Isolastic Rubber Hardness

The RGM ones seem too hard also. I thought someone on here did a comparison a while ago by measuring the hardness somehow. The conclusion was the AN ones were softest and closest to the originals.
 
I've fitted 2 Norvil front mount sets this year and was told the rubbers are 45 shore....which eliminated the vibration issues experienced .....mind you the old rubbers removed were shagged
Very interested to hear the hardness test results of the AN or RGM rubbers that are now for sale currently...or if anyone has asked them.
 
SteveC said:
A little while back I bought a cheap durometer to check the hardness of the tyres on my old bikes. If truth be told, I don’t ride enough and most of my tyres harden with age before they wear out. The durometer has done its job well identifying some old tyres with a hardness of 80 that were starting to be skittish.

I am presently rebuilding a 1972 Commando and I thought that it would be interesting to compare the hardness of modern isolastics against the originals. My Commando was laid up in 1977, so I am reasonably confident that the isolastic rubbers I have taken out are original.

My durometer is not calibrated, but it measured a hardness of 58 on a new tyre that I recently fitted that has a specified hardness of 60. So I have a reasonable confidence in this instruments measurements. The durometer measures type A Shore hardness.

So, I measured the dimensions and hardness of my original Isolastics and mark 3 vernier type isolastics from AN and RGM. In each case I took 3 Durometer readings and took the average.

I know that this does not match up to Dyno Dave’s work, but I wanted to know how current products matched up to the originals.

Results

1. Hardness

Isolastic rubber Original AN RGM

Front Outer 48 44 57
Front Inner 80 44 57
Rear Outer 49 65
Rear Inner 70 65
Click to expand...
In the link below I reported Shore A durometer of new AN vernier isos back in 2014 and they agree with some of the numbers above, i.e., 45-50 Shore A range. All the values I recorded (many measurements taken around circumference of inner and outer front rubbers) fell in the stated range and no outliers were recorded.
www.accessnorton.com

Shore hardness

I notice a few members having trouble with things cracking/breaking as late...Now i now Norvil produce EXTRA soft isos.."for added comfort" But as the engine now shakes more ...stuff hanging off the motor is more prone to fracture...When the commando was designed this vibration and rubber...
www.accessnorton.com www.accessnorton.com
 
WZ507 said:
In the link below I reported Shore A durometer of new AN vernier isos back in 2014 and they agree with some of the numbers above, i.e., 45-50 Shore A range. All the values I recorded (many measurements taken around circumference of inner and outer front rubbers) fell in the stated range and no outliers were recorded.
www.accessnorton.com

Shore hardness

I notice a few members having trouble with things cracking/breaking as late...Now i now Norvil produce EXTRA soft isos.."for added comfort" But as the engine now shakes more ...stuff hanging off the motor is more prone to fracture...When the commando was designed this vibration and rubber...
www.accessnorton.com www.accessnorton.com
Click to expand...
Why did that one get locked? Looks like all the kids were playing nice...?
(US Mom's stearn directive to "PLAY NICE!")
 
EstuaryBoy said:
Time expired I'd guess...... It was around nine years since the last post???
Click to expand...
Thanks.

I should know it, but keep blocking it out. 🤡🤣



We changed from Syteline at work for parts & service to "ServiceNow"

The pocket protecter group 🤓DISCARDED every bit of information over 3 years old.

We all swear, every day, a lot.🗣️🤯🤬

Probably why I can't ever remember the story here.
I just block it out. 🫣
 
Last edited:
concours said:
Why did that one get locked? Looks like all the kids were playing nice...?
(US Mom's stearn directive to "PLAY NICE!")
Click to expand...

Threads over approximately* 2 years old (or 2 years from the last post) are locked.

*(Locked in batches so not necessarily '2 years to the day')
 
L.A.B. said:
It wasn't officially announced back in August '22 when the locking of older threads began so it's possible you just hadn't noticed.
Click to expand...
What was/is the rationale for locking stale threads? Seems if they found again one day, and people want to make responses, they would now have to start a new thread, re-hashing much of what has been covered previously.
 
Tornado said:
What was/is the rationale for locking stale threads?
Click to expand...

The problem was that too many old threads were being responded to as if they were new threads after a reply had been posted to an old thread thus resurrecting it to page 1, resulting in some confusion when other members didn't notice the thread date and would reply to the latest post or the original poster/posters who perhaps hadn't logged in for several years.

Tornado said:
Seems if they found again one day, and people want to make responses, they would now have to start a new thread, re-hashing much of what has been covered previously.
Click to expand...

If a member has a legitimate reason to want to reply to an old thread then they can ask either Jerry or (preferably) myself to unlock the thread.

Tornado said:
re-hashing much of what has been covered previously.
Click to expand...

Not necessarily as a link to the old thread can be inserted in the new thread.
 

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