In the planter closing wheel discussion thread below, there is discussion about and reluctance to change the tail piece on a 7200 planter.

Before buying ANY closing wheel, or even using the OEM wheels, release the spring pressure on your tailpiece and try to move the tail piece from side to side.

As the center to center distance at the tightest point on most closing systems should be just a tad more than your seed depth especially for corn, if you can move your tail piece more than maybe 1/4" side to side THAT should be where you put your money before buying any brand of closing wheels and before planting any $150-$300/bag seed!!!

Lateral movement of the tailpiece means that your closing wheels are not centered over your seed slot much of the time.

The last 7200 was manufactured around 1996 or 18 seasons ago. Most are over 20 years old. The 7200 OEM tailpiece was manufactured out of relatively thin sheet metal.

Most 7200 tail pieces I've seen should be replaced before putting one seed in the ground.

The idea that people will plant hundreds of acres of expensive corn seed but balk at the idea of spending $50-75/row to replace or rebuild the closing wheel tail piece on their 20+ year old JD 7200 or 7300 planter defies logic.

The RK rebuild kit is excellent, Shoup, SI and JD parts all have replacement parts. If you are replacing the tail piece I suggest you go with a part which uses bolt on closing wheels rather than the 7200 stud. You can reuse your existing 7200 wheels by supplying a new 5/8" bolt, nut and washers.

It is critical to planting success to keep the closing wheels as centered as possible over the seed slot. Not rocket science.

Jim at Dawn

Dawn did manufacture a ball bearing version of our Curvetine closing wheel but we have discontinued the ball bearing version and only produce our regreaseable Timken tapered roller bearing/triple lip seal version.

Any brand or type of tooth type closing wheel is much harder on bearings than a smooth OD rubber tire. The intermittent load of an individual tooth hitting sometimes hard ground puts different stresses into bearings than a smooth rubber tire.

The standard, inexpensive imported 203 class sealed ball bearings used by OEMs will likely have a shorter life with any type of toothed closing wheel than it will with a smooth rubber tire.

And for all the winter preparations for planting, all the dollars spent on planting technology, if a simple $3 closing wheel bearing goes out you have to stop and fix it.  And what is down time worth on a planter in the spring when the time is right and the sun is shining?

I didn't see what closing wheel spring they were using, Did you? ( just scanned all 288 pages, the last couple nights)

Was it a factory spring or a 1/2 rate spring?

Hi Loran.  Our standard spacer on the JD cat 1700 and later tailpiece provides about 2-3/8" center to center on the teeth at the tightest point if both wheel are in the front hole.

We find that is the best all around spacing for corn and soybeans.  We do have a narrower spacer that we have sold for the previous Curvetine in cotton.

There are tradeoffs in spacing.  An issue is the lateral play in both the row unit tailpiece and the row unit itself. And then there are curves and sideslopes, all of which tend to cause the planter row units to crab a bit.  No vee closing wheel should be directly over the seed.

The new M series Curvetine does offer more adjustability in addition to several other improvements.

As far as down pressure on closing wheels and needing "more" according to the Beck's study, I think we need to be very careful with that.

More often I see too much down pressure on Curvetines rather than too little.

The standard 12" od x 1" wide OEM rubber tire has 4 or 5 sq in of contact area per side or 8-10 sq in of soil contact area per row.  What they were probably seeing is that with this much contact area a lot of pressure is needed in many soil conditions to eliminate air pockets around the seed. I believe that.   The standard Deere and especially the new White tail piece spring put an incredible amount of down force on closing wheels.

Another approach is used with the Curvetine. Two Curvetines per row have only 3 or 4 sq in of contact with the soil at any given time and therefore do not need anywhere near the tail piece down force that the OEM rubber tires do in any given soil condition.

Too much down pressure can make bricks around the seed in some soil conditions.

The way to judge is to dig seed behind the planter: is the seed down in the bottom of the seed slot with good seed to soil contact and no air voids right around the seed?  On the JD 1700 and later tail piece we rarely get out of the lightest spring slot. JD also offers a half rate tail piece spring through dealers parts counters for those in highly tilled or lighter ground.

Note that what ever down pressure is applied to the tail piece tries to unload/lift the row unit and can in fact affect seed depth unless you have a lot of down force on the row unit air  bag, springs etc.

Note in this stiff, wet SE WI clay notilling beans between corn rows this White 6000 planter has the tailpiece spring in the second lightest notch. If he had two Curvetines per row the first notch would be more than adequate even in this tough soil. Look at the seed slot sidewall ahead of the closers

Look at the rubber tire side, look at the Curvetine side, and if you were a seed which side would you rather emerge from?  Two rubber tires and a lot more down pressure would be very harmful to emergence in this condition as well as many others.

I hope this helps.

Jim at Dawn

(One OEM rubber closer (top) + One Curvetine (bottom) in heavy clay notill pic 2.JPG)

(One OEM rubber closer (top) + One Curvetine (bottom) in heavy clay notill pic 3.JPG)

One OEM rubber closer (top) + One Curvetine (bottom) in heavy clay notill pic 2.JPG (91KB - 761 downloads)

One OEM rubber closer (top) + One Curvetine (bottom) in heavy clay notill pic 3.JPG (98KB - 792 downloads)

Loran, with you paying attention to planter maintenance (no lateral play in the tail piece) and the goal to have that distance approximately equal to your seed depth combined with your crop results I'd say that you shouldn't change a thing.

I would definitely watch your closing wheel down pressure.  Being that close to the seed especially you do NOT want excessive pressure which to put the Curvetines below seed depth. 

For most folks the approximately 2-3/8" standard spacer distance on the JD cast iron tailpiece is a safer setting.

Thanks for the picture. I'm glad these gave you your "best stand ever".

Jim at Dawn

I agree on the importance of eliminating L/R closing bracket slop, as well as any tendency to not operate smoothly up/down due to wear.  I'd also like to point out that we at Exapta also have closing bracket updates for the 7200s, 7000s, and Kinze 2000s to convert them to closing wheels held with bolts.  And our Thompson closing wheels have always been built with extremely durable bearings -- we guarantee them for 5 years, and most are still running after 8 - 10 years.

Loran, like many things related to planting, there is just no concrete answer.

I think the best guide is that you said you had your best stand ever last year with your Curvetines set as they are.  "If it ain't broke don't fix it" comes to mind.

The thing to do again as every year is to check there is little to no lateral play in your tailpieces, or row units for that matter. Parallel link bushings also affect the ability to keep the closing wheels centered on the seed.

We space them out a bit further to be a bit cautious for those folks that are crabbing more for various reason.

Summary: grease your Curvetines, check for side play and you should be good to go.

Jim at Dawn

Your parallel link bearing system is probably part of the reason you had such a good stand last year, Loran.  It kept the closing wheels centered on the seed slot very well.

Jim at Dawn