can anyone explain?

[dullbird]

OK as embarrassing as it is.....because I have had my tyres on over a year now and have only just noticed this:angel:

but can anyone explain why my 255/70/16 mongrels have 32/10.5/r 16's on them

AS WELL!!!:eek:


Could it actually be that my tyres are not 255 and maybe slightly bigger and that is why they rub in the rear wheel arch? and have dented my camel cut guard!

[lokka]

Metric and Imperial sizes thats all

[dullbird]

Metric and Imperial sizes thats all

but i'm assuming 32/10.5 means the tyres are 32? or is that not right

coz as far as I was aware 255/70's equate to some thing like 30.1

[B92 8NW]

Aren't they a remould?

Might be a 32x10.5 carcass they used?

[dullbird]

but how can you make a 30" tyre on a 32" carcus?

and why would they write it on the tyre it's self

[JDNSW]

The metric and imperial sizes, as you point out, do not agree. What the actual size is, would seem to be a matter for conjecture, but presumably something the manufacturer decided they could sell to both metric and imperial markets.

Tyre manufacturers have never been particularly truthful in their tyre sizes - for example, a couple of years ago I had to replace a rear tyre on my tractor - the only readily available tyre was five inches different in diameter to the ones fitted, so I ended up having to get two (but sold the good one second hand to someone who had the same problem).

John

[V8Ian]

Remould, recap, retread, call it what you like, it will never change the tyre size. the two stated sizes, as previously mentioned, are metric & imperial.

[long stroke]

To me your tyres look more like 32s anyway;)

[JDNSW]

Remould, recap, retread, call it what you like, it will never change the tyre size. the two stated sizes, as previously mentioned, are metric & imperial.

Yes - but 255mm = 10.04" not 10.5,
and 255mmx0.7x2 + 16" = 30.06" not 32.

or putting it the other way,

10.5" = 267mm not 255mm
and (32" - 16")/2 = 8" = 203mm = 76% of 267 or 79% of 255, not 70% of anything.

there is no way to make 32 x 10.5 the same as 255/70 - 16

John

[V8Ian]

El cheapo tyres straight out of the whoflungdung rubber company?:confused:

[dullbird]

so would there be away of working it out to try and find out exactly what I have one....I'm intending on changing my tyres soon and I dont want to go smaller!!! which would be what i was doing if I had infact not had 255's on

[scrambler]

so would there be away of working it out to try and find out exactly what I have one....I'm intending on changing my tyres soon and I dont want to go smaller!!! which would be what i was doing if I had infact not had 255's on
Drop a tape measure from the top of the tyre to the ground. See whether the measurement is more or less than 30 inches.

[isuzurover]

so would there be away of working it out to try and find out exactly what I have one....I'm intending on changing my tyres soon and I dont want to go smaller!!! which would be what i was doing if I had infact not had 255's on

If you want to see what size they really are, just measure the section width and diameter (without weight on it).

But just get some 255/85-16s for the next tyres.

[dullbird]

If you want to see what size they really are, just measure the section width and diameter (without weight on it).


But just get some 255/85-16s for the next tyres.


actually I was thinking of getting 265/70/16's..........

[dullbird]

Drop a tape measure from the top of the tyre to the ground. See whether the measurement is more or less than 30 inches.

might do this on the spare as that has all the tread there

[dullbird]

ok so I just measured the spare its about 30/31"

So what size would I be looking at for a 32 in metric......sorry I can't even blame it on the hair colour either :D

[rick130]

The most accurate way to measure the diameter is run a tape around the circumference and divide by Pi.
We used to do this with race tyres just to match them up in pairs as they varied so much batch to batch. (as in run a stagger tape around them. We couldn't care less what diameter they were exactly, as long as they were within Xmm in circumference)

The Maxxis 255/85's when I bought them measured up almost exactly 33.3" diameter.

[LandyAndy]

Mongrels are a remould.
The new tyre size is what they glued on to the old tyre.
The other is probably the original size on the original carcass.
Good tyres for off-roading,but wouldnt have them as every day drive tyres.
Andrew

[dullbird]

people you don't need to tell me they are a remould I brought them remember!!! :lol2:

Andy like I said before and feel free to answer how do you fit a 30" tyre on a 32" carcus if that is the case?

[lokka]

The most accurate way to measure the diameter is run a tape around the circumference and divide by Pi.
We used to do this with race tyres just to match them up in pairs as they varied so much batch to batch. (as in run a stagger tape around them. We couldn't care less what diameter they were exactly, as long as they were within Xmm in circumference)

The Maxxis 255/85's when I bought them measured up almost exactly 33.3" diameter.

Yep this is the only real accurate way of doing it as for tyre sizes i run 33x12.5x15 maxxis buck shots wich are only 32.2in tall ;)

[dmdigital]

people you don't need to tell me they are a remould I brought them remember!!! :lol2:

Andy like I said before and feel free to answer how do you fit a 30" tyre on a 32" carcus if that is the case?

