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I got a Sirrus Sport this winter. Added new water bottle holders, rack, paniers and fenders. When I commute to work every time I hit the smallest bump something rattles around and I cannot seem to pinpoint the problem. I need suggestions on what is the likely problem and perhaps some steps to figure out what the heck it is.

My other bike had a small rattle in it, and I finally figured out it was a small piece of weld slag that was stuck in my top tube. I had to take the whole head apart to get it out.

truman

I just repeatedly pick up my bike and drop it to make it rattle, then repeat the process till I locate the area it's coming from. At that point, I'll start holding things like the rack or fender while I drop it to see if it stops. Once I make it stop, I figure out what I need to do to permanently stop it.

Once, took out my friend's handlebar plug and put an 8 mm nut in there, then replaced the plug. Took him weeks to find it.

EKW in DC

Sure you already checked but just in case... I've had similar before and both times it proved to be a loose nut/bolt attaching a rack so they rattled when I hit a bump, even though I feared it was something mechanical. My bike at the time was always having issues.

Truman's method seems like a good way of trying to isolate the sound. My approach was less scientific. BTW Truman - cruel joke to play on your friend.

HardyWeinberg

Any time you thread anything into a bike you need to grease the threads generously and make sure they are fully engaged.

HardyWeinberg

My two most recent rattles were a brake cable (after loosening/rewinding bar-tape) and my left crank (dust cap came off crank bolt so everytime it rains more than half an inch a day, which has been at least weekly for a while now, all the grease washes out and I need to regrease it)

I_like_cereal

Take off the most likely culprit. The rack and fenders. Recheck and reassemble. Failing that I like Truman's method.

Yan 

Check your fenders.

AltheCyclist

If nothing obvious is loose, try a little 3-1 oil between the spokes (where they touch). They will sometime produce a "rattle" but need weight on them.

Andy_K 

+1

I once had a rattle where the plastic clip that holds the rear fender to the bridge between the seat stays was just a little loose. I fixed it by putting a piece of old tube between the clip and fender.

dcrowell

I'm glad I'm not your friend.

AltheCyclist

That is pretty harsh! Reminds me of old SNL skit where the prankster took of those musical chips out of a greeting card and slipped it into a small hole in his buddy's coat - the coat was emitting musical "happy birthday" whenever he moved, driving him crazy of course ..

RichardGlover

Pfft.

Amateurs.

https://www.thinkgeek.com/gadgets/electronic/b278/

Koa C.

On my old bike i had a rattle when the back wheel fender support would rattle against the rear rack support. The way it was set up, the fender support bar was touching the rear rack support and every time the fender would shake it would rattle. This would happen on every little bump because the fender would shake very easily. I fixed it by wrapping a piece of old inner tube around the rack post in between where they touched. Hope this helps...

Fenway

One thing I would suggest is going to a hardware store and buying neoprene rubber washers. When placed at various attachment points they'll act as shock absorbers and eliminate a lot of rattling. If you search around the forum you'll see plenty of pictures of racks and fenders utilizing leather washers, the neoprene ones work just as well.

L.L. Zamenhof

I'm experiencing a major rattle with the rear fender. There isn't enough clearance to put their little bracket on the fender, so it's just sitting there loose. So every time I go over a bump, it rattles. Severity depends on street. Sometimes it's silent for miles, other times it's chattering constantly.

Koa C. just gave me the idea of putting a piece of foam tape on the contact point. That should be enough to shut it up.

CliftonGK1

I always get rattles from the adjustable rack mounting tabs at the seatstay. The excess length under the rack platform rattles against the platform with every little bump in the road. I bend them down toward the fender after sizing everything up and getting it all mounted right.

MVclyde

True story.......I had a rattle last week that I couldn't pinpoint. Then I hit a patch of ice on Friday and crashed. The rattle went away after the crash so my recommendation is to crash your bike.

Actually, now that I think about it, it was more of a squeak.....never mind......

GRedner

Presta valves? I sometimes get a hard-to-localize rattle if the little threaded washers on the valve stem come loose.

Wilbur Bud

Mine was the J-hook at the bottom of the panniers bouncing against the rack mount notch, and I put one of those squishy hollow cylinders from a ball point pen on the long-tall part of the J and now it compresses against the rack without the rattle.ANy tubing would do, but the pen parts seem to live the longest before replacement.

flippinsweet

Thanks for all the tips. I checked all my bolts on the racks and fenders, all were nice an tight. I did put removable lock-tight on them, so that was not it. I resorted to dropping it in the garage until I figured it out. The problem is the internal wiring of the rear break. This years model of the Sirrus has the cabling jump into the top tube near the head, and out by the seat post.

So my question now it what the heck can I do to fix it? I don't know if more tension is the answer, or if there are other cool tips? Thoughts?

HardyWeinberg

more tension; never want any hint of slack in rear brake cable