AT4 114 tyres

For those kind enough to offer help---- I had a run down South Road (that's Adelaide) on Saturday when I went in to watch something called "football", I thought the Crows would be playing but apparently not.
Nobody "haddem", all thought they could "gettem" and in the interest of comraderie, all referred me to the next bloke along who gave me the same story. The closest I got was a shop who were prepared to take a deposit and order in, when I asked what the price would be I got the "dunno". Now I know I look stupid cos the missus keeps telling me but I declined.
I contacted an interstate enterprise but they were out of stock so I sent an email to ask when they might be available again, Didn't know. Another email to ask to be put on a list of some sort because I want them. Nope.
Went to Palmer, did you know that with enough revs in crawl gear and an empty truck the wheels will spin? :woohoo: accidentally of course on a steep uphill takeoff. These tyres won't last long at this rate :silly:
Oh well I will keep looking, one day someone will have a full set for free :whistle:

Here are the real numbers. From the Tyre and Rim Association Standards Manual (ADR reference specifications).

Eddy wrote: DD ... 7.00 tyres have a 7 inch tall sidewall.
Imperial sizes measure sidewall height,

Not quite that simple on a 7.00X16 the 7.00 will be width.

www.carbibles.com/tyre_bible.html

All the early tyres were 100% aspect ratio so there was no reason to give this in the branding. The crossply truck tyres are the same height as the width.

All vintage tyres up into the 30's used to be marked as the height and width, for example 33X4 1/2, with no wheel size. Because they were all 100% aspect ratio - width same as height. 33 is the overall height of the wheel and tyre. 4 1/2 is the width of the tyre. Some industrial and agricultural tyres still use that old system.

To find the wheel size you just take the height of the tyre top and bottom off the overall height. In this case it is 4 1/2 + 4 1/2 = 9 for the tyre top and bottom and take that away from the overall height of 33 to come up with a wheel size of 24.

If you look at the current tyre size chart above and convert the figures (overall height and section width) for a 7.00x16 tyre into inches and assume you do not know the rim size. Do the vintage tyre calculation and there you have about 16 inches for the rim.

Modern tyres of course started getting lower and wider so we have to have the 3 figures - width, aspect ratio (height) and wheel size.

Lang

Dodgeydude wrote: Paul, I thought the 7.00 meant the tyres were 7 inches wide. The 205 equates to more than 8 inches so probably not on the skinny rim properly and they appear to be a ute tyre and maybe not load rated? Softer side walls would give a softer ride though. I think the aspect ratio, sidewall height, affects the overall gearing which may account for the puss.

Ok twas a few years ago now and the grey matter has been thinking on this and I reckon your right sort of but also wrong

I seem to recall that yes 7.00 is 7 inches of tread on the ground and 205 isnt 7 inches in fact it is closer to 8 inches as you say

I have a very vague memory of asking this same question and was told ( at least I think I was told ) that metric rubbish is measured at the widest part of the tyre ie the walls

Dunno if Im dreaming this up or making it up or maybe even might be true

Some brains on here will be able to tell me if Im full of crap or not because I really dont know any more

Paul

If you can read the page above sideways it gives not only the tyre dimensions but the legal rim widths. If you want the pages with modern tyre sizes I can put that up for you.

The tread width has no bearing on the dimensions. Remember when those super flash G800 tyres came out with the tread rolled over the edges as opposed to standard narrow treads - tyre size remained the same.

This is what all the names and numbers mean. From the ADR manual.

If you want to replace your 7.00x16 cross plys with modern 205-85R16 radials they are almost an exact match

7.00x16 Width 202mm Overall height 752mm
205-85R16 Width 209mm Overall height 755mm (still legal down to 5 1/2" rims)

Lang

Lang, I remember G800 (+S!) tyres - ER78S14 (78% aspect ratio) on my Kingswood. A very confusing system and good riddance! Earlier was 185SR14 (80 %), later was P195/75SR14 (75%)

Nowadays, truck tyres are this complicated!

Jarrod.