Community Forums

rtr · 11-12-2013, 10:47 AM

I have a 2007 Sightseer with 19.5 tires are there advantage to going to 22.5 tires? my thought was taller tires slower rpms om the freeway . I would have to have my Speedo recalibrated. I have a 6 speed allison transmission. also, how much taller are the tires does anyone know?

Chiefbvfd · 11-12-2013, 11:17 AM

There are a number advantages to the 22.5" tire and wheel, ride and load carrying capacity at the top of the list. But I am not sure you can just change over to the 22.5's from the 19.5's. You need to make sure the bolt patterns are the same and make sure the wheel wells will except them, not only for the diameter but also for the cramp angle of the steering wheels. If your MH's suspension is setup for the 19.5's, I'm not sure if the benefits would be worth the investment..But i am far from an expert on the subject... Just my $0.02 worth...

tanstaafl · 11-12-2013, 11:19 AM

Quote:

Originally Posted by Chiefbvfd

There are a number advantages to the 22.5" tire and wheel, ride and load carrying capacity at the top of the list. But I am not sure you can just change over to the 22.5's from the 19.5's. You need to make sure the bolt patterns are the same and make sure the wheel wells will except them, not only for the diameter but also for the cramp angle of the steering wheels. If your MH's suspension is setup for the 19.5's, I'm not sure if the benefits would be worth the investment..But i am far from an expert on the subject... Just my $0.02 worth...

Plus I think the speedometer would need to be recalibrated.

Mr_D · 11-12-2013, 11:21 AM

The tire companies publish guides that give the specifics of each tire. Those will answer your questions. You need to know the tire brand, model and size of what you now have and then compare it to a tire of similar weight capacity.
Personally I say the high cost would outweigh any benefit to changing.

forest · 11-12-2013, 11:32 AM

You will not likely be able to do it, as the sightseers with 22.5 wheels have larger wheel wells to accomodate turning.

gruelens · 11-12-2013, 03:23 PM

Changing up to 22.5" rims opens up a whole Pandora's Box of issues that can be conquered, but certainly cost prohibitive. As stated wheel wells are too small. In addition, completely change the geometry of your suspension, alter gear ratio drastically, change bolt pattern on wheel, etc.

There may be alternative sizes that are near to what you run now. Use the calculator on the website here to help you with options.

Tire Size Calculator - Compare Tire Sizes

CJBROWN · 11-25-2013, 03:16 PM

The worst of it would be buying new wheels, then your gearing would be way too high. They are geared to high to begin with to help with fuel economy. Putting taller wheels on would make it even worse.

Just buy a new set of Michelins and be happy.

Eric n Karen · 11-30-2013, 06:06 AM

I have wondered about this too, but have no desire to change to 22.5" tires & wheels. Does anyone know what the largest diameter 19.5" tire is? I remember with my (very) old class C, they used to make what they marketed as a "mile-maker" tire in 15-16" sizes that was a slightly oversize tire. Is something like that available in a 19.5" size? It would be nice to pick up a 5-8% improvement in mileage if there is a 19.5" tire with a 35" circumference, instead of the standard metric 32-33" circumference.

Triker56 · 11-30-2013, 08:13 AM

Price a new set of 19.5 tires and a new set of 22.5 tires.
You will probably stay with the 19.5"

Probably would be cheaper to add a Gear Vendor OD unit.

vsheetz · 11-30-2013, 08:22 AM

Not worth it to change. The cost and difficulties to do so far outweigh the advantages.

My 19.5's work fine for me even with a large gasser coach. And it's easier on the wallet when it comes time for a new set. Makes it easier to carry a Soare as well.

CJBROWN · 11-30-2013, 10:11 AM

Quote:

Originally Posted by Eric n Karen

I have wondered about this too, but have no desire to change to 22.5" tires & wheels. Does anyone know what the largest diameter 19.5" tire is? I remember with my (very) old class C, they used to make what they marketed as a "mile-maker" tire in 15-16" sizes that was a slightly oversize tire. Is something like that available in a 19.5" size? It would be nice to pick up a 5-8% improvement in mileage if there is a 19.5" tire with a 35" circumference, instead of the standard metric 32-33" circumference.

I did a quick search thru the various 19.5's from michelin and there are 225/70 and 245/70 sizes and nothing else. The 19.5 rim size is non-standard - everything else is semi truck size - 22.5.

The biggest issue with straying away from a RV tire is that you end up with a tire designed for higher load carrying - as for a utility truck or semi. The sidewalls are stiffer and the tread is thicker. This makes for a horrible ride in a RV. And that's why the XRV is the best riding tire made for an RV - thinner tread to be more compliant, softer sidewalls to absorb bumps, even the tread depth is shallower to reduce squirm. And since we don't require high-mileage the tread depth is more than sufficient.

Michelin also has the best weather-crack warranty in the biz, and a better anti-aging additive to prevent it - 8 year weather check warranty, 10 year replacement recommendation.

I was going to try and cheap out on replacements since the damn XRV's are like $500 mounted up, but no one in the tire biz said anything would ride like the XRV's. So that's what I got, the coach still rides like new. I'm still running some originals, the two inside duals were unchecked so they're still on there. Probly this year will replace those too.

I think I read ALL the tire threads on the forum here, and did a TON of research on tire options. Winnie selected the best tire in the biz with the XRV's.