Thoughts on Tires

[Steve N Sal]

Boy, you sure did your homework. Glad it all worked out for you and hope you get plenty of quality miles out of them. They sure can put a dent in the old checkbook. I found that out last Spring myself. That's OK though I now have piece of mind.

[Chuck 1935]

Originally Posted by mr300ce

Yep. But the tire store has been in business for 35yrs, and sold 100's to Motorhomes with no issues, so I'll runn with them.

What tire store do you use. It sounds like they have good deals.

[Midniteoyl]

Originally Posted by 336muffin

That is a trailer tire.

Not only..

Premium Low Profile All-Position Multi-Use tire

The Double Coin RT500 is a low profile all-position multi-use tire designed for a wide variety of applications. This 5-rib, tire provides superior handling and traction in steer drive and trailer positions.

[Midniteoyl]

Originally Posted by Gary RVRoamer

Just for the record, Double Coin is a Chinese brand, not Korean. And they don't make tires - they are just a private label for tires produced by the Chinese Manufacturers Alliance (CMA), a group of Chinese tire and rubber plants that have a cooperative marketing agreement.

China Manufacturers Alliance, LLC (CMA) is the North American sales and marketing arm of Double Coin Holdings, Ltd. Shanghai Tyre and Rubber Group Co. Changes Name to Double Coin Holdings, Ltd | Business Wire
And, Shanghai Tire & Rubber used to make Michelins as Shanghai Michelin Warrior Tire and still retained the tooling... They are now called 'Double Coin' and are ISO9002 certified: Finance News | Michelin Corporate

[Midniteoyl]

Also..

Michelin set up its first JV operation in Shenyang, Liaoning Province at the end of 1995. In April 2001, Michelin Group and Shanghai Tire and Rubber Co., Ltd. (STRC), formed a new joint stock company, Shanghai Michelin Warrior Tire Co., Ltd. (SMWT). In the same year, Michelin (China) Investment Co., Ltd. (MCIC) was founded in Shanghai. Up to date, Michelin has around 5,500 employees and four plants in China.
Double Coin Holdings, Ltd. (formerly called Shanghai Tire and Rubber Co., Ltd.) is China’s first State-owned tire company that floats both A-Shares and B-Shares at the Shanghai Stock Exchange. The company is also the first tire manufacturer headquartered in China to have a commercial truck tire added to the U.S. Environmental Protection Agency’s (EPA) SmartWay list of verified technologies, sources said.

http://www.chinaautoreview.com/pub/C...e.aspx?ID=5966

[Gthree]

This is an update on my purchase of DC RT500 tires back in January, for my class-A 27-footer (225/70R19.5). Well, I wish it was a simple story but it's not. But it does have a happy ending.

BASIC SUMMARY:
The DCs are a tough, heavy, long-life tire with absolutely superb customer support. However, they are not as supple or precise as high-end tires like Michelin or Goodyear, and need more care and attention when purchasing and mounting/balancing. I did have some issues, but I'm happy now. Do not even consider buying these tires from anywhere but an authorized warranty dealer who is equipped with Road Force Balancing equipment.

MORE DETAILS
From the start, I had an intermittent vibration problem, starting at about 55mph and getting worse at 60-65. Just like a wheel balance problem. I stopped along the road and had the front wheels checked and re-balanced. No help.

I started doing some research, and discovered the technology of Road Force Balancing. RoadForce checks not only the WEIGHT balance like all other systems, it also checks for out-of-round (tire, wheel, and overall), and net stiffness variation as the tire rolls through a full circle. RoadForce will discover a well-balanced tire that still vibrates, and why. If you want to find out more about this excellent technology, start at the Hunter website gsp9700.com to learn a whole bunch of interesting stuff about tires, wheels, and vibration. (Hey, I'm an engineer so this stuff fascinates me.)

So I searched and found a RoadForce place in New Mexico (Alamorosa Service, great shop and great guys). I had them run through the Hunter RoadForce equipment. WAY OUT, and not fixable. Alamorosa was not a DC warranty station, so they balanced them as well as possible and off I went. Only a slight improvement. We drove the rest of our trip at 55mph or less. Oh well, at least I was saving gas.

After we got home, I contacted DC customer support (a real human voice in less than 2 minutes!!!). They gave me the cell phone number of their western region support manager (a real human voice on the 3rd ring). He gave me the cell phone number of his regional technical support guy (3rd ring again!!). Within 10 minutes of making my first call, I was talking to the authority who would authorize any "adjustment" (replacement) of my tires.

