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RM48 deck belt routing improvement

Posted: Wed Nov 16, 2022 10:32 pm
by thebuildist
I don't like the deck belt routing on my RM48 deck. On my old J44, I never had any problems with the deck belt slipping.

But on my RM48, I've now changed the belt twice, the first time fixing a hack the PO did, probably because he was having problems too.

The PO had abandoned the factory belt tensioning method,
2022-11-16 22_03_38-DeltaCad - [LOADERB.DC _].png
and just went with a belt that was fairly snug right around the three pulleys.
2022-11-16 22_05_24-DeltaCad - [LOADERB.DC _].png
I mowed with it like that for a month or so, but I could hear one or more blades slow down when I got in thick stuff.

When I investigated, I ordered the correct belt (82" long) and installed it correcly.

But I still felt like the blades slow down too easily.

I ran it that way for a season and the next time I checked, it was completely shot. This time I ordered a kevlar belt to see if that helped.

So as of today, I can see that the problem is still present, it's just way too easy to slow down the blades.

Experience with other decks/manufacturers tells me that in the factory design, the belt doesn't wrap the center pulley enough. A 1/4 of the pulley just doesn't provide enough grip.
2022-11-16 22_13_01-DeltaCad - [LOADERB.DC _].png
So what we need to do is move the idler pulley farther to the left, so that the drive pulley has the belt wrapped more like halfway around it.
2022-11-16 22_16_33-DeltaCad - [LOADERB.DC _].png
It'll be simple cutting/grinding welding, to just move the idler arm/pulley over there.

But right now I have the deck installed, and it is usable, and I have a lot of leaves to blow and suck up. (The new high-lift blades are awesome while they're spinning.)

So I don't want to pull my deck this instant. And I need to order a belt in advance, ready to do the work.

But what belt to order?

I began by drawing my current belt routing in CAD. I know that I have 17" blades on the outers, and that they cover a 48" swath. And I'm pretty sure the deck pulleys are about 4". So I draw in those two pulleys.

Then I know that the center blade is forward far enough for the blade tips not to strike each other, so I draw that in.
2022-11-16 22_22_50-DeltaCad - [LOADERB.DC _].png
From there I draw in the (I'm guessing) 5" idler pulley, and draw connecting lines to represent the belt.
2022-11-16 22_03_38-DeltaCad - [LOADERB.DC _].png
Time for a sanity check: I know that the stock belt is right around 82". So I add up the lengths of the straight belt, plus the arc lengths where the belt wraps the pulleys. And it all adds up to about 82". So my model isn't insane.
2022-11-16 21_55_33-DeltaCad - [LOADERB.DC _].png
Then all I have to do is move the idler pulley over to where I want it, and re-do the belt measurement process.
2022-11-16 21_55_53-DeltaCad - [LOADERB.DC _].png
And it comes back to about 98". However: I don't want the idler any farther to the left. And the idler might be a little smaller than 5".

So I'm going to fudge downward to 96". I'm perfectly confident that I can find a pulley location that'll work with that belt length.
2022-11-16 21_58_31-D&D PowerDrive A94_4L960 V Belt, 1_2_ x 96_ OC, A Section, Rubber_ Amazon.com_ I.png
I'll report back some time next week with an update and some photos of the finished process.

Bob

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 1:00 am
by Eugen
You are brave and determined to do this mod Bob. Very cool! :thumbsup: I'd have measured the pulleys and distances though.

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 5:26 am
by propane1
I would put an stationary idler over there on the left. That way it would wrap around the left pulley more and around the centre pulley more. Just a thought I had. And my drawing is not very good.

Noel

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 5:59 am
by DavidBarkey
Both Bob's and Noel's ideas a widely used across the industry . Both have there merits. Bob's has one less part while Noels would be simpler . The lack of contact on the drive pulley is a definite design flaw . Good on you Bob for recognizing it and wanting to fix it .

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 6:29 am
by propane1
The deck on my Case 224 is the same way other than it’s opposite. Deck belt only wraps around the centre pulley about 1/4 the way. I thought that was my trouble when the blades were slowing down because of the belt slipping. But it turn out that my slippage was coming from the engine to deck belt. I didn’t have it tight enough. Once I adjusted that it worked fine. No slipping in the heavy grass.

