maximizing ground clearance after lift kit on a 2020 Bambi

[Zia_Bambi]

Folks,


I recently had the 3" Dexter lift put on my Bambi.


In an effort to maximize the clearance for the axle, and also add more trailer ground clearance, it seems I can get another 1.7" if I go to a 16" wheel and and the largest high quality trailer tire available for durability.


The existing wheel/tire (225 75R15) comes in at 28.3" OD.
A 16" wheel would allow a 235 85R16, which has a 31.7" OD.


That's a 3.4" overall increase in OD, and a 1.7" increase in the axle's ground clearance.


This approach keeps what looks like the largest standard trailer tire, with the assumed benefits of the enhanced durability that trailer tires are supposed to have.


Here's the tire I was considering:
https://www.petestirestore.com/ST235...y_p_11571.html


I have a weight distribution hitch that should be able to be adjusted to the new required tongue height that will result from the 3" axle lift as well as the increased tire diameter.


I also understand that I'd need a new spare to match.


This is easily over $1000 to achieve the additional 1.7" in clearance, but it would also result in a much higher rated tire for this trailer, which I assume has no downside.


I would love for someone to critique this approach and call me on my assumptions!


Steve in New Mexico

[tjdonahoe]

1” remember 2 “ larger will raise you 1”

[Wazbro]

Tires that much heavier duty might give a rougher ride to your Airstream.

[Zia_Bambi]

True, but not from just having more tire, which if anything means more squish and a more compliant ride.


The real consequence to ride quality would probably be the big increase in unsprung mass, which the Dexter axle is probably not designed for.


Steve

[BikeCamper]

On our 19’ Bambi, the 15” spare only BARELY fits in the underbelly storage location. It is a really tight squeeze. I know a taller 16” would never fit.

Just another aspect to consider…

[AlbertF]

Your trailer has a GVWR of 5000 lbs. This would theoretically result in a maximum load of about 4500 lbs on the axle, 2250 per tire. Of course, one side may be heavier than the other, although the 19, with the refrigerator on the streetside, is probably well balanced.

FWIW, our 22FB has the same empty weight of about 3650 according to Airstream. GVWR on ours is listed as 4500 lbs, but the axle itself is rated for 4500. We're usually on the road with about 3900 lbs on the axle. I chose Michelin Defender 235/75/15 tires with a load capacity of 2271 lbs each, and I'm quite happy with them. They run cooler than my tow vehicle tires.

If you actually load to 4500 lbs on the axle, a 2500 lb load capacity is probably a minimum with a 10% margin. The original Goodyear Endurance tires were were rated for 2680 @ 80 psi, I believe.

The original tires also weighed 34 lbs each, which reflects a fairly robust construction. (My Michelins are also 34 lbs each.) Passenger car tires with a standard load index in that size probably weigh about 25 lbs. However, the Carlisles you are considering weigh a full 50 lbs. They're Load Range G tires with a load capacity of up to 4400 lbs each, probably designed for very heavy equipment trailers. Think a landscaper hauling around a skid steer loader.

That gives me pause. Sufficient load carrying capacity is important, but a massively heavy tire is not going to do you any favours. I am concerned that you will end up with a tire that has vibration issues (terrible for an Airstream's construction), rides very hard at any pressure (max is 110 psi), and beats up your trailer.

Not everyone will do what I've done, that is, use a 15" tire that previously sold as an LT, close to the limits of load capacity. Unless you go back to Goodyear, I think the best choice by far is a Michelin LT in a 16" size. Look at the Agilis Cross-Climate or similar. The load capacity for the 225/75/16 is 2680 per tire, just like the originals. I've calculated the overall diameter at 29.29". You can also buy a 235/85/16; the maximum load is 3042 lbs @ 80 psi. According to the inflation charts for LT tires, about 60 psi should be sufficient. These tires still weigh 43 lbs each.

Some people use Michelin XPS ribs and really like them. Those are highway commercial tires for heavy vans and the like, and retreadable. They weigh 56 lbs each! Again, I think the Agilis, designed for the consumer market, is probably a better choice for an Airstream.

