B7200 new tyres and rims

[Paul Allwood]

So close

Three of the four new wheels and tyres are now fitted - both front and the right rear. Now it looks like a tractor (to me).





The threads on the studs on the left rear are pretty damaged and I'm not keen to run the threads on the new wheel nuts the first time I put them on. I should have checked - now I'll need to wait until I can get a M14 x 1.5 die nut to clean up the threads. Should work well enough, otherwise I'll need to replace the studs.



I also weighed the rear wheel assemblies using a couple of 20 kg weight plates as a reference.
- Turf tyre/wheel assy: 31.5 kg (69.3 lb)
- Skid steer tyre/rim assy: 51.7 kg (113.7 lb)

This adds a total of 40.4 kg (88.9 lb) to the rear wheels.

Here's the fancy weighing setup with one of the new rear wheel assemblies:



I've lost a little width at the rear:
- Turf tyres - 1390 mm outside-outside
- S/steer tyres - 1250 mm outside-outside

I'm interested in your thoughts - is it worth adding spacers to get back to the original width ?

 

[Paul Allwood]

All done and tested. I fixed the damaged rear left wheel studs and mounted the last wheel this afternoon.











I moved a few pallets of bricks and a new (to me) rotary hoe, and the wheels didn't even break or fall off. Pretty happy with that.



I tried the push it on concrete test as suggested by @North Idaho Wolfman to check the wheel rolling circumference ratio. Managed to push it about 30 feet (the longest stretch of concrete we have) reasonably easily with 4WD engaged. There was a little resistance when disengaging 4WD, but no more than it had been using 4WD with the turf tyres on dirt. Also drive around for a while with 4WD engaged - no resistance to disengaging after about 5 minutes.

It's nice to actually finish something - it doesn't seem to happen often.

Next post I'll list sizes of tyres and rims that I used.

 

[Paul Allwood]

I've listed what I've used below - not listed as options for the B7200 but I had trouble finding the specified sizes here in Australia. Probably not the only option, but I'm happy enough with it.

Front

Tyres: 23x8.5-12
Rims: 12x7

Rear

Tyres: 12-16.5
Rims: 16.5x9.75

If you try these sizes yourself, suggest you find the rolling circumference spec for the specific tyres you use to confirm a suitable front:rear ratio first.

 

[tsp159]

I'm going to say, you're doing all the things to your 7200 that I've thought for my 7100. I like the idea of using the Bobcat 16.5" wheels with heavy adaptors. That solves a ballast issue and a tire sizing issue at the same time.

The welding work on the 12" wheels is great for a DIY job. Stealing that idea, shamelessly.

 

[Paul Allwood]

I'm going to say, you're doing all the things to your 7200 that I've thought for my 7100. I like the idea of using the Bobcat 16.5" wheels with heavy adaptors. That solves a ballast issue and a tire sizing issue at the same time.

The welding work on the 12" wheels is great for a DIY job. Stealing that idea, shamelessly.

Thanks for the comment on the welding. Steal away - hope it's useful for you.

 

[North Idaho Wolfman]

Can I make you cry?
Or should I say, I'm gonna make you cry?
And I'm sorry to be the bearer of bad news!
But both hubs and axles have major issues.

Do you know that someone has welded one of the rear hubs to the axles, ruining the hub, and the axle?

I was wondering why you wanted to use spacers, and was going to say just move the hubs, well that ain't happening.

Shocked someone did that!

And WTH is going on with this hub?????

 

[Paul Allwood]

Can I make you cry?
Or should I say, I'm gonna make you cry?
And I'm sorry to be the bearer of bad news!
But both hubs and axles have major issues.

Do you know that someone has welded one of the rear hubs to the axles, ruining the hub, and the axle?

I was wondering why you wanted to use spacers, and was going to say just move the hubs, well that ain't happening.

Shocked someone did that!

And WTH is going on with this hub?????

Yeah, I noticed. My brother in law looked at it for me before I bought it so I didn't know until after I had paid for it and collected it from him.

Apart from not being able to slide anything in and out along the hexagonal section of the axle, or change any of these external hub fittings, what problems will these bits being welded on cause ?

 

[North Idaho Wolfman]

I would be worried the heat welding on them can cause tha axle to fracture or even soffen.
Just keep an eye on it.

 

[Paul Allwood]

I would be worried the heat welding on them can cause tha axle to fracture or even soffen.
Just keep an eye on it.

Thanks - will do

 

[North Idaho Wolfman]

If you could cut the hubs off without damaging the axles you could get new hubs so you have adjustability.

Hubs

 

[Paul Allwood]

If you could cut the hubs off without damaging the axles you could get new hubs so you have adjustability.

Hubs

Thanks

 

[Paul Allwood]

Great project you’ve started there! Adapting skid steer rims and improving the mount plate sounds like a solid upgrade.

Regarding the wheel nut setup, Kubota’s use of plain holes and flat washers is likely a cost-effective and simple solution for securing the rims. This approach works well for light to medium-duty tasks where precise alignment isn't as critical.

On the other hand, using tapered wheel nuts with countersunk holes provides better alignment and even pressure distribution, which is why you’d typically see that on higher-performance or heavy-duty equipment. If you're planning on heavier work or more frequent wheel changes, moving to the tapered system might be a good idea.


Keep us posted on your progress interested to see how the new rims perform!

Thanks David. They got a bit of a workout this afternoon moving some heavy firewood logs with the front forks. I used 4WD for most of this - very little resistance to disengage 4WD when I finished - indicates that the wheels are sized right front to back and/or there's enough slip in the ground to not cause wind up.

I ended up with countersunk holes for the front and back wheel nuts. I used 90 degree included angle rather than the standard automotive 60 degree as that's the countersink I have. Just had to turn the cone on the front end of each wheel nut to match.

So far, so good. All still tight.

I also mowed after moving the logs - I could see a few tracks from the skid steer tyres on the bare dirt but none on the grassy areas.