Thread: Durometer

Originally Posted by smoothrideronli

I am about to purchase a durometer (to determine tire life) and I wondered what is considered an acceptable reading on the guage?

I suppose that would depend on the tire and what the manufacturer specifies. Long lasting tires will be harder, short/sticky ones softer.

Unless you want to track changes (new vs. older) then I don't know how that will help you much to determine life ... but maybe there is a way.

Originally Posted by gt702

I suppose that would depend on the tire and what the manufacturer specifies. Long lasting tires will be harder, short/sticky ones softer.

Unless you want to track changes (new vs. older) then I don't know how that will help you much to determine life ... but maybe there is a way.

I didnt realize the manufacturers gave that info...worth looking into.

Originally Posted by Repeater

Use a penny? I know useless..

Not concerned with tread wear...more like rubber life due to heat cycles.

If you cannot get the info I would guess that you could measure the tire when new and then periodically. This should give you an idea on how the tire is getting harder.

Originally Posted by SheepOfBlue

If you cannot get the info I would guess that you could measure the tire when new and then periodically. This should give you an idea on how the tire is getting harder.

Problem with that is the tires I have are not new. Granted I got them last summer and they dont have a lot of mileage, but they do have a hard track day or two and some hard street riding...a bit of bluing on the edges. While I am sure I still have life in them, what reading on the durometer will be too low to be safe.

Originally Posted by smoothrideronli

Problem with that is the tires I have are not new. Granted I got them last summer and they dont have a lot of mileage, but they do have a hard track day or two and some hard street riding...a bit of bluing on the edges. While I am sure I still have life in them, what reading on the durometer will be too low to be safe.

Go to a dealer and ask to test a new one of the same type. I would think most parts people would love to see the gadget and test a bunch of tires (you could make a list) Of course some parts people will refuse and I recommend you avoid their Pedrosa like charm.

Originally Posted by smoothrideronli

I didnt realize the manufacturers gave that info...worth looking into.

I don't think they do. And if they do, there are too many variables for it to be reliable.

We are working on some rubber isolators here at work and the tolerance from the manufacturer is +/-5 ... on fresh parts, direct from the manufacturer, in a quality controlled process. The durometer "specifications" we are dealing with are in the 50 - 60 durometer range (Shore hardness scale? saw that on a print but not sure if it is the same).

I am not an expert, but would guess tire durometer is useless as an indicator unless you knew what that particular tire started at, and how heat cycles would affect it.

Push that penny, that SoB mentions, into a set of fresh rubber and the set you are looking at to see what kind of impression it makes. It would likely be as accurate and a lot cheaper than buying a gauge.

Originally Posted by smoothrideronli

Problem with that is the tires I have are not new. Granted I got them last summer and they dont have a lot of mileage, but they do have a hard track day or two and some hard street riding...a bit of bluing on the edges. While I am sure I still have life in them, what reading on the durometer will be too low to be safe.

I would think age/heat degradation would harden them and the number would go up ... not down

Unless they are really ragged out or subject to strange conditions, I would not expect a current set of tires to be affected by a couple heat cycles. This was much more of an issue in the past. Maybe if you spin up the tires a lot, but otherwise ...

As for bluing, I've never given it much of a concern. In my racing days I would notice some bluing depending on how the tires cooled off, especially if there was a little moisture on them. Within a scrub lap this was all gone, and all good. The oils that come off can cast a bluish haze.