Noel

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 8:17 am
by thebuildist
Good observation. Presumably my old L44 deck had the same routing and I just never noticed a problem.

But in this case I had just installed my deck, and the main drive belt was plenty snug.

And when I reach under the deck and wiggle one of the blades, I can very easily make it slide while leaving the other two blades stationary. That tells me that I don't have a sticky enough connection between the blades, so it seems natural that that's where my slipping is coming from.

Now, I'm not guaranteed to be correct. But it is observable that the current belt routing/tensioning is less than ideal. So I'll address the visible defect/issue, and then see if that resolves the overall problem.

Thanks for the info.

Bob

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 10:03 am
by MattA
Bob - I modified by RM44 and then my RM48 belt drives back in 2017. I used Noel's method for both decks but later thought of using your method. The only reason I didn't use your method is that I don't have a welder and I would have had to coordinate with a friend to do it which just delayed my project. I think your method is the preferred method. Anyways I received a lot of push back from users on the old forum for doing this. They essentially stated I was the only one with the problem and the belt drive was sufficient for 1000's of users which both of us disagree with. One thing they were right about was my center drive spindle was worn out and needed replacement. The pulleys were pitted and worn down.

RM44 deck - I only ran this setup for maybe a year before finding and rebuilding my RM48 deck. I sold the RM44. The one issue I had was with the belt creeping up on the idler pulley I added. I ended up shimming my pulley setup to fix this.
Standard belt tension. Tensioner spring is stretched 3.76".
Standard belt tension. Tensioner spring is stretched 3.76".
Mounting bolt bottom side
Mounting bolt bottom side
Initial mounting bolt setup. Those are 0.25" thick washers.
Initial mounting bolt setup. Those are 0.25" thick washers.
Shimmed mounting bolt
Shimmed mounting bolt
Modified tension. Tensioner spring is stretched 4.238".
Modified tension. Tensioner spring is stretched 4.238".
Modified belt drive
Modified belt drive
Belt riding up on the pulley
Belt riding up on the pulley
Plan B (shift the pulley more to the left)
Plan B (shift the pulley more to the left)
RM48 deck - I've ran this setup for the past 4 years. I do not have the belt creep issue on the idler pulley with this deck. I did have the bearings go out on the added idler pulley and ended up replacing both idler pulleys (this year?). Both idlers were new stens replacements in 2017. I also still had issues with both belts slipping on the center drive pulley even with my modifications but only in thick deep grass. After one bad mowing I had black dust all over the deck and mule drive. The main drive belt was toast and the internal drive belt had signs of slipping. I replaced the center drive spindle with a RM38 drive spindle (faster speed) and now neither belt slips. My 16HP vanguard just looses RPMs now when in deep grass. My outer spindles are also pitted. One slips more than the other causing the blades to drift in and out of sync every few seconds. I just bought replacements from Bob but haven't installed them yet. I've also had issues with the internal tensioner bracket bushing wearing out and seizing to the bracket. I've replaced it twice and the last time I drilled out the bracket and used a beefier spare bushing I had laying around from the mule drive.
RM48 deck with modified belt drive. The belt is a Gates High Power 2 A83.
RM48 deck with modified belt drive. The belt is a Gates High Power 2 A83.
Closeup. Tensioner spring is stretched 4.565". The added pulley may be a little too close to the center drives spindle?
Closeup. Tensioner spring is stretched 4.565". The added pulley may be a little too close to the center drives spindle?
End ramble :cheers:

Make sure you have adequate tension on the internal tensioner spring. I'm also not a fan of the factory RM48 drive belts. Every one I've bought from various vendors was old dried out rubber. I'm happy with the Gates High Power 2 belts I am using.

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 5:09 pm
by propane1
Great ramble Matt.


