new +2 koni rear dampers don't fit

[AlistairF]

Hi, I wonder if anyone can advise on +2 rear damper fitment. My +2 has AVO dampers and the bottom of the damper has a large "pimple" which fits into the same shape in the bottom of the strut tube.

My new Konis have rounded bottoms with no pimple. The length of the AVO and Koni damper tube are the same. I think the shape of the Koni causes it to sit higher in the strut tube such that you can't get the retaining gland/nut to engage into the strut tube more than a quarter of a turn because there is not enough depth to the thread to reach into the strut tube thread. I have two retaining nuts .. one that came with the Koni's and has two peg holes, and my existing one which is marked 4954 on the hex shaped top like those from TTR or Kelvedon.

I can think of only two solutions:

1. Return the Konis and get the AVOs refurbed and refitted because I know they fit!
or
2. Machine out a 4954 gland nut from TTR so it has more reach/depth into the strut tube to engage sufficient number of threads?

Anyone else have this issue or have suggestions?

Thanks

Alistair

[oldelanman]

Some damper inserts use a donut shaped spacer in the bottom of the strut tube .. maybe your AVO ones do and it's still at the bottom of the tube?

Screenshot 2023-03-26 205451.png (101.93 KiB) Viewed 706 times

[AlistairF]

Ah this is interesting. I have measured the strut tube internally and externally and there is only a few mm difference so I don't think I have any packing or spacing in there unfortunately.

I shall continue to look at options today.

Many thanks

Alistair

[AlistairF]

I visited TTR this morning and we tried the TTR bespoke dampers and these are slightly shorter than the Koni's and fitted a treat.

It seems to me there can be a bit of variation in strut tube lengths and there can be about 10mm difference in brands of damper too and different shapes of damper bottoms too which impact how they sit in the tube.

Some people need spacers to get the height of the damper correctly positioned and some not!

Anyway, I am back on the refurb job now!

Thanks

Alistair

[Harvey]

AlistairF,

I fitted a set of Koni's (yellow tube) to the rear of my Plus 2 a couple years ago and had no trouble of the type you have experienced. If you still want to fit the Konis I will go back and review my notes on how I fit them. I purchased them from Dave Bean Engineering in California. If you want to call Ken Gray he will probably be able to answer your questions better than I can. I think there are some proprietary parts to the Konis that allow them to fit the Plus 2 struts.

Lee

[AlistairF]

Thanks Lee,

I am sorted but thank you for your suggestion. The guys at TTR were great and took their time to check over my struts in detail and compared the AVO I had with the new Koni and their TTR damper. It's difficult to tell if my strut tubes are original or not but they looked old but not 50 years! They differed only by some welded rings to prevent movement in the carrier casting which suggests they may have been replaced, as I expect someone may have thought they may otherwise move?

The AVO and Koni dampers were identical lengths but shaped differently at the bottom. The AVO is shaped to locate in the depression in the centre of the bottom strut cap. The Koni has a rounded bottom that rests on the outer diameter of the depression in the centre of the bottom strut cap, and thus sits about 7mm higher than the AVO. This means the retaining nut/gland doesn't quite reach. We checked there was no packing at the bottom of the strut tube.

The solution was to use the TTR damper which was designed by an ex-Koni engineer. This damper also has a rounded bottom but is a bit more rounded than the Koni so may sit a mm or two lower into the depression and is shorter by about 10mm. This sits lower in the tube and the gland nut easily engages and tightens properly. I suspect some strut tubes have slightly different lengths?

The AVO at the top is 10mm longer than the TTR damper:

The AVO at the top has a pronounced pimple that sits lower into the depression at the bottom of the strut tube than the TTR damper (which is more rounded than the Koni not shown):

So hopefully this information might be useful.

Thanks

Alistair