Firstly I believe they should be. But as they obviously have I would think it has to do with how much rubber they take off vs how much they reapply. Remembering of course that this includes the tread depth (when new). So the originals could well have had sufficient tread depth that the tyre was well and truly a 30" with a lower tread depth. That said this would be 1" difference in tread depth between the old and new :confused:

[V8Ian]

Firstly I believe they should be. But as they obviously have I would think it has to do with how much rubber they take off vs how much they reapply. Remembering of course that this includes the tread depth (when new). So the originals could well have had sufficient tread depth that the tyre was well and truly a 30" with a lower tread depth. That said this would be 1" difference in tread depth between the old and new :confused:

It apears that the retreader glues the size onto the case. If they glue 16-8-28 onto it that doesn't make it so. Some very ordinary QA methinks

[dullbird]

Firstly I believe they should be. But as they obviously have I would think it has to do with how much rubber they take off vs how much they reapply. Remembering of course that this includes the tread depth (when new). So the originals could well have had sufficient tread depth that the tyre was well and truly a 30" with a lower tread depth. That said this would be 1" difference in tread depth between the old and new :confused:


that really doesn't make sense to me:confused:.......can you explain it in a little more dumb dumb:D

[dmdigital]

OK I'll try...

The diameter of a tyre is the total outer diameter which includes the tread.
Tyre treads are of different depths which can vary by several millimetres.
This also has a factored in maximum wear (wear indicator bars) so one tread might be 13mm deep but have a wear limit of only 5mm whilst another might be 10mm deep but allow for wear down to 3mm.

When they retread the tyre they take the carcass back to the rubber above the belts and fuse on a new outer surface and tread. This tread has what ever depth they have settled on in their retreading process and so differs from the original tyre, making the diameter more or less. Added to this is the amount of rubber between tread and belts and the amount of rubber reapplied and thus you have a few factors for possible differences in diameter.

... I think I need to re-try that sounds just as confussing:confused:

[Redback]

The most accurate way to measure the diameter is run a tape around the circumference and divide by Pi.
We used to do this with race tyres just to match them up in pairs as they varied so much batch to batch. (as in run a stagger tape around them. We couldn't care less what diameter they were exactly, as long as they were within Xmm in circumference)

The Maxxis 255/85's when I bought them measured up almost exactly 33.3" diameter.

Apple or cherry:p

Lou, Maxxis Bighorns 265/75/16, 31.8, great tyre:D

Baz.

[dullbird]

OK I'll try...

The diameter of a tyre is the total outer diameter which includes the tread.
Tyre treads are of different depths which can vary by several millimetres.
This also has a factored in maximum wear (wear indicator bars) so one tread might be 13mm deep but have a wear limit of only 5mm whilst another might be 10mm deep but allow for wear down to 3mm.

When they retread the tyre they take the carcass back to the rubber above the belts and fuse on a new outer surface and tread. This tread has what ever depth they have settled on in their retreading process and so differs from the original tyre, making the diameter more or less. Added to this is the amount of rubber between tread and belts and the amount of rubber reapplied and thus you have a few factors for possible differences in diameter.

... I think I need to re-try that sounds just as confussing:confused:

ok I understand that a bit better.......BUT the carcus are bf's and wranglars SO I would have to assume they were almost 32's with a road tyre originally prehaps becasue i cant imagine and m/t having a tread depth of over 2"
as the tyres I have being 30" in size have a tread depth of I think 10 possibly 13mm...

So if I have this right in order for my 30's to be on a 32 carcus we have to assume that they took way more than 2" of that tyre before glueing the remould on maybe? personally I think this doesn't sound right.

BUT I just had a thought if I remember tomorrow i will see if I can see the sizes from the inside as its not moulded from side to side so you can see the carcus from the inside:)

[hook]

Dosen't matter.

I believe Motorway are out of business, now.

[dullbird]

Dosen't matter.

I believe Motorway are out of business, now.

not really sure what that has do do with asking about two sizes?

[mike 90 RR]

feel free to answer how do you fit a 30" tyre on a 32" carcus


I believe Motorway are out of business, now.


not really sure what that has do do with asking about two sizes?

Same theory as sticking a square peg in a round hole :p ....

Some moron on the casing machine? .... that's why they are out of business?


Perhaps it's because of the following
The Construction of the Casing itself, is below 30" and combined with the original tread depth of the tyre pattern, was huge in depth, and ended up measuring 32"

So when they stripped the remainder tread off & got back to the casing size only, and then applied the new tread rubber ... the casing was suitable for a 30" rubber tread mould ... as this new tread is not as deep as the original


Hope this explains it

[dullbird]

Same theory as sticking a square peg in a round hole :p ....

Some moron on the casing machine? .... that's why they are out of business?


Perhaps it's because of the following
The Construction of the Casing itself, is below 30" and combined with the original tread depth of the tyre pattern, was huge in depth, and ended up measuring 32"



So when they stripped the remainder tread off & got back to the casing size only, and then applied the new tread rubber ... the casing was suitable for a 30" rubber tread mould ... as this new tread is not as deep as the original


Hope this explains it

yeah it does explain it....but what confuses me is the carcus I have are not aggressive tyres, so I just cant imagine them taking off or even being able to take off that much rubber to lower it down enough that when my rubber goes on with10mm of tread depth it can still be a 30" tyre....does that make sense?

I'm not saying that its not the case....onlythat I find it very hard to believe

[p38arover]

It took a while for me to realise that a "carcus" is a carcass! :p