5v vs B section belts. Toro mowers

[LD1]

Posed this question on lawnsite and awaiting a response.

With years of industrial experience I am very familiar with the difference between 5v and B section belts. And they are pretty much considered NOT interchangeable and even use different pulleys/sheaves

Well, in my semi-retirement I took a part time job working for a friend that owns a local landscape company keeping their equipment serviced. They have a dozen or so mowers.

One thing I am trying to accomplish is inventory and application of the various v-belts for the mowers and such. And I have hit kinda a snag....

They have two toro grandstand mowers with 61" decks. Model # are different, 74583 and 74513. BOTH use the SAME spindle pulleys....toro # 120-6434.....so one would think they use the same belt right.....WRONG.

One uses a toro belt 106-7369, which is a B-section 175.625" belt and crosses to a gates/napa bladerunner 6661br.
The other us toro # 131-1123, which is a 5v section, 175.00" and crosses to 6885br

There are two other mowers. Both toro 6000series 72" decks. One model # 74961 the other 74928. And like the grandstands, they BOTH use the SAME spindle pulleys.....toro 105-7733

Yet....one uses a toro 109-9023 belt which is 5v, 219.25" long, and crosses to a 6851br
The other uses a toro 114-5859 belt which is a B-section, 219.625 and crosses to a 6884br

Can anyone explain a reason behind this?

Or more importantly.....what would be a reason to stock 4 different belts for these 4 mowers instead of narrowing it down to 2.....since for all intents and purposes the belts are the same length?

It would be a lot easier pill to swallow to stock all 4 different belts if the sheaves were different and specific to a 5v or B application. But they are not.

Anyone ran across this before?

Also, just FYI incase anyone else uses bladerunner belts from napa or where ever.....there is ALOT of overlap on sizing and BIG difference on pricing. I actually took the time to spreadsheet out all of the bladerunner belt #'s and sort them by size for this specific reason.

Just as an example....One of the belts on the toro 72" mower crosses to a napa 6884br. b-section 219.625" and price through napa is $113.15
Well a 6947br belt is 219". (5/8" shorter isnt gonna make a hill of beans difference on a 219" belt). Cost is about half at $66 and change. BOTH are aramid/kevlar belts too

Another example is the cross reference for toro 110-5043 belt. B-section, 121.25". Napa crosses to a 7048br which is $91.07 a 6574br is also 121.25" b-section aramid belt and is $68

These are just a couple examples but the same can be found all across the spectrum. That was a little off topic but I am really curious as to why some toro belts are 5v and some are B section with the same pulleys?

 

[RandyT]

Th thing you need to watch is cross reference manuals tend to generalize belts sometimes and just because a belt crosses to something else doesn't mean it is an exact match. OEM to exact match is one thing but general cross reference is not.

 

[radios1]

as you can see here, they are not interchangeable..

 

[LD1]

as you can see here, they are not interchangeable.. View attachment 661655

Hence my question....

Why does toro use a B-section on one mower
And then turn around and use a 5v on another mower with the EXACT SAME spindle pulleys?

Take the belts off the mowers completely....and you have two identical mowers (as far as pulleys) sitting there. WHY stock two different belts? Just because someone at toro used a 5v on one and a B on the other?

 

[radios1]

all I can say is the B belt is larger, so better, but, one of the belts is the wrong size for the pulleys, and won't sit right in it!. the belt that sits perfectly in the pulleys is the correct one!..

 

[RandyT]

It isn't so much as belt width as it is cut angle, and how it sits in the groove. too low and it will bottom out and not get any grip. But if the cut angle is the same between the two styles of belts they will sit at different heights in the pulley groove, but will still work.

 

[LD1]

all I can say is the B belt is larger, so better,

Not sure I understand this one?

Yes, a B is technically wider @ .69" vs .62 for the 5v...

But all the power charts rate a 5v belt as able to carry more HP

 

[radios1]

Not sure I understand this one?

Yes, a B is technically wider @ .69" vs .62 for the 5v...

But all the power charts rate a 5v belt as able to carry more HP

it's possible if the 5v belt is deeper, and has more contact area. I didn't see specs on the depth(height)..

 

[LD1]

it's possible if the 5v belt is deeper, and has more contact area. I didn't see specs on the depth(height)..

Depth was on the chart YOU posted.

 

[radios1]

Depth was on the chart YOU posted.

ok, I misread it, thinking it was the minor width listed on the side.. now looking at it again, it is depth..

 

[LD1]

ok, I misread it, thinking it was the minor width listed on the side.. now looking at it again, it is depth..

If you look at any of the belt power charts.....and can understand them....5v are typically rated alot higher.

Lots of variables though. Pulley sizes, rpm, etc.

But apples to apples....5v = rated for more than B

According to baldor chart......6" pulleys and 3500rpm.....a B is good for 8.77hp, a BX is good for 12.65
.....................................5.9" pulleys and 3500 rpm....a 5v is good for 12.99hp and a 5vx good for 22.24

https://www.baldor.com/mvc/DownloadCenter/Files/MS4050

 

[Lgim]

A couple of questions

You said the spindle pulleys are the same but are the drive pulleys the same on both machines?

and are the pulleys built for a 5V or B belt?

I could see them having a 5V pulley on the drive for some reason and then using a B pulley on the spindle just because they stock those spindles.

gary

 

[LD1]

A couple of questions

You said the spindle pulleys are the same but are the drive pulleys the same on both machines?

and are the pulleys built for a 5V or B belt?

I could see them having a 5V pulley on the drive for some reason and then using a B pulley on the spindle just because they stock those spindles.

gary

Good question. Not sure actually.....because the "drive" pulley is the mower clutch. They do show different toro part numbers for those.....but not sure whether that necessarily means 5v vs B

The spindle pulleys.....again....no idea if they are actually designed for 5v or B. But those toro part numbers are the same on the 5v and B application

 

[Lgim]

I would guess the drive is the difference. That being said if it were me I would put one of the cheaper belts on just to make sure there is clearance everywhere and then run it to see if the life span is equal to the expensive belt. If that doesn't work try the expensive belt on the other machine, stock whichever is best. The problem with this theory is by the time you know which is best it might be time to replace one of the machines.

gary

 

[Old man here]

You need this. V-Belt/Sheave Groove Gauge Set.

 

[radios1]

it's interesting, and very sad that even Toro don't know what they are doing:shocked: . it must be a problem with their parts supplier, as Toro has parts made for them, it would be too expensive if Toro made everything!..