BMW OEM ESA II Rear Shock is leaking. Rebuild? Replace?

[pwillikers]

Vehicle: 2011 BMW R1200RT w/ESA II (Model: K26, 0440), ~45K miles.

 

I purchased an '11 RT in December of 2022.  Being in otherwise decent shape, the suspension was very harsh, not at all what I'd expect from a touring oriented bike.   Additionally, there was very little, actually imperceptible, differentiation between the three damping settings.  

 

My initial attempt at rectifying the defect was to "Calibrate the Rear ESA" using the MotoScan app and a Bluetooth OBD2 adapter.  Unfortunately, repeated attempts at  ESA calibrations, both front and rear, failed.  (I'm working this issue in another thread).

 

While staring at the bike wondering what to do next, I discovered that there was oily grunge on the lower part of the rear shock.  It was leaking.  It wasn't leaking on my prior inspections.  My options at this point were:

• A replacement BMW OEM rear shock with all new ESA function which, according to RealOEM, would be over $2300.
• The Beemershop could transfer the ESA function from the old OEM shock to a new Wilbers shock for about $1000. 
• EPM Performance Imports could rebuild the OEM shock (which was purported to be non-rebuildable).  I spoke to them on the phone.  They install a nitrogen charge port in the shock body (which makes it rebuildable), rebuild it and bench test to confirm proper ESA function.  They include a one year guarantee.

I pulled the shock and sent it off to EPM hoping a rebuild would render it fully functional, i.e. "calibrate-able" and exhibit differentiation between the damping settings.

 

I received the shock back from EPM after about two weeks and installed it.  Actual cost, all in, was $409. (including return shipping and $20. in extra parts).  It was all spiffy and clean.  This time ESA calibration of the rear shock was successful (via MotoScan and an OBD2 Adapter).  Onboard computer "LOAD" settings function as designed.  I can feel the ass end jack up and down in response to my modifying the setting.  YAY!

 

Riding impressions with the refurbished shock are now what I would expect a properly functioning ESA system to exhibit.  With small surface irregularities, there is not much difference in the three damping settings, however, at speed (on an elevated concrete highway with crappy seams between the concrete sections which cause profound pogo effects) there is definitely a perceptible difference.  I'd describe the pogo behavior on the offending concrete seams as follows:

• "Comfort":  down+up+down+settle, definitely controlled and soft, verging on floaty. 
• "Standard": down+up+settle, firm, definitely not floaty, nicely controlled and smooth.
• "Sport": down+settle, the concrete seams produced a kind of hit, not terribly harsh or objectionable but the wheel's movement was transmitted perceptibly to the rider, not sportbike like extreme (most of my riding experience is on sportbikes) but just an abrupt brap.

I hope these descriptions are sensible. 

 

The suspension settings I've settle on are STANDARD damping and LOAD = two helmets.  I've been riding with a large top case, no side cases and no passenger.  The two helmet load setting quickens the steering a bit which I prefer.  

 

In any case, I'm very pleased with the rebuilt shock.  Good work EPM.  Thanks.

[RadioFlyer]

I have a buddy with a similar experience. The dealer said it was non-rebuildable but I did some research and found Accelerated Technologies in Ontario who does this routinely. Another option that may be attractive given the Canada-US dollar exchange rate.

[Lowndes]

"HEY BMW: No service manual = no new bike."

 

+1 !!

[Skywagon]

That’s good info to know about the rebuilders of non-rebuidable shock. That question is asked here often. The usual response is ditch ESA and get expensive Ohlens, Beemershop, or EBay. I hope if and when my shock is ready I can remember this thread. 

[Hosstage]

Text it to yourself. Email it to yourself. Save it to a file on your PC. Print it and put it in your toolbox, in your saddlebag or top box. Put it your owners manual or service manual.

I've got some files on my phone that transfer automatically when I get a new phone.

Or, when it comes time, think, hey, there was a thread on a rebuild, I think! Damn, where was that?

