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2017 Street Glide Special wobble

malthous

malthous

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Jun 2, 2016
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Since about 13,00 or 14,000 miles on my 2017 SGS, I have been experiencing some handling oddities. It is similar to what used to be called "bagger wobble," but not as severe. Still, some instability can be felt, especially in higher speed, sweeping turns. There are a handful of factors that could be causing it, but I have eliminated all but one: I have eliminated tire pressure, balance and wear (both are new, full and balanced), I have eliminated the stock suspension, literally, with Legend Suspensions front and rear and I had the neck bearings adjusted and tightened. All that is left is the swingarm and engine mounts. The rear engine mounts are an integral unit with the swingarm and swingarm shaft and has been the source of problems since HD went to rubber mounted motors on the touring bikes many years ago.

I decided that, since the dealer has not been able to replicate the problem (speed limits and such get in the way), I would take my GoPro Sessions and mount one on each side looking right at the pivot shaft. The ends of the shaft are supposed to vibrate a little within the mount, but what I captured on video seems to be excessive. The dealer "isn't so sure," they say they can't be sure if it is a warranty issue without taking it apart - and if they determine it's not, it's out of my pocket. Here are the two videos, right and left. This dropbox link goes to the videos.

https://www.dropbox.com/sh/o52vloul9cmh1ea/AAA-_Mqt3bPurRGxVYd_7EM3a?dl=0
 
You need a video during a wobble episode, however, that does not look abnormal to me.

You may need to adjust your suspension.

Watch this old but good video.
 
hulkss said:
You need a video during a wobble episode, however, that does not look abnormal to me.

You may need to adjust your suspension.

Watch this old but good video.
Click to expand...

As I noted in my original post, I have replaced the stock suspension (which, contrary to HD's spin, is no better or different than my 14 SGS - and it handled much better than my 17 does now). My Legend REVO-As have not only preload adjustment, but also rebound dampening adjustment, too. The short answer is yes, I have tried adjusting my suspension. A lot.

I'm no engineer, but I have spun a wrench or two in my time. I understand the idea behind the rear motor mount/swingarm assembly. But physics says that wherever that swing arm shaft goes, so too does the swingarm. It has to. In the videos, the right side is far more stationary than the left, but even the right is all over the place compared to the front mounts, and all the front mounts do is hold the engine - there is no "assembly" affixed with or integrated into them. I didn't shoot the front mount because I only have two GoPros and I don't think they are worn. Also, in the video you can see the swingarm move relative to the frame. Most of that is up and down, like a swingarm is supposed to move. But it also moves for and aft, and the left side moves more than the right. That changes the rear tire alignment. Those mounts are only supposed to reduce vibration, they are not shock absorbers.

But lets grant that the amount of movement is "normal." Shouldn't both sides move the same amount? Seems to me that if they don't, and with both sides mounted via the same shaft, something is moving outside of the vertical plane. The rear wheel plane can only be perpendicular to the swingarm shaft. If the swingarm shaft moves at all, the only way the wheel assembly stays in the same plane as the frame is if both sides of the shaft move in the same direction at the same rate. Anything else has to produce a misalignment. The question is, I guess, is how much misalignment before handling is compromised?

Anyway, I'm installing urethane mounts front and rear. If that doesn't solve the problem, I'm selling the bike. It can be someone else's problem.
 
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I would sell the bike then. The urethane mounts will likely bring you a whole new set of problems after a lot of work.

BTW, did the bike have a weaving problem before you changed the suspension? Have you tried max tire pressure (within sidewall listed limits)?
Wheel bearings OK?
 
hulkss said:
I would sell the bike then. The urethane mounts will likely bring you a whole new set of problems after a lot of work.

BTW, did the bike have a weaving problem before you changed the suspension? Have you tried max tire pressure (within sidewall listed limits)?
Wheel bearings OK?
Click to expand...

Yes, yes and yes. The tires are brand new and I can only assume the dealer checked all that other stuff on the 20k service last week, especially since I raised the concern to them. And to be clear, it’s not “weaving.” It’s a small wobble induced when a bump is encountered in a high speed turn. On rare occasion it turns into an oscillation that is easily remedied by backing off the throttle. The point is that compared to my 14 SGS, it is noticeable in its mere presence. Nothing like what is depicted in that video you shared is happening. I like the bike, obviously, I put more than 20k miles on it in a year. I am committed to a point. After the mount replacement and the installation of a True Track (once the 2017 version is in production - it’s still in development), I will have done everything within reason to reel it in. At that point I either live with it or get rid of it. I only posted this to see if anyone else had some experience with the issue on the new touring bikes, but it’s becoming clear that few have that many miles on a Milwaukee Eight, so far. It might be an anomaly - the clutch going south at 7,000 miles apparently was. No reason could explain it, but the replacement clutch has given me no problems in the 13k since. This is the risk of buying the first model year of anything new. Anyway, thanks for the input, but it seems everyone has a different theory and solution. No one, including me, “knows” what it is. I was hoping someone would. I will post my results as they become available because if it is not an anomaly, others will experience it, too.


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Are you able to convince your dealer to have a technician take a couple of 2017's out for a ride with you GoPro cameras mounted on them for comparison purposes?

I am wondering if the bushings have just worn out within the 20K miles. While the urethane mounts sound like a good idea to try, I don't know how well they will hold up long term in extreme hot and cold temperature conditions. Would you be changing the front as well?

Have you had the swingarm off of the bike before? I am asking because if my memory serves me correctly, the rubber mounts have to go on a certain way. Is it possible that one or both could have been installed incorrectly?