I then found a RoadForce provider about 40 miles from home, and went over to have things checked out. Three out of seven tires (wow!) were out of limits and had to be replaced. They would weight-balance okay, but the roundness and stiffness were well above limits (and of course that's what I felt on the road). That's pretty horrible news, a huge percentage of bad tires. The lot number was 1111 -- the eleventh week of 2011. Further bad news was that one of the 4 tires pulled from stock at the dealer (5011) was also out of limits. The 5211 and both 2012 tires did seem to be of better quality. The message here is that you have to "cherry pick" these tires, and only the RoadForce equipment allows you to do this.

Because I did not buy from a warranty dealer, I had to pay for balancing ($150), but the 3 new tires cost nothing, fully warranted.

The coach now drives likes it's on glass, smooth as the proverbial baby's bottom at all speeds.

What are the pluses of the DC's? Well, they're almost half the price of the high-priced jobs, that's obvious. Less obvious is how heavy they're built. Twice the rubber (they are re-grooveable, not that an RVer would do so), they are about 25% heavier than a Michelin, and they seem impervious to rocks and ruts and potholes and such attacks. A very tough tire, and that is good news for my sometimes-incautious boondocking driving habits. The tread sipes are wider and deeper, providing slightly better traction in loose dirt, and (I believe) a bit of an edge in sloppy wet conditions.

So yeah, I'm happy but I went through a dramatic learning curve, and had some troubled times before all was said and done. In the end, I've saved about $1400 over a set of Michelins or Goodyears, and I think I may have a tougher set of tires in the bargain. Would I do it again? Absolutely -- but only because I've learned the "formula" to get it right the first time.

[cannon man]

biggest michelin dealer in tucson told me "if your not going to wear them [michelins] out, your wasting your money."

[Midniteoyl]

Originally Posted by Gthree

This is an update on my purchase of DC RT500 tires back in January, for my class-A 27-footer (225/70R19.5). Well, I wish it was a simple story but it's not. But it does have a happy ending.

BASIC SUMMARY:
The DCs are a tough, heavy, long-life tire with absolutely superb customer support. However, they are not as supple or precise as high-end tires like Michelin or Goodyear, and need more care and attention when purchasing and mounting/balancing. I did have some issues, but I'm happy now. Do not even consider buying these tires from anywhere but an authorized warranty dealer who is equipped with Road Force Balancing equipment.

MORE DETAILS
From the start, I had an intermittent vibration problem, starting at about 55mph and getting worse at 60-65. Just like a wheel balance problem. I stopped along the road and had the front wheels checked and re-balanced. No help.

I started doing some research, and discovered the technology of Road Force Balancing. RoadForce checks not only the WEIGHT balance like all other systems, it also checks for out-of-round (tire, wheel, and overall), and net stiffness variation as the tire rolls through a full circle. RoadForce will discover a well-balanced tire that still vibrates, and why. If you want to find out more about this excellent technology, start at the Hunter website gsp9700.com to learn a whole bunch of interesting stuff about tires, wheels, and vibration. (Hey, I'm an engineer so this stuff fascinates me.)

So I searched and found a RoadForce place in New Mexico (Alamorosa Service, great shop and great guys). I had them run through the Hunter RoadForce equipment. WAY OUT, and not fixable. Alamorosa was not a DC warranty station, so they balanced them as well as possible and off I went. Only a slight improvement. We drove the rest of our trip at 55mph or less. Oh well, at least I was saving gas.

After we got home, I contacted DC customer support (a real human voice in less than 2 minutes!!!). They gave me the cell phone number of their western region support manager (a real human voice on the 3rd ring). He gave me the cell phone number of his regional technical support guy (3rd ring again!!). Within 10 minutes of making my first call, I was talking to the authority who would authorize any "adjustment" (replacement) of my tires.

I then found a RoadForce provider about 40 miles from home, and went over to have things checked out. Three out of seven tires (wow!) were out of limits and had to be replaced. They would weight-balance okay, but the roundness and stiffness were well above limits (and of course that's what I felt on the road). That's pretty horrible news, a huge percentage of bad tires. The lot number was 1111 -- the eleventh week of 2011. Further bad news was that one of the 4 tires pulled from stock at the dealer (5011) was also out of limits. The 5211 and both 2012 tires did seem to be of better quality. The message here is that you have to "cherry pick" these tires, and only the RoadForce equipment allows you to do this.

Because I did not buy from a warranty dealer, I had to pay for balancing ($150), but the 3 new tires cost nothing, fully warranted.

The coach now drives likes it's on glass, smooth as the proverbial baby's bottom at all speeds.