[Lowndes]

9 hours ago, Skywagon said:

That’s good info to know about the rebuilders of non-rebuidable shock. That question is asked here often. The usual response is ditch ESA and get expensive Ohlens, Beemershop, or EBay. I hope if and when my shock is ready I can remember this thread. 

Everything will be different by then.  Shops closed and new shops opened and technology improved.  We'll have mag-lev instead of springs and plasma charged dampening systems.  "Plan ahead but don't cross the bridge..."

[pwillikers]

I've had a chance to put a thousand miles on the rebuilt BMW OEM ESA II rear shock and have an observation (which may be obvious, old news to some, most?, of you). 

 

I've learned that the BMW OEM ESA II rear shock does not modify compression damping, only rebound damping.  I began to suspect that this was the case when, with a newly rebuilt shock, I could sense no differentiation between "Comfort", "Normal", and "Sport" on roads with crappy road surfaces (when compression damping is most obvious).  Research confirmed my suspicion: "... this system provides riders with electronic controls that not only facilitate adjustments to the rebound-stage damping ...".  (My initial assessment of ride quality at speed, as described above, where rebound damping is obvious, still holds true.)

 

In any case, the ride quality was unpleasantly harsh on crappy road surfaces.  Maybe I just need to bite the bullet and spring for Wilbers with adjustable compression damping?

 

A bit of history, the RT came with Michelin Road 6 GT tires which were installed by the prior owner.  When I took ownership, they had roughly 5K miles and were showing evidence of uneven wear and mild cupping.  Based on internet lore, the solution is to over inflate the tires to 40f, 42r.  RT-P officers are purported to ride at 42f, 42r.  So, I over inflated the tires to 40f, 42r and forgot about it.  I will say that the steering is delightfully nimble with rock hard tires.

 

This internet recommendation is in stark contrast to the owner's manual's recommended of 32f, 36r (for a single rider, no luggage).

 

Attempting to alleviate the harsh ride, I reduced tire pressures to BMW's recommended 32f, 36r.  What a difference this makes!  Small road surface irregularities are no longer obnoxious teeth rattlers.  The steering is perceptibly heavier but in no way problematic.

 

In hindsight, if the ride is harsh, the first and simplest thing I should have thought was to lower the tire pressure (I'm an idiot, yes I am).  Ah well, all's well now.

[jdub53]

Your thoughts and findings on, as you put it, over inflating Michelin tires (and I agree with your thought) to make them steer more nimbly are dead on to what I experienced after buying my RT with Michelin PR4GTs, except mine still had an unacceptable heavy steering feel when over inflated up front.

 

Tossing the PR4GTs and replacing them with Bridgestone T32GTs inflated to reasonable/more standard levels immediately improved my RT's handling from the first time I rolled out of the driveway with them.

 

When I was exploring the heavy steering feel cause with the PR4GTs, I was surprised to find so many folks were OK with inflating that front so high just to get it into the territory of acceptable feel.

[9Mary7]

Authority bike tire pressures are 37F and 42R........ 'cause they are heavily loaded.

My personal Hexhead and Camhead were run at 33F and 36R. As always, YMMV.

[dirtrider]

On 4/13/2023 at 3:07 PM, pwillikers said:

Attempting to alleviate the harsh ride, I reduced tire pressures to BMW's recommended 32f, 36r.  What a difference this makes!  Small road surface irregularities are no longer obnoxious teeth rattlers.  The steering is perceptibly heavier but in no way problematic.

 

In hindsight, if the ride is harsh, the first and simplest thing I should have thought was to lower the tire pressure (I'm an idiot, yes I am).  Ah well, all's well now.

Morning Paul

 

I also use 32F/36R (corrected to 68°f) for most riding. If heavily loaded for a long high speed trip then I might add a couple of pounds to the rear & add a pound or two to the front but typically I keep them at 32F/36R (corrected to 68°f). 

