimate Adventures rigs, as they have to go from off-road air pressure to road pressure and back.
Jeff
Via nuts@4wheeloffroad.com
A We have run every type of onboard air imaginable over the years on our UA trucks, and every one of them has its pros and cons. The CO2 tanks are great and very fast, but they cost about $20 every time you need to refill them and after a few years they need to be certified for reuse, another cost. An engine-driven compressor isn’t bad, but they are harder to mount and complicate your engine bay.
This brings us to electric air compressors. Last year we ran a Warn VTC compressor, and this year we fitted the UA Jeep with a Warn Power Plant winch/air compressor combo (www.warn.com). The VTC compressor worked great, but it was kind of big, and unfortunately Warn discontinued its air compressor line. If you are concerned about space in your Jeep you should consider the Warn Power Plant winch or the new ARB Twin compressor (www.arbusa.com), which uses two compressors and is capable of filling large tires as well as running ARB Air Lockers.
Nuts, I’m Confused
Ultimate Tires?
Q I am interested in going on the Ultimate Adventure some day and am currently building a Jeep YJ Wrangler. I am wondering about tire size. I would like to build my Jeep around a certain size tire (not too big, as I only have a four-cylinder engine) but don’t want to underbuild it. I am willing to change the axles if need be, as the stock units are pretty small. Please help!
Joe E.
Hastings, NE
A Tire size is an important consideration when building any 4x4. I like to start with the desired tire size and then build using axles strong enough to support the tires. From there you need a suspension to clear the tires and a powertrain to move the vehicle. Your Jeep has the 2.5L I-4, a great little engine and with proper gearing capable of turning quite big tires, but I think for an all-around 4x4 (such as you would want on the UA) I would aim for a 37-inch tire. 37s on the wheelbase of a YJ will give you adequate belly clearance and still be good on the road days. The past few years we’ve had some Samurais on the trip all running 37-inch tires, and they worked just fine with four-cylinder engines. I know there is always a tendency to go to a bigger engine, but I like seeing small powerplants on the trail. They often work great and reduce the concern of drivetrain breakage, overheating, and fuel consumption. I’m not saying a healthy V-8 isn’t fun, but a properly built four-banger is great in a road and trail machine.
Returning to tire size, we have had everything from 35s up to 44s on the trip, and the 37s to 40s seem to be the most common. Of course, a longer wheelbase seems to demand a taller tire to assist in breakover angles, such that a fullsize on 42s is similar to a smaller Jeep on 35s or 37s. I think the best option for you is to build the Jeep how you would for your local wheeling. Get to know it well, daily drive it, and take the time to make it work and haul all your camping stuff. More often than not the builds that are finished just before the UA or that recently underwent major changes are the ones with the most trouble.
Thanks for your question. I think a lot of readers are wondering about how best to build for a trip like the UA. We’ll delve into that further in an upcoming issue, but since your question was so timely I chose it as this month’s Nuts, I’m Confused letter. I’ll be sending you an Ultimate Adventure T-shirt.
Everyone, I have a few more of these shirts available, so send in your questions and you may just be next month’s chosen letter.
Submission Information
Confused? Email your questions about trucks, 4x4s, and off-roading tech using “Nuts, I’m confused” as the subject and include a picture (if it’s applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file. Also, I’ll be checking the forums on our website (www.4wheeloffroad.com), and if I see a question that I think more of you might want to have answered, I’ll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes. Write to: Nuts & Bolts, 4-Wheel & Off-Road, 831 S. Douglas St., El Segundo, CA 90245 fax to: 310.531.9368 Email to: nuts@4wheeloffroad.com