Yet another tire question, 315's on steer?

[smlranger]

Sorry folks but I am still pondering the possibilities. I am at max weight on my front axle (14,200 and maybe a tad more) and I am wondering if I could upgrade from 295/80's to the 315's. Specs for the Continental tires I am considering say acceptable wheel widths are 9.00 and 8.25". So my 8.25" Accurides should do.

However, I do wonder about clearance especially when making tight turns.

Has anyone with an Allure of my vintage upgraded the steer tires to 315's? Other than a bit of added weight capacity, is there any other advantage?

[1doodadd]

https://tiresize.com/comparison/ Check for yourself, does not seam that much difference.

[Smitty77]

On 8.25 rims, this could be one of those dang if you do, or dang if you don't situations!

As you know, many tire manufactures do not authorize their 315's on 8.25. Some that due, then derate the load capacity, which is the 'dang if you do'.

I don't recall Continentals policy on 315's on 8.25.

I talked this over with the TCI Tire Manager outside of San Diego, at the Lakeside location. He's a season tire vet, and has a great reputation in the region. He convinced me to go from 12R's to 295/80's - as it brought several other tire choices that were not available in the 12R size. I talked with him about 315's on my 8.25 rims. He said he personally did not recommend it, but went out and looked over my 04 Allure and said he thought it would be real close as far as possible contact. Said he'd be willing to mount two so we could check for actual clearance.

One thing that stood out, was he said those with 8.25" rims that were looking for more carrying capacity, would usually be better served by going up a load rating, vs going with the 315. He said even those tire manufactures that authorized the 315 usage on the 8.25 rims, confused him. He felt their was no way that two identical tires on 8.25 and 9 inch rims - would carry the same weight... The tire on the 8.25 rim would have, in his opinion, less weight carrying capability.

Our 40' front axle actual weight (heavy with fuel and water and loaded for travel) is 11.9K pounds. So I had no need for the 315's, or a higher Load Rated tire.

You might check on the higher Load Rated tires available for your front... And of course, if you have the clearance, you could always shell out for 9" rims to handle the 315's... (Easy to spend other people's funds@@@!!!).

Best to you,
Smitty
(And from the other thread on tires. Bummer that TCI would not want to work with you on the AH12's. The Denver region TCI Manager I worked with, really liked them. Felt they were a very good bang for the buck, and he personally had them on his Class A and felt they were a good performing tire... The Lakeside store did not have them, but said they would get them for me if I wanted them. And, that Manager that I mentioned above, understood the 6 months or younger tires quest of RV owner's - as he too was one... He said he'd had a rather heated conversation at a conference, when other TCI Managers and Tire Specialists, were complaining about the 'Whining RV Owners!'. He said he was not too popular with some of his fellow TCI mates, as he spoke out and explained that RV owners don't wear out tires like Over The Road truckers do. They replace tires by age, not wear. Said he felt it should be a TCI policy to try and work hard to provide the younger Born On Dates for RV owners. Including having an inventory policy that included the DOT's as part of the tires serial number, so that online inventory could be readily searched, with a newest to oldest date search by tire and size added to their software. Took some heat on that one, but a Regional Director talked with him offline about this a bit more. And when he pointed out how they had started to bar code the control of tires for inventory management, it would be easy to add the tires SN and Born on Date as part of the control. He said he felt it would TCI manage their shelf life on tires. Which as I understand it, was once a tire in their inventory reached 2 years of age, they started purging them out to secondary sales sources... I felt it was good that we had some RV owners with TCI - so they could try to see it from our angle. A totally different experience then I had with the Manager of Bob Dickman's in Junction City - who tried to 'educate me' about how little RV owners knew about tires... Not a great 'customer' experience from my perspective!)

Sorry I went on so much on this one... But it is one of those things that bug me about how RV'er's are sometimes perceived as more of a nuisance, then a customer, at some of the larger trucking tire centers! Rant off..

[TurtleKent]

I have considered the same upgrade to my Allegro Bus.

Yes, clearance is an issue, both diameter and sideways when turning(check with coach both raised and lowered).

Using my coach/wheels as an example, the limiting factor with the 8.25" rims is their 8100# capacity. My Michelin 295 tires capacity is 7830#, the 315s tire capacity is 9090#, so to keep the 8.25" rims you only increase capacity by 230#. By upgrading to 9.0" rims you have a 9000(or greater)# capacity. However, my ZF steer axle 'cradle' has a 16,000# capacity, so 9.0" rims don't result in much overall improvement in capacity.