 

If I check/correct  below  48°f then I lower to 30 psi ft & 34psi rear (I never lower more than 2 psi even if colder than 48°f (even well below 48°f)

Same If above 88°f if I check/correct  above  88°f  I raise the front to 34 psi ft & raise the rear to 38 psi  (I never raise more than 2 psi even if hotter than 88°f (or well above 88°f). The above 88°f cold has never happened in my area though. I have added 1 pound (33/37 a few times with a 78°f cold check. 

 

Basically the cold tire pressures change about 1 psi for every 10°f change in tire temperature but there is a common sense thing here also so cap it at 2 psi either way. 

[bruce2000ltc]

Is your front tire cupping at those low pressures?  My '13RTs front tire would start cupping at about 4000mi when I ran 36psi.  I raised the front tire to 38psi and the cupping was greatly reduced and only mildly appears at 6000-8000 miles. I run the rear at 42psi.  This is on Dunlop Roadsmart 3 and I'm 210lbs and run the bike with the ESA set at rider+luggage.  Almost all of my ridding is two lane highways at an average of 55/65mph.

[dirtrider]

2 hours ago, bruce2000ltc said:

Is your front tire cupping at those low pressures?  My '13RTs front tire would start cupping at about 4000mi when I ran 36psi.  I raised the front tire to 38psi and the cupping was greatly reduced and only mildly appears at 6000-8000 miles. I run the rear at 42psi.  This is on Dunlop Roadsmart 3 and I'm 210lbs and run the bike with the ESA set at rider+luggage.  Almost all of my ridding is two lane highways at an average of 55/65mph.

Afternoon  bruce2000ltc

 

No, I get pretty even tire wear without cupping, I do get a little rear tire step-wear with dual compound tires but that is pretty normal for multi-compound tires. 

 

But, just to clarify, I am a fairly aggressive rider so no matter the tire brand, or the tire pressures I typically don't get long tire life.   

[pwillikers]

jdub, T32 Bridgestones are some of my favorite tires.  They stick like sport tires and have a round, hence progressive, profile.  I really like them.  I have an SV650 (actually two) and I just got home from a two-hundred mile Saturday morning Texas Hill Country breakfast run with the fellas.  I was on my '08 SV which has T32s.  This is about as sporty as I like to get on the street.  :-)

 

 

[pwillikers]

For those who have bikes with the OEM ESA II shocks, I'd be interested in your assessments of ride quality with different tires at different tire pressures.  Are your observations consistent with mine (as stated above)?  Reiterating, I found over inflated Michelin Road 6 GTs to be obnoxiously harsh, no surprise eh?

 

I'm considering whether I need to spring for new shocks to obtain the ride quality I'm hoping for.

[jdub53]

16 hours ago, pwillikers said:

For those who have bikes with the OEM ESA II shocks, I'd be interested in your assessments of ride quality with different tires at different tire pressures.  Are your observations consistent with mine (as stated above)?  Reiterating, I found over inflated Michelin Road 6 GTs to be obnoxiously harsh, no surprise eh?

 

I'm considering whether I need to spring for new shocks to obtain the ride quality I'm hoping for.

 

Giving a bit more detail on my comments above on (to me) an over inflated front tire, when I bought my RT five months ago the PR4GTs on it were about half worn with 6k miles on them and from the dealer the tires were set to (IIRC) 36F/42R. I believe this dealer services many RT-Ps for MD State Police, and the dealer had likely set those pressures as they'd gone completely through the bike after getting it on a trade.

