Wheels sizes and Tyre sizes.

[Marshy0201]

Hi All, I have a New Holland 8340 in current refurbishment stage. I’m at the point of sorting out my wheels. I currently have 420/70/28R on the fronts and wanted to put on 540/65/28R.
I was unsure as to whether they’d fit on the same rim. It’s the width of the rim that is a worry.
Any help much appreciated. TIA

 

[Simon Chiles]

Hi All, I have a New Holland 8340 in current refurbishment stage. I’m at the point of sorting out my wheels. I currently have 420/70/28R on the fronts and wanted to put on 540/65/28R.
I was unsure as to whether they’d fit on the same rim. It’s the width of the rim that is a worry.
Any help much appreciated. TIA

You’ll need to tell us the rim width first, it’ll be stamped on it.

 

[john432]

Or measure across the rim, estimating the width of where the rims of the tyres actually sit, usually to the nearest inch

 

[Boohoo]

Standard rims will be too narrow. You know you'll also need to change the rear tyres?

 

[Marshy0201]

The rim width is 330mm / 13 inches

 

[Marshy0201]

I have 600’s for the back to change them from 520’s

 

[Alistair Nelson]

You want to change to 480/65r28 otherwise it will through your transmission ratio out and wind it up if fitting 600’s on the rear.

 

[Drillman]

@Nearly tyre chart time again

 

[Boohoo]

I have 600’s for the back to change them from 520’s

You'll need 650/65r38 rears if you want 540/65r28 fronts.

 

[Nearly]

@Nearly tyre chart time again

 

[Nearly]

You want to change to 480/65r28 otherwise it will through your transmission ratio out and wind it up if fitting 600’s on the rear.

You'll need 650/65r38 rears if you want 540/65r28 fronts.

Yes, 540 65 28 are a height size up from what you have. 650 65 38 needed on back to match. Michelin say so!

Fronts don't normally look as silly as rears at these wide sizes but going out to 540mm is 21.6 inches so a bulge of 4 inches at each side of the rim.
This is not within spec for that size of tyre. Tyre fitter / company will wriggle out of any warranty if you're fitting fresh tyres.

 

[Marshy0201]

The width of the fronts and backs make no odds. That won’t wind up the diff. No different than having duals on the back but not the front .
@Nearly thankyou for your response and the chart, i’m pretty sure I have seen 540’s on the rims I have (which are standard factory fitted rims) but it was something that kept bugging me as to whether they’d fit.

 

[Nearly]

The width of the fronts and backs make no odds. That won’t wind up the diff. No different than having duals on the back but not the front .
@Nearly thankyou for your response and the chart, i’m pretty sure I have seen 540’s on the rims I have (which are standard factory fitted rims) but it was something that kept bugging me as to whether they’d fit.

The combination of the width and the sidewall height means the tyres you have mentioned using do not match. They are different widths but also different heights / radii.
Almost anything will fit, but using mismatched sizes causes problems, especially in 40 series and younger as the 4wd comes in when the brakes are used at speed on the road.
It's up to you. We're just trying to save you from large repair bills.

 

[Netherfield]

This should be made a sticky

 

[Boohoo]

The width of the fronts and backs make no odds. That won’t wind up the diff. No different than having duals on the back but not the front .
@Nearly thankyou for your response and the chart, i’m pretty sure I have seen 540’s on the rims I have (which are standard factory fitted rims) but it was something that kept bugging me as to whether they’d fit.

For the same profile, tyres get taller as they get wider. You can't go up to the next size on the front without going up on the back.
Either 16" or 18" rims are recommended for 540/65r28, putting them on narrower rims looks awful, makes them wear the middle of the tyre faster and most importantly you don't get the full benefit of the wider tyre.

 

[Marshy0201]

@Nearly Thankyou, I always assumed the width makes no odds. The new ones I have are
600/65/38
540/65/28
The middle number is the same. So when purchased I thought this would be okay.
I have also a NH T6.175 with 650’s and 520’s on. And had no issues with this one.

 

[Nearly]

I have a pair of 8340's and a 7840.
All 3 run on 18.4 38 rear equivalants according to the chart above. Including rowcrops, 18.4 38 (480 85 38), 520 70 38 to 600 65 38.

The fronts are 14.9 28 (380 85 28), 420 70 28 and 480 65 28. These tyres are all the same height as each other on the above chart and in real life in my tyre shed.

The second figure in the tyre size is a percentage figure of the sidewall height compared to the overall width.
As the tyre gets wider, even at the same % profile the tyre will also get taller. It's not a consistant height measurement, but varies with width.

Just compare the fronts you have against each other.

 

[Nearly]

 

[glasshouse]

Is that the moffett?

 

[Grouse]

Personally I would and have gone for 480/70/28 on the front and 580/70/38 on the back - they are the largest diameter tyre you can fit to an 8340 without being too wide and give you an extra 4 mph - plus they look absolutely fierce