Hi All,
This tire dilemma is not easily solved, at least by me. I want to get this right the first time, and I am confident that pclausen feels the same way.
I have been trying to do as much research on the internet as I can. I am now primarily interested in Michelins, although if Caledon or anyone else would like to educate me more about Firestones, I would definitely be all ears. Also, in a previous post Caledon described having seen a new 5 series tractor recently at a dealership that had the 13.6R24 -- 16.9R34 combination that can be ordered from the factory. He said that he like the way it looked. I would be open to this combination, but I hestitate because for the additional expense I am not growing my flat plate very significantly. The 13.6R24 has a flat plate of 168.3 and the 16.9R34 has a flat plate of 289.2.
The two tire combinations that I have come down to are:
width Diam. Circ. Flt. Plt. wheel
Multibib:
XM108 420/65R24 15.6 45.7 134.8 214.2 W11
MultiBib 540/65R34 20.9 62 183.3 316.8* W16L
Agribib:
Agribib 14.9R24 16.1 49.6 147 212.4 W13
Agribib 18.4R34 18.8 65.4 194.2 315.1 DW16L
On a farm forum in the UK I have read about Michelin tires from 4 or 5 years ago having sidewall cracking problems. It is unclear whether this was caused by under-inflation, or manufacturing defect. If it was a defect, I believe that Michelin has fixed the problem by now. To be on the safe side, I think that it is important to insist that the supplier provide tires that are no more than one year old, ideally just off the assembly line. This is also important because for warranty issues the tire manufacturer goes by the date of manufacture, and with tires older than 5 or 6 years, your chances become pretty slim of getting satisfaction. From what I have learned, it seems that the reason people get such long life out of their bias tires is that they are not run at low inflation so they do not have the same stress on the sidewalls. Even though the radials are designed to be run at low pressure, it is very important to adjust pressure for machine weight, speed, and kind of work, in order to extend tire life. Considering that to replace the four Agribibs (not including wheels) would cost about $5500, maximizing tire life becomes something to take seriously.
From examining the specs above, you will notice that the two combinations are fairly similar in several ways. First, comparing the Agribib to the Multibib, you will notice that they have a similar width and flat plate. In the case of the back tires the flat plate is about the same, but the Multibib is wider and the Agribib is taller, so its footprint is longer.
As I have mentioned in my previous post, the Multibib combination would keep my tractor at the same height it is now with its factory installed Goodyear Dyna Torque radials. (12.4R24 -- 18.4R30). If I choose the Agribib combination, the tractor will rise 4".
From what little I have learned, the Agribibs are a more common tire combination, both in size and design. Although, I have read about farmers in the midwest having success with Multibibs. There seems to be a trend moving toward wider tires for more flotation and better traction.
Choosing either of these combinations will be a substantial upgrade from a monetary standpoint. Caledon paid about $3000 to upgrade from his stock tires to his Firestones that are the same size as the Agribibs. Depending upon the source of the tires, it would cost me about the same. In the case of the Multibibs, it would cost $4000
Any thoughts would be greatly appreciated.
Island Farmer