Wheel studs and rims cracking

Try lowering the tyre pressures a bit. This will ease the dual wheel "slap" which causes shock loading on rims and bolts.

I think 30 psi is recommended. I am at 28 psi
How low can you go with no tyre damage ?

KWO said:

I think 30 psi is recommended. I am at 28 psi
How low can you go with no tyre damage ?

Click to expand...

I`m no tyre expert and I don`t operate a Combine. but 30 PSI or even 28 on Duals seems too high. I`d try lowering that to 25 and see how you go.
I always lower pressures significantly when mounting Duals on a tractor, depending on application of course, but typically I`ll go from 30 PSI on a tractor with singles and a 3pt sprayrig, to 15/17 PSI on the same tractor with duals on a 23 tonne single axle graincart.
Lowering the pressure improves ride comfort and as I said reduces that dual wheel slap, and shock loading on the bolts and rims, which becomes worse the harder the ground is.
What is reccomended "Singles" tyre pressure on that Combine.

Haven't got the book handy but I think its around 50 PSI

I am shocked to read that some dealers are putting duals on without cleaning paint off of the mating surfaces!! Of course that isnt going to end well, regardless of color!! Our local dealer cleans all surfaces when installing duals so that there is bare steel on bare steel. Only guys I know of around our area that were having issues with wheel bolts breaking were running NON-FACTORY hopper toppers and 40' heads. I guess 450 bushels of tough, heavy wheat plus a 40' header starts to push the limits of the machine. We have an 8230 with a factory hopper and 620 duals. Haven't had any issues, so far at least!!

My dealer has written 23psi next to the valves

Must be why the dually rims are an inch thick on the Lexions.

Had 3 rims crack on the 8010. Very common problem here in West Aussie. The new 7230 is on singles and the new Ultraflex tyres. Will be interesting to see how it goes this season.

We make a 1/2" thick ring spacer that goes on the outer surface of each rim to prevent them from cracking out. The factory 1" thick bushing spacers cause localized pressure on the bolt holes that causes the cracking. A full ring plate provides distribution of the load throughout the entire mating surface. We've repaired a set of 4 rims by removing the centers, and replacing them with 1" thick rings welded in. But as a preventitive measure these ring spacer plates work well. The factory lug bolts work with these. The set of 4 spacers are available for $200.00 though Supreme Welding Inc. Home

The new CNH operators manual recommends 42-44 psi depending on the size of the header. My thoughts are that the rims flex too much with lower tire psi. Another note, on the CNH combines you don't want to put antisieze on the bolt threads as they already have a special coating on them and by putting antisieze on them it can cause inconsistent bolt torque. New torque spec is 1000 ft/lbs which I believe is to keep the rims from shifting under high stress which is probably when the bolts/rims start breaking.

Got a nh 9060 done 4 harvests both left side rims have cracked haven't pulled off other side yet just trying to negotiate with dealer to see if nh will pay anything

Had this happen on our NH9060 this year. Noticed a intermittent pop coming and got out and found 2 studs missing. The rims were not cracked.

We were popping lug bolts, went from like 34 all around down to 26 on the inside and 18 on the outside of our 7230 with a 12 row drago corn head. No more broken bolts and it rode a little better.

The newer CNH duals have gone from 12mm to 14mm centres with different dishing which helps.

Upgrading to 12.9 grade studs from 8.8 also has been an improvement.

NH required as a warranty job to crank ours up to 1100 insanely tight but have been 1000h trouble free.

We have also dropped our 620 duals from recomended 35?psi to 28, prefer to split sidewalls at 4000+h than break rims and studs every 500.

Personally think one of the bigger flaws is that they should have a inside and outside rims. Inside rims (normally go first) dont require the large holes to clear the 5 inner nuts which is a huge weak point.

We have a rim with a 20mm welded centre if you want to have a look nobby

It appears the majority of these broken wheels are using spun centers? If possible, can some one take a straight edge across the flat area around the lug holes?

The mating surfaces of these wheels has to be perfectly flat. That should be obvious, but I'm wondering if the wheel manufacturer is either using too heavy of steel for the center making machine or the machine is out of spec.

If you look at a truck hub piloted wheel system, both wheels are tightly piloted on the hub and the wheel mating surfaces are perfectly flat. Flat to the point that the center has a bulge where the mating surfaces come together. Paint in there does not matter as the surfaces are correctly manufactured and the wheels are properly piloted.
How are the duals piloted on these machines that break the duals?

foxwell_87 said:

The newer CNH duals have gone from 12mm to 14mm centres with different dishing which helps.

Upgrading to 12.9 grade studs from 8.8 also has been an improvement.

NH required as a warranty job to crank ours up to 1100 insanely tight but have been 1000h trouble free.

We have also dropped our 620 duals from recomended 35?psi to 28, prefer to split sidewalls at 4000+h than break rims and studs every 500.

Personally think one of the bigger flaws is that they should have a inside and outside rims. Inside rims (normally go first) dont require the large holes to clear the 5 inner nuts which is a huge weak point.

We have a rim with a 20mm welded centre if you want to have a look nobby

Click to expand...

Had the Cleve dealer mods done at the end of 2013 harvest Tony, it involved new higher grade studs 1000 ft/lb torque, and grinding paint off the rim contact areas. No cracking or broken studs this year (350hrs).

SupremeWelding said:

We make a 1/2" thick ring spacer that goes on the outer surface of each rim to prevent them from cracking out. The factory 1" thick bushing spacers cause localized pressure on the bolt holes that causes the cracking. A full ring plate provides distribution of the load throughout the entire mating surface. We've repaired a set of 4 rims by removing the centers, and replacing them with 1" thick rings welded in. But as a preventitive measure these ring spacer plates work well. The factory lug bolts work with these. The set of 4 spacers are available for $200.00 though Supreme Welding Inc. Home

Click to expand...

This makes sense.

I had a 2010 R76 with 20.8x42,with michelin's, ran 20 psi inside and 18 psi outside. Ran 4 years without any issues. Same set-up on 2014 S78, no issues. Gleaner makes a very good dual set-up, But to high of tire pressure might just cause some grief, pluse give a bad ride. Just saying might try lower air pressure.

I got duals on my S78 and was worried as my neighbour's have trouble with their CIH rims. Titan rims are used on Gleaner as well as Case, the difference I see is the Gleaner studs for the outer rim are bolted further out in diameter on the rim with lots more bolts which I feel the outer rim has less leverage on the studs. I haven't heard of Gleaner rims breaking, Not saying they don't and obviously there is a lot less Gleaners. Time will tell