9 replies to this topic

[Stu1961]

Just a quick one. When it comes to engines steady bush's which are best Polyflex or Rubber.

 

Cheers

 

Stuart

Edited by Stu1961, 06 July 2014 - 03:58 PM.

[Mini Manannán]

Rubber has much better vibration absorption qualities.  Depends what you mean by 'best'.  

[RedRuby]

For me it's rubber, have heard that some poly bushes are badly made and prone to sudden failure although this may be more prevalent in the engine mounts

[dbcool20]

rubber absorbs vibrations better as said above, but also tends to wear and crack quicker than poly bushes...

[Stu1961]

Rubber has much better vibration absorption qualities.  Depends what you mean by 'best'.  

I thought rubber may have better absorption property's and in that respect that is the bottom line. If the only advantage of Polyflex is that it lasts longer but is not really fit for purpose, no contest. In what other respects is one better than the other? I can see the advantage of Polyflex for coolant hoses but would I be correct in thinking it has no benefits elsewhere.   

[Mini Manannán]

Poly comes in bright colours, that, as far as I can see it its only advantage

[The Matt]

Poly - becauseracecar

Rubber - perfectly adequate

[HarrysMini]

rubber absorbs vibrations better as said above, but also tends to wear and crack quicker than poly bushes...

I have to disagree with that. I suppose it depends on which brands you buy, but some of the poly bushes on our Land Rover Discovery were worn out after about a year (12,000 miles). The rubber bushes they replaced had only just started wearing out after 142,000 miles (9 years).

 

Poly bushes are also sometimes prone to suddenly failing (snapping for example). 

 

For an engine, I really don't see the point of poly bushes, especially if it's a road car, all they're going to do is transmit more noise into the cabin.

Edited by HarrysMini, 06 July 2014 - 05:24 PM.

[dbcool20]

 

rubber absorbs vibrations better as said above, but also tends to wear and crack quicker than poly bushes...

I have to disagree with that. I suppose it depends on which brands you buy, but some of the poly bushes on our Land Rover Discovery were worn out after about a year (12,000 miles). The rubber bushes they replaced had only just started wearing out after 142,000 miles (9 years).

 

Poly bushes are also sometimes prone to suddenly failing (snapping for example). 

 

For an engine, I really don't see the point of poly bushes, especially if it's a road car, all they're going to do is transmit more noise into the cabin.

 

Like you say it always depends on the brand and quality i agree, you may have crappy poly bushes that don't last and great rubber bushes and vice versa.... for an engine on a road car i have to agree with you. But if you take the rest of the car like for the tie bars, lower arms, subframe ext... fitting poly bushes can increase the stability and driveability of the car. true this is more useful for race applications but i personally  feel my car is much more enjoyable to drive now with the poly bushes as it is more steady and rolls around much less when taking curves for example. but then again i'ts just my opinion. 

[Stu1961]

Thanks for the reply's gents, some interesting points think I will go with the rubber engine mounts and steady bar bush's. Just out of interest do any modern day car manufacturers use Polyflex, thinking about it  I suspect not, though I may be wrong. Have to agree with Mini Man on the whole if pretty colours is the only advantage then they can keep the Polyflex.