View Full Version : Timing Your Blades

Jerrys Lawn Service
03-01-2001, 09:17 PM
Hey guys and girls I found out something new today, I found out about blade timing. It seems that you need to position
your blades as to uptimize air flow and lift. They said that while changing blades it matters how they are positioned when put back on. If you have a three blade set-up, one blade goes vertical, one horizontal, then one vertical. This was new to me, has anyone heard of this or could tell us a little more about this.

Good Luck!

plow kid
03-01-2001, 09:23 PM
what happens when you turn off the pto?, they slow down at their own rate and would mess up the pattern.

03-01-2001, 09:23 PM
I have a Kubota with a belly mower w/ t3 bladea and in the manual it says that you are supposed to position them a certain way. Itried if diffferently one time and It cut terrible. They dont go as you said though. The angles are a little different.

03-01-2001, 09:24 PM
Never heard of this but always wondered. I have always postioned my blades in the same direction. I will try to stagger them this week and see if it makes a difference. Do you know the reasoning behind this? Also if running double blades should you stagger the blade setup? thanks for the thread. Just another reason LS in an invaluable resource.

03-01-2001, 09:30 PM
Great concept! However, just not practical. Like it was said, not just when you disengage the blades, but as soon as you engage them, some will grip just a little sooner than others, throwing the whole pattern off. Try it and see!

03-01-2001, 09:32 PM
I've never given it any thought until now. I just mount the blades in any random position. Interesting question, though. Maybe I've been wrong all this time. Lets see what responses this brings.

03-01-2001, 09:42 PM
pretty sure what runner said is fact

03-01-2001, 09:43 PM
TJLC, If that's what you have been doing all this time, then....you've been doing it right! Saaame here!

plow kid
03-01-2001, 09:47 PM
i have never done anything special either, just slap them on torque them down and go

Jerrys Lawn Service
03-01-2001, 10:43 PM
I've been thinking about this after reading some of your thoughts,now on my mowers all of the blades are held in sync
as one complete unit by spring loaded idler pullies. all three blades are kept under belt tension all the time. So when you kick in your electric cluch all three should turn at once,and when you turn off your PTO all three should slow
down at the same rate, the only thing that would change the pattern is belt slippige.

03-01-2001, 11:54 PM
I don't know what type of mower you have? But the only time you should time the blades is on a cog belt. Like a timing belt on an engine. I have only seen one of these belts on a lawn mower years ago where the blades overlapped each other. They would hit each other if not timed. The main reason for a v- belt is so that it WILL slip. All a blade has to do is hit some dirt or tall grass and slip. Those blades spin at 16,000 to 19,000 feet per minute so the blades would appear as if they were solid anyway. Even if you cut a perfect lawn the blades will drift from the original line up. On paper you would think it wouldn't but it does. Cog belts would put such a strain on the components on the unit that it wouldn't last very long. Just my opinion. Good luck. Kenny

[Edited by khouse on 03-02-2001 at 04:00 AM]

03-02-2001, 01:23 AM
If its a V-Belt set up, the blades will lose their position the first time they are turned on.

03-02-2001, 03:06 AM
I've tried this before. Doesn't matter what configuration you put the blades at they will be totally different after just a few revolutions. What difference would it make anyway even if they did stay in a set configuration. There is so much turbulance under a mower deck and the split second of difference between one blade and the other would be to short for anything major to happen. Making a mower mow well starts with the original design of the deck. Vacuum and deck capacity are the two major factors. Just a thought.

03-02-2001, 09:20 AM
Might work on a shaft driven machine, but a belt driven one, no way. Even if you started out with them set the way you want, they will slip some in thick grass. Waste of time.

03-02-2001, 09:44 AM
I have a John Deere GS30 36" WB that REQUIRES blade/belt timing because as mentioned above the blades on this machine overlap and will strike each other if not timed.

03-05-2001, 06:01 PM
Walkwrs with shaft driven gear box decks just about all of them are timed because of the closnes of the blades if they hit you stand to break some high dollar parts.....but my toros i see no diff or reason too plus on belt driven spindals as soon as they loosen up or one hits a stick the belts would slip and thats the end of your timming but you can still keep cutting

03-05-2001, 09:13 PM
I also run a JD 36" walkbehind and the
blades are timed, and I have also heard
the bobcat ztr are timed also. I think?

03-06-2001, 05:20 PM
Slip happens! but more than that....
V-belt pullies are never exactly the same diameter as others on your deck so the timing will change in just a few seconds when the blades are first turned on.
Even if one pulley is 5.256" diameter and another is 5.255" diameter, it won't take long for the timing to be off.

03-06-2001, 09:55 PM
Hello Everybody:

If it's belt drive, they will not stay in place!

V-belts are suppose to slip, that's one reason they were made, to asorb shock & slip when needed.

This is what you need to worry about!:-)

Don't give a residental customer a multi page contract!
If your blades are dull, Please sharpen them!
If you own anything, get business insurance!
Don't form a Corperation until your a Millionair!
If you can't pay cash for your ZTR, you don't need a CPA!
If you do not know when your blades are dull, how will I know?
If you knock a window out, Replace it?
Don't get a big check book unless you got big Money?
If you do not know the website address to Scag mowers by now, you never will?
If you think you are a scrub you probably are?
If you think you are a Pro, you probably are!
If you are worried about the Competition, you are probably not!
If you spend more time on this site than with your family, save your money, because you will need it soon?
If you don't know when to change your oil, I don't either!
If you have a Dually & pull less than a 16ft. trailer you are close to being a pro? But I'm not sure?
If you trimer with a curve shaft trimmer long enough, your back will hurt!
If you live up north right now & your grass is brown it's dormat!
If you live in the South in July & your grass is brown it's dead as hell? LOL
If you do not check your oil your engine will lock up or blow up! That's a Fact Jack!
If you can't make it working 5 days a week, you will never make it.

If you spend 5 to 10 hours looking for a mower, you probably have multipage residential contracts, no insurance, a CPA, dull blades, broken windows, a big empty check book, worried about the competition, can't find http://www.scag.com, LOL don't know where your family is right now, have dirty oil, a dually with a 10 foot trailer, a sore back, dormat grass on the 4th of July in JawJa, ain't never checked your oil, work 7 days a week & don't know how to use the search function on this forum either!!!!! :-)

Trying to turn the Lawn Service Business into Rocket Science is the Major Down Fall of this Business!

Keep it simple & you will be rewarded very nicely!

03-06-2001, 10:37 PM
So how can I tell if my oil needs to be changed? And does anyone know where I can find the Dixie Chopper website? Do flyers work? When should I put them out? Is Exmark really better than Scag? Should I bag my grass or double cut it? Is Eric really a Russian spy attempting to take over all of Americas finest lawn companies by giving us all bad advice about double blades? I want some answers NOW!

02-19-2002, 08:58 PM
FastEddie, you hit the nail on the head. Even if there was no slippage the blades will not stay timed. Real life example: After adjusting my spindles(hit 3/4" rebar) They were never quite the same. Sometimes new blades would touch slightly when they would line up. While mowing you would hear a ticking noise for about 30 sec. About 10 min later you would hear it again. The ticking was the blades contacting each other. 10 min was the time that it took for the faster blade to rotate 1 rev more than the slow one.