2019 T@B 400 Boondock Tires: Rainier Apex ST235/R75

Awca12a · December 2018

While compiling the specs on our new 2019 T@B400 Boondock Lite, I looked for a PDF tire brochure to know the limitations, warranty, etc. After a 2-day education cycle during which the factory tech support did a great job of accurate and valuable response, I was able to gather together what I'd need to know should I have a sidewall problem in the field and need a new tire.

The tires are Rainier Apex ST APC-X ST235/75R15 110/106M mounted to an aluminum rim and 5-bolt pattern.
They come with a 6-year warranty and a speed rating of 81-mph
Using the TREDIT ADVANTAGE app from Google or Apple, you can receive nationwide roadside assistance under this warranty.
http://www.tredittire.com/tredit-advantage-program

The spare is an ST205/75R15 mounted on a steel rim.

This post is just for general reference by the community as the tire is not readily available other than in through www.tredit.com at their Elkhart or Oregon locations at the present time. As this model doesn't appear on their website and local branches may not be aware of it in the off road configuration, you may need to give them part number #RNAP235X15CTL.

From what I've seen and heard, the above information shouldn't be needed but if you do, this will simplify the replacement process. New boondock owners can register the tire on the Tredittire website.

N7SHG_Ham · December 2018

Really unfortunate that a no name tire in a ST size almost non existent was used. Going to be very hard to find replacements in that size of any tread pattern. Likely a lot of these will be replaced with ST225/75R15 which is a common trailer tire size. The stock Boondock tires are the ONLY ST tire I have found with an aggressive tread pattern, let alone in the required size.

Bayliss · January 2019

@Awca12a and @N7SHG_Ham , thanks for the info re the Boondock tires. I have been researching the same issue, but am also interested in who manufactures the aluminum wheels. It appears that they are manufactured by Sendel Wheels and are the "Thoroughbred" model in matte black (made in China). The wheel is stamped "CAVALLIS" on one spoke on the reverse side of the wheel. I did find "Cavallis Wheels," which makes sport-type wheels, but I could not find a wheel that matches the one included with the Boondock package.

The Boondock wheel is also stamped "L55205R" and "15X6.0J" on another spoke. I have not been able to figure out what those refer to. The wheel is a 15" with 5 lugs (4.5) wheel, so I would not think the "15X6" references a 6 lug wheel. Any ideas on what the stamps refer to?

Also, @Awca12a , did you question nuCamp as to why they say to contact Lionshead Tire and Wheels (http://www.lionsheadtireandwheel.com/) re the tires and wheels warranty? I searched the Lionshead website and they do not appear to carry either the Rainier ST tire or the Thoroughbred wheel.

I agree that it is going to be difficult to replace the current Boondock tire or wheel with a short turn-around time frame, since a tire shop would likely have to special order both. The aggressive look of the Rainier ST APEX is part of the appeal of the Boondock package, so it is a shame that it may not be available (or at least easily available) in the future.

Image: https://us.v-cdn.net/5021717/uploads/editor/ff/vhp04fyi5bpa.jpg

MuttonChops · January 2019

Bayliss said:

. . . "L55205R" and "15X6.0J" on another spoke. I have not been able to figure out what those refer to. The wheel is a 15" with 5 lugs (4.5) wheel, so I would not think the "15X6" references a 6 lug wheel. Any ideas on what the stamps refer to?

15x6 is the wheel rim width bead-to-bead; 6.0J being 6-inches. All tires can be mounted on a range of rim widths with 6.0 as the smallest for our 235x75x15 tire. In general different widths change the tire sidewall shape but don't impact overall diameter much due to steel belts.

Reference source 1: https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=198

Reference source 2: https://www.tyresizecalculator.com/tyre-wheel-calculators/wheel-rim-size-calculator

Rim Ranges 235x75x15 from source #2:

Image: https://us.v-cdn.net/5021717/uploads/editor/gx/pn0bxnh9i21s.png

rcuomo · January 2019

“J” is the collar profile for the tire bead and means the wheel is for passenger tire usage.

Bayliss · January 2019

@MuttonChops and @rcuomo , thank you both for the explanation. I appreciate it. I will hang on to the info and links for future reference.

