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      01-10-2015, 10:28 PM   #18
fe1rx
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Drives: 135i, 328i, Cayman S
Join Date: Jan 2008
Location: Canada

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Quote:
Originally Posted by mike082802 View Post
i wonder what the dinans are. i was thinking about getting those to pair with my koni yellows and bmw performance springs. how the ride for you? i see you went with the ohlins.
The Dinan upper mount uses a thinner lower part per the attached image from the Dinan website:

Name:  12 Dinan Upper Mount.jpg
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It appears to be a cast polyurethane part, like the Powerflex mount, but thinner.

In my experience cast and microcellular urethanes are quite happy being compressed to half their original thickness. They will compress more, but may temporarily take a set in the process. They will recover their original thickness with time. Accordingly I figure that under normal conditions they shouldn't be called on to compress more than 50%. The OE lower mount is about 14 mm thick in its relaxed state. That means it should not be called on in service to compress to thinner than 7 mm (if you buy into my logic). It is compressed on installation to about 11.6 mm thick, giving a usable stroke of 11.6 - 7 = 4.6 mm. I actually tested the upper mount to a bit over 5 mm stroke from the installed state. I didn't include this data point in the previous graphs because it falls in the non-linear range of the mount, but here it is below:

Name:  13 OE Combined.jpg
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Dinan claims that their mounts "increase shock travel by 10 mm for improved ride quality and performance". The only way they could increase shock travel by 10 mm is if the lower mount compressed to a thickness of 11.6 - 10 = 1.6 mm. Since (I am assuming they are) made from cast urethane they would need to be only about 2 mm thick to increase travel by 10 mm, and this would only be true if the OE mount itself was compressed to 2 mm in service (which is extremely improbable).

As usual, the marketing hype is overblown and vague.
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