JD tyre question

[JD 2140]

Hi guys

I am looking to buy a John Deere 6200 and currently it has some smaller than usual tyres on the rear and possibly the front.

Tyres are as follows:
Rear - 16-9 - 30 on 15inch rim.
Front - 12.4 - 24 on 11inch rim.

First question are those the standard sized rims for that model?
What would be the largest tire size I could go on those rims? I basically would like to fill up some space, so that the tyres are near the guard.

 

[deere5105]

Hi guys

I am looking to buy a John Deere 6200 and currently it has some smaller than usual tyres on the rear and possibly the front.

Tyres are as follows:
Rear - 16-9 - 30 on 15inch rim.
Front - 12.4 - 24 on 11inch rim.

First question are those the standard sized rims for that model?
What would be the largest tire size I could go on those rims? I basically would like to fill up some space, so that the tyres are near the guard.

I recommend looking unit up on tractordata.com. They often list this information along with optional sizes.

 

[Zebrafive]

I think the front wheel might be 10" not 11"
As far as standard they were the smallest offered. Also 34" rears with 24" fronts and 38" rears with 28" fronts.

The MAIN thing is there is a ratio for the front to rear that must be maintained.(fronts driven 1% to5% faster than the rears) Different tires sizes came with different axle ratios front and rear and there are a large variety of gear sets for the ratio of the front wheel drive gear box to the transmission. So you can NOT just add larger rear tires for looks.

 

[JD 2140]

Thanks for the reply,
Say if I change the rims and centers to 34" Rears running 18.4-R34 tyres, what size should I be running at the front?

 

[Zebrafive]

You are going from a 16.9-30 rear with an index radius of 695mm to a 18.4-34 with an index radius of 770mm. This is a 10.8% increase.
So you need to increase the fronts by 10.8% too.
12.4-24 fronts have an index radius of 540mm. 10.8% would be 58mm, so 540mm + 58mm = 598mm. Closest tires to that are 14.9-24, 590mm and 12.4-28, also 590mm.
To really calculate this correctly you need the ratios from the tractor: Differential gear pair 47/10, 53/10 or 53/9. Front axle ratio 13.13 or 15.89. And the tranmission ratio for front wheel drive (too many ratios to list) . Differential gear pair and tranmission ratio will be on the transmission ID tag. Front axle ratio will be on the front axle ID tag.
John Deere reccommends maximums sizes for each rear differential gear pair.
47/10 no more than 665mm 14.9-30
53/10 no more than 745mm 16.9-34, 15.5-38
53/9 no more than 820mm 18.4-38