14.9X38 compared to a 15.5X38

old · Aug 18, 2020

So on my Oliver S88 the 14.9X38 tire has a big hole in the side wall. I have a good used 15.5X38 on hand an I am thinking there is probably not enough difference in the 2 to matter much. The other tire on the Oliver is an almost new 14.9 where as this 15.5 if who know how old

centash · Aug 18, 2020

Check the section height. Some 15.5, while having a wider face, have a lower section height or profile and will stand a bit lower than a 14.9. It should fit the rim OK.

Ben

Hayfarmer · Aug 18, 2020

I have been told the 15.5x38 is a wider version of a 13.6x38 and that you can use a 13.6 as duel on 15.5. That being said the 14.9 is quite a bit taller tire. I have 14.9 s onan SMTA and the 15.5 on a 560, there is a notable difference but it may work

David G · Aug 18, 2020

14.9 are much higher, as discussed 15.5 is a low profile tire designed to be a wide 13.6

old · Aug 18, 2020

The 2 appear to be close to the same size but that is only eye balling them form about 100 yards. Apart that is. Starting to also wonder if the rim the 15.5 is one will fit on the Oliver S88. I think the rim is off and IH tractor and has what appears to be 3 bevels to the inside of the rim. The rim that is one it right now came off a JD 60

DeltaSteve · Aug 18, 2020

David is right. 14.9 is a taller tire. Wont work right beside a 15.5.So,Find one more of either size. Dont mix em.

Hockeygoon · Aug 18, 2020

Doesn't make a bit of difference - except maybe in road gear.

I don't know how hours we put on tractors with a single on one side and a dual on the other plowing. The constant slip caused by a mounted 4- 5 or 6 bottom plow under hard pull is many times that of an inch or two difference in tire height.

Traditional Farmer · Aug 18, 2020

If you have both tires why not set them up side by side?

old · Aug 18, 2020

That is the plan after I can get them both side by side. The 15.5 has had fluid in it and the 14.9 is still on the tractor so there a 100 yard aprt from each other right now

old · Aug 18, 2020

All my Oliver S88 ever does is pulls the NH850 round baler

JDIH · Aug 18, 2020

(quoted from post at 18:56:05 08/18/20) Doesn't make a bit of difference - except maybe in road gear.

I don't know how hours we put on tractors with a single on one side and a dual on the other plowing. The constant slip caused by a mounted 4- 5 or 6 bottom plow under hard pull is many times that of an inch or two difference in tire height.

I agree. I can't believe in the long run it would make any difference

fastfarmall · Aug 19, 2020

I agree centash, the 15.5 is a 1/2 wider, but not quite as tall a sidewall !!

RCP · Aug 19, 2020

One tire size chart I found said the 14.9 was 2" in diameter larger than the 15.5", probably look a little funny, but probably will not hurt anything.

Rich

Carlyle hoffman · Aug 19, 2020

14.9 is nearly half again as fast as a pair of 15.5 on the highway

Mike M · Aug 19, 2020

Going to be hard on the differential if you use it much.

rustyfarmall · Aug 19, 2020

The 14.9 was designed to be a replacement, and a step up, for the 13.6. The 14.9 will fit on the same rim as the 13.6.

The 15.5 is an entirely different animal and requires a wider rim.

If you can't find a 14.9, simply go back to a 13.6. The tractor will never know the difference.

old · Aug 19, 2020

The whole point is I have this 15.5 that is good and a bad 14.9. I do not have 13.6 laying around so it is use the 15.5 or buy a 14.9 or 13.6

Roger Tomfohrde · Aug 19, 2020

As mention before about the height difference. Only thing to add is the rim will make the tire side walls bulge more which will actually cause the tire center to get a larger diameter if changed to the rim. Put used 15.5 on a 504 and it did that. If you are not pulling the "tar loose" you probably will not notice the difference if you use the narrower rim. If you are changing it with the rim you will see it. Over inflate the 15 and run the 14 a bit low. Like I said if just puttering around it will be ok.

old · Aug 19, 2020

I use this Oliver to pull my round baler on 14 or so acres of land and that is all it does. The 15.5 is on a rim so I may use that rim

504 · Aug 19, 2020

Use it.

sotxbill · Aug 20, 2020

(quoted from post at 06:22:49 08/19/20) Going to be hard on the differential if you use it much.

Why?? the diffy is designed to allow axles to run at different speeds and does this its whole life. As long as its not locked, the differential will do exactly what its design allows... and that is power the side of least resistance and the other side "floats".

To say the because the axles turn or the bearings turns, wear things out.. is not a correct statement. The spiders simply let it float and turn as needed.. spiders spin in bearing their whole life just as the axle bearings and pinion bearings spin their whole life.

comments??

Mike N Mo · Aug 20, 2020

"14.9 is nearly half again as fast as a pair of 15.5 on the highway"

According to the Firestone catalog, a 15.5X38 is 61.6" tall. A 14.9X38 is 64" tall. Both are Traction Field and Road, so we're comparing apples to apples. That's a difference of 3.9%. My math says that's a long ways from 50%. Just sayin'.......

Texasmark1 · Aug 20, 2020

Differentials are designed for turning corners. Continuous use may depend on amount and ability of available lubricant to keep metal off metal.

On circumerence differences, changing air pressures could accommodate that. A bias, non belted tire changes rolling circumference as a function of air pressure. At high air pressures the center is forced out and the sidewalls give up that material. At medium air pressures there is a balance in overall circumference and diameter. At low pressures, the diameter is the largest and the circumference....due to the fact that the center of the tire folds inward, is the smallest. BTDT My 2c and worth every penny you paid for it.

old · Aug 20, 2020

I know this is not a true measurement but I took a tape measure out yesterday and measured how tall the 14.9 tire is and it came out a tad over 61 inches tall. I am going to do the same thing latter today with the 15.5 and if close I'll use it since I have it on hand

14.9X38 compared to a 15.5X38

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