 

The RT's ride was very harsh from the outset, which was corrected to a great extent after I recalibrated the ESA suspension using my MotoScan app, but the steering was so heavy it was a constant distraction while in the twisties (required constant pressure on the bar to maintain my line, plus a lot of effort to initiate a turn). I didn't believe the heavy steering was due to RT's front end weight compared to the '14 GS I'd just come off of, or to the '07 GSA I'd owned for years previous to that. When I brought this up on another forum, I was advised to pump up the front to 40-42 psi to lighten the steering and to keep the front PR4GT tread from cupping (it had no cupping at that time). I was told there that RT-Ps are commonly run at 42 psi F & R with these same tires. Bumping up the pressure in my front did somewhat lighten the steering effort, but it was still unacceptably heavy for me. Even though the front still performed well on cold and damp twisties, I just didn't like or trust having that very high pressure there. 

 

I removed the PR4GTs with about 10k miles and some life remaining on them after I'd had enough,  and spooned on new T32GTs. After a bit of playing around, I've settled on 36F/40R for my typical day-tripping rides with a tankbag being my only luggage. The RT now feels like a sportbike in the twisties with the T32GTs, light/neutral steering with cornering confidence/enjoyment and the ride quality (feel and feedback increased/harshness decreased) so much better than before. The T32GT tread pattern is different than that of non-GTs like on your SV, and although I only have about 1k miles on them so far I have zero complaints about them in any conditions including heavy rain. Jury is still out in tread life, but from what I'm seeing so far these are the only tires my RT will be wearing. Here they are after scuffing them in on my first ride, where you can see the tread pattern difference (the line visible on each is from the left hand 180 degree turn on my dirty driveway prior to backing it into the garage):

 

 

 

 

[pwillikers]

Excellent write up. Very informative and thorough.  Thank you.  It's great you were able to find the tire, pressure, ESA II shock combination that works and it sounds from your description that you are an aggressive rider, as am I, so apples to apples.

 

I've had many sets of Michelin Pilot tires in the past.  On the hottest days in the TX summer (110F) they'd get uncomfortably squirmy, kinda like riding on a permanent tar snake.  It rains here infrequently so wet weather performance is less of a concern.  The earlier versions had a pronounced V profile which was nice and stable when leaning a the optimum angle but getting leaned over and straightened back up was inconsistent.  They are the most expensive by far (and I go through a lot of tires) so I stopped using them. 

 

I've been using Bridgestones, T30, T30 evo, T31 and T32 both GT and non-GT (and S21, S22 on my sporty bikes).  Longevity has always been a concern.  I ride most "aggressively" on rural roads with very abrasive chip-seal surfaces.  This raises hell with longevity regardless of other variables.  I'm envious of those who get more than 10K miles on a set.

 

Motorcycle Consumer News' Moshe Levy reported 17K miles on a set of Dunlop Roadsmart IIIs commuting to work in NJ.  I believe he has relocated to San Antonio.  I wonder what tire mileage he's getting here in TX.

 

Given my long distance aspirations with this RT, I bought a set of RS IIIs.  They're stored (safely sealed in black plastic garbage bags) in the garage and will be the next set I try.

 

You've encouraged rationality.  I'll banish all thoughts of new shocks for the time being. :-)  Thanks again.

[9Mary7]

Camheads didn't come new with Michelins....... there was and is a reason........

 

Michelin Fanboys, let the flaming begin!!

[pwillikers]

JDUB53, I'm curious how the T32GTs are wearing now that you've had some time with them on your RT.  What's your report?

[jdub53]

The T32GTs are wearing well with 5k miles on them now. I forgot to measure the tread depth until they had 450 miles on them, and at that time the front was 4mm and rear was 6mm. Front and rear are both now at 3mm, with one 1,600 mile interstate highway trip (75 to 80 mph avg) and the rest of the miles playing on back roads and in the twisties within 200 miles of home.

 

At this wear rate I expect another 3k to 4k miles, and then I'll definitely be spooning on another pair. Zero complaints no matter the road conditions (cold/wet/dry) and nothing but confidence inspiring all the way to the edges. The front feels a bit twitchy at times (sensitive to the lightest steering inputs), but that's not a detriment in my book. I'll take that light (but not vague) steering feel everyday of the week over the heavy steering of the previous PR4GT.