7x12 vrs 23x8.5 x12

[99S10]

My new to me 855 is going to need front tires. The original R1s are on it and pretty well dry rotted. I see a lot of these with what appears to be a skid steer tire. I did a lot of searching which gets confusing. I see some using a 23x8.5x12. Would this be compatible with the OE rears? In other words the same rolling dia as the 7x12 on it. Will they fit the ag tire rims I have?
Thanks

 

[techwrtr2]

The tires you're seeing are R4 industrial. The general consensus is that the R4 is inferior to the R1's in terms of raw dirt traction. Are you sure the fronts are 7x12? I think 6x12 is the R1 front size with 9.5x16 in the rear.

 

[beenthere]

99S10
Prolly will need to stick to the tires that fit your rims.. or if you go to R4 (they will be better for lawn mowing with the finish mower you mentioned), you may need to buy rims. I'd prefer R4's if running on lawn, instead of R1's, but as mentioned the R1's have better traction in mud (and carry more mud with them too. )
In a post earlier you said the frt tires were new. Maybe just the tread "looked" good?

 

[99S10]

Thanks, I ended up with a different tractor than the one with new frts. That one had turfs.

The R1s are not a problem for where I mow as it's more of a field than a lawn. Plus the extra traction would be better for loader work. The rears are still in good shape. The fronts are available in the 7-12 size but rather pricey. I was just wondering if there was a less expensive alternative ?

 

[techwrtr2]

What size is in the rear? That's going to basically dictate what tires you put up front.

 

[99S10]

What size is in the rear? That's going to basically dictate what tires you put up front.

Rears are 11.2x16 fronts are 7x2 They are the original tires.

I eyeballed the fronts with a tape and they appear to be about 23" dia. Rim looks to be about 5" wide. I was thinking the 23x8.5x12 in a R1 ag tire. Considerably less money than the 7x12 providing they fit the rims OK.

Edit, I did a little searching and it appears I would need a set of turf rims to run the 23x8.5x12 as they are 7"wide compared to the AGs which are 5"

 

[techwrtr2]

Rears are 11.2x16 fronts are 7x2 They are the original tires.

I eyeballed the fronts with a tape and they appear to be about 23" dia. Rim looks to be about 5" wide. I was thinking the 23x8.5x12 in a R1 ag tire. Considerably less money than the 7x12 providing they fit the rims OK.

Edit, I did a little searching and it appears I would need a set of turf rims to run the 23x8.5x12 as they are 7"wide compared to the AGs which are 5"

According to TractorData, those aren't the standard factory size tires. TractorData.com John Deere 855 tractor dimensions information

I would NOT use a 23x8.5-12 with those rear tires. I think they are about 36" tall where the turf tires using the 12" rim use a 33" rear tire. What this means is running in 4wd can/will do damage. In fact, I wouldn't use the current front tires with those rears in 4wd. You want a tire that's about 25" diameter to maintain the correct front/rear tire size ratio.

 

[99S10]

They evidently have the info wrong for the 855 or mixed up with a 2wd. Check what they have for a 955 which is basically the same tractor.
Standard tires (ag): Front: 7.00-12. Rear: 11.2-16

Anyway, that's what came on it from Deere. Got this from the original owner. He showed me the invoice when he bought it and the tires are obviously the originals.

 

[techwrtr2]

955 has a different front axle and the tractor has different gearing. Don't assume what works on a 955 also works on an 855.

 

[Mechanos]

955 has a different front axle and the tractor has different gearing. Don't assume what works on a 955 also works on an 855.

The "rear axle" on 955 is different as well. It's actually a transaxle. While the case is the same on the 855 and 955, the ring & pinion is different, the planetary final drives are different and the axle shafts are different. Like mentioned above don't assume that what works on the 955 will work the same on the 855.