Thread: can anyone explain?

Originally Posted by dm_td5

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

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

Originally Posted by dm_td5

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

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

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

Originally Posted by 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.

Apple or cherry

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

Baz.

Originally Posted by dm_td5

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

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

Dosen't matter.

I believe Motorway are out of business, now.

Originally Posted by hook

Dosen't matter.

I believe Motorway are out of business, now.

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

Originally Posted by dullbird

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

Originally Posted by hook

I believe Motorway are out of business, now.

Originally Posted by dullbird

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

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

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