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Old 09-25-2019, 10:01 AM   #1
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Changing 8R19.5 Tires To 225/70R/19.5

Thought I would post this article here also. I had two 225/70/19.5 tires mounted on one of my Alcoa aluminum rims and one of the steel to see how they fit due to the different post made on this site about will fit and won't fit. I have 1 1/2" gap between the tires that currently have 80psi in them as seen in pic with the 3/4 plywood between them. The wheels studs stick out just a little after tightening the lugs.
Speaking on buying tires I did notice on the tires the outside tire is a Goodyear 647 load range F which is squatting a little and the inside is a General and has no squatting. The General tires would give a tad more spacing due to no squatting. Hope this helps others on considering going to the 225/70/19.5.
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Old 09-25-2019, 07:50 PM   #2
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Hey,
I got 245x70x19.5 on our coach. They don t kiss. We run 74 pounds on all tires. I like wider tires, and definitely, on the fronts. And we re running a highway tread as opposed to the deeper lugged tread. One, all 9 tires are interchangeable, two, they re quieter, and I believe a highway tread runs cooler. The only disadvantage to street treads is snowy roads or a muddy camp sight. DJ
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Old 09-25-2019, 09:42 PM   #3
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Quote:
Originally Posted by davejay View Post
Hey,
I got 245x70x19.5 on our coach. They don t kiss. We run 74 pounds on all tires. I like wider tires, and definitely, on the fronts. And we re running a highway tread as opposed to the deeper lugged tread. One, all 9 tires are interchangeable, two, they re quieter, and I believe a highway tread runs cooler. The only disadvantage to street treads is snowy roads or a muddy camp sight. DJ

What brand/model tire are you running?
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Old 09-26-2019, 06:05 AM   #4
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davejay,
Those tires were trial run for testing on the 310. I am trying to decide on what brand and style to purchase. Can't see purchasing Michelins due to cost and living on a firefighters pension and the Goodyear squatted a little. What chassis do you have.
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Old 09-27-2019, 06:03 AM   #5
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OK, I'm going to do this again, but this time I'm going to save a copy in my files:

If you start with 8R19.5's, they are supposed to be 8.0" wide on a 6.00 rim, with an overall diameter of 33.8", a minimum dual spacing of 9.1", and a load carrying capacity of 3525# at 110 psi for a Load Range F.

A 225/70R19.5 is supposed to be 8.9" wide on a 6.75" rim, with an overall diameter of 31.9", a minimum dual spacing of 10.0", and a load carrying capacity of 3640# at 95 psi for a Load Range F.

Assuming for the moment that you have 6.00 wide rims to start with, the 225/70R19.5 will be about 8.5" wide on that 6.00" rim. Since it is common for chassis manufacturers to specify minimum dual spacing rims, the net effect is that there will be a loss of about 1/2" space between the duals. I urge caution in this area.

Also, the diameter change results in 6% change - which means the speedometer will read 60 mph when it is going 57 mph.

And lastly the load. In order to carry the same load the 8R19.5 does at 110 psi, the 225/70R19.5 only needs 92 psi.

So the real danger areas are the rim width (minimum 6.00" for a 225/70R19.5) and the dual spacing (9.6" for the 225/70R19.5 on a 6.00" rim)
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Old 10-02-2019, 04:42 PM   #6
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Trying to get a price on 225/70R/19.5 tires. Found one place Tire Discounters that can mount 19.5 tires. They have the Michelin XZE 225/70R/19.5 six mounted and balanced for $3,000.00. Will give me a little break since my rims have no tires. The other tire shops around me that can mount 19.5 tires only carry Chinese and Japanese brands. Checked on Goodyear, Bridgestone etc. run around $2,600.00 to $2,800.00 if their distributor has them DOT dates iffy. Online stores have some but DOT dates are as far out as seven years on their warehouse tires. Anybody got any better places, looks like a road trip if I can find some reasonable and not been in a warehouse forever.
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Old 10-02-2019, 05:36 PM   #7
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Cole, I've got about 30,000 miles on my Hankook (Korean I believe) 8r19.5 without any issues so far. They are right at 5yrs old. I bought them at a shop called Tire Barn, which is a national chain but goes under a couple different names depending on where you are. I believe I paid in the neighborhood of $1800 for six, mounted and balanced. I've since bought Centramics for the front. FYI

The DOT dates were less than a year old.
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Old 10-02-2019, 06:56 PM   #8
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Mayco,
Thanks for the info. I had been looking at Hankooks and found the 225/70R/19.5 tires on Amazon for around 1,900.00 shipped free, DOT unknown. I had a shop price me the 8R19.5 tires then he said he could no longer get them a month later. I will check out Tire Barn for sure.
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Old 10-03-2019, 10:48 AM   #9
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Hey Cole, we are on the road in Colorado right now and my files are at home.....gave you bad info yesterday on where I bought my tires. The place is called Tires Plus not Tire Barn.
I got to thinking about it last night and looked it up on google maps to be sure. So.....
TIRES PLUS is where I bought them.

