Has anyone tried these tires as steer tires. I have been told they are comparable to the Michelin XZEi in the 275 size
If so what pressure would you run them?
I am running Bridgestone R283 295 R75 and I have been running them at 90 PSI.
That's the tires that came with the coach and I am happy with them. When I go to
the Island again I will weigh the coach and the go by the Bridgestone chart.
I just had the Bridgestone tires installed and the dealer even does not have the inflation charts! He has said that I should be running them at 110, but my thoughts are that is too high. My gvwr is 12350 and I suspect ,the way my wife packs, it will be close to that...lol
Thoughts on pressures anyone. Thanks for your pressures old guy,I do not know whether both our tires are the same "rated" and I wonder about the coach length and gvwr differences???
I have R283's and run my front at 95 and rear at 90.
https://commercial.bridgestone.com/content/dam/bcs-sites/bridgestone-ex/products/Databooks/TBR/Bridgestone-TBR-Load-And-Inflation-Tables-08-08-2018.pdf
Mark
My Bridgestone 295 call for 110 on the stamp, I run 100 all around. Heat is my greatest concern with the country I run but 100 works satisfactory in that regard.
The difference in load ratings between G and H is around 500 lbs for each tire at max stamped pressure with the G at a maximum of 110 psi and the H rated tire at 120 psi. The speed rating of L is 75 mph and M is 81 mph. But the speed rating is at the maximum rated pressure and maximum load. Lower pressures mean a reduction in the speed rating but less weight may counteract that. Simply put, you can only drive at 75 mph with L speed rated tires if you run the maximum placarded pressures and don't go over the weight maximum.
Here is a quote: Load Range G tires are rated to 6,175lbs (single) and that adds up to 12,350lbs. This seems to be just fine for those 12,500lb axles on most trucks.
Load Range H tires are rated to 6,610lbs (single) and adds up to 13,220lbs - and that matches the 13,200lb steer axle max
We have a maximum of 10,500 lbs on our front axle so the H rated (M speed) tires along with our approx weight of 25,000 lbs means we are safely under the maximum weight and can drive 81 mph at a lower pressure of 105 psi. Not that we want to but is a margin of safety.
Since the tandem tire load maximums are lower and many coaches are closer to the max weights, it does not make much sense to drive in hot weather with low pressures, especially if driving close to the tire speed limit.
Foretravel axle weights for all models: Foretravel Motorhome Vehicle Weights: Year, Model, Front Axle, Rear Axle... (http://www.allthingsforetravel.com/2020/02/19/foretravel-vehicle-weight/)
The difference between G and H tire ratings: https://az184419.vo.msecnd.net/schneider-trucks/PDF/maintenance/TireLoadRangeGvsH.pdf
Pierce
So just had the tire installed. Pic shows wheels turned moderately to the left. Any issues with this???
100 lbs in front. 90 lbs in rear
Looking at those pictures it would make me nervous we seen what happened to Elliott my vehicle plate calls for 275/80RX22.5 single 97 PSI. Dual 83 PSI I Believe in fallowing it I believe the Coach was tested for that size of tire why change it just to save money or look for a safety problem.I'm not looking for trouble or have this on my mind rather be safe than sorry !
OK, I just went out and looked at ours. Photos on a flat slab with the coach at operating pressure and level.
It's really close at the rear of the front tire on the curb side. More room the same place on the driver's side.
Lots of clearance at both sides of the front of the front tires.
The only place I have seen any polishing the the curb side front of the front tire.
It would appear that a 275/80 would also be just as close as the tire is the closest about a half inch in from the edge.
From what I can gather, your tire would really dig in (as would ours) if the body of the coach were lower (bag with less air). Now imagine the coach will less pressure in the bags dropping the body down a bit.
This would possibly be a clue to the off road mishap that Elliott had. Unusual attitude with the tire catching or even digging in on the air bag plate. A troubling thought.
Again, the 295/75 and the 275/80 are the same diameter and within one revolution per mile.
Pierce
The tires are the same diameter and would do the same thing in the situation that Elliott had happen and also in the photos I posted along with Peter.
I've never had any kind of issue in the past with two sets of 295/75 with 120,000 combined on them. It looks to me that all possible positions of the coach for air bag clearance were not tested. As I've said before, only a slight polishing of the front of the curb side bag plate.
Pierce
Pierce,
When you say that there's more room on one side than the other in the same place does that not raise some concern? Does that indicate a slight twist, the reason I ask is shouldn't the bag mounts be symmetrical mounted.
Yes, but in the photos, you can see one side misses by perhaps 1/16" while the other side has perhaps a 3/8" clearance. I know our slab is dead level but the coach could be a degree or two at an angle which could explain the difference. What is difficult to explain is Peter's new tire making contact with the bag mount. As the rear of the tire would be coming up with the coach going forward, any downward movement would result in the tire biting into the bag bottom plate. Now, go the Peter's photo and see how the tire is touching and then visualize what would happen with the steering and tire at the same angle but the body of the coach leaning over because of the uneven terrain. I think that may be the cause, especially with the shop unable to find anything wrong with the suspension.
As I have said, we are always off the pavement but for this to happen, our steering would have to be turned at just the right angle to allow contact. It's easy to drive like this a hundred times but it only takes one time with the wheel turned just at the right angle and the body leaning over.
And what happens when the HWH tries to level the coach and drops the side down on the tire when in that position?
Not going to pat myself on the back yet but today's photos combined with Elliott's mishap make that a very possible scenario.