Noel

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 6:33 pm
by thebuildist
MattA wrote: Thu Nov 17, 2022 10:03 am Bob - I modified by RM44 and then my RM48 belt drives back in 2017. I used Noel's method for both decks but later thought of using your method. The only reason I didn't use your method is that I don't have a welder and I would have had to coordinate with a friend to do it which just delayed my project. I think your method is the preferred method. Anyways I received a lot of push back from users on the old forum for doing this. They essentially stated I was the only one with the problem and the belt drive was sufficient for 1000's of users which both of us disagree with. One thing they were right about was my center drive spindle was worn out and needed replacement. The pulleys were pitted and worn down.

RM44 deck - I only ran this setup for maybe a year before finding and rebuilding my RM48 deck. I sold the RM44. The one issue I had was with the belt creeping up on the idler pulley I added. I ended up shimming my pulley setup to fix this.
standard-tension.jpg
mounting-bolt-bottom.jpg
initial-mounting-bolt-setup.jpg
shimmed-mounting-bolt.jpg
modified-tension.jpg
modified-belt-drive.jpg
belt-riding.jpg
plan-b.jpg

RM48 deck - I've ran this setup for the past 4 years. I do not have the belt creep issue on the idler pulley with this deck. I did have the bearings go out on the added idler pulley and ended up replacing both idler pulleys (this year?). Both idlers were new stens replacements in 2017. I also still had issues with both belts slipping on the center drive pulley even with my modifications but only in thick deep grass. After one bad mowing I had black dust all over the deck and mule drive. The main drive belt was toast and the internal drive belt had signs of slipping. I replaced the center drive spindle with a RM38 drive spindle (faster speed) and now neither belt slips. My 16HP vanguard just looses RPMs now when in deep grass. My outer spindles are also pitted. One slips more than the other causing the blades to drift in and out of sync every few seconds. I just bought replacements from Bob but haven't installed them yet. I've also had issues with the internal tensioner bracket bushing wearing out and seizing to the bracket. I've replaced it twice and the last time I drilled out the bracket and used a beefier spare bushing I had laying around from the mule drive.
20170705_204451.jpg
20170705_204501.jpg

End ramble :cheers:

Make sure you have adequate tension on the internal tensioner spring. I'm also not a fan of the factory RM48 drive belts. Every one I've bought from various vendors was old dried out rubber. I'm happy with the Gates High Power 2 belts I am using.
Yes, I figure I would get some pushback either for the insult to the divinity of the original engineer. Or for the hubris to think that I can do better.

And I am all in favor of brand loyalty. And I certainly have never seen any brand of lawn tractor that I like as much as a Case / Ingersoll.

But my loyalty to basic physics surpasses my loyalty to the brand


:52:
Bob

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 6:44 pm
by thebuildist
Nice work, Matt. It looks real clean when you're done.

My hesitation to go that route stems from the fact that I'd have to track down a whole extra part, the idler pulley.

And because that idler pulley is now in the tension path of the belt, as opposed to the slack side of the belt, that idler is going to be subjected to greater stress on the bearing than you would normally expect an idler to experience. So the bearings in that static idler are going to have to be replaced more often.

But your well done and easy to follow post reminds me that I should post the same in the process. Complete with the diagram and measurements in case other people want to follow.

Bob

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 8:49 pm
by JSinMO
Anyways I received a lot of push back from users on the old forum for doing this. They essentially stated I was the only one with the problem and the belt drive was sufficient for 1000's of users which both of us disagree with. One thing they were right about was my center drive spindle was worn out and needed replacement. The pulleys were pitted and worn down.


[/quote]

Yes, I figure I would get some pushback either for the insult to the divinity of the original engineer. Or for the hubris to think that I can do better.

And I am all in favor of brand loyalty. And I certainly have never seen any brand of lawn tractor that I like as much as a Case / Ingersoll.

But my loyalty to basic physics surpasses my loyalty to the brand


:52:
Bob
[/quote]

Having a well reasoned discussion on the pros and cons of an idea can be quite helpful during a project, but to receive negative feedback simply because the original design of something must have been at the apex of engineering and couldn’t possibly be improved seems ridiculous to me. I have experienced this on other sites, this is why I’m happy I found this place! You can actually put an idea out there and get good feedback, not just a snarky comment.