Looks like they have a store fairly near you in Chattanooga
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Old 10-03-2019, 05:52 PM   #10
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Thanks mayco I will call them tomorrow. I did find six Hankook Smart Flex 225/70R/19.5 tires mounted and balanced at a Tire Barn commercial store in Knoxville Tn. which is about hour and forty five minutes from me. The others in Knoxville did not have the machine to mount 19.5 tires and one recommended this store. Sales guy also said they can align my 310 once I get the wheels put on and bring back to them. The first place that said they could align the 310. Beats $3,000.00 for Michelins especially on a retired firefighters pension now days. May have my mechanic see about installing longer lug studs to give a little extra thread for the aluminum wheels if they are available. He said DOT dates are within a year also. He said they sell a lot of Hankooks.
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Old 10-06-2019, 04:01 PM   #11
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Hey,
Hancocks are a good tire. We got mastermile tires on our 325. 245x75x19.5 we got an inch of air between the duals I looked at the sidewall, and these are G rated tires. At 110 pounds of air they can take 3600 pounds per tire. Plenty of tire for the weight . I boasted the air up to 90 pounds per tire. I believe I payed 1700.00 for all 9 mounted. I highly recommend you get a set of centermatics balances. They are constantly balancing the whole rolling mass of the wheel,hub assembly. Cuts down on that annoying little vibration you get from just balancing the wheel. The aluminum wheels are about a 1/2 thick. So unless your running both inside and outside aluminum wheels, I think your studs should be good. All you need is a full nut when they re all torqued down. Also, you may consider running a highway tread, as opposed to a lug tread. They are quieter, and don t sing so much interchangeable between front and rears too. Just a thought. Michlens are pricey, great tires, thought. If I was full timing, I may go that way, but for running 5-10 thousand a year? They lol rot out before you wear them out. DJ
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Old 10-06-2019, 04:53 PM   #12
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davejay,

Thanks for the info. I will definitely call them Monday morning and price the 225/70R/19.5 tires. They are 16 miles from me, beats a two hour drive for the Hankooks. Probably still have to drive two hours to get my front end aligned since nobody in my area will touch my 310 chassis. I spoke to Centermatic Friday and the guy told me they still have the front and rear centermatics and he verified that they have the holes for 5/8" studs. He said don't take to long due to not having a lot of them. It's coming together finally.
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Old 10-06-2019, 08:15 PM   #13
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Hey,
I wish I was closer to you, I'd bring my alignment machine, and do it for you.. How far off of i65 are you, can you wait till thanksgiving? We may be going to Alabama . I could bring it down. Just. A thought. DJ
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Old 10-07-2019, 06:58 AM   #14
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davejay,
I-65 goes thru Nashville Tn. so you would be about 2 hours away. I live just north of Chattanooga Tn. Depends on how you would come to Soddy-Daisy Tn Interstate 24 or thru Murfreesboro to Hwy 8 then Hwy 111 which has some nice views. Check out Google for routes and see what you think.
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Old 10-07-2019, 08:14 PM   #15
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Hey,
I l check with my wife, plans aren t solidified yet. That may be a little to far away, given our time frame. It ll only take an hour or two to do it, but, that ll be a 6 hour delay. Doesn't t the shop putting the tires on, do alignments? Does your coach need an alignment. How did the old tires look. How does it handle. You may be fine, I lol let you know if we lol be going at thanksgiving . DJ I hate this spell check thing. I lol is I ll.
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Old 10-08-2019, 06:32 AM   #16
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No problem. I have the old 8R19.5 tires that are about 12 years old. The tire store that sells Hankook does alignment they are a big truck shop. Only place I have found that will align my 310. Have a fellow checking on the Mile Star tires today, when I called yesterday at Tire Discounters the fellow said he could not get them but this fellow works there and said he could, Happy tire people.
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Old 10-09-2019, 09:36 AM   #17
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davejay,
Well after numerous phone calls it's a no go on MileStar tires in my area. Hercules and Ironman and a few other foreign made tires available. Looks like a road trip and some cash. Thanks for the offer on alignment and I understand on the extra hours travelling.
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Old 10-12-2019, 07:59 PM   #18
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Quote:
Originally Posted by cole3444 View Post
Thanks mayco I will call them tomorrow. I did find six Hankook Smart Flex 225/70R/19.5 tires mounted and balanced at a Tire Barn commercial store in Knoxville Tn. which is about hour and forty five minutes from me. The others in Knoxville did not have the machine to mount 19.5 tires and one recommended this store. Sales guy also said they can align my 310 once I get the wheels put on and bring back to them. The first place that said they could align the 310. Beats $3,000.00 for Michelins especially on a retired firefighters pension now days. May have my mechanic see about installing longer lug studs to give a little extra thread for the aluminum wheels if they are available. He said DOT dates are within a year also. He said they sell a lot of Hankooks.
Cole: need you to call me.
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423-503-8003
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