42" SD deck blade speed

[Dave85zxt 0]

Does anyone know what blade speed (rpm) the RM-425 deck is supposed to run at? Or can someone lead me to a manual for it?

I bought an RM-425, rebuilt it and fit it to my 856. Now I want to make sure that I get the correct blade speed before summer rolls around.

Thanks,

Dave

[TT-(Moderator) 1,162]

Unless you knowingly changed diameters of any of the pulleys, it should still run at the originally intended speed. I'm not sure that I have ever seen a manual containing that information. I'm not even sure where to begin the search for that information.

I do know that a 42" deck on an 8hp tractor is asking a bit much and you might end up spending a lot of time in first gear. :clap:

[Dave85zxt 0]

Per my signature its no longer an 8hp. The K181 was shot when I bought the tractor so I fit a 13.5 hp robin subaru on it. Plenty of power, trust me.

The reason I ask is that I have seen other members with the RM-425 deck and they have a much larger PTO pulley than the one that came on the K181. I am using that same pulley (i think its 4" dia) on the new engine. It might be correct but i would like to make sure.

Maybe a better question would be.... For RM-425 users, what size PTO pulley do you have, what size input pulley is on your deck and what engine speed are you running?

[TT-(Moderator) 1,162]

I can't tell you what size pulleys are on the deck without going out and measuring mine. (yes - I have an RM-425 but will never use it due to the belt routing nightmare)

The tractors they were designed for (1045/1055/1075) had the 2 1/2" PTO pulley with the foot pedal tensioner.

Engine speed should be no less than 3/4 throttle. (something like 2700 rpm)

[Dave85zxt 0]

Awesome. Thanks for the info. I was off on the pulley dia. Mine is 2.5 in and I am running 3000 - 3600 rpm.

Now I need to find new blades. Do you know a good place to get them?