Tires on my tractor not to manufacturer's spec

[Skyfair]

Recently while shopping for tire chains, I realized that my Mahindra 1635 was delivered with tires sized differently from what the manufacturer specifies. The tractor is supposed to come with 43x16-20 rear tires. Mine came with 15x19.5. (This is the size they spec for the smaller 1626). The tires are Titan R4 and filled with ballast. I find tire sizing a mystery but think these two sizes differ in the following way:

Should I be concerned that I don't have the larger rear tires? Does the difference in size make any real difference? Given all the supply chain issues this year (I bought the tractor new in early 2021), I wonder if they substituted one tire for the other because of lack of inventory. Thanks for your insights.

 

[Roadworthy]

I really think Mahindra or your dealer would be a good source to ask. Changing the rear tire size should have had a corresponding change to the front wheel size. There is a specific ratio of outer diameters between the front and rear to consider on a four wheel drive tractor.

 

[LS Tractor Owner]

Is the front tires sized accordingly? Meaning are they also slightly smaller? They should be..... having different circumference ratios will mess with the drivetrain to catastrophic results!

You mention that the size you have on the rears match to the specs of the 1626.... double check that the fronts are also the size spec for the 1626. If they are, you'll be ok. If they aren't, I would have the dealer provide the correct tires!

You probably wouldn't notice any performance differences between the two different sizes, but the ratios need to match what the engineers specified.

 

[LouNY]

Some interesting number to look at here;
Do you have R-4's or Turf tires? you say R-4's.
The 43x16-20's are turf tires.
Of course I believe that some of this information from TractorData may be incorrect also as the 1635 industrial rear is called for to be a 13.6-16 which I don't believe to be an R-4.
What size is your front tire.
The ag tires are listed to be the same on both models.
On many tractors there are several "stock" sizes.

From TractorData.com

Mahindra 1635 Tires
Ag front:	7x16
Ag rear:	11.2x24
Lawn/turf front:	28x8.5-15
Lawn/turf rear:	43x16-20
Industrial front:	25x8.5-14
Industrial rear:	13.6x16

Mahindra 1626 Tires
Standard tires (ag):	Front: 7-16. Rear: 11.2-24
Lawn/turf front:	25x8.5-14
Lawn/turf rear:	13.6x16
Industrial front:	27x8.5-15
Industrial rear:	15x19.5

 

[arrow]

Recently while shopping for tire chains, I realized that my Mahindra 1635 was delivered with tires sized differently from what the manufacturer specifies. The tractor is supposed to come with 43x16-20 rear tires. Mine came with 15x19.5. (This is the size they spec for the smaller 1626). The tires are Titan R4 and filled with ballast. I find tire sizing a mystery but think these two sizes differ in the following way:

View attachment 719695

Should I be concerned that I don't have the larger rear tires? Does the difference in size make any real difference? Given all the supply chain issues this year (I bought the tractor new in early 2021), I wonder if they substituted one tire for the other because of lack of inventory. Thanks for your insights.

The 43's are only specified on the 1640 currently from the latest specs..
The 1635's have the 15's.
Awhile back, Mahindra had some errors from their spec print outs in relation to tire size and mid stream, corrected their specifications on tractors actually shipped.
What they will go by is the current specifications and you'll be hard pressed to a skirmish going your way.
If it were me, I'd go for it anyway if and only if you have proof of the old, incorrect specification.
Increased tire size benefits in a multitude of ways from increased tractor weight (filled), tire longevity, stability and of course traction.
1600-Series-Brochure-2019.pdf

 

[arrow]

Some interesting number to look at here;
Do you have R-4's or Turf tires? you say R-4's.
The 43x16-20's are turf tires.
Of course I believe that some of this information from TractorData may be incorrect also as the 1635 industrial rear is called for to be a 13.6-16 which I don't believe to be an R-4.
What size is your front tire.
The ag tires are listed to be the same on both models.
On many tractors there are several "stock" sizes.

From TractorData.com

Mahindra 1635 Tires
Ag front:	7x16
Ag rear:	11.2x24
Lawn/turf front:	28x8.5-15
Lawn/turf rear:	43x16-20
Industrial front:	25x8.5-14
Industrial rear:	13.6x16

Mahindra 1626 Tires
Standard tires (ag):	Front: 7-16. Rear: 11.2-24
Lawn/turf front:	25x8.5-14
Lawn/turf rear:	13.6x16
Industrial front:	27x8.5-15
Industrial rear:	15x19.5

You are correct. The 13.6x16 is incorrectly stated as an industrial for the 1635. It is a turf tire specified for the 1626 and 1635.
This publication didn't even get the turf tire size correct stating an industrial tire size instead of the turf's which are
41 x 14-20 rears for the 1640.

So when specs are given to the printer who is making up the brochures or web site info and mistakes like these are made, it becomes a headache for the tractor manufacturers.
Yours is not an official publication from Mahindra but even though a mistake, an argument can be made by the purchaser from an incorrect official Mahindra print out.

 

[LD1]

Id only be concerned if the fronts are something other than a 27 x 8.5-15

 

[ROUSTABOUT]

Front and rear can be within .25 of each other and be fine.

 

[LD1]

Front and rear can be within .25 of each other and be fine.

But nobody makes a 26.75 or 27.25 tire.

They need to say 27 on the side and you are fine

 

[90cummins]

It can be a big deal!!
If you put it in 4wd going straight and it binds up and starts to whine and you can’t get it out of 4wd you need to investigate it.
my tractors OEM turf tires were so grossly miss matched it would bind up within several feet going straight on hard pack.
I used a tire calculator and found replacements that I was able to exactly match by adjusting front & rear tire pressures.
90cummins
90cummins