N7SHG_Ham · January 2019

Yes agree a 15" diameter 6" width rim/tire.

My dealer did say several "off road" trailers use the ST235/75R15 size with aggressive tread. I have a real concern about any mud/gravel balling up on this tire will likely be rubbing the minimum clearance fender and start breaking the plastic. The Boondock lite package adds 2 1/4" additional ground clearance (I finally found that published in the NuCamp brochure) and other than the aluminum tub (which is actually a better design and more durable) I see the Boondock Lite package mostly as an appearance package with a slight bit more ground clearance, BUT in no way does it add a ton of off road capability.

Quoting my dealer; "Most of my manufacturers use Westlake (sometimes sold as Goodride) in a more aggressive mud tread, but there have also been more all-terrain treads, too. I think it all has to do with what is available at the time they are ordered."

I will see how these Boondock tires work out, BUT may ditch them for Goodyear Endurance ST205/75R15 so as to have same size as spare. or possibly ST225/75R15 on all three rims.

I plan on adding a TST TPMS as soon as I can too, knowing tire pressure and temperature is very important if you want to help your chances of NOT having a tire failure with subsequent damage to the trailer.

Bayliss · January 2019

@N7SHG_Ham , I purchased the matching Boondock spare and wheel, but since it does not come standard with the Boondock Lite package (which doesn't make a lot of sense), I understand why you are considering changing to the Goodyear tires. I agree with your assessment that the Boondock package is more for appearance, and it does enhance the "look" of the camper. I like the additional clearance, but that's about all it provides. I plan on using the Tire Traker TT-500 TPMS to monitor my tires. I used it with my 5th wheel and liked it. I purchased the TPMS after a blowout in Washington on the 5th wheel. Fortunately, another driver let us know one of our tires had blown, but the rim was already damaged. It is because of that incident that I am interested in who manufactured the wheel that comes with the Boondock package. Thank you for your input.

Brett · January 2019

Great thread. Thank you for all of the information!

i was wondering if an LT tire with the same dimensions would be a suitable replacement for the odd sized ST stock tires? It seems that the LT tires are much easier to find in this size.

Would an LT tire with a C load range be a good choice for a 400? Or is it a bad idea to replace ST with LT in general?

N7SHG_Ham · January 2019

I am unsure, there are untold discussions about the ST vs LT tires. I think as as long as weight rating is equal or higher and the tire fits, maybe it is OK. I would refer you to this page for more info than you probably want to read: http://www.rvtiresafety.net/?m=0

rcuomo · January 2019

ST or special trailer tires generally have higher load capacity and higher inflation capability to support the higher load. Often they have stiffer sidewall construction to support driving on a blown tire. LT or light truck tires also have higher load capacity than passenger tires but not always the higher inflation and multiple sidewall plies to support a blown tire, thought process being you can steer a truck with a flat tire but not a trailer. You can probably match up a LT tire with load capacity but IMO I would not switch out an ST with an LT.

N7SHG_Ham · January 2019

@rcuomo good comments, I agree with NOT using a LT tire but I know some do if you can match weight rating. A LT tire in same size as a ST is usually going to have a lower weight rating. I stick to ST tires on trailers, inflate to correct pressure and keep it under 65 mph.

MuttonChops · January 2019

While shopping for my T@B 320S all the Boondock/Outback models on the dealer lot had Westlake ST 235/75R15 tires. When my factory order unit arrived three months later it had Milestar 235/75R15 XL tires.

'XL' are extra load and have stiffer sidewalls at the sidewall-tread interface. They are not 'ST' or 'LT'.

Milestar load rating is 2271#, speed rating 118 MPH

Awca12a · March 2019

UPDATE: We started to put air in the drivers side tire and the valve gave way and started hissing air. Quickly took out the valve stem tool that is in the hitch bag and tightened it enough to stop the leak. Capped it and proceeded 500-miles home. Valve was shot and is is brand new.

Took the opportunity to replace the cheap valve stems with the high-pressure type that is rubber near the tire and metal on the stem. If you have one of these tires, check your air in the driveway before heading out.

Bayliss · March 2019

Not good, @Awca12a ................ is the valve stem depicted in the photo below the same as the one that was on your wheels?

