Urethane or rubber mounts

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Slippers
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Urethane or rubber mounts

Post by Slippers » Fri Jul 17, 2015 7:31 pm

I am in the process of fitting Creative IRS to my bus and although the Creative instructions say to replace the original Gearbox mounts for urethane I have heard that a lot of people advise not to as they cause unwanted vibration through the chassis.
What have others done?

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richandsue
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Re: Urethane or rubber mounts

Post by richandsue » Fri Jul 17, 2015 9:08 pm

heard this for the spring plate rubbers. not sure about gearbox mounts .

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split999
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Re: Urethane or rubber mounts

Post by split999 » Fri Jul 17, 2015 9:28 pm

Stick with rubber.
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JonnyCJ
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Re: Urethane or rubber mounts

Post by JonnyCJ » Sat Jul 18, 2015 7:28 pm

Also interested in the pros and cons of this.

As far as I understand the urethane are harder wearing but prone to vibration. Rather than have just a "use one or the other" answer it would be interesting to have a reason why so I can make an informed choice.

From what I've read so far rubber seems to get a universal thumbs up, but they must make urethane for a reason ?

Got urethane fitted at the moment, but with the gearbox out I'd rather make the best choice now than have to go through the hassle of pulling the engine and gearbox when it's put back together.

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Re: Urethane or rubber mounts

Post by JonnyCJ » Sat Jul 18, 2015 8:39 pm

Just thinking on from this....

To my mind urethane as a material shouldn't transmit much more in the way of vibration compared to solid rubber.

Looking at the construction of the urethane mounts they have a metal sleeve going through the mount which prevents the bolts "sawing" through the urethane.

All that the sleeve does as far as I can see is protect the body of the urethane and spread the load onto the bolt.

The problem is that the sleeves are effectively the same length as the hole in the mount that they go through, so when you tighten up the nut and bolt you will have the washer and mounting area at the other side both in contact with the sleeve ? That way any vibration is going straight from the engine to the gearbox and into the chassis.

If I'm thinking correctly, shortening the sleeves on each mount so that the washers contact the urethane and don't touch the sleeve will reduce the vibration significantly.

That way you still get the benefit of the sleeve and urethane with no transmitted vibration.

If you think of the OG set up there's no metal to metal connection at all, the vibration is all lost in the rubber.

Thoughts welcome !

Cheers

Jonny

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vwJim
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Re: Urethane or rubber mounts

Post by vwJim » Sat Jul 18, 2015 9:24 pm

I see no benefits of using urethane at all.
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Slippers
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Re: Urethane or rubber mounts

Post by Slippers » Sun Jul 19, 2015 7:37 pm

Rubber it is then, thanks for your replies.


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Re: Urethane or rubber mounts

Post by JonnyCJ » Mon Jul 20, 2015 11:32 am

yep - just ordered a pair as well ! C&C do genuine VW ones.

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Re: Urethane or rubber mounts

Post by Hongkongphooey » Mon Jul 20, 2015 3:12 pm

Fitted Urethane before on the bug, (2.0 engine) as they are meant to be heavy duty, within a year I had removed them all and gone back to the decent quality Grey VW ones that Stateside Tuning etc sell, so so much better.. oh and the Urethane ones with hardly any miles on them were like cheese when they came off! rubbish.
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