suspension

[markbrunt]

My sportster is now on the road (3.5 RV8) however the ride is incredibly hard. the car had been stood for at least ten years before I took it on and believe the dampers are shot ! Can any body advise me on what type and size of dampers are usually fitted. I beleive the exisitng one are GAZ but there are no marks on them anywhere

[Patrick]

Gaz shocks https://www.gazshocks.com/ are a great company, they were able to send me some parts for shocks I bought 20 years ago. I'm sure if you provide them info and some photos, they'd be able to help out. Even rebuild the existing ones if needed.

I don't have any spec on the front shocks. However, I took a bit of a different route from normal for the rear due to the spring mount locations being welded to the chassis in the wrong place from the factory and the advice of using heat to collapse a progressive coil spring to work with the Sportster was not something I wanted to do.

I chose to use gaz coil overs for the rear of an E30 - part number GP8-2015. It did require notching and flaring the shock tower a little to clear the springs. The only down side is they are a little bit on the short side, I'd still plan on try to add a 4 to 5cm spacer at the top shock mount but have not gotten around to trying that, but it works fine as is, I have the damper set a little harder than normal so it doesn't bottom out.

The other less good thing for comfort are the ball/heim joints. The top mount I've changed to using a powerflex BMW top mount (an OE BMW would also work from an E46 or newer), they were not able to get parts for the original style top mount, but they were able to supply the ball joints for the lower mount. The top mount change took a lot of micro vibrations away, which I like a lot better: https://www.msportster.co.uk/2022/09...refurb-part-2/

The spring rate - I used what Gaz recommended for the weight of the car - I don't recall what this was I can only find an email from 2006 asking for 300lb/in but I don't know if that's what they supplied. I think I spoke with them on the phone to finalise the order.

Details here on the coil overs: https://www.msportster.co.uk/gaz-rear-coil-overs/

A few pics of the original install:

https://www.msportster.co.uk/rolling-chassis-build/nggallery/page/22

https://www.msportster.co.uk/rolling-chassis-build/nggallery/page/23

and body clearance here: https://www.msportster.co.uk/bodywor...gallery/page/9