Hi all, I recently bought a k1100. It's driving fine but I find I an getting backache after longish rides, I notice that the suspension is very hard over bumps. I have adjusted the rear shock but it's still affecting my back.  I am wondering if the 13" shock from my k75 will fit the k1100, the k1100 shock is 14". I am 5"11 and weigh just over ten stone. Is this usual for the k1100 rear suspension to give people these issues?

Hi Johnny

Not sure about that one but at 10 stone you don't qualify as a Harley rider so it should not have much preload on if you have got a standard BMW rear shock on the K1100. The K1100 shock I presume has preload options but possibly you have some other issues with it.

If you are doing a replacement I had a K1100 rear shock in my possession some months back, to put on the K100 as a temporary measure. It would apparently fit so presumably the K75 will fit yours. The difference in length on the K75 unit will leave your rear end sitting a little lower and will alter the handling but I expect it will be softer.

Have a look at YSS rear shocks. I got one for the K100RT and very impressed with it. I have very little preload set up in it and increased it a little for carrying the camping gear. It as a vast improvement.

However also do have a look at your handlebar positioning, consider bar risers.

Its the spring and compression damping that will make the ride harsh. The best shock I have used is the RAM from http://www.realmengineering.com/page15.html

A K100/75 shock will not solve the problem, they have basically the same characteristics just that one is 30mm longer.

Johnny kidd wrote:Hi all, I recently bought a k1100. It's driving fine but I find I an getting backache after longish rides, I notice that the suspension is very hard over bumps. I have adjusted the rear shock but it's still affecting my back.  I am wondering if the 13" shock from my k75 will fit the k1100, the k1100 shock is 14". I am 5"11 and weigh just over ten stone. Is this usual for the k1100 rear suspension to give people these issues?

are you riding an RS or an RT? What's a "longish ride"?
An RS may give you back problems because the bars are much lower.
Lowering the rear with a shorter shock would only benefit someone with shorter legs.

Thanks for the replies lads much appreciated,  I adjusted the preload today and now I have working rear suspension 
I find the ergonomics on the k1100lt which is the model I bought a lot tougher on my back and knees than my k75s, time will tell Wether I keep it or not.

The 75's do have a 'softer' spring than the 100's, with a wire diameter of 9mm compared to 9.86mm.

Just a thought.
Paul.

Johnny kidd wrote:Hi all, I recently bought a k1100. It's driving fine but I find I an getting backache after longish rides, I notice that the suspension is very hard over bumps. I have adjusted the rear shock but it's still affecting my back.  I am wondering if the 13" shock from my k75 will fit the k1100, the k1100 shock is 14". I am 5"11 and weigh just over ten stone. Is this usual for the k1100 rear suspension to give people these issues?

possibly and likely ... the shock is cactus

I changed my rear shock to something different ..... and an amazing difference was noticed straight away .

so possibly ..like all old bikes, the replacement might be a good thing regardless of the height differences

sidecar paul wrote:The 75's do have a 'softer' spring than the 100's, with a wire diameter of 9mm compared to 9.86mm.

Just a thought.
Paul.

Thanks Paul, that's a very useful bit of information for lighter K100 riders. I have very little preload on the YSS shock I am now using, started off with zero and have only adjusted twice, first was to set up for myself, then a second one for camping trip with all the gear on but still very little preload used.