A bit OT, 48" mower drive belt?

[CalG]

I've got an old Mighty-Vac 48 inch cut walk behind mower. I guess they are all Skagg now.

I've had the mower more than twenty years and got it cast off from the previous owner. He wanted something new.

I've replaced the blade drive belt twice over these years, and each time with the closest V-belt from the local auto parts store.

Of course, a regular vee belt is not designed to be bent backwards as it runs over the tension pulley, so the inner belt V starts breaking up before the chord is shot.

The thing is, I have no information on the correct belt size/ length except for the belts that have come off. By the time the old belt gets replaced the flat side is so worn there is nothing to read regarding belt specs.

Last belt I fitted took three tries to get the length to run over the pulleys and get the lever actuated tensioner to fall within it's adjustment range. Fortunately the counter man was good natured, and I didn't scuff up the new belts during the fitting attempts. I wrote the belt size down on the sheet metal with a marker. 84" IIRC.

The mower needs a new drive belt now. There are more cracks on the inner V than there is good material. It's hanging by the cords, and I would like to get a real "mower belt" this time. There are no "full service mower shops" around that I know of anymore. Buying by guess over the internet isn't something I enjoy (unless the correct belt came the first time! ;-) There is no way of telling if the sizes will run true between the mower belts and the B series belts I've been fitting.

What might be a good path towards a new belt? I can't see carrying the belt around in the truck in case I happen to drive past a good mower shop. It's a bit of a task to refit the belt, and would really only like to do it only one more time. Using history as a guide, one more time aught to do it for either the mower or me. We will see who gives in first ;-)

TIA for you comments

 

[5030]

Not that it matters but I usually have a spare belt on the shelf, just in case. With me, drive belts (on my Cub 60" tank) break at the most inconvenient times.

 

[CalG]

The old belt just went in the trash last Thursday. I kept it hanging there all these years, thinking "in an emergency", all the while thinking I would come up with the "correct belt". but ,,,,noooo. ;-)

I can still pull it out of the bin if I need to... ;-)

 

[WranglerX]

Wrap a string around belt path and then measure length of string.....

Might want to try cogged style belt...

Order new belt, nail sleeve (that belt comes in) to garage/shop wall with note "mower belt"...

Dale

 

[tomplum]

Main Belts Sizes Reference could help you out. Gates green if you need one quick and in a hurry.

 

[CalG]

Wrap a string around belt path and then measure length of string.....

Might want to try cogged style belt...

Order new belt, nail sleeve (that belt comes in) to garage/shop wall with note "mower belt"...

Dale

Order a new belt is exactly what I want to do. Giant-Vac doesn't have literature on the mower I have, so I have had a difficult time finding a part number for the belt.

Then there is the issue of the belt type. Issue solved with the OEM part, but not so easy at the auto parts counter. I bought a "kevlar" belt once, ( was it green in color? I think so ) but it shredded it's self to bits in short order. I took that as a sign that it was NOT the correct belt for the application. ;-)

It's getting that sleeve nailed to the wall that is the issue. If I had that, I would be asking.

 

[CalG]

Main Belts Sizes Reference could help you out. Gates green if you need one quick and in a hurry.

Interesting that the Reference doesn't include any belts near 84 " length. I may need to double check ....

My experience with the green belt was not positive. The back (cord) is crowned, not flat, and crawled off the guide pulley and ended in shreds.

 

[rangerfredbob]

There are many cheap idler pulleys meant for the back side of belts on amazon and whatnot, if the idler pulley you have is just flat I could see a belt falling off that way.

I've had decent luck with the wrapped belts from NAPA, and unlike mower shops you can actually buy belts by length instead of needing a model and serial number if you are lucky enough to have that and it fits into their computer or stack of books... not selling belts by dimension is stupid in my opinion, I understand wanting to sell OEM parts as part of the business model but it would be nice if the dimensions were available...

 

[CalG]

There are many cheap idler pulleys meant for the back side of belts on amazon and whatnot, if the idler pulley you have is just flat I could see a belt falling off that way.

I've had decent luck with the wrapped belts from NAPA, and unlike mower shops you can actually buy belts by length instead of needing a model and serial number if you are lucky enough to have that and it fits into their computer or stack of books... not selling belts by dimension is stupid in my opinion, I understand wanting to sell OEM parts as part of the business model but it would be nice if the dimensions were available...

I share those feelings on the p/n vs description. And in the same breath, the parts list for fasteners will list the size and include "common hardware" as it NOT being something to purchase from the factory. Go figure. ;-)
I can't be bothered to sell the correct length fastener, but this $100 V belt that cost me $25? That's a "dealer only item. Oh well. I'll get another belt from the FLAPS , A few years at a time works for me.

 

[tookielee]

You changed the belt twice in 20 years? Sounds like the belts you
are using are holding up fine.

 

[radios1]

Interesting that the Reference doesn't include any belts near 84 " length. I may need to double check ....

My experience with the green belt was not positive. The back (cord) is crowned, not flat, and crawled off the guide pulley and ended in shreds.

you need a green or brown belt, designed for mowers, auto belts won't last, to fix your problem, replace the defective idler pulleys!. I NEVER had a green or brown mower belt have a problem with good idler pulleys!.. too much play, or bearings locking up is not good for belts!..

 

[WranglerX]

Interesting that the Reference doesn't include any belts near 84 " length. I may need to double check ....

What???? Try putting 84 in "length" search box....

Main Belts Sizes Reference

Could this be your mowers latest incarnation....

SW Belt-Drive Walk-Behind Mower - Scag Power Equipment


Dale

 

[CalG]

Well, the belt chunked today as I was trying to get some of the leaves off the yard prior to this big rain tonight.. A 6 inch piece of the inner V rubber just parted from the cord. Gone in a mask of smoke and squealing rubber.

Went to the FLAPS and used the belt measuring device to size a replacement. The identification on the back worn off and no longer readable. The old belt measured at 87" So I bought a 5L X84 Gates. Counter man indicated that was the right Gates number for the 87" length.

Nothing doing! Too short! The belt just went on the pulleys with the actuator lever in the disengaged position and the adjustment rod fully shortened. ;-(

Made the drive back and got the belt an inch longer. Compared it to the old belt in the measuring device and it sure looked a good match. BUT, NOPE! still too short to allow the blade drive engagement mechanism to go over center.

I'll go back tomorrow and get an 89" length . Third time is the charm, but this feels like DeJa Vu all over again.

The 5L 89" length appears frequently under the SCAG brand in the reference so kindly posted by tomplum. SCAG being where Mighty-Vac ended up.
Main Belts Sizes Reference

If they weren't near $40 each I would buy two ;-) I will nail the sleeve to the wall this time, as well as write the belt size information on the underside of the belt cover where it won't get rubbed off.

The only thing I can figure is that the belts bed into the pulley grooves and make a "short belt" measure long.
And for those comments on idler pulley condition, all are fairly new and the bearings run smooth and quiet.

Now if only new belts would mend the rusty deck ;-)

 

[CalG]

What???? Try putting 84 in "length" search box....

Main Belts Sizes Reference

Could this be your mowers latest incarnation....

SW Belt-Drive Walk-Behind Mower - Scag Power Equipment


Dale

There are NO 84 inch belts under the Giant-Mow catagory. Sure there are 84 inch belts.

Yes, the SCAG mower appears to be the latest version. Electro-magnetic clutch, SCAG blade spindles (different than the Gian-mow in shaft size) and a revised deck. It would be a stretch to assume the belt length to be the same across those changes.