Image: https://us.v-cdn.net/5021717/uploads/editor/qy/nx5g23oeqfaz.jpg

NCNative · March 2019

I have had the same problem with my stems as well from the beginning. I need to get them replaced. Thanks for sharing

Awca12a · March 2019

@Bayliss - Mine looked the same and it had a red tipped hex cap but didn't think to take photos.
My replacement cost $4.50 at the local commercial tire shop and was a VTR TR-600HP 1-1/4" High Pressure Brass Rubber stem.

Image: https://us.v-cdn.net/5021717/uploads/editor/yb/0qpdrdnxni9t.jpg

JEB · March 2019

Awca12a said:

@Bayliss - Mine looked the same and it had a red tipped hex cap but didn't think to take photos.
My replacement cost $4.50 at the local commercial tire shop and was a VTR TR-600HP 1-1/4" High Pressure Brass Rubber stem.

I know it’s a little late to ask, but were the stems themselves shot or just the cores?

Awca12a · March 2019

The tires have about 1,000 miles on them so it would be the core that was shot. But I tried to re-seat the core using the valve tool and it just wouldn't seat and it was happening on both sides. Without running a die/tap into the valve, I couldn't know for sure contact surface was the problem (core or valve) so for $20 it was cheaper to just replace the valve assembly and upgrade to a high-pressure brass/rubber combo. Whenever I get new SUV tires, I ask for those valves so this was something I've had good experience with in the past.

JEB · March 2019

Awca12a said:

The tires have about 1,000 miles on them so it would be the core that was shot. But I tried to re-seat the core using the valve tool and it just wouldn't seat and it was happening on both sides. Without running a die/tap into the valve, I couldn't know for sure contact surface was the problem (core or valve) so for $20 it was cheaper to just replace the valve assembly and upgrade to a high-pressure brass/rubber combo. Whenever I get new SUV tires, I ask for those valves so this was something I've had good experience with in the past.

Certainly the safest route. Thanks for the heads up. I’ll carry some spare cores with me in case I spring a leak on the road and need to do a quick fix until I can get the stems replaced.

N7SHG_Ham · March 2019

Replacing the stems is a case where labor is way more than the parts

Awca12a · March 2019

My local shop did it for $20.

NorthIsUp · March 2019

I wasn't aware that ST tires are limited to 65 MPH, at least according to Tire Rack. https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=219
That page also states, "Also consider that Special Trailer (ST), as well as Light Truck (LT) tires are fully rated for trailer applications. This means ST- and LT-sized tires can carry the full weight rating branded on the sidewalls when used on a trailer." That was a key point for me.

In reading this and some of the Airstream Forums I feel like just driving the stock BL tires for this season and switching to Michelin Defender LTX M/S 235/75R15 XL when life quiets down a bit. This is in lieu of searching down the road for that one obscure pair of ST- tires that will work on the BL and look aggressive and cool.

In your spare time:

Older posts, but very useful for the technical details and 1st hand experience::
http://http//www.airforums.com/forums/f438/235-75r15xl-vs-225-75-15-trailer-tire-83262.html

http://www.airforums.com/forums/f438/anyone-look-into-the-235-75-r15-michelins-166118.html

...and, when all was said and done:
http://maze.airstreamlife.com/2015/08/26/why-you-might-be-wrong-about-everything/

morey000 · March 2019

Bayliss said:

...I agree with your assessment that the Boondock package is more for appearance, and it does enhance the "look" of the camper. I like the additional clearance, but that's about all it provides....

Well, that and the front rack!

Edited for language - Sharon

Awca12a · April 2019

Would appreciate any advice and/or confirmation on what to replace the stock Boondock ST235/75/R15 with.
While I'm aware of the ability to use an LT tire, I'd like to stick with ST tires even if it is a boneheaded move.

Nobody makes an ST235/75/R15 tire and the only dealer who handles it for nuCAMP doesn't show it on their website or brochure. They did, however, confirm by phone that the tires are load rated C/6 with a 2340# carrying capacity and fits on 15" x 6" wheels.

