Aluminum vs. Cast Iron Sindles

[MBDiagMan]

Aluminum vs. Cast Iron Spindles

I was told by a friend who has run a front mount 718, 61" deck GH for 15 years that the 72" deck models have cast iron spindles. The last time he rebuilt his spindles, he needed new housings, so he bought the cast iron ones.

When I went for new spindles, they took a 72" version off the shelf and it was aluminum. I ended up buying aluminum. They said that the spindles are aluminum because it dissipates the bearing heat better.

Has anyone ever dealt with this issue?

Larry

 

[reynoldston]

If your bearing are getting so hot that they need to dissipate the heat you have a bearing problem not a spindle problem.

 

[MBDiagMan]

Very good point.

 

[MBDiagMan]

Someone gave me an old 61" deck to scrap out. I tore it apart this morning and it had four bolt, cast iron spindles. My 9861 deck from 2003 or 2004 has 6 bolt spindles that are much larger. I am now anxious to talk to my friend and see if his machine has four bolt spindles. If it does, that will explain a lot.

I was looking forward to getting a spare gearbox from the scrap deck, but it was different too.

 

[djdicetn]

Someone gave me an old 61" deck to scrap out. I tore it apart this morning and it had four bolt, cast iron spindles. My 9861 deck from 2003 or 2004 has 6 bolt spindles that are much larger. I am now anxious to talk to my friend and see if his machine has four bolt spindles. If it does, that will explain a lot.

I was looking forward to getting a spare gearbox from the scrap deck, but it was different too.

I'm still relatively new to ZTR technology, but when I was shopping last fall for my first ZTR the consensus I got from all of the different brand dealers was that the cast iron spindles were "industrial/commercial" grade and far better than the aluminum housings for durability and longevity. Of couse they all wanted to sell me a commercial ZTR with cast iron spindles too:0)

 

[MBDiagMan]

The grasshopper aluminum spindle housings are BIG, assumedly to make up for the lower material strength as opposed to cast iron. The story they give is that aluminum conducts heat away from the bearing better. My six bolt aluminum spindle housings are WAY bigger than the four bolt cast iron ones that I took out of the old scrap deck.

I expect that this is one of those Ford/Chevy type debates that will be argued to the bitter end. I tend to agree with the earlier poster that said that if the bearing is too hot there are other issues in play. Although that is true, possibly, the aluminum allows it to run a little cooler which brings it into a heat range that matches up better with the lube or something. Who knows?

I think if an aluminum spindle is made beefy enough, it will hold up adequately well. It's not as if grasshoppers are known as throw away equipment.

My original post was an effort to find out if anyone had ever replaced the aluminum spindles with the 72" versions that I have been told are cast iron, but cannot confirm.
Larry