You guys have more than shown well reasoned, logical solutions to observable problems. Not changing something because it’s going on display is one thing, but improving the machines usefulness is quite another. Frankly people that push back for the sake of pushing back can pound sand!

I’m sure no one here needed me to say this, but after reading @MattA and @thebuildist posts I couldn’t help myself!

That ends this ramble, please carry on!

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 9:00 pm
by MattA
thebuildist wrote: Thu Nov 17, 2022 6:44 pm And because that idler pulley is now in the tension path of the belt, as opposed to the slack side of the belt, that idler is going to be subjected to greater stress on the bearing than you would normally expect an idler to experience. So the bearings in that static idler are going to have to be replaced more often.
That's probably why the bearings in my idler pulley lasted about 4 years. I'd go with your approach but I don't have a welder. I'd probably end up hooking the spring up to a bolt or something.

How does your main drive spindle lower pulley look? Pitted and worn? Is the belt bottoming out in the pulley V groove? Are you getting enough spring tension? Is your idler bracket moving freely?

I'm excited to see what you come up with. My approach works but I've thought for several years that the approach your going with is a much better way to do this.

Re: RM48 deck belt routing improvement

Posted: Thu Nov 17, 2022 9:21 pm
by thebuildist
I'll try to address this very questions in my soon coming post.

Bob

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 11:47 am
by thebuildist
I got to this project last night, and I'm pleased with the result.

Pulling the cover off, we find that the belt isn't tight all all. To quote Clem down t' the gas station: "Well, THERE'S yer' problem!"
PXL_20221120_142448070.MP.jpg
PXL_20221120_142456687.jpg
I honestly have no answer for why it's like this. It's an 82" belt, matching Ingersoll spec. Maybe it got oil on it and stretched? I really don't know.
And what is with all those packed in leaves over there??? That has to be fixed too.

But moving on:

I cut off the welded on tab using a cutting wheel in a 4.5" grinder, since it's right in the middle of the area we want to move to, and painted the bare steel with matching paint.
PXL_20221120_162003249.jpg
PXL_20221120_164944932.jpg
Then I unbolted the idler arm and, with the new 96" belt in place, I positioned the idler in a spot that isn't rubbing the main pulley and won't interfere with the long belt run at the trailing edge of the deck.
PXL_20221120_164457355.jpg
PXL_20221120_162615898.jpg
I grabbed a sharpie and marked the new bolt/pivot point.
PXL_20221120_163116284.MP.jpg
PXL_20221120_163128432.MP.jpg
It turns out to be 3.5 inches from the edge of the center pulley and 2.75 inches from the "wall".

I drilled the 3/8ths inch hole (the size of the bolt) and then grabbed a square file. 5 minutes of filing produced a square hole that the carriage bolt can slide up into.
PXL_20221120_164059773.jpg
And then bolted the idler arm back into place.

When I stretch the spring using a vise, I find that it can stretch about 2 inches. So with the belt in place and the ilder pulled snug, I marked the point that the spring tab touches the deck. And then welded the spring tab 1 inch farther back from that mark. (About half of the spring's stretch) If I had it do do over again, I would have located the spring tab ONE AND A HALF inches farther back from that mark. I think it's ok as it is, but another 1/2" of stretch would be better.
PXL_20221121_130559972.MP.jpg
PXL_20221121_130656245.jpg
PXL_20221121_131135787.jpg
Note that if I didn't have a welder, I could have used a bit of angle iron as the spring tab, and bolted it in place with a couple of carriage bolts.

A little paint over the welded area, and it's ready to reassemble
PXL_20221121_131744306.MP.jpg
PXL_20221121_132024120.jpg
(continued on next post)

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 11:56 am
by thebuildist
Now I like the overall routing, but I don't like that the belt could vibrate over and hit the idler arm where the "1/2 inch ratchet tab" sticks out.
PXL_20221121_132024120.jpg
PXL_20221121_132026714.MP.jpg
I think that over time that steel edge may chew up the belt, so I grabbed the cutting wheel and zipped it off.
PXL_20221121_132510903.jpg
That ratchet hole part is unnecessary anyway. You can easily install a belt like this just by engaging the belt hard against the edge of the final pulley and then rotate the pulley through one full turn, and the belt will just feed itself right into the pulley groove.