Pierce
Next question is "how much play/wear is there in the bushings that locate the axle. Enough to allow for substantial movement???
If so, irrespective of tire choice, is it time to rebush the suspension links?
So a lot of valid comments. I should also add that I had an alignment done at the same time. Don't know whether that makes a difference.... but that being said, back to the reality question of whether the coach is safe to drive? The coach in those pics are a t ride height
(Approximate)
I can't imagine any amount of bushing wear resulting in enough movement to allow the tire to hit the bag plate. The bushing were checked in Elliotts' and found to be good for quite a while longer. I seen no evidence in any wear or movement in ours and the clearance is about the same on that very side. A very worn bushing would crate suspension noise. I will take a second look at ours to rule out that possibility. When a busing goes in a shock absorber, you can sure hear it.
Check Peter's tire where it's hitting the bag and imagine what would happen with the tire rotating upwards with the body of the coach including the air bag plate moving downward. There would be a number of degrees covering an area on the tire where the plate would dig in to the tire. And not just on the edge of the tire.
Pierce
Don't think alignment has much to do with the bag and tire conflict. While your coach is at ride height, the ground may not be level or the coach may be leaning a degree. Seeing that ours is in about the situation, we just went on about a 700 mile trip and have around 1000 miles on the new tires. No sign of touching anywhere. The same size Coopers only very occasionally touched and it was always the front plate on the curb side. Our coach goes straight down the road without any offset front to rear so the spacing of the air bag mounts may be just a tiny different after welding and assembling the front end.
I would drive it but keep checking for interference. A new tire is going to have a larger diameter compared to a used tire. Don't think you are going to have much of a choice since a new 275/80 and a 295/75 are going to have the same diameter. Only thing to do would be to cut the plate back 3/8" to give a little more clearance most of the time.
Pierce
And, while I'm thinking about it, the air bags could be taken off, the plate cut back a little and the mounting holes for the bags elongated so the bags could be spaced a small amount further away from each other but still leaving room to remove the nuts so it could be easily removed and replaced. When the air bags don't have any air in them, they would also come close to the tire if it is in that position. The photos show the air bag in the normal ride height position.
Oh, for just one more inch apart.
Pierce
What is the measurement from 75 to 80 what is the brake down of a tire size. 295? 75? 22.5?R is for radial tires what is X. 275/80RX22.5 my schooling got lost when everything changed over to metric.Every one is saying that the tires are the same diameter but are the tires The same width if they are wider when the tire is turning the tire May rub on the bottom plate if it's rubbing it doesn't fit
Apologies to all for going down a rabbit hole as the bottom plate should not move in relation to the tire. Scott has an excellent reply on the other off road post.
No bushing movement at all on our so still trying to figure it out how our front tire contacts the plate in certain conditions and if this could have been part of Elliott's off road event.
Pierce
So could I cut a chunk of the bottom hard plastic base off so the tire clears?? Is there ANY issue with doing that??
I think you could take a slice off the base without hurting the bag when it's in the deflated position. Looks as if you have a new bag in that position. So, not only the plastic if it's a Conti but a bit of steel too on the mount. A quarter inch in a small area would seem like enough. Probably good to radius the edges after cutting.
Pierce
The top seems to clear... just the bottom plastic piece so I will start with that
So attached are pics of my air bags after I shaved about 3/8 of an inch off each side. I now get total clearance with the wider tire with no effect on the air bags. Easy to do. Just turned the tire and reached in. Then put a bit of gloss black paint on them so they would not rust. Thanks to Pierce for the solid advice!
Just a clarification on the info on the data plate. It is specifically for OEM tires (likely Michelin XZA-somethings, LRH). The inflation is what matches the load/inflation table for
that specific tire to match the axle weight rating for the axle it's mounted on.
If you are running near 100% GAWR for that axle with that OEM tire, the plate shows the correct inflation.
If you are running a different tire and/or have lower actual loaded axle weight, your inflation requirement can be different.
(if you have higher actual loaded axle weight, your coach needs to go on a diet ;) )
And you have to look up your axle capacity as they are different, model to model to make sure you are not overloading the rated capacity of the tire at the maximum pressure indicated for the indicated load on the side of the tire that you have mounted. This is a COLD pressure. Never let air out of a tires as the temperature changes during the day. Tires only lose pressure in storage so check often, especially in hot weather when the tires are most susceptible to damage.
You cannot drive even close to the speed rating for your tires if the pressure is less than should be for the load. L rating is 75 mph, M is 81 mph.
Peter, Thanks!
The reason your dealer recommended 110 psi is that it has no down side other than a firmer ride. In hot weather like we have been having and bad roads, the maximum pressure is an insurance policy. With our 10K axle and not full timing with the big load, I feel OK with the H rated tires at 105 but if heading down I-5 with it's big potholes and concrete overpasses/bridges with a 3 or 4 inch lip at the start, I will bump them back up to 120. This was also the tire dealer recommendation. At about 25K lbs, we are lightweights compared to the later Foretravels.
Pierce
I just wanted to reply that I finally got an answer from Bridgestone on this and they included a chart(see attachment) that states air pressure. The Bridgestone rep says the pressure chart is the same as the R 284 tire so if that is the case with 12300 front axle which is what am close to, maybe under 300to 400 lbs, the pressure I should be running is 100 lbs in the steer tires. That MAY explain the slight wander I had when they warmed up when I had 105 lbs in them
Don't think 5 psi is going to make any difference. Note that the pressure listed is the minimum for the load so the word "should" is very subjective.
Pierce
Point taken. I will have to experiment around with the pressures