OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Ride On Mowers Questions on Greenfield Ride On Mower Frames Greenfield Sprockets

Hi all, new to the forum

I have a 2000 greenfield 32" ride on. Its striped the top sprocket so I have removed the drive & will change bearings & clutches in the process.

Question I have is about the rear sprocket. I know in the older ones the rear sprocket was part of the axle, but I was shocked to find that is still the case with this model even though it has the differential axle. The sprocket is actually used to mount some of the planetary gears to.

i have come up with a complex way to machine a new sprocket to fit but I thought I would ask here first to see what other have done in the past.

I'm considering having the existing sprocket machined off 50mm or so from the diff housing then have the last 25mm of the circumference reduced to 1/2 its thickness which will make a step. then machine to new sprocket the same dimensions but machined on the opposing face. when the two are put together the sprocket alignment should remain the same is my aim, will drill six holes or so bolt the two together.

I hope it will be strong enough, but as i said its a complicated way to go what have others done?

I don't know of anyone else reporting that problem, greenfield. The parts list I checked (Evolution 2000 Mk II, 16-32) shows the entire rear axle being serviced as an assembly, not part by part. The sprocket, including pivots for the planetary gears, looks as if it may be welded to the longer axle shaft, and the other side plate of the differential may carry a bearing for the shorter axle shaft.

It is important that the sprocket runs true, even though it rotates rather slowly in this case. I would suggest a less complicated and simpler machining job than you had in mind. It involves making an additional side-plate for the differential on the sprocket side, so it picks up the existing mounting bolts, which would need to be slightly longer so that the bolts can pass through the existing sprocket as well as the new additional side plate. The outside diameter of the of the additional side plate would be 1" smaller than the OD of the sprocket. Using a lathe, turn off the old sprocket at the outside diameter of the differential. Bore a replacement sprocket to fit closely over the outside of the differential. Bolt the new sprocket to the additional side plate. From then onward, when you wanted to replace the large sprocket it would not involve any special machining except boring the new one to differential-size, and drilling holes for the attaching bolts. You can make the new additional side plate of any thickness you choose so long as it is substantially greater than the thickness of the existing sprocket. The side plate is simply a flat disk, bored on the inside to clear the axle shaft weld, and turned on the outside to 1" smaller diameter than the sprocket. It will have to be drilled accurately for the differential bolts, since they will be what makes it run true: to get a quality job, those holes should be drilled or bored on a rotary table on a milling machine, and they must be a close fit to the differential bolts, not a normal clearance fit. Alternatively of course you could bore the new side plate to be a close fit on the axle, then bore it from one side only to clear the weld attaching the old sprocket to the axle. If you did that the bolt holes for the differential bolts would not need to be especially accurate.

Thank you very much for such a detail response, very much appreciated.

You have the model correct also, its an evolution 2000. Yes the sprocket is welded to the longer shaft. Our local dealer says all these parts are obsolete & unobtainable now that's what brings me to attempting this. Don't mind a bit of tinkering with such things anyway.

Both your suggestions are spot on. I was just concerned that either of these methods will move the sprocket inwards on the axle by either the thickness of the new backing plate for the differential or the thickness of the old sprocket if machined down & left. This will cause a misalignment with the top sprocket. Although I should look a this in more detail it may be simplest to preform your second suggestion on the rear sprocket, then machine equal to the old sprocket thickness from the inside of the top sprocket & make a spacer to go the other side.

I will check for clearances ect today.

Thank you very much for your time

We aren't on the same page yet greenfield, what I suggested did not cause any alignment issues. The idea was to leave the old sprocket welded to the axle, cutting the outer part of it off so it is the same diameter as the differential. Bolt an extra plate to the side of it (using the existing differential bolts), on the inboard side (the opposite side to the differential). Bore out a new sprocket to differential diameter so it can sit exactly over the old sprocket, perfectly in line with it. Bolt the new, bored-out sprocket to the new plate, which is sitting on the inboard side of it (that is, with the hub of the old sprocket and the outside part of the new sprocket in line with each other, between the differential and the new plate).

Ah yes I do understand now. that is a much simpler machining process. Will definitely look into it.

As a general rule a picture of a problem is a big help.
In this instance a bit hard if its all pulled down allready.

Theory with a motorbike is that you replace the chain and sprockets together.

Given that, is there room to mount a new sprocket on the same side of both sprockets. Step both across the width of the sprocket.
Either bolt or weld them in place.

You do not need the same pitch chain and tooth count. You can use anything so long as the ratio is the same.


Its a ride on mower, not a race car.

Cheers, Bob.

We may have had this disagreement before Bob: I think if you do the job to a workshop standard, there are advantages:
- the repair will be reliable
- future repairs will be made easier
- resale value of the item will be higher
- the repairer/owner feels proud of what has been done, not apologetic about it.

Of course it is up to the person doing, or paying for, the repairs to decide how they should be done. However it is the policy on Outdoorking to recommend only good workshop practice, for various reasons including the ones listed above. (Another reason is that good practices, like good manners, tend to be catching.)

How is it bad advice???


Greenfield mowers are rudimentary at best, granted theres a fair difference in the engineering in a 2000 model than a 70's job. But the design has changed little. Almost all parts are fabricated and the whole basis of the design is about not having to machine a gearset. Even the steering gears on the old ones are cast alloy.


Why go to the trouble and expense of having to remove and strip axles and shafts from the machine to the pont where they can be mounted up in a lathe to be machined only to find that the parts were made to a very opened ended specification to begin with?


