Stock TT Tires:

[Mac123]

I am new to the TT/RV world. I recently purchased a new 2013 Keystone Cougar 21RBS TT. It was equiped with Towmax STR Power King ST225/75R15 tires. 5ply on the tread, 2ply on the sidewall. I have heard experienced RVers say they are not good tires and should be upgraded to better, stronger, more reliable tires. I have heard as many say, "they are fine, the manufacturer and dealer would not be in business very long if there was a problem with their tires being unreliable or unsafe." Ok, that said, give me some opinions and ,please, if possible, back up what you say with reliable facts. I'm looking to be educated and well informed here. Thanks, Kevin

[therink]

I had the same tires on my 2010 fiver. They did OK, but just replaced them as they were 3 yrs old. I never had a problem with them, but I didn't like they way the sidewalls flexed and the way they sat under load. I was constantly worried when towing.
I replaced mine this summer with Maxxi 225 75R 15 E's 10ply. Night and Day between the two tires. When I got a look at the Towmax tires unmounted, I could not believe how flimsy they were. I can't believe they lasted as long as they did.
I would say you should be OK for a couple years, but do plan on replacing them down the road.
Steve

[hankpage]

Kevin, If you do a forum search for "Towmax tires" you will find over thirty threads on the topic. Spend some time reading and see what your conclusion is. Most important is keep them inflated properly and check them at least daily while traveling. Travel safely , Hank

[smiller]

Same experience here, did not have a Towmax fail on me but when I upgraded to Maxxis I was surprised at how much better-constructed they seemed to be. Comparing both tires off the rim the Maxxis was much heavier and had considerably more substantial sidewall construction. I guess I can't say exactly how much this contributes to increased reliability or safety... but I can guess. It should also be noted that there are several reports of Towmax failures on this and other forums but virtually none for the Maxxis, FWIW.

It's probably just as important to compare your GVWR (or the total capacity of both axles) to your maximum tire weight ratings (the weight rating off all four tires added together.) To be safe you really should have at least a 20% safety factor. And as Hank says, whatever else you do keep them inflated properly at all times. That is free and can make all the difference.

[CWtheMan]

I am new to the TT/RV world. I recently purchased a new 2013 Keystone Cougar 21RBS TT. It was equiped with Towmax STR Power King ST225/75R15 tires. 5ply on the tread, 2ply on the sidewall. I have heard experienced RVers say they are not good tires and should be upgraded to better, stronger, more reliable tires. I have heard as many say, "they are fine, the manufacturer and dealer would not be in business very long if there was a problem with their tires being unreliable or unsafe." Ok, that said, give me some opinions and ,please, if possible, back up what you say with reliable facts. I'm looking to be educated and well informed here. Thanks, Kevin

I really don’t like to go pro or con on trailer tire brands. But, in this case it’s called for.

Tire brands that are used as Original Equipment tires on RV trailers are often abused by the manufacturers that use them. TowMax is in that category. Keystone will use the same size tire along a complete model line-up until the load capacity for that size cannot support the vehicle’s GAWR. Many of those models on the heavy end of the model line-up will have OE tires with very little load capacity reserves. Those tires - no matter what brand - are just not going to last very long.

TowMax is continuously improving their ST tire line. This year - 2012 - they have issued new warranty standards. Five years from date of purchase. They have a nation wide free roadside assistance program. All of their ST tires size 15” & 16” now have nylon overlays covering the body plies. That added protection greatly reduces the incident of tread separation.

Your trailer is on the best end of a model line-up for Keystone OE tires. According to your trailer’s specs your maximum GAWR is 6620# and your tires provide you with 10160# of load capacity. Operate them within their designed parameters and they will last out their warranty period.

http://www.keystone-cougar.com/index.php?page=specs

CW

[Mac123]

Thank you, all of you, for your info and advice. Your comments were exactly what I needed to hear. I trust the voice of experience most. I just like to feel like I know what I'm doing and I want to be safe and sensible. I went to 10ply tires on my truck and heavier side walls and noticed immediately that I had less sidewall flex, thus less bounce. I think that I will go to a heavier duty tire next year. Good advice. Thanks again.
:) Kevin

[fla-gypsy]

No experience with Towmax but plenty with the Chinese made Duro's. They were total junk. Replaced them with Maxxis and have been totally satisfied

[dave-g]

Same experience here, did not have a Towmax fail on me but when I upgraded to Maxxis I was surprised at how much better-constructed they seemed to be. Comparing both tires off the rim the Maxxis was much heavier and had considerably more substantial sidewall construction. I guess I can't say exactly how much this contributes to increased reliability or safety... but I can guess. It should also be noted that there are several reports of Towmax failures on this and other forums but virtually none for the Maxxis, FWIW.

It's probably just as important to compare your GVWR (or the total capacity of both axles) to your maximum tire weight ratings (the weight rating off all four tires added together.) To be safe you really should have at least a 20% safety factor. And as Hank says, whatever else you do keep them inflated properly at all times. That is free and can make all the difference.


