RZT 50" deck belt comes off or snaps randomly!

Sorry, I don't know that part number. The spring should be fine I would think. .And I don't know how many different idler numbers there might be. I wouldn't think there would be a lot of different ones.. but what do I know! LOL.

RZT50 - Looks like there are 2 of the same and one different...

According to your diagram, looks like #30 attaches to the moveable arm. Thank you very much

Thank you! Ive looked for diagrams like that everywhere with no success. Whats the link to that diagram?

It'd be the one spndncash posted on the previous page... scroll down under "browse catalog" to "zero turn riders", select which one you have and then you'll see all the different diagrams for all the components.

Before buying the pulley I would make sure that the Belt Keeper is not pressed against that pulley. Look at the pulley where this Keeper bends to run under the puller. The pulley edge might be sitting on the radius of the bracket. Belt Keeper is that piece of steel in the picture that is supposed to keep the belt from vibrating off the pulley. Belt sits between pulley and that Keeper. On other machines, that Keeper can be adjusted to be close to pulley so belt can't jump. Maybe yours is touching the pulley.

Is that from the Cub Cadet webpage

PACub100 said:

It'd be the one spndncash posted on the previous page... scroll down under "browse catalog" to "zero turn riders", select which one you have and then you'll see all the different diagrams for all the componen

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Dan Fitts said:

Hi, i own an rzt 50 zero turn mower. Have had problems with my belt either snapping or falling off. I have people and myself thinking that maybe because at full throttle, when i go in reverse and it stops the deck, going back forward kind of jerks it around. Not sure though. Please help!

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I would at least slow the engine down before going back to forward. You ever floor a straight stick and pop the clutch ??

Wallace Fiala said:

You ever floor a straight stick and pop the clutch ??

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Every chance I get!

tkhoffman said:

Before buying the pulley I would make sure that the Belt Keeper is not pressed against that pulley. Look at the pulley where this Keeper bends to run under the puller. The pulley edge might be sitting on the radius of the bracket. Belt Keeper is that piece of steel in the picture that is supposed to keep the belt from vibrating off the pulley. Belt sits between pulley and that Keeper. On other machines, that Keeper can be adjusted to be close to pulley so belt can't jump. Maybe yours is touching the pulley.

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I am with Tony. This looks like it is contacting the pulley
It looks like you had this off and put the belt keeper back without a spacer or the spacer is in the wrong spot in the stack up

As I said regarding that tab, if it's like ours, there are 2 "bumps" or "dots" that will act as an index so it can only go in one position. If you haven't ordered a replacement part yet, remove the pulley and tab for inspection. Maybe you installed them wrong previously?

I think my buddy repositioned the tab. I believe the tab was toward the back side of pulley to start. So it def was moved. I will look.

Dan, I've been following this with interest....others have already said there's a good chance your belt keeper is the issue..When removing check carefully for shiny spots on keeper..there shouldn't be any. I've experienced others putting the belt over the keeper not knowing it was there.To test a deck I put 2x4 under it to get it off the ground(after removing deck) ..use a drill and proper socket to spin drive pulley and you will get a clue ..This does not test drive from engine belt...any stickiness in idler in drive means replacing...the speed of drive multiplies bad bearing issues

My TANK LZ-54 Cub Cadet zero turn doesn't turn the mower off in reverse. It's a commercial machine, there's a few things I wish were different, like throttle mounted away from where stray branches can turn the throttle down, or worse yet, key mounted where branches turn the engine off. And Everything requires the parking brake to be set. Sometimes I can catch and turn the key back on but it shuts off a time or two per mow. The "other" side of the mower, the right side is the discharge chute, everybody trims with the left side, a more protected switch location is needed.
Parts guy at my dealer says all my belts are Arimid ( kevlar) reinforced, and heavy cross section, I have spares for everything. I had an idler pulley start squeeking at me on the first mowing this season, sealed greaseless bearings of course. I need to figure out which tensioner pulley it is and get a spare. Think my Ray-Tech temp gun is the right tool for that job, the dry bearing should be several hundred degrees hotter.
Over-all I'm pretty happy with how easy it is to service. Oil and filter changes are a snap. Lots of zerks to grease, one sorta hard to get at zerk on each spindle, front spindles and frt wheel hubs easy to grease, the 2 spring loaded belt tensioners have zerks on pivots.
I read on another forum a guy got an expensive ticket mowing his roadbank next to the road with no SMV emblem. I have the decal, need to cut the sheet metal backing and zip tie it to my ROPS.
The stock 12V battery has struggled to start the engine first time every spring, I put my charger on it an hour or two, then switch to Boost while cranking and it usually goes. Mowing week to week starts are no problem. I think an EFI engine would start better.
SON is starting to drop more frequent hints that I should be mowing with a new SKAG, since he's Quality Mgr at the plant they're built at. But seriously, I'm hard pressed to find fault with my Cub Cadet other than the few things I mentioned. My local SKAG dealer has a less than enthusiastic sales and service staff, I've bought a couple oil filters from them.
To ME, the real Head Turner in zero turns is the new "self driving" Cub Cadets, it's GPS guided.

Denny,

Those 2 things have been addressed on the ULTIMA series Zero Turns. The Key, Throttle and Deck PTO Control are all on the right side (as sitting on the seat) in a little console that actually angles toward the operator. Also, on these, there is no separate parking brake. When you push the control bars out, it automatically sets the parking brake. The only time I have had the engine cut out is if I am leaning over too far trying to miss a low branch.... if you get too much weight off the seat, it will shut the engine down. My solution to that, is to trim the bush, or tree.... I don't think I've ever has a branch turn the key off or throttle back. But, as you mentioned, I am trimming with the left end of the deck, so the control bars, and my body are between the trees and the controls. The only "control" on the left side is a large knob that sets the deck height, and you can't turn it if the deck is on the stop..... To adjust the height, you actually have to put your foot on the deck lift pedal and raise it a bit, to be able to move the knob.....`

A most recent discovery on a zturn cub...it's not a first by any means...a huge number of idler pulleys are now plastic...this pic shows what happens when bearing stops turning...eventually the belt melts away plastic while it's getting severely stressed ..then the belt gives...If you were looking at this pulley not running the odds are you wouldn't notice because the other side looks fine ...this was idler on main drive to hydros....drag marks on outside of belt was the only clue

Is this a current MTD thing, or are others doing this now?

i think they are all doing the plastic junk thing,lucky my 2020 ultima zt1 -50 is all steel, knowing there is zero grease in every bearing i yanked them, carefully removed the seals and hand packed them, the deck tensioners were not fun,
had to drill out all the rivets to get at the bearings, than bolt them back together using loctite and self locking nuts alternating sides . 3 years now same parts are in place

i should note we have both a scag and the cub in our family, the cub cuts as well as and for 2K dollars less, plus it has a kawasaki twin over the 7000 kohler scag uses

These plastic idlers have been in use for quite awhile..the plastic actually holds up well but the cheap bearings don't,that's when the wear starts...