lucky7chief
Well-known member
If you had a choice between 18.4-30 and 16.9-34 rear tires, which would you pick and why?
18.4-30 vs 16.9-34
- Thread starter lucky7chief
- Start date
Help Support CattleToday:
Travlr
Well-known member
On a golf cart?
What does it call for in your manual? I know that 18.4-30 tires will fit on a 16.9-34 rim. The 16.9's will sit a little lower and give you a bit less traction. The 18.4's will give better traction and give you a touch more road speed. At least, that is my understanding.
Dsth
Well-known member
18.4-30 just because they will have wider lug contact.
Dsth
Well-known member
the rim width will work for both sizes, but the rim diameter will be different. you will not be able to install a 34 inch tire on a 30 inch rim or vis-versa.
Nope
Not quite the last number is the rim diameter. Can’t put a 30 inch tire on a 34 inch rim.
You can put a 16.9 -34 on the same rim as a 18.4 -34 but it will also change preformance based on rim width not just size of tire
Last edited:
Contact with the ground can be altered quiet drastically by adjusting air pressure.
chevytaHOE5674
Well-known member
18.4's for the wider footprint.
IMO the only reason for a narrow tire like a 16.9 is if you need to get between rows for spraying or cultivating.
IMO the only reason for a narrow tire like a 16.9 is if you need to get between rows for spraying or cultivating.
Dsth
Well-known member
lucky7chief
Well-known member
Thanks for the replies. I was asking because I might start shopping for a new tractor. Some offer either option. I wasn’t sure which would be better. The 18.4-30 is wider and would have a wider footprint. The 16.9-34 would be little taller and have a longer footprint
Huge difference between the contact width at 8 psi vs 25 psi . Both are acceptable in various situations
Dsth
Well-known member
chevytaHOE5674
Well-known member
Change tire pressure all you want but at the end of the day the 18.4 will always be wider.
But a 16.9 will always give you a lower center of gravity in all situations. Wider isn’t always better . A wider tire has less lbs per sq. Inch of down pressure at the same vehicle weight. In some situations that means reduced traction and decreased steer ability and handling.
Wich leads back to my original comment.
Wich leads back to my original comment.
Depends entirely on the situation. Bias vs Radial, 6ply rating ,8ply,10 ply all will effect it as well
kenny thomas
Well-known member
If you are on steep hills the lower profile will make you feel much better on it.
chevytaHOE5674
Well-known member
From the BKT book their 16.9-34 is 62.4" tall and their 18.4-30 61" tall.
So the 18.4 will offer a lower center of gravity and a wider footprint.
So the 18.4 will offer a lower center of gravity and a wider footprint.
And in the Goodyear book they have a 16.9-34 that is 61.1
A 18.4-30 that is 61.7
So in that case the 18.4 -30 is a higher center of gravity wider footprint.
That is why you have began to see more metric sizing in ag and industrial tires to increase uniformity between manufacturers.
A 18.4-30 that is 61.7
So in that case the 18.4 -30 is a higher center of gravity wider footprint.
That is why you have began to see more metric sizing in ag and industrial tires to increase uniformity between manufacturers.
chevytaHOE5674
Well-known member
So from the GY book is that .3" higher going to be noticeable? I'll still go with the 18.4 footprint for any sort of stability, only take a 16.9 of I needed to cultivate or spray row crops.
Metric sizing doesn't change anything. Actual tire dimensions vary a bit between manufactures. There is no set standard dimebsionsfor any given tire size.
Metric sizing doesn't change anything. Actual tire dimensions vary a bit between manufactures. There is no set standard dimebsionsfor any given tire size.
Metric sizing changes quite a bit . For example all 18.4 -34 tells you is that at its widest point in the sidewall it 18.4 inches wide .and is on a 34 inch rim.nothing about how tall the sidewall is thus allowing for a wide variety in side wall dimensions.
Where a 460/85r34 . Gives you width . Aspect ratio(percentage of side wall height to width )wich is side wall height.as well as rim diameter.
So it is 460mm at its widest point. 85 aspect ratio( 460mmx .85 =391) so a side wall height of 391 mm
R =radial
34=rim width.
While there is some variation between manufacturer about where and how they measure. And percentage of variance that is acceptable. Metric sizes are far closer in size between different manufacturers than the old measurement. Wich is becoming more of a issue.
Since sidewall height is directly related to rolling circumference. Wich newer tractors have far tighter tolerances before damage occurs to the drive train.
While some ag tires aren’t regulated. Any tire with a dot stamp is must meet federal regulations.
