Community Forums

tom chelbana · 07-24-2015, 09:25 AM

Would like to change on a Dutch Star 43 ft on Spartan chassis tires from 305- 70 to 295-80. Have different answers from sources.

GaryKD · 07-24-2015, 11:11 AM

Hi tom chelbana,
Why do you want to make this change?

tom chelbana · 07-24-2015, 12:15 PM

My buddy has a 2010 Dutch Star on a Spartan chassis and has had problems getting 305-70 and would like to switch to the 295-80. I know a couple months ago in southern California there was only one 305-70 available. If you have tire problems down the road it could be a long time getting the 305-70,

Mr_D · 07-24-2015, 12:18 PM

Big difference in diameter too. The 305/70 is about ½" larger than a 275/70 and some 2" SMALLER than the 295/80's as I remember. Yep, just checked the Michelin charts.
That difference will cause clearance problems in most rigs.

Algoma · 07-24-2015, 12:29 PM

I have the same 305's on my coach and have heard the same issue. Michelin make a batch once a year and when they're gone they are gone. I had 295/75 on my previous coach but the weights are different on this Newmar so you would have to carefully check rotations per mile and using the pressure tables make sure a particular tire can handle the axle weight and not exceed the 120 psi rating of the rim. Going slightly smaller means that the dual tire spacing will not be an issue.

Mr_D · 07-24-2015, 01:32 PM

On our '02 DSDP I went from 275/70's to the 305/70's on the front. I also got Alcoa wheels as the 305's needed wider wheels.
The tires are wider and slightly larger in diam and I did run into clearance issues but only if the tires were not straight ahead and I aired down.
I did the change in order to use the full capacity of the 14,600# axle.

Miramichi · 07-27-2015, 08:20 AM

I hear your pain on availability but I personally wouldn't venture into changing tire size. It may be best to just change tire manufacturer. Possibly Goodyear or Continental?

Algoma · 07-27-2015, 08:57 AM

Quote:

Originally Posted by Miramichi

I hear your pain on availability but I personally wouldn't venture into changing tire size. It may be best to just change tire manufacturer. Possibly Goodyear or Continental?

I think you will find the 305 70 is unique to Michelin.

Gaetan Lavoie · 07-27-2015, 09:10 AM

I have made the swich from the 305 to the 295 as I could not get the 305 from Michelin until the following year. One positive aspect of the 295 is that it is readily available just about anywhere as this size is widely used on 18 wheelers.
In so far as clearance is concerned: the jack pads are not interfering when the wheels are turned to the maximum positions left or right. There is very little clearance in the wheel wells when you bring down the suspension. YOU MUST HAVE THE WHEELS POINTING FORWARD OTHERWISE YOU WILL DAMAGE THE OUTSIDE WHEEL PANELS as mentioned by Mr. T
I have driven on these tires for some 10,000 miles without any problem. I feel that I am getting a smoother ride with the 295 than what I was getting with the 305. Based on my total weight, the tire pressure did not change: 90 PSI for the rear tires and 100 PSI for the front tires.

newmarpusher · 07-27-2015, 10:20 AM

If availability was your main concern, wouldn't buying an extra unmounted 305/70 and taking it with you be a better option?

Gaetan Lavoie · 07-27-2015, 11:26 AM

Quote:

Originally Posted by newmarpusher

If availability was your main concern, wouldn't buying an extra unmounted 305/70 and taking it with you be a better option?

In so far as I am concerned, there was no such option due to the unavailability of that tire size and secondly I am not willing to give up so much room to store the tire in my bins.
I am no longer worried about not finding a 305 in the event of a tire failure.
Have you ever tried to find a tire that mach the weight rating and diameter of a 305 tire? Good luck.

Algoma · 07-27-2015, 12:54 PM

No one carries a spare that size. It wouldn't even fit in any of my bays if I wanted to.

newmarpusher · 07-27-2015, 01:14 PM

Quote:

Originally Posted by Algoma

No one carries a spare that size. It wouldn't even fit in any of my bays if I wanted to.

I've been thinking of something like this for years.

http://www.motorhomeadvice.com/roadm...-tire-carrier/

There is another similar one on the market that can carry an unmounted tire in the same manner. That is the route I'd probably go.

Harm · 07-27-2015, 02:55 PM

Tom: I have a Spartan chassis on my 2006 Dutch Star and had the same concern as you in obtaining a tire on the road. I went to Spartan in Charlotte, MI and they changed out my tires to the 295/80's and checked out clearance aired up and aired down and declared it good to go. They even hooked up a laptop and changed my speedo to read correctly with the larger tires. It's been three years and I am very happy I changed over.
Your front tires should always be straight ahead when you air down with any tire.