Sizing a disc mower for a Massey 135

[PROFarms]

Always run a km22 drum mower on our 135 but it’s always been a bit light on the front end when on the road so been thinking of getting a disc mower as been told they’re much lighter. Have seen plenty of 8’ plus disc mowers but know ours wouldn’t handle anywhere near that but nothing much in about 6’ which is what I was looking for. Enorossi and Polish company Pronar both days that their 7’ models will have minimum hp rating of 32 or 35hp respectively. Is this something that is right as just seems too big for my thinking. If people agree and it is possible to run that big on a 135 I’d be keen as we are looking to get a slightly bigger tractor in the next year or two but don’t want to buy them find I can’t run it!
Cheers

 

[Cowabunga]

Back in the day, the 35 and 135 would have run 5ft cut cutterbar mowers which would be much lighter than a 7ft cutterbar mower. This is why I always suggest people buy at least a 165, ideally with square axle and disc brakes. Or a Ford 4000, rather than a sub 50hp tractor.

However, Vicon/Kubota do a nice light 5'6" [1.7m] disc mower that should be suitable for a 135. You will probably need to order it for delivery for the 2021 season as it is unlikely that there will be stock of this model anywhere at this stage in the season. But you never know.

 

[Boohoo]

I'd stick with the KM22, it has a lower power requirement than a disc mower of the same width. A 7ft cut disc mower will be beyond a 135.

 

[Little squeak]

maybe buy some front weights

 

[Cowabunga]

I'd stick with the KM22, it has a lower power requirement than a disc mower of the same width. A 7ft cut disc mower will be beyond a 135.

Disc mowers have a lower power requirement than drum mowers. Both in terms of starting torque and acceleration and when in work. You may be thinking of mower-conditioners.

 

[Boohoo]

Disc mowers have a lower power requirement than drum mowers. Both in terms of starting torque and acceleration and when in work. You may be thinking of mower-conditioners.

Definitely not thinking of mower conditioners, just a real world comparison between 5'6" drum and disc mowers. Once you get drums spinning it's easy to keep them spinning.

 

[Cowabunga]

Definitely not thinking of mower conditioners, just a real world comparison between 5'6" drum and disc mowers. Once you get drums spinning it's easy to keep them spinning.

I do not agree. They have exactly the same power requirement per unit of cut as a disc mower and the inertia is irrelevant except that if the engine is lugged down, there is more mass to get back up to speed in the drum mower. The extra power requirement for a drum mower comes from having to move the crop to the centre and push it through the gap between the drums. The heavier the crop the bigger the power requirement difference between types of mower becomes.

 

[PROFarms]

I do not agree. They have exactly the same power requirement per unit of cut as a disc mower and the inertia is irrelevant except that if the engine is lugged down, there is more mass to get back up to speed. The extra power requirement for a drum mower comes from having to move the crop to the centre and push it through the gap between the drums. The heavier the crop the bigger the power requirement difference between types of mower becomes.

So realistically do you think the claim from the manufacturer that 35hp can run a 7ft mower is true? If I can get away running 7’ on ours I’d like to as I know we will be upgrading the tractor in a few years

 

[Cowabunga]

So realistically do you think the claim from the manufacturer that 35hp can run a 7ft mower is true? If I can get away running 7’ on ours I’d like to as I know we will be upgrading the tractor in a few years

Yes, I certainly believe that a 135 will run a 7ft disc mower. You probably won't be running in fifth gear of course Probably down in third sometimes. The last 135's are 47hp and really outperform their stated power. They are also surprisingly heavy on the front.
The weak point on such a machine on that tractor will be the external stabiliser chains, which are tiny and have a pathetically weak adjusting thread. Best find a solid external bar stabiliser in my opinion, or an aftermarket heavy duty set of adjustable ones. It will be working hard but as long as it is in good, well serviced condition, it should be fine.