front wheel spinning roughly - any ideas?

[nimm]

The front wheel on my bike has begun to spin roughly. It's a Shimano WH-R550 with about 4700km on the clock. It spins 100% true, but rather than silky smooth as it used to you can definitely feel roughness if that makes any sense. It's evenly rough throughout a revolution, not notchy or rough at a specific point.

Any idea what could have happened to cause this - and how to fix?

I removed the wheel and re-seated it just in case it had something to do with that. I also made sure it was solidly clamped in but no difference. There isn't any side-to-side play either - everything feels / looks like normal.

[Kalgrm]

That sounds like a classic case of chewed out bearings. Try taking the wheel off and turning the axle by hand. If it does not feel silky smooth, your bearings (and possibly the cones) are shot.

Bearings cost about $5 for a handful, so no big deal there. Cones I'm not up with on price, but last time I got some, they were't expensive.

Cheers,
Graeme

[dr.gonzo]

i just replaced the cones on my 550 front wheel! cost was around the $30 mark. now its as good as new! They almost looked pitted! not sure if its bad hardening or what!

[Kalgrm]

i just replaced the cones on my 550 front wheel! cost was around the $30 mark. now its as good as new! They almost looked pitted! not sure if its bad hardening or what!

That's what happens when the bearings break down: the cones cop a hiding and get little holes in them as the balls lose their roundness.

$30 is okay though.

Cheers,
Graeme

[dr.gonzo]

thats what i thought! but i checked the bearings under light/magnification and they were perfect!

[buster]

It sounds like your front wheel bearings are stuffed. Have a look at this video which should give you a few clues about what to look for.
http://bicycletutor.com/overhaul-wheel-bearings/

[nimm]

Thanks fellas.

I'll take a look over the weekend - although I'll need to grab some tools to actually pull it apart.

[big.birdd]

hmm cool

[il padrone]

The right sized cone spanners are about all you'll need.

[Kid_Carbine]

The bearings will feel rough of they have any dirt in them. If the hubs have been wet, ... with muddy water, then this is also a posibility.
If left unchecked, the contaminants in the lubricant are ground down untill the bearing balls are running in an abrasive paste.
This is also a common cause of bearing failure.

Once the hub is stripped, clean it untill it is almost sterile & examine the bearing cups in the hub. If the surface is still serviceable, then look at the balls & cones, but replacing these is a waste of time effort & money if the hub surfaces are not up to snuff.

I prefer to use a marine grease when repacking these bearings & do your final adjustment of the bearings in the frame or fork. You will find that when you tighten the skewer, it actually compresses the cones together just a hair & can ruin your precision adjustment, so adjust, clamp in fork & test, then release, re-adjust, clamp & test etc.
A pain to be sure, but once you get it absolutely right, you will feel the difference on the road.