Tire Issue...

[Elain Moria]

I seem to have 2 different tire types/sizes on my new to me RV. They are as follows:

Steering: 245/70R 19.5 (LR G)
Drivers/Trailing tires: 8R-19.5/12 (LR F)

RV: 1988 Holiday Rambler Imperial 34'

I am unable to find any solid information on which tire size this RV is supposed to be using. I can get 8 245's or 8 8R's and change the tires all the way around (they need it) but I don't want to put incorrect tires on this thing as I intend to drive the heck out of it.

Does anybody know the appropriate size for this RV?

~Elain

[gemert]

Excuse me if you know this but I noticed you just joined the Forum. There should be a plate behind or around the driver's seat somewhere with the tire info on it. Good luck

[John USA]

Also, if you have the books and manuals for your motorhome, see if you have one for the chassis. The info should be in there, too.

[Elain Moria]

Originally Posted by John USA

Also, if you have the books and manuals for your motorhome, see if you have one for the chassis. The info should be in there, too.

Nothing like that sadly. Most of the manuals I have are useless as they are stuck together. I have to order new ones. However I did find the plate that gemert mentioned and it calls for 8x 19.5 tires with what looks to be a load range in the F category all the way around (maxim GAWR on this thing is as follows.

front: 5000 gawr
drivers: 9840 gawr (dual)
tagalong/trailing: 5560 gawr


IF I understand GAWR and Load Range then I should be able to use 245/70R 19.5 LRF tires all the way around or if I want to match the current rears 265/70R 19.5 LRF+. Would someone with better knowledge check me on that?

~E

[ga traveler]

The 8R19.5 tire is a truck tire. It is made for delivery trucks that go many miles and wear out fast. The tire design people came up with the 225 and 245 tires for motorhomes. They were designed to resist ozone and sun damage and to ride better. Check with a tire EXPERT before replacing your rear tires with the 245. There may not be a wide enough space on the rear for the 245 to clear each other. You can NOT let them rub together.

[CaptainGeezer]

Originally Posted by Elain Moria

I seem to have 2 different tire types/sizes on my new to me RV. They are as follows:

Steering: 245/70R 19.5 (LR G)
Drivers/Trailing tires: 8R-19.5/12 (LR F)

RV: 1988 Holiday Rambler Imperial 34'

I am unable to find any solid information on which tire size this RV is supposed to be using. I can get 8 245's or 8 8R's and change the tires all the way around (they need it) but I don't want to put incorrect tires on this thing as I intend to drive the heck out of it.

Your coach is a 1988. If it is a chevy chassis, it probably came with 8R19.5 tires as standard equipment. They are a narrower tread tire, but do an adequate job of hauling the weight that your coach carries

The reason for your mismatch tires is that someone put "oversize" tires on the steer axel. That size would have sidewall rub if applied to your dual tire rear axel, therefore, they were kept at the original size.

I would go 8R19.5, but if want, you SHOULD be able to substitute 225/75R19.5 (the metric substitute) and be just fine. Also, I would look at Cooper Road Masters. This is all just my opinion based on SOME knowledge and is not intended as EXPERT information.

[Elain Moria]

Originally Posted by CaptainGeezer

Your coach is a 1988. If it is a chevy chassis, it probably came with 8R19.5 tires as standard equipment. They are a narrower tread tire, but do an adequate job of hauling the weight that your coach carries

The reason for your mismatch tires is that someone put "oversize" tires on the steer axel. That size would have sidewall rub if applied to your dual tire rear axel, therefore, they were kept at the original size.

I would go 8R19.5, but if want, you SHOULD be able to substitute 225/75R19.5 (the metric substitute) and be just fine. Also, I would look at Cooper Road Masters. This is all just my opinion based on SOME knowledge and is not intended as EXPERT information.

Yeah it's a Chevy chassis. I'll do some checking around. I found the 8R's for $268 ea and i'd really like to try and find something not quite as expensive if I can. While I can afford to replace all 8 at that price.... i'd still like to see if I can find something that isn't going to make my bank question my sanity.

Thank you all for the information and help you have given this novice. I jumped in the deep end head first on this one but I am seriously loving driving and living in Endora (My RV's name).

~Elain

[jcgribks]

Go with the 225's as they have a wider tread than the 8R's do and will ride better. On my 96 I couldn't go with the 245's as they would touch on the rear duals. I went 4 yrs ago with the Bridgestone tires and have been happy.

Even though you can find the 8R's where you're at the 225's are more ready available if you have a problem out on the road.

[Hooligan]

Welcome to IRV2-

Your chassis probably came with the 8R19.5 tires.. There are several factors to consider when changing tires. (dual spacing, wheel well clearance, rim width, tire pressures, etc)Your previous owner did not change to the newer 'low profile' 245's because they probably would not provide sufficient spacing between the tires. (Minimum dual spacing).

I had a 1990 MH with the 8R19.5 Bridgestone tires and had no problems at all. UPS used that tire also. Rather than getting into a lot of "what if's" you should be just fine with the 8R tires. A quick check on prices, I think the 8R19.5 cost less then a 245--. You do want a steel radial.... A good tire dealer would be a big help.

Different size tires on the front & rear axle is not a big deal because most RV tires are not rotated..

Article here may help: The Effects of Changing From 8R19.5 to 225/70 19.5 Tires | eHow

[Steady_Rest]

The linked article states that an 8R-19.5 is 33.1 in dia.
The tire specs for my Double Coins state 34.1, which is what they measure. The DC 225/70 is 32.3 in diamter. The mounted width of the tread of the 8R-19.5 is 8.2" and 8.8" for the 225/70. So less than 5/8" difference in tread width. There is a 1lb difference in weight of the two tires.
The previous set of my 8R-19.5 tires which were a different brand, were also a 34" dia. tire. Plus the taller tire looks cooler, the guys that are changing from 19.5 to 22.5 wheels for the look of the taller tire will agree.
All tires have anti-aging compounds, but these compounds do not work well unless the tire is regularly exercised. That is one reason mh tires crack prematurely.

[Elain Moria]

I'll need to swing by my local Les Schwab and see what they can do. I'd prefer to go with a more readily available tire if possible so IF my rims will seat the 225's and the duals don't rub then I think I will switch out to them.. which means buying 9 tires as the spare is also an 8R-19.5.... but I'd rather have a tire that can be found in most places than one that will be a pain in the hind side to find if things go bad.

After that.. I will need to take Endora into a transmission shop and have them work on the Gear Vendor OD because I don't think it is working properly (3200 RPM at 55 mph). One step at a time though. First new tires.... the ones on her are... not safe to drive. At all.

Thank you again for all your help and advice. This RVing is an interesting learning curve for me. o/

~Elain

[CaptainGeezer]

Originally Posted by Elain Moria

I'll need to swing by my local Les Schwab and see what they can do. I'd prefer to go with a more readily available tire if possible so IF my rims will seat the 225's and the duals don't rub then I think I will switch out to them.. which means buying 9 tires as the spare is also an 8R-19.5.... but I'd rather have a tire that can be found in most places than one that will be a pain in the hind side to find if things go bad.

I whole heartedly agree with this decision.