How to fit 10" rims

[CheekyD1]

Seeing that the other thread has degenerated into the usual “Which is the best tyre” debate.
I thought I would explain the Mickey Thompson Rep’s suggestion regarding 10” wheels (in a new thread) which went along these lines

If you have managed to fit tyres wider than 11.5 inches to your Rover in the height of your choice!
You have fitted 11.5 inch (or better) wide tyres in your choice of height!

And if it doesn’t rub anywhere and the turning circle has not been reduced to that of a Power Steering Falcon Station Wagon, it is a well fitted TYRE.
Woot Woo, joy you can lend it to others without a big preflight briefing.

So you have 8” wheels but did you know you can have 10” wheels

How you ask, well you have already have fitted an 11.5 (or more) wide Tyre; I proved that at the start!

All you need to check is that you have at least an inch clearance from the inside of your current wheel’s rim to your steering tie rod ends.

It works like this
Say you are currently running 16x8 wheels with a 4” back space for example
You simply pop out and get some shiny new 16x10’s with a 5” back space.

You get and inch on both sides of the centre of the rim and your tyre stretches wider an inch each side AT THE WHEEL RIM or tyres bead.
The TYRE REMAINS in the SAME SPOT on the car and the same size.
All that has happened is that you have taken the bulge out of the tyres sidewall.

A 12” tyre is still 12” wide regardless of what wheel it’s mounted on.
On an 8” wheel it bulges 2 inches each side to be 12” wide
On a 10” wheel it bulges 1 inch each side to be 12 inches wide.
The size of the middle of the sidewall has not changed. the sidewalls are just straighter on the 10”.
The size at the middle of the tyre is the widest point of the tyre.

See magic, less bulge to get sticks stuck in.

What’s more you get a better contact patch to grab onto whatever is under the tyre.
The harder you bulge the sidewall the more you bend the edges of the tyres tread away from the ground, loosing contact area.
The straighter the sidewalls the squarer the tyres contact patch.

If you look at the Mickey Thompson catalog the 12.5” wide tyre can be fitted to an 8”, 10” or 12” wide rim.
The reps advice was that while the tyre “can” be fitted to the other sizes it was designed for the 10”, and as such works best on the 10”.

A picture might show what I am rambling on about
See how the sidewall is pulled in, from the centre of the tyre to the bead, when on 8” rims



Now see the 10”


I know this is a MTZ instead of a claw, the point being all that changes is the angle from the centre of the tyre to the bead.

Thanks for reading, hope you found it interesting

Gaz

[Tombie]

I know exactly what you're saying...

I ran 16x10s on Lara the Defender..

But 10's are, without doubt, totally, utterly illegal throughout Oz...

But I still loved running them

[Outlaw]

Nope can't get into legalities please

[Slunnie]

A 12” tyre is still 12” wide regardless of what wheel it’s mounted on.
On an 8” wheel it bulges 2 inches each side to be 12” wide
On a 10” wheel it bulges 1 inch each side to be 12 inches wide.
The size of the middle of the sidewall has not changed. the sidewalls are just straighter on the 10”.
The size at the middle of the tyre is the widest point of the tyre.

I'm not sure what the rep has told you is completely correct.

The width measurement is through the widest part of the tyre, which is the bag in the tyre. If you increase the width of the rim by 2" it is logical that the widest point of the tyre, being the bag in the middle of the sidewall will increase in width by 1". The treadface of course remains the same.

Here is a quote from BFGoodrich

>> Section width varies approximately 0.2" (5mm) for every 0.5" change in rim width.

[CheekyD1]

I'm not sure what the rep has told you is completely correct.

The width measurement is through the widest part of the tyre, which is the bag in the tyre. If you increase the width of the rim by 2" it is logical that the widest point of the tyre, being the bag in the middle of the sidewall will increase in width by 1". The treadface of course remains the same.

Here is a quote from BFGoodrich

This was how I thought it would behave too.

The MT rep had noticed that I was running 33 x 12.5 MT Claw on 8" rims and made the comment that they would perform better on the design rim of 10", I was just as cynical that what you suggest would happen.

I was assuming that the tyre would pivot from the corner of the tread block forcing the bag wider. (lots wider)
This I have recently found not to be the case, when I fitted 10's
In my experience, when you pull the beads of the tyre together (ie smaller than its design rim) the tyre seems to pivot in from the bag to the rim leaving the bag and remainder of the tyre virtually unchanged in width.

I am not aware of the BFG information, but in my experience it was not as great as the ratio quoted.
Like I said I could not pick the difference in the bag width going from an 8 to 10 for a 12.5.

It is a hard thing to describe so again maybe a picture

Because the tyre is pulled in on an 8 when this is released fitting to a 10, the sidewall seems to pivot at the green dot. If anything the green dot seems to have moved in.

I have recently heard of reports where a Tyre was actually wider on a smaller than design rim, but I have no information to support such a claim.


regards

Gaz