When if there is room you could get two new sprockets that make the same ratio, if needed trim the teeth or some diameter off the existing sprocket for chain clearance with a gas axe or plasma and with some careful measuring drill and bolt the new srpockets to the old one.

If you used a motorbike based sprocket you would have something thats hardened, not what at best is probably a mild steel machinery sprocket. You could also fit an O ring type chain, in the end you would have a setup that would thrice outlast the original setup. And when it did wear out is easily replaceable even if you welded it.
Obvioulsy where you to weld it you would do so at your own risk, mixing steel grades can be bad. But it would not make for difficult replacement.


Hence the statement, its not a race car.

Thanks for the input guys. Once cleaned up I did find the sprocket to be a separate piece to the long axle. But it does have a centre spigot & it is the mounting face for the planetary of the differential. I really should take photo's.

The sprocket being a separate piece has made things easier, I purchased a generic sprocket with a couple of more teeth but the same pitch. only issue is it is a little thicker. Machine shop has it now to swap over the spigot & copy planetary mounting holes. because of the extra thickness we have decided to machine 1/2 of the thickness difference from the differential mounting area, this should result in a original sprocket alignment. The chain i purchased suits the new wider sprocket, I don't foresee an issue with the slightly narrower top sprocket

on a different subject I am starting to piece the drive back together . I have removed the old corks. Noticed when i was cleaning them it looks like contact cement that held them. I was intending to use arildite. After a search on here I notice that contact cement is the normal procedure, just wondering if there is a specific reason why it is favoured over the likes of arildite for this job.

Contact cement is deformable, epoxy cement is not. Generally, you use a deformable glue to stick a deformable substance, because there is less risk of separation.

Been a while getting around to completing this, finally have some time right now to finish it.

here is a photo of the old sprocket verses the new with the machining completed on the new sprocket. As I explained earlier the new sprocket is thicker this is why I chose to have 1/2 the amount the sprocket is thicker machined from the planetaries mounting face to over come any alignment issues. But I have later worked out this was unnecessary because you can simply repositioning the axle in the wheel bearings before locking down the locking collars and grub screws

this is a pic of the mower before starting assembly.



I then found a problem with the sprocket side drive mounting here



it doesn't show up real good in the picture but what it has done is that when the chain jumped a tooth an jammed it created enough load on the drive mounting to collapse the chassis 15mm or so in this area. I had to cut this section out straighten everything back out and carefully measure and weld back in that section of chassis. It looked like this




then I added up right supports in the chassis between its upper and lower section with 25mm by 5mm flat bar in an effort to over engineer this section of the chassis incase it ever happened again

more new bits



drive unit is shimmed assembled and test fitted




Now I just goto remember where all these bits come from to assemble the differential

I'm following this process with interest, greenfield 32. The repair to the bent chassis would have been easier to follow if you'd taken a picture of the chassis in the horizontal plane instead of taking it from above, but your description was clear. My preference with repairs like that is to do a dummy assembly of the relevant bits, including the surroundings, after tack welding but before full welding. That is the way it used to be done with new models in the car industry until three dimensional computer aided drawing reached its current advanced level. The dummy assembly was called a "buck". I've found over the years that it is very frustrating to have to make design changes to fully machined and welded parts - after you've done it two or three times to the same component, it looks like rubbish even when you finally get the design right.

That differential looks considerably better designed than I expected. If it has a lock, though, I don't see it in the pictures. Please post pictures step by step as you assemble the differential - they will be useful in our archives, for other Greenfield owners.

You have shown the clutch axle assembled and re-installed in your second-last picture. Have you adjusted the clutch clearance yet, or was that just a practice assembly? If you have adjusted the clutch, how did you do it?

Hi grumpy,

Yeah I was disappointed with the photo of the bent chassis also. I didn't realise till I loaded the photos on the computer and I had had already cut it up by then. I should have preassembled it but I was fairly confident that I only had to get the location front to rear right before welding the chassis as the height I could continue to manipulate till the strengtheners were in place.

Before assembling the clutch shaft I had no idea about the clutch clearance adjustment on these drives. Luckily I spend some time searching on here just prior to assembly and picked up on a conversation between yourself and aldot in relation to the shims on the clutch shaft. I ended up with a single thick shim in each side (be about 30thou I think) and when assembled it just drags on the corks and when dummy assembled in the mower the pedal travel seems minimal.

I will take more photos on assembly of the differential, the diff does have a lock but it is not internal, it actually uses the wheel hub to lock the differential which is kind of clever in that it places zero load on the differentials internal parts when locked .... a little fiddly to engage/disengage.

Thanks for that detail, especially in relation to the clutch clearance setup you used. I think a very slight drag would be just right - immediate smoothing wear should then make it completely free.

I have not understood your description of the diff lock so far - perhaps you can show how it operates when you post pictures of the assembly process.

here's some pictures of the major components in the differential

Here are the pictures of the reassembly, notice with the planetary gears that two go one way and two go the other.

And note the shim that has to be installed an the inner shaft

Notice in this photo the two key ways, one is on the short larger diameter shaft. This is where the hub mounts. the smaller
inner shaft is obviously the long axle shaft that travels all the way across the mower. This smaller keyway is how the diff lock operates. When engaged the diff lock locks these two shafts together at the hub face using a square plate and square block.





the black plate with the square hole in it goes over the wheel studs and the square block drops in and out of that square hole in the plate depending on if you want it engaged or not