Hi all, I ordered some new blades for a mate, but he is telling me when he fitted them, the blades are touching when he rotates them. I am not in a position to have a look, as he is a few hours from me these days. I ordered them going by what the supplier listed for the model, so I am at a loss to think what could be wrong. Any ideas that could save me a long trip would be great. Regards. Geoff

Hi Geoff

Its worth noting that rideon blades have to cross over - otherwise you would have thin lines in the lawn were the blades miss

It is of importance to 'time' the blades so they don't touch at a minimum - although I believe there is often a specification for where each blade should be in relation to the other to give the least vibration

The blades can not be timed. They are driven by a simple v-belt. But yes the do have cross over cutting wise as they are offset. Basically while the deck is on the mower the right hand blade trails the the left hand blade. As for low vibration it called having the bar blades in balance.

Geobee double check the blade specs. These are Gator type mulching blades. But JD original blades are mulching style blades that are m\no tooth but the specs are the same other than the thickness.



C to C 3-3/4" (the two outer holes)
Center Hole 11/16"
Length 21-3/8" (measured diagonally)
Outer Hole 13/32"
Thickness .187
Type Toothed
Width 2-1/2"

It is worth there are timed bar blade decks but they use a timing belt and timing pulleys.

Hi AVB

Good to know. With regards to the right blade trailing, I presume that is allow the left to throw clippings toward the side shoot.

For some reason someone once told me if they are more than x degree out of phase, it will cause vibration. Makes sense it wouldn't if balanced as its the same weight spinning in an non interfering way

Tyler, Just think of the bar blades as a weighted flywheel. Even your vehicle wheels are basically a flywheel or rotating mass that must be in balance. It is the same for aircraft props. Flywheel themselves are not always completely round either. A good example is the dog bone flywheel that Stihl uses on their backpack blowers.

Now there are decks on some equipment that both blades attacking the grass at same time. These have longer blades that would be constantly hitting each other if not timed by a timing system. On these systems the blades are timed 90 degrees of each other but they still need to be in balance. Some of the Cub Cadet walk behind commercial mowers uses this system and there is also some John Deere riders too. I have worked on both of these OEMs but don't know any models numbers off the top my head. These are usually two blade systems. So far I haven't seen a three blade timed system.

It is however much more common to have a v-belt driven deck with one side trailing the other which simplifies the deck setup.

Over the years so far I have only seen a couple after market blades that were too long by few thousandths and they ping every so often due bearing play. The solution was to shorten the blades a little bit while keeping them in balance.

Just an update on this. Well, without explanation, I get a refund into my bank account for the blade set. This was after I sent the supplier an email re the issue. I then questioned why they simply refunded without reason, and they said, oh, those blades are made wrong, they are 1mm too long. Would have been nice to know this before my mate went to the trouble of fitting them. Looks like they were just going to let it ''through to the keeper'' and wait until we come up with the problem. As soon as we queried the blades with the supplier, they refunded, so they knew there would be a problem in the first place. One supplier in my little black book.

I got one vendor like that. They have left a bad taste in my mouth per say about their after market belts where every one is shorter than spec'd.. At they still got blades that are right plus the Briggs parts are still reasonable. Anyway the sales to me has dropped from 3500 usd per year to right at 2000 usd this year and they will be dropping further next year; unless, things change for the better. I know that don't sounds like a lot but my actual parts purchase is at least 50% this year as I have rerouted purchases to other vendors.

If you pay enough attention to your purchases you will find other tricky vendors too.

We that was a good win, just cut 1mm off the end of each blade and you have a free set of blades, I'd be happy with that.

Geobee

At least you got a refund easily. As Norm said, cut 1/2mm off each end, balance them and off you go