This is where the problems start!!!!! I agree a 20% safety factor would be great- but that is not how they ship. My 325srx has a max weight of 12200 the tires are rated for 12320. Depending on how it is loaded ( or over loaded) the tires are near max with no safety reserve. Yes I know the pin is 1000-1500 lbs, but the numbers start to get very close. Let the pressure be below max by 10 psi and your over loaded.

I also read that most tires are de-rated about 10% for every 10 mph over 65 mph.

[smiller]

My 325srx has a max weight of 12200 the tires are rated for 12320.
The axles are rated for 5200 lbs. each and you would have to so grossly overload them to come anywhere near the tire rating that the tires would be the less of my worries. As long as you stay within the axle ratings (and hopefully you are!) then the stock 235/80R16E tires should provide plenty of headroom. And FWIW my 325SRX loaded for full-time use with a motorcycle in the back is still well under the axle rating so I think you can rest easy with regard to your OEM tire size/ratings. Now OEM tire brand, that's another thing... ;)

[CWtheMan]

This is where the problems start!!!!! I agree a 20% safety factor would be great- but that is not how they ship. My 325srx has a max weight of 12200 the tires are rated for 12320. Depending on how it is loaded ( or over loaded) the tires are near max with no safety reserve. Yes I know the pin is 1000-1500 lbs, but the numbers start to get very close. Let the pressure be below max by 10 psi and your over loaded.

I also read that most tires are de-rated about 10% for every 10 mph over 65 mph.


According to the Keystone specs for your trailer your tires are rated for a total of 14,080# at 80 psi. Are you saying the tire placard is telling you to use less than 80 psi tire pressure? Or are you mistakenly using the dual table?

http://www.keystone-cougar.com/index.php?page=specs&year=2011

http://towmaxtires.com/tires/Landing.aspx?application=towmax-product-line

FastEagle

[dave-g]

when reading my side walls it says 3080 lb at 80 psi. Not 3520 like the web link. I'll have to put my reading glasses on and recheck it for a single rating.

[dave-g]

The axles are rated for 5200 lbs. each and you would have to so grossly overload them to come anywhere near the tire rating that the tires would be the less of my worries. As long as you stay within the axle ratings (and hopefully you are!) then the stock 235/80R16E tires should provide plenty of headroom. And FWIW my 325SRX loaded for full-time use with a motorcycle in the back is still well under the axle rating so I think you can rest easy with regard to your OEM tire size/ratings. Now OEM tire brand, that's another thing... ;)

Is that you going on the scale?

[smiller]

Is that you going on the scale?Not quite sure what you are asking but if you mean am I referring to actual weights, yes.

325SRX empty: Steer 4060, Drive 4920, Trailer 7740, Gross 16720 (3/4 fuel, water tanks empty, one occupant)

325SRX loaded: Steer 4400, Drive 5480, Trailer 9420. Gross 19300 (full fuel, full propane, 1/3 fresh water, two occupants)

[dave-g]

Not quite sure what you are asking but if you mean am I referring to actual weights, yes.

325SRX empty: Steer 4060, Drive 4920, Trailer 7740, Gross 16720 (3/4 fuel, water tanks empty, one occupant)

325SRX loaded: Steer 4400, Drive 5480, Trailer 9420. Gross 19300 (full fuel, full propane, 1/3 fresh water, two occupants)

what do you have in the garage at those weights? I dry camp with water full and 1000 lbs of dirt bikes and gear in the garage. I really have to get to a scale.

[AlCorr]

Not quite sure what you are asking but if you mean am I referring to actual weights, yes.

325SRX empty: Steer 4060, Drive 4920, Trailer 7740, Gross 16720 (3/4 fuel, water tanks empty, one occupant)

325SRX loaded: Steer 4400, Drive 5480, Trailer 9420. Gross 19300 (full fuel, full propane, 1/3 fresh water, two occupants)

Sorry, I though this was the Lite Weight Trailers section, a gross weight of 19,300 lb. What do you tow that with?

[smiller]

Sorry, I though this was the Lite Weight Trailers section, a gross weight of 19,300 lb. What do you tow that with?
A 2003 Dodge 2500 CTD HO 2WD 5-speed, 20,000 lb. max. GCVR so I make it within (all) manufacturer's towing specs, barely. But again that is fully loaded for full-timing, with a light motorcycle in back. And from what I read around here that might actually be considered light... :D

[AlCorr]

A 2003 Dodge 2500 CTD HO 2WD 5-speed, 20,000 lb. max. GCVR so I make it within (all) manufacturer's towing specs, barely. But again that is fully loaded for full-timing, with a light motorcycle in back. And from what I read around here that might actually be considered light... :D

:)Sorry:), Your talking your truck and trailer weight at 19300lb.