If you don't like Micheiins because of a bad experience (I understand, I've had consistently bad results with Goodyears except for the Endurance STs), there are many LT options for a 16" wheel.


I'd keep the existing spare. A bigger tire may not fit. And temporarily running one side low shouldn't be a big issue; it's done with temporary spares on cars all the time. With the 235/85, the radius difference is 1.72 inches, and with the 225/75/16, only a half inch. And with LT tires, it's unlikely that you will ever need the spare.

[Johnco]

Not sure if there have been modifications to the spare carrier since 2006 but I upgraded to 16 inch Michelins shortly after purchasing the Bambi new and a 16 inch spare does fit in the carrier. Snug, but it fits.

[Zia_Bambi]

AlbertF,


Thank you very much for your detailed analysis and excellent recommendations. I will take them to heart. The load and weight considerations are very useful. I don't know much about the Dexter axle or its damping mechanism, but adding significantly higher unsprung mass than it was originally designed for could yield poor road holding behavior and potentially excessively stress the mechanism. I will have to do some more investigation on those issues.


Much appreciated,

Steve in NM

[Zia_Bambi]

Thank you!

[Wazbro]

Another option to consider is replacing the axle with one that has an increased down angle. This option could add another 2" or so ground clearance.

[Florida239]

I have a 19 ft Bambi i replaced the tires with bigger and tougher either 8 or 10 ply and it was noticeable on the tow on rough roads and not in a pleasant way. You could aee the trailer bouncing around more. I actually had fridge wall bounce loose and a rivet pop on first trip. For 4 years prior and plenty of rough roads I had never had any issues.

[tjdonahoe]

How far from the ground to your axle? Now that is a problem

[Blind Wille]

We bought our trailer lightly used and the Airstream dealer had installed the 3" lift kit for the original owner. We have been down some pretty rough unpaved roads with our Caravel 20FB without issue. Examples include the road out to Chaco Canyon and back as well as the 60 mile roundtrip to Horseshoe Canyon (The Great Gallery trailhead) in Utah. I thought about larger rims and tires also but decided it really wasn't needed. We tow with a 2013 Surburban LTZ with four wheel drive. I did get an extra set of 18" rims for the Suburban with BFG K02 All Terrain tires. The stock tires were lower profile 20" highway tires. We recently replaced the trailer tires with the stock Goodyear Endurance ST225/75R15. They can take a beating.

[Life is a Highway]

If you need this much ground clearance on a 22 you bought the wrong trailer my friend. You need a boondock overland trailer your Airstream will be shaken apart if you play dirt trail man. We can’t keep them from breaking on the tough pavement let alone a Jeep Trail

[Zia_Bambi]

Originally Posted by Blind Wille

We bought our trailer lightly used and the Airstream dealer had installed the 3" lift kit for the original owner. We have been down some pretty rough unpaved roads with our Caravel 20FB without issue. Examples include the road out to Chaco Canyon and back as well as the 60 mile roundtrip to Horseshoe Canyon (The Great Gallery trailhead) in Utah. I thought about larger rims and tires also but decided it really wasn't needed. We tow with a 2013 Surburban LTZ with four wheel drive. I did get an extra set of 18" rims for the Suburban with BFG K02 All Terrain tires. The stock tires were lower profile 20" highway tires. We recently replaced the trailer tires with the stock Goodyear Endurance ST225/75R15. They can take a beating.

This is good to know, much thanks for the testimonial real world test. Very useful information!


Steve

[Zia_Bambi]

Originally Posted by Life is a Highway

If you need this much ground clearance on a 22 you bought the wrong trailer my friend. You need a boondock overland trailer your Airstream will be shaken apart if you play dirt trail man. We can’t keep them from breaking on the tough pavement let alone a Jeep Trail

Point taken! I've already had to apply custom fixes to things like the reefer cabinet (and other Airstream build deficiencies) that couldn't hack the 3 mile rough dirt road to my house!


Much appreciated,

Steve