CMOS

I have Shimano Ultegra, tripple in front. The rear is on a Nimbus rear wheel (6600 hub). The cassette is a 105 CS5600 10 speed, 11-25. (This is part of a home trainer setup, not for the road.)

All seems fine in the trainer when spinning in lower gears. When I shift to the last 2 cogs and to the big ring in the front, I get a rumbling noise and a vibration. The souce seems to be the rear setup.

Any ideas for diagnostics and/or possible causes???

Thanks in advance -

ken cummings

Ditto for me. The LBS"overhauled" my commute bike and now it rumbles and squeeks in the top 5 gears.

CMOS

Maybe that the guide pulley is rubbing up against the chain. You have to turn the 'b' screw to move the pulley away from the chain. The Park Tools Web site has some good instruction on this. Here is the link:
https://www.parktool.com/repair/readhowto.asp?id=64

As far as "squeaks goes, something may not have been torqued down enough.

neutron7

"rumbling"

can be the chain not running smoothly on smaller cogs because it was cleaned, mismatched/new chain etc.
can be caused on large cogs because the b-tension adjuster needs to be turned more (usually biggest cog only)
rumbling in any gear can be because the bearings in the hub or freehub body are toast.

Bill Kapaun

Wheel balance**********