ATR deck drive.........Mule pullys or shaft & gearbox??

ddg

LawnSite Member
Location
Kansas City
Still ZTR shopping, Had about decided on something with a shaft & gearbox driven deck, (Scag Turf Tiger) but have been hearing some negative stuff about it here. The anti-drive shaft people say go with an all belt drive, like Exmark Lazer. I've heard mechanical effeciency suffers with an all belt drive, and I've heard shaft drive sap horsepower too. Who do you believe? Is there a mechanical advantage with shafts over belts? I've used a super A farmall with an all belt drive Woods L-59 belly mower for 20 years with no problem, so I know a little about belt drives.
 

Eric ELM

Husband, Father, Friend, Angel
Location
Chicago, IL USA
ddg: I've got a 430 20 HP diesel JD with shaft drive mid mount 60&quot; deck and it's noisy compared to belt drive. I've got an all belt drive (mule type drive)26 HP diesel Chopper with a 60&quot; deck. I think the all belt drive is nicer. <p>----------<br>&lt;a href=&quot;http://pages.prodigy.net/eric.erickson/&quot;&gt;Eric@ELM&lt;/a&gt;<br>The Grass is always Greener on the other side of my competitors fence
 

Lazer

LawnSite Bronze Member
I think a shaft drive makes more sense, myself. I don't like the looks of the Lazer/Z-Master twisted, turning mower belt.<p>But they're almost trouble-free, so go figure.<p>I don't think I'd let it be the deciding factor.
 
OP
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ddg

LawnSite Member
Location
Kansas City
I guess my finger decided to use an A instead of a &quot;Z&quot;. Anyway I'm trying to figure out the selling points of both designs, and I think this is the place! I want a good, commercial grade mower to handle about 3 1/2 acres in MY OWN YARD,for the next 20 years. I'm looking at the Scag & the Exmark 61&quot; 23-25 HP machines. I like Scag's single 10 gal. gas tank, shaft drive, & large drive fluid capacity, but want to give Exmark's belts, Mobile 1 & twin 5 gal. tanks every chance before I decide.
 

fdew

LawnSite Member
Location
Upstate NY
OK. I have all these books so I looked it up. <br>Drive shaft efficiency goes down as the angle goes up. So a drive shaft coupling will be somewhere between 97 and 98% at the end of every drive shaft on a mower there needs to be a set of gears. Spur gear including bearings are 93-96% depending on the polish on the teeth. <p>Belts are about 96 to 98 %. But need no gears at the spindle. SO the answer is the belt from a vertical shaft engine to a mower spindle is probably a little more efficient. But it is close. Probably to close to call with out spending a couple of days with design drawings of the mower and a computer. I think the bottom line is complexity/ maintenance/ cost. If a mower could not be serviced I would want a drive shaft. (Automobile drive shafts don't fail often but when they do it is expensive to fix them.) Because a mower is easy to service and belts are not to expensive I would vote for a belt.<p>Frank
 

fdew

LawnSite Member
Location
Upstate NY
With 3.5 acres either machine should last between 50 and 80 YEARS depending on mowing speed. But hay, I bought a 61 in Ferris (used) so I only get 30 to 50 years. Then I got hooked on this forum.<p>Frank
 

Eric ELM

Husband, Father, Friend, Angel
Location
Chicago, IL USA
It's easy to do Frank, I've been hooked for a year now.<p>----------<br>&lt;a href=&quot;http://pages.prodigy.net/eric.erickson/&quot;&gt;Eric@ELM&lt;/a&gt;<br>The Grass is always Greener on the other side of my competitors fence
 

Keith

LawnSite Platinum Member
Location
Central Florida
My thoughts on Belt vs. shaft<p>I have a Grasshopper (shaftdrive) and a Kees ZTMax (almost an Exmark). If you look at them, you say &quot;that shaft drive sure is complex, it must be better&quot; You're half right, it is more complex, but I see no benefit. To me the Kees with it's mule drive transfers power better. With the shaft, you still have belts, you have just thrown a shaft and gearbox into the mix. When I first looked at the mule drive, I thought to myself, &quot;you must be kidding, that belt will slip and break too easily.&quot; It doesn't!<p>Now I really decided the belt was better recently. One day while going down a hill with the Grasshopper tractor and up a hill with the deck (like a V), the driveshaft slip yoke came apart and the driveshaft seperated. These two pieces seperated and flopped around out of control. I took it back to the shop and determined I needed to replace a couple of parts. First I needed to replace the PTO belts (about $30) and the two slip portions of the driveshaft (about $100) They were worn and had a lot of slop in them. While doing this you would have to replace a couple of U-joints ($40). When I pulled the QD off the powershaft I noticed it had play in it, probably the pillowblocks (they are about $60 for two). Yep, and it had managed to groove the powershaft (about $70) too. While attempting to take the pto pulley off the powershaft, I proceeded to break to pulley (about $45). Total damage: about $350 + tax if you fix it yourself. The gearbox would add another $150+ I would imagine. And that is not all, there are a couple more pieces that can go bad (the QD section of the shaft and deck yoke). You will also, most likely need access to a hydraulic press. Now what does this complex belt-shaft-gearbox system do? The exact same thing as one belt and a couple of idler pulleys on the Kees. <p>While other shaft drive decks may be less complex, it seems to be a waste, at best for this application. <p><br>&lt;font size=&quot;1&quot;&gt;Edited by: Keith<br><p><font size="1">Edited by: Keith
 
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