Fender Wobble

[Ben Adrian]

Hey all! 

I have SKS Fenders on my Ram. I live in L.A., so I rarely need them. Still, there are puddles of gross water, damp mornings, and smatterings of rain, so I really appreciate them when I need them and I leave them on. Now, they do move a bit when riding. I'll look down and see them moving from bumps and wind. I know they're not the best fenders and I'm okay with that.

There's something else that happens on this bike. When cornering, I sometimes feel it getting a little noodle-y. There is a wobble, and not all the time. It never feel dangerous, but it is a bit disheartening and weird. I'm wondering of the lateral wobble of the fenders is also giving a wobble to the cornering sometimes. Perhaps it's something else, and the wiggling fenders are becoming the scapegoat.

So, anyone else have anything like this happen? My instinct is to just take them off and see if it happens again. I guess the result would be the same either way; it's the old fenders so I buy nicer fenders because I like having them, or it is the fenders, I fix it with the fenders off and I buy nicer fenders because I like having them.

Cheers!

Ben

[Joe Bernard]

You might get rid of some fender wobble with a bolt-tightening session at all the mounting points, it's not my experience that SKS fenders move around much. 

The wobble you feel in turns is concerning and probably not fender related. What's the bags/racks situation on your Ram?

Joe Bernard

[Ben Adrian]

I’ve never used a rear bag… just an under seat wrap.

I had a handlebar bag for a bit, and now a front porteur rack with an average bag on top. It’s usually pretty light.

[Joe Bernard]

In spite of how often people do it and seem fine with it, I really don't like front loads on Rivs. Even the weight of a porteur rack with no load was enough to make my steering feel sketchy. Did you have the problem before you installed it? 

[brendonoid]

There are so many possible sources for disheartening and weird wobbles. It seems to me that fenders are an unlikely culprit. My instinct is the same as Joe's RE: the front rack.

It could also be something as simple as the tyre pressure getting a bit low in the front wheel.

[Patch T]

Re: fender wobble - Have you checked all contact points to ensure everything is still fastened?

Re: the other wobble - I'm no expert, but if it's a new sensation that you hadn't felt before with that rack and bag + load, I'd check things like QR skewers, headset, hub locknuts. 

Take it to the wonderful folks over at Golden Saddle for a look-over?

Patch in NYC

[Patrick Moore]

Shaking fenders won't make your bike mishandle in corners,  something else is causing that. As others suggested, check tire pressure, wheel bearing adjustment, fork bearing adjustment, or a wagging rear load (and even a wagging rear load has to be pretty heavy to upset cornering).

As to SKS fenders, I've used probably a dozen pairs, and  while they're not as stiff as good, well installed metal ones, and while they do vibrate visibly over bumps, none of mine, from 35s to 65s, have "wagged." Check the mounting bolts, particularly under fork crown.

Good luck, and let us know the cause when you find it.

[Ben Adrian]

Hey all! Thanks for all the advice so far. When I see Fender wobble my brain goes more to a telecaster with a Bigsby... not my bike!

Here are responses to questions and comments.

At one point my rear wheel went out of true. I trued it and found one spoke was totally slack. I though that would fix it, but no. I will go back and check spoke tension. Just because it's straight doesn't mean there's not a tension problem.

I've had strap and clamp on handlebar bags. It has wobbled with those. I have done very few rides with nothing on the bike. I will remove fenders and racks and all bags and go do some cornering; see if I can make the problem happen with fewer variables.

I've checked headset. Will re-check skewers and wheel tightness. Also, will check hub bearings for play.

I don't have a lot of fender experience. These SKS fenders came used with the bike. I've watched videos and I'm pretty handy mechanically. The struts have flex in them that is not very damped. I can whack the fender laterally with my hand and it will oscillate for about 1-2seconds. It's like a fast pendulum swaying from the mounting points.

I just went to the garage to check, and there's a crack in the rear fender on the left lower strut. Maybe this is it. It can flex to hit the tire, and it might be bouncing against the wheel as I turn. Maybe it's been a broken fender all along.

It's not supposed to rain for a while. Off with the fenders soon for testing!

Cheers!

Ben

[Ben Adrian]

I finally got around to taking the fenders and front rack/bag off of my bike. I only had time for a short ride, but it does seem to have a significant change of feel. I never though that it handled poorly with the front rack. The best way to put it is that maybe the bike seems "sleepy" with the front rack and bag. One thing I did notice is that it really wants to be a wheelie machine without the front rack. My front wheel kept coming up when climbing steep hills.

Tonight I have a longer ride planned with a friend. We'll see how it does with a non-trivial distance.

Cheers!

Ben