The C/6 load rating according to the tire experts/salespeople seems to be the problem. When you put a higher load rated tire on the trailer but don't load the tire to within it's rating while still inflating it as specified, you end-up wearing down the center of the tire because it's the equivalent of over-inflating. At the same time, inflating less than specified impacts more than just a reduction in load rating; apparently, it effects the sidewall stability which is the purpose of an ST tire. So, I was advised to stick with the C load rating and possibly the D but certainly not the E. Note: C/6 means 6-ply, D/7 means 8-ply and E/10 means 10-ply.

There are no ST235 tires commonly available or even after making a concerted internet search so we have to use ST225 which is 1/3" smaller but will fit the 15" x 6" wheels.

Tire Track said the only tire they could offer is the Power King TowMax STRII with a D load rating of 2540# capacity when run at 65psi. Etrailer offers the Taskmaster Contender Radial C22515D with a D/8 rating of 2540# at 65psi.

When I brought-up the Goodyear Endurance ST225/75R15 to both, i was told its E/10 load rating of 2830# capability at 80psi is simply too high. Etrailer affirmed that the Taskmaster has the quality to do the job and in that respect compares comparably with the Goodyear. While they offer a C rated one from Karrier, I didn't get a warm feeling about it's quality. While searching reviews, I ran accross a Q&A covering this: https://www.etrailer.com/question-251209.html

If you had to replace your Boondock ST235/75/R15's, what would you do?

Actual trailer weight and equipment details given to the salespeople were:

Image: https://us.v-cdn.net/5021717/uploads/editor/mf/zj77vho0svgd.png

N7SHG_Ham · April 2019

@Awca12a it is a quandary for sure! I am thinking about a Michelin Defender LT235/75R15 tire rated at 2271 pounds. I think other option would be to drop back to the regular 400 smaller size (ST205/75R15) and use the Goodyear Endurance. That tire would surely be adequate as that is standard 400 size as well as the spare size for the Boondock's. In that size the Endurance is a D tire rated at 2,150 pounds. As you noted the ST225/75R15 Edurance is an E tire with 80 PSI inflation.

In a name brand tire, that is only two options I found. One of the reasons I wanted to buy ST205/75R15 tires on a Boondock was what we are discussing here (standard trailer tire size), but was told no "partial" Boondock package, all or none. It is an easy enough swap I suppose, but a waste of money after the fact.

Anyone know if lug patterns, rim width, offset, etc. are the same between standard 400 rims and the Boondock version? I guess worse case, order a set of standard wheels, take them to the tire store and get some proper trailer tires mounted.

NorthIsUp · April 2019

So we have a trailer that we can't find replacement tires for, can't decide how to jack up, can't figure out the true tongue weight or its actual overall weight or what exactly is needed to tow it. And, we're all still in love with it. Amazing.

Awca12a · April 2019

Sort of.
The procedures to jack it have been cleared by the factory and I hope are cogently documented in the Unofficial Manual.
Tongue weight is figured out. If you have a Boondock it’s higher tongue weight than if you don’t. Nobody know why. So Buyer beware and plan accordingly. In retrospect, no value in the Boondock package given the tire and weight problems but now nobody can claim ignorance.
Tires remain a problem but can be solved for under $300. If there was an answer to the field replacement of a damaged tire, factory probably would have chimed in. I expect they will eventually post specs for a standard ST225 and show new weight capacity and clearance specs if you do.
Trailer is great and I would buy it again only without Boondock. Just wish I didn’t have to buy the TV twice.

klenger · April 2019

I don't think I'd be overly concerned about running higher rated tires (within reason) than the load demands. There are many examples of utility trailers that are towed around empty for long distances and then loaded without problems. Also, I just sold a 3/4 diesel Ram truck that I used for towing a 10,000 lb travel trailer. I inflated the rear tires to the spec pressure for loaded towing, but drove 85% of the miles empty and never had an issue.

ChrisFix · April 2019

N7SHG_Ham said:

Anyone know if lug patterns, rim width, offset, etc. are the same between standard 400 rims and the Boondock version?

I'd also like to know the answer to this question. If not different from the standard T@B 400, then a tire swap to standard 205/75 is straight forward.

falcon1970 · April 2019

On my TAB 400 at least the lug pattern on the alloy wheels is 5 bolt-4.5" diameter, with a 5" rim width and 0 offset. However, the steel spare wheel is a 6" wide rim width.

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2019 T@B 400 Boondock Tires: Rainier Apex ST235/R75

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