E85 - E86 ride quality.

[curvature]

I drove a friend's roadster yesterday and was amazed at how smooth it felt compared to my coupe.

They are both on the sports suspension from the factory although mine has replacement Bilstein shocks but they are OEM replacements.

I've read that the coupe as a car is a lot stiffer.

Are they really that different?

 

[roblightbody]

Tyres are crucial.

The coupé has a stiffer shell, because it has a roof, but I don't see why the ride would be different to a comparable roadster model.

 

[curvature]

Neither car is on run-flats.

Pirelli on my coupe and Goodyear on the roadster.

 

[patriot66]

The E86 Coupe "has a torsional rigidity of 32,000 Nm per degree of body twist and the E85 Roadster has just 14,500 Nm per degree of body twist". So, yes they are massively different

 

[Beesza]

Tyre pressures can also make a big difference.

It also won’t surprise me if the stock spring rates were different between the Coupe and Roadster (and between roadster engine sizes).

 

[Mr Tidy]

I drove a friend's roadster yesterday and was amazed at how smooth it felt compared to my coupe.

That's interesting.

I've never been in a Roadster, but it makes me think I should try one - obviously only for comparison purposes!

 

[buzyg]

I drove a friend's roadster yesterday and was amazed at how smooth it felt compared to my coupe.

That's interesting.

I've never been in a Roadster, but it makes me think I should try one - obviously only for comparison purposes!

Yup. Certainly in the ///M models the set up is much stiffer in the Coupe. One interesting result of that is that a number of road test back in the day had the MR a 10th or so quicker off the line than the Coupe as it would squat down and dig in more from a hard launch. In the real world I have always found the MC too stiff for me. But I prefer the more direct steering.

 

[curvature]

All being well my coupe will be back from the body shop this week so I might be able to do some back to back tests.

Thanks for the comments, it's very useful.