What are the pluses of the DC's? Well, they're almost half the price of the high-priced jobs, that's obvious. Less obvious is how heavy they're built. Twice the rubber (they are re-grooveable, not that an RVer would do so), they are about 25% heavier than a Michelin, and they seem impervious to rocks and ruts and potholes and such attacks. A very tough tire, and that is good news for my sometimes-incautious boondocking driving habits. The tread sipes are wider and deeper, providing slightly better traction in loose dirt, and (I believe) a bit of an edge in sloppy wet conditions.

So yeah, I'm happy but I went through a dramatic learning curve, and had some troubled times before all was said and done. In the end, I've saved about $1400 over a set of Michelins or Goodyears, and I think I may have a tougher set of tires in the bargain. Would I do it again? Absolutely -- but only because I've learned the "formula" to get it right the first time.

danke schön!!

[slickest1]

Not trying to be smart about it but the difference could come out in a panic stop. Believe me I have had it happen when a previous employer put a set of cheaper tires on my truck to see how they would do and on wet roads they had no stopping traction at all. With an empty trailer behind I could spin the drive tires on barely wet pavement. I always ran Michelin, Bridgestone or Toyo. I have also had Yokohamas and Hankooks and felt safe with them. I hope you have good luck with your choice they may well be just fine.

[Steve Ownby]

I hope you get good service from your new tires. Make sure you are inflating to the correct PSI for your corner weights. The 14 ply rated Michelin tires were load range G. If your new tires are 12 ply rating that is load range F. The load range F tires will have to be inflated to a higher pressure than the load range G tires. The ply rating is a throw back to the 1950's and 60's. The actual plies present in both tires is 1 sidewall ply and 4 or 5 tread plies.

[Midniteoyl]

Originally Posted by Steve Ownby

I hope you get good service from your new tires. Make sure you are inflating to the correct PSI for your corner weights. The 14 ply rated Michelin tires were load range G. If your new tires are 12 ply rating that is load range F. The load range F tires will have to be inflated to a higher pressure than the load range G tires. The ply rating is a throw back to the 1950's and 60's. The actual plies present in both tires is 1 sidewall ply and 4 or 5 tread plies.

Not correct. The higher G rating means it can be aired to a higher PSI and thus hold more weight. If your weights are low enough to enable you to use a F tire, it will be filled to the same PSI as a G.

[Steve Ownby]

I stand by my statement. I went to the Michelin load tables and picked a tire which was made in two load ranges.

Michelin 275/80R22.5 in G and H LR

The H tire was rated 540 lbs higher at 90 psi. The H tire was rated higher all through the psi range. At max inflation the H tire was rated at 1000 pounds higher than the G at 10 lbs greater psi.

If he inflated the F rated tire to the same psi as the G tire, he could be under inflated for the weight he is carrying.

[Steve Ownby]

Originally Posted by Steve Ownby

I stand by my statement. I went to the Michelin load tables and picked a tire which was made in two load ranges.

Michelin 275/80R22.5 in G and H LR

The H tire was rated 540 lbs higher at 90 psi. The H tire was rated higher all through the psi range. At max inflation the H tire was rated at 1000 pounds higher than the G at 10 lbs greater psi.

If he inflated the F rated tire to the same psi as the G tire, he could be under inflated for the weight he is carrying.

I may stand by my statement but I also stand corrected! I went back to look at the OP's tire size. At his size there is no difference in weight carrying at a given psi and the higher rating occurs at max psi. Turns out that the difference in weight carrying at a psi does not occur in smaller tire sizes. In the OP's wheel size of 19.5 you have to get up to 255/70 before you start to get a difference in weight at a given psi.

Very long story short; the OP is fine at a psi his G tire was inflated to, just be careful as yours could be different.

[Gthree]

Per the previous postings about load ratings and tire pressures:

My corner weights range from 2500-2700 pounds. In Michelin's excellent data table, the XRV in my size is recommended to run at 65psi. My coach data plate says to run tires at 75psi. A silly number of tire shops I've been to say to run tires at the sidewall max (95psi), which is just word-of-mouth superstitious nonsense.

I've run the Michelins briefly at 65psi and it was a poor, squirrely ride. 75 worked much better. The 65psi sidewall bulge on the Ms was so pronounced that running even my light-weight tire chains (on the rears) would have been problematic.

One my my (small) grievances against Double Coin is that they offer NO pressure/load table that I could find. The customer support guy suggested 95psi as did so many others. (NOTE: I think this blind adherence to the max-pressure number is because it allows a greater margin for leakage before the tire is running under-inflated.)

The DCs are now running at 75, per Winnebago's data plate, and per my personal experience with sidewall bulge, handling, and temperature (I run a pressure/temperature TPMS system).

Interesting side note: although the tires are rated up to 3640 (range F), my steel coach wheels are stamped at a maximum load rating of 3000.