Why Do I Have Flat Spots on the Tires of My 26 Foot Coachman Travel Trailer

Question:

I Have a question on tire scuffing on my 26 foot coachman travel trailer. The tires are Duro brand on the unit since new and have about 7000 miles on them. They are 7 years old. I have always kept the pressure at 50 lbs. as per the decal on the trailer. The tires have severe flat spots on the outside of the tread. I am planning to replace them this year but am wondering about the problem with the uneven wear or scuffing which fellow RVers have said. The size is H78-15 ST ST 225/75 D 15 Any comments? Thanks

asked by: Bill B

Expert Reply:

The tire problem that you have described will cause you several issues. First of all, while traveling, you will notice a sort of wobbly ride and hear a distinctive WHOMP WHOMP WHOMP as you roll down the road. First it will only be noticeable at slower speeds, then all the time.

You will also experience a shaking or vibrating steering wheel. The wobbliness, the WHOMP WHOMP, and the vibrations are more or less just annoying. To me, that is reason enough to change the tires asap.

But there is another problem. With these flat spots (and they will only get worse) you have less tire gripping the road which makes for an unsafe ride. I recommend changing them as soon as you can.

There are several things that could cause this problem. To help reduce developing flat spots in the future there are some measures you can take. First, make sure that the trailer is level when it is fully loaded and ready to tow. Also, you will need to make sure that the tongue weight is within the limits of your hitch.

If you are using a weight distribution system, make sure the spring bars are not installed too tight. If it has built in sway control, make sure your spring bar tension is correct. If you have separate sway control, make sure it is not too tight.

Finally, if your suspension is worn out, this could lead to the tires developing flat spots as well.

The tire you referenced is a radial. Radial tires are constructed differently, the tire will have more flex allowing for better ground contact. This will improve traction and tread wear as well as provide more stability.It has a 2,540 pound maximum load at 65 psi. Consult your owners manual for tire recommendations. I have included a link to a Tire Measuring FAQ that explains what the various codes mean on a tire.

expert reply by: Michael H