Or if you're not used to doing that, then you can just use a Crescent wrench to grip where the ratchet used to insert.

Voila! Our belt routing improvements are complete.
PXL_20221121_132708028.jpg

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 12:11 pm
by thebuildist
Lastly, a couple general deck improvements:

1. I didn't like those leaves packed up in there with the belt. I decided to make some caps to put on the open ends of the bolt-on deck belt cover.
PXL_20221120_142448070.MP.jpg
I grabbed some cardstock and cut/folded it to the shape of the caps I want to make.
PXL_20221121_133426908.MP.jpg
Then I used the cardstock as a template and cut out both end caps from some 1/32" sheet metal, and bent them to shape.
PXL_20221121_135126880.jpg
Then I riveted the new end caps onto the ends of the main deck belt cover.
Note that it's important to use STEEL rivets when riveting steel pieces together. If you use aluminum rivets, it will very quickly begin corroding due to galvanic/dissimilar metals corrosion.
PXL_20221121_140438628.jpg
A little more painting and the improved cover is ready to install.
PXL_20221121_141710607.MP.jpg
Lastly, I needed to repair and reinforce the left edge of my deck. In one of the spots I mow I end up backing the left edge of the deck into some landcaping blocks, and the last time I did it, it bent the deck edge inward, causing the blade to strike and damage the deck.
PXL_20221121_152035088.jpg
So after I welded the place where the blade tip penetrated through the deck, I grabbed a strip of 3/16" steel plate, bent it to the correct profile, and welded it in place at the outermost lower edge. That covers up the welded repair, and also adds some general strength to the deck in that area, so it shouldn't bend as easily next time.

(If you can't improve your driving, then fortify your equipment. :)) :rofl: :rofl: :rofl:
PXL_20221121_152023587.jpg
And with that, the deck is ready to go back on the machine.
PXL_20221121_152244224.jpg
PXL_20221121_152251109.jpg

Bob

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 12:58 pm
by Eugen
Looks like significant improvements Bob. You don't fool around do you! Nice! :thumbsup:

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 5:04 pm
by MattA
Looks good Bob. If you could do it over, would you move the idler up and to the left some more? I like your idea of using angle iron for the spring mount.

Your old belt is likely worn down which causes it to sit lower in all three spindle pulleys. Since the belt is sitting lower in the pulley "V", the pulley circumference is now less which is why the belt seems too long.

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 5:45 pm
by thebuildist
Matt,

If I moved it any higher up, it strikes the center pulley when it's loose. You MIGHT fudge it 3/8 of an inch, but certainly not a lot.

Thanks for the observation on the old belt.

Bob

Re: RM48 deck belt routing improvement

Posted: Mon Nov 21, 2022 9:18 pm
by Seabee
Thanks for the information. I get a lot of leaves and grass in there.

Bill Moyer

Re: RM48 deck belt routing improvement

Posted: Tue Nov 22, 2022 4:35 pm
by thebuildist
Just a quick update:

With the new high lift blades and a belt that is not slipping, this deck now puts out A LOT of air!

It is precisely the improvement that I was hoping for. When I run down the leaf filled street now, It leaves a perfect clean sweep behind and throws the leaves five and six feet off the road out into the underbrush. Just exactly what I was hoping for.

Meanwhile hooked up to the leaf vacuum, I did four loads in big heavy oak leaves including some sticks and twigs and debris, and never got a clogged discharge chute a single time. That is a first.

Woo hoo!

Re: RM48 deck belt routing improvement

Posted: Tue Nov 22, 2022 6:51 pm
by Jancoe
Great improvements I'd say. I feel the same way as you. The oem tensioner pulley is in the wrong spot. At any given time I can grab and easily spin one of the outer blades with just a finger or two. This is definitely on my list of deck upgrades. I always felt that my pullies were slipping on the belt. My rm48 needs some service as there is quite a bit of slop in the mule assembly and hope to fix it up in time for spring. Thanks for the idea.

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