That said, the 315s have 2plies additional, a stronger sidewall, and can operate at 5psi lower for same weight, so probably resulting in a smoother ride than on the 295s.

Safety is my overriding concern. A steer tire blowout can easily result in loss of control, rollover, serious injury or death. A rear tire blowout is a nuisance and perhaps $$ for body/undercarriage repairs, but unlikely to result in loss of control. I will be upgrading my steers to 315s this year before I travel again, still undecided on upgrading to 9.0" rims.

Good luck with your decision, keep us posted.

[CarlAda]

For what it's worth, my 07 Intrigue has 315s on the steer (stock) and according to Damon's website, the 08 Allure went to 315s as stock.

[smlranger]

Thanks guys for the helpful info. At this point I don't want to change out the rims so will stay with the 290's. Also, looking closely at my existing tires and space, I believe tire rubbing could be possible.

The TCi thing is a mystery. I even tried calling their corporate in SC but could never get to a real person.

[Steve Ownby]

Originally Posted by TurtleKent

I have considered the same upgrade to my Allegro Bus.

Yes, clearance is an issue, both diameter and sideways when turning(check with coach both raised and lowered).

Using my coach/wheels as an example, the limiting factor with the 8.25" rims is their 8100# capacity. My Michelin 295 tires capacity is 7830#, the 315s tire capacity is 9090#, so to keep the 8.25" rims you only increase capacity by 230#. By upgrading to 9.0" rims you have a 9000(or greater)# capacity. However, my ZF steer axle 'cradle' has a 16,000# capacity, so 9.0" rims don't result in much overall improvement in capacity.

That said, the 315s have 2plies additional, a stronger sidewall, and can operate at 5psi lower for same weight, so probably resulting in a smoother ride than on the 295s.

Safety is my overriding concern. A steer tire blowout can easily result in loss of control, rollover, serious injury or death. A rear tire blowout is a nuisance and perhaps $$ for body/undercarriage repairs, but unlikely to result in loss of control. I will be upgrading my steers to 315s this year before I travel again, still undecided on upgrading to 9.0" rims.

Good luck with your decision, keep us posted.

A minor point, but the tires don't actually have more plys. These all steel tires typically have 1 sidewall ply and 4 or 5 tread plies. The ply rating is derived from the load rating and is a throwback to the 50s.

[RVNewbie55]

Just my .02 but went with the 315's as they are more readily available due to the fact that 295's are only used on RV's where as the 315's are used on many HD trucks as well as larger RV's . The 315's were also less expensive by around $50.ea. through the Michelin Program on FMCA

[Smitty77]

Originally Posted by RVNewbie55

Just my .02 but went with the 315's as they are more readily available due to the fact that 295's are only used on RV's where as the 315's are used on many HD trucks as well as larger RV's . The 315's were also less expensive by around $50.ea. through the Michelin Program on FMCA

Was this on 8.25 or 9" rims? If you had 9" rims, and 315's had no clearance problems - for sure a good move for the steers. If 8.25" not quite an easy a change on some coaches...

Curious if your era Navigator had 9" rims?

TIA, and best,
Smitty

[RVNewbie55]

Originally Posted by Smitty77

Was this on 8.25 or 9" rims? If you had 9" rims, and 315's had no clearance problems - for sure a good move for the steers. If 8.25" not quite an easy a change on some coaches...

Curious if your era Navigator had 9" rims?

TIA, and best,
Smitty

I would assume they are 8.25". Did not think to measure when they were apart. I was told there could be some rubbing in tight turns but have watched and listened very carefully and have not had any. When I level I do make sure the wheels are pointed straight ahead though.

[Smitty77]

Originally Posted by RVNewbie55

I would assume they are 8.25". Did not think to measure when they were apart. I was told there could be some rubbing in tight turns but have watched and listened very carefully and have not had any. When I level I do make sure the wheels are pointed straight ahead though.

From a memory that will occasionally fade, and or fail, I believe the Navigator is on the Roadmaster S chassis. I'm pretty sure that was with 295/80 22.5 tires as OEM, which would then match your assumption of 8.25" rims...

I only ask, as many chassis with 8.25" rims would not have the space for the 315's... Glad they're working well for you!

Best,
Smitty