How to detect if I have lowered suspension?

Technical aspects and performance of the BMW R1200RT/1250 RT
009jim
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How to detect if I have lowered suspension?

Post by 009jim »

Hi Folks, I am fairly new to the forum and have had my 2012 R1200RT for about a month. I've done about 800 miles, and I have a suspicion the bike's suspension may have been lowered. First sign of this was that I have to keep it on the "Sport" setting or the front bottoms out on any substantial bumps which does not occur on my other bikes. Secondly the specifications say that the front suspension travel is 4.7 inches, but on mine once I am sitting on it, there is only about 2.5 inches left. Thirdly, two of my friends have the same bike and told me these are very easy to put on the centre stand because you don't have to lift the bike much, just roll it back, but mine is a huge effort to put on the centre stand and then there is about a 1.5 inch gap under the back tyre when it is on the centre stand.

This bike has only 20,000 km on it, so seems unlikely the suspension is worn out..

So my question is:- does anybody have a suggested way for me to check if I have in fact got a lowered front suspension? Is there a specification for the length of the front shock absorber unit?
Last edited by 009jim on Sun Apr 09, 2023 9:44 am, edited 1 time in total.
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exportman
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Re: How to detect if I have lowered suspension?

Post by exportman »

Hi

Not sure on the 2012 but on the 16 and the 23 if you have the suspension on dynamic then the damping is very stiff so it may feel like its bottoming out
The back wheel on both has been about about 1 inch or so off the ground not measured it particularly but at the moment I have a piece of 22mm board that I run the back wheel onto before using the centre stand in the garage as I'm a little tight on space and it makes it easier. Out and about if the boxes are loaded it can be quite a challenge sometimes to put it on the centre stand especially if the ground is not level.
The only way to be certain would be to get it measured, You could I guess put it along side the same model that is know to be standard but they would both have to be in the same state ( eg without boxes and on the same suspension setting)
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Re: How to detect if I have lowered suspension?

Post by 009jim »

exportman wrote: Sun Apr 09, 2023 9:35 am Hi

Not sure on the 2012 but on the 16 and the 23 if you have the suspension on dynamic then the damping is very stiff so it may feel like its bottoming out
The back wheel on both has been about about 1 inch or so off the ground not measured it particularly but at the moment I have a piece of 22mm board that I run the back wheel onto before using the centre stand in the garage as I'm a little tight on space and it makes it easier. Out and about if the boxes are loaded it can be quite a challenge sometimes to put it on the centre stand especially if the ground is not level.
The only way to be certain would be to get it measured, You could I guess put it along side the same model that is know to be standard but they would both have to be in the same state ( eg without boxes and on the same suspension setting)
Thanks. My settings are "Comfort" "Normal" and "Sport". On the "Normal" setting it was bottoming, so I put it on "Sport" and the bottoming is minimal. On a recent 5 day overnight ride I had the boxes on with small quantity of luggage and it was impossible to put on the centre-stand. Only without boxes I can just barely get it onto the stand.
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Re: How to detect if I have lowered suspension?

Post by exportman »

Sound plausible your bike has had some modification then or you have a very weak spring. On the suspension travel don't forget this is measured from fully extended to fully compressed. Once you are on the bike the spring will be partially compressed
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Re: How to detect if I have lowered suspension?

Post by David. »

As the bike is fitted with ESA, what is the payload (inc. rider) on the bike, what is the suspension preload set at and is it working.

The "Comfort", "Normal" & "Sport" settings are damping, which I wouldn't expect to influence he suspension travel.
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Re: How to detect if I have lowered suspension?

Post by 009jim »

David. wrote: Mon Apr 10, 2023 2:59 am As the bike is fitted with ESA, what is the payload (inc. rider) on the bike, what is the suspension preload set at and is it working.

The "Comfort", "Normal" & "Sport" settings are damping, which I wouldn't expect to influence he suspension travel.
You are correct. I weigh 70kg and I had about 10kg in the panniers and top box. I have the ESA set on "rider + luggage". Changing this did not make an appreciable difference, whereas changing from "Normal" to "Sport" made a noticeable difference.

There is a good tabulation in the Haynes Manual which describes the changes that each of the settings does.
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Re: How to detect if I have lowered suspension?

Post by David. »

The Haynes manual table also confirms that, on an RT, there is no preload adjustment on the front shock absorber, just damping.
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Re: How to detect if I have lowered suspension?

Post by 009jim »

David. wrote: Mon Apr 10, 2023 11:33 am The Haynes manual table also confirms that, on an RT, there is no preload adjustment on the front shock absorber, just damping.
Thanks David, Could you please give me the page number in the Haynes manual so I can read about that. I read through Page 4-19 and did not come to the same conclusion, but I remain open minded.

I note that Diagram 10.26 shows some measurement points but that appears to be for the R1200R (not the RT). The paragraph for the RT suspension on Page 4-19 says that one must get the dealer to check the preload function.
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Re: How to detect if I have lowered suspension?

Post by David. »

009jim wrote: Tue Apr 11, 2023 4:56 amCould you please give me the page number in the Haynes manual so I can read about that.
Page 4-19, paragraph 22 refers to the pre-load settings for an R1200 GS and GS Adventure. "For off-road riding - small mountains and large mountains" can be selected. In the table, a front shock ride height measurement is given for these two settings. Unlike the GS, the RT front shock absorber doesn't have a pre-load adjustment motor, only damping adjustment at the bottom.
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David.
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Re: How to detect if I have lowered suspension?

Post by David. »

009jim wrote: Tue Apr 11, 2023 4:56 amThe paragraph for the RT suspension on Page 4-19 says that one must get the dealer to check the preload function.
The preload function can be checked by adjusting it and watching the rear of the bike rise and lower when changing the settings.
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Re: How to detect if I have lowered suspension?

Post by 009jim »

David. wrote: Tue Apr 11, 2023 6:34 am Unlike the GS, the RT front shock absorber doesn't have a pre-load adjustment motor, only damping adjustment at the bottom.
Do you think it's possible somebody has fitted mine with a shorter, or weaker, spring?
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Re: How to detect if I have lowered suspension?

Post by David. »

009jim wrote: Tue Apr 11, 2023 8:14 amDo you think it's possible somebody has fitted mine with a shorter, or weaker, spring.
With the bike on the centre stand and the front wheel off the ground, what is the spring free length with the suspension fully extended.
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Re: How to detect if I have lowered suspension?

Post by David. »

009jim wrote: Sun Apr 09, 2023 8:21 amThere is about a 1.5 inch gap under the back tyre when it is on the centre stand.
When my 2012 Camhead is on the centre stand, the rear (brand new) tyre is 38 mm (1.5 inch) off the floor.
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Re: How to detect if I have lowered suspension?

Post by David. »

David. wrote: Tue Apr 11, 2023 10:01 amWith the bike on the centre stand and the front wheel off the ground, what is the spring free length with the suspension fully extended.
The front shock absorber on my 2012 Camhead has a (white) spring free length of 141 mm.
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Re: How to detect if I have lowered suspension?

Post by Doctor T »

My 07 has the same suspension setting as yours. Over large bumps, it can feel like the front is bottoming out but it's not. On the center stand my rear wheel is off the ground by 1.5 inches. I believe David's is the same. Getting a bike on the center stand is all down to the person's strength, weight, height, and technique. I've owned bikes in the past that people say are easy to put the stand down, but i struggled.
Trust me I am a retired Doctor and lecturer at Oxford University of Structural and Mechanical/Electrical engineering.
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