That would mean the rim is machined to a few of thousands of an inch. Not likely! If you slacken the nuts on any tractor wheel, there is almost bound to be some up and down movement..
Front wheel hubs breaking
- Thread starter jamie
- Start date
Exfarmer
Member
- Location
- Bury St Edmunds
That was always my understanding. Most of the earlier tractors I had experience with had nuts with a taper to locate and secure the wheel dish and no weight was taken by the hub.
Then I think it was fords who introduced wheels with flat nuts and washers which held by sheer torque..
Even then I have not come across wheels which have fitted on the hubs so tight that it is not the bolts which hold the wheel. If the wheel moves at all then it will quickly come loose.
There is an issue on this hub which the dealer should have seen and sorted. By replacing the hubs they obviously recognise there is an issue. We had similar on a small new model ( at the time ) Jcb Teleporter it took 2000 hours to sort it and a complete replacement of axles.
I think the real issue is too big a loader on the front
There will be,a lot of them use chamfered nuts for this very reason.
Nearly
Member
- Location
- North of York
All it needs is a slight countersink on the hub and a slight chamfer on the inside of the wheel centre.
By the look of the poor pics it doesn't even touch?
- Location
- South West
The rep put the 75c into the farm as a replacement for a JXU and said it would be a direct replacement but was far from a direct replacement as it was a way lighter built tractor and on smaller wheels etc
Fendt hub. (I'm not happy that you made me go out in the snow..) No contact at all.
Attachments
Good ol Sam (or Keith).There is no JXU replacement still in my opinion,but should have been a Farmall U.
- Location
- Welshpool Powys
The hub and rim should be machined in such a way that the rim sits snugly on a step.
Dave W
Member
- Location
- chesterfield
Do we know what the tractor is yet?
yes its should all be correct fitting together ie mating surfaces of the hub and wheel. Tightness of the wheel nuts/studs is very important because actually the thing that should in theory take the brunt of the weight and turning stresses etc is the friction between the wheel (centre ) and the hub.
see here Graham
shows us about it,its all explained in mathematics of course
in practice weve all seen what happens when a wheel gets loose and goes all droopy drawers.....
try to keep grease and oil away from those mating surfaces as well goes without saying.
Last edited:
Courier
Member
- Location
- M62 - M1 - M18 triangle
Had a 4’6” wide silage grab on a 2wd DB 990 years ago - the grab was filled with silage by rotating it forwards to pull out of the clamp - no way would it have torn out by a lifting action.
Used a big counterweight but never had any bother with 7.50 x 16” front wheels, countersunk wheel studs or the front axle.
Courier
Member
- Location
- M62 - M1 - M18 triangle
The all load on wheel studs ( other than tension) is taken on the angled surfaces of the head/nut - never on the threads .
Courier
Member
- Location
- M62 - M1 - M18 triangle
This is not a situation where friction comes into the equation - coefficient of friction only comes into play where two surfaces are moving against each other. A wheel / hub combination should exhibit zero relative movement.yes its should all be correct fitting together ie mating surfaces of the hub and wheel. Tightness of the wheel nuts/studs is very important because actually the thing that should in theory take the brunt of the weight and turning stresses etc is the friction between the wheel (centre ) and the hub.
see here Graham
its all explained in mathematics of course
in practice weve all seen what happens when a wheel gets loose and goes all droopy drawers.....
try to keep grease and oil away from those mating surfaces as well goes without saying.
GeorgeK
Member
- Location
- Leicestershire
The bolts are in tension. They clamp the flat surfaces on the wheel and hub together. The friction generated is what takes all the forces.
Like strapping say a fuel tank down on a flat trailer. The straps don't have to touch the sides of the load to keep it in place, it's clamped down and friction against the bed stops it from moving.
Like strapping say a fuel tank down on a flat trailer. The straps don't have to touch the sides of the load to keep it in place, it's clamped down and friction against the bed stops it from moving.
ah well, i got the wrong video then
GeorgeK
Member
- Location
- Leicestershire
It's true that something stationary will have no forces of friction acting on it, but as soon as you try and move it friction will push back with an equal force until it moves. Many bearings are friction fit (aka interference or press) and they're designed not to move.
ok in simpler terms lets call it grip , the wheel centre surface needs to be totally gripped against the corresponding surface of the axle hub or else damage of some form will start to occur .
GeorgeK
Member
- Location
- Leicestershire
Apologies for rabbiting on but it's something I find interesting. For example a grade 10.9 M22 stud can take a tensile load in excess of 25,000kg (called the proof load) so with 10 of those cranked up on a commercial axle there's some serious friction stopping the rim from moving.
It is called friction grip. Basically the clamping load in the joint generates a shear load in the joint which has to be overcome before movement can occur. This website discussed it a bit.
A M22 10.9 bolt has a recommended torque of 652Nm. A manufacturer will not recommend adopting this torque as it goes up to 70-90% yield, so if the studs are repeatedly tightened low cycle fatigue will become a problem.