Your discovery also makes me think that you might have found the cause of dreaded weave or death wobble that no one seemed to know how to cure. I'm thinking that perhaps the pre-Rushmore bikes that have this problem use a softer mount and Harley Davidson has since switched to a stiffer (but not stiff enough) mount for the Rushmore bikes in an effort to cure it. I can tell you that on my 2015 SGS, I have experienced rear end weave in curves while riding two-up at highway speeds. It did not seem as bad as what I have seen on some of the YouTube videos, but I still would rather there be none. I hope you get it figured out soon.
 
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My bike also had a tendency to "wiggle' a little after hitting small bumps or tar snakes in high speed corners. I improved it by making two changes to undo "cosmetic" alterations from H-D.

1. I raised the rear of the bike to "standard" ride height for the touring frame with 13" Ohlins shocks.

2. I went to an 18" front wheel and tire as used on earlier model year Street Glides with more sidewall height to keep the "standard" rolling diameter. This provides more compliance in the front tire to absorb small impacts and not upset the bike as the stiffer low profile tire does.
 
It's seems you could place the bike on a stand and unload the shocks and check for some play in the wheel and swing arm. If it seems there is questionable movement, disconnect shocks and rear wheel and further inspect swing arm bushing play. From your posts, you seem to be experiencing vibration rather than wobble. I agree with Hulkss, the video seems like normal movement.
I would spend the time and money for a proper diagnosis, if you are feeling play at the rear wheel when riding. There are to many possibilities from wheel bearings, eng mounts,swing arm, bushings, isolators. I would note the speed and rpm range and profile you are experiencing issues, have a mechanic of your similar size test ride.


Sent from my iPad using Tapatalk
 
I posted this same post to my Facebook profile in the hopes of getting input in much the same way I have here. While some of it has been from those who are very experienced, the input is still all over the map. Of course, there are also comments from those who know nothing about Harleys or bikes in general who are just regurgitating the old, worn out, doomsday Harley tales. Such is the life of the "king of the hill." Anyway, for those interested, the post is public, here is the link:

https://www.facebook.com/michaelalthouse/posts/10101142929417343?pnref=story
 
hulkss said:
My bike also had a tendency to "wiggle' a little after hitting small bumps or tar snakes in high speed corners. I improved it by making two changes to undo "cosmetic" alterations from H-D.

1. I raised the rear of the bike to "standard" ride height for the touring frame with 13" Ohlins shocks.

2. I went to an 18" front wheel and tire as used on earlier model year Street Glides with more sidewall height to keep the "standard" rolling diameter. This provides more compliance in the front tire to absorb small impacts and not upset the bike as the stiffer low profile tire does.
Click to expand...

I'm upgrading to an 18 inch rear wheel with a lower profile tire. Anytime you have more sidewall you'll get more "squirm", that's why you don't see sport bikes with 65 series tires. And believe me they don't have "wobble" issues at all.
 
DynaMike said:
And believe me they don't have "wobble" issues at all.
Click to expand...

Sport and racing bikes wobble, but at a higher speed. Look at YouTube.

I changed my front tire from a stylish 130/60B19 to a better performing 130/70B18. The 60 series tire does not maintain grip in the corners unless the road is almost perfectly smooth. You need some compliance to maintain grip on irregular (most roads) surfaces.

Many sport bikes run 70 series (aspect ratio) tires. Here is a typical comment from Ducati.MS:

"What's your guys' opinion on 120/60 vs 120/70?.......The 120/60 front scared the **** out of me a couple times. They look cool as hell but offer no feedback, confidence, or grip at maximum lean. I scrubbed 'em right to the edge and I could honestly feel that they were limiting my cornering ability. It felt like the bike would reach a hard lean threshold that wanted to push it back up, and if I encountered any road irregularities the front would actually lose traction and begin to wash out. That flat, low profile front was just no good."
 
hulkss said:
Sport and racing bikes wobble, but at a higher speed. Look at YouTube.

I changed my front tire from a stylish 130/60B19 to a better performing 130/70B18. The 60 series tire does not maintain grip in the corners unless the road is almost perfectly smooth. You need some compliance to maintain grip on irregular (most roads) surfaces.

Many sport bikes run 70 series (aspect ratio) tires. Here is a typical comment from Ducati.MS:

"What's your guys' opinion on 120/60 vs 120/70?.......The 120/60 front scared the **** out of me a couple times. They look cool as hell but offer no feedback, confidence, or grip at maximum lean. I scrubbed 'em right to the edge and I could honestly feel that they were limiting my cornering ability. It felt like the bike would reach a hard lean threshold that wanted to push it back up, and if I encountered any road irregularities the front would actually lose traction and begin to wash out. That flat, low profile front was just no good."
Click to expand...

I guess it's up to personal preferences, I for one won't be changing my Grand Sports tires from a 25 series tire to a 75 series.
 

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Sell it before it kills you, I have an issue with wobble on my 17 as well. They cost too much money to have problems like they do. Is it worth it to ride a motorcycle just for a name when it lacks quality especially when the lack of quality could cost you your life? Harley takes one step forward then takes two steps back. Everybody says upgrade this upgrade that. Why upgrade? I buy a car off the lot, a boat, a lawn mower they all run fine without upgrades but my Harley does not. Hmmm. JMO
 
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Gosh guys, I have a 17 and had zero problems with wobble. In fact the only wobble issue I ever experienced was on my 2014 and that turned out to be low front tire pressure.
 
malthous said:
Came in yesterday, going on Saturday. I'll have a review sometime next week.
View attachment 13624
Click to expand...

Let us know about engine vibration too. Since you have an M8 with a balancer you're probably OK.

I read a few reviews were Twin Cam owners went through the trouble to remove the Glide-Pro components due to engine vibration being too uncomfortable.
 
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