SRAM GPX bottom bracket question
08-19-25 | 01:52 PM
#1
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SRAM GPX bottom bracket question
I picked up this old VISP (and I am surprised at how much I enjoy riding it) that came to me equipped with a SRAM GPX bottom bracket and SRAM GPX Truvative Omnium crank assembly.
Riding it with the fixed rear sprocket engaged, the bike is ALWAYS silent.
But when I flip the wheel, and am riding the bike with the freewheel sprocket engaged, the bike is silent until it isn't.
In the course of a hour-long freewheel ride there will be 8 or 10 times when I will hear an audible intermittent clicking sound from down there somewhere for just a few minutes.
If I stop pedalling forward and pedal backwards for a few revolutions, the clicking disappears.
Intermittent problems are hard to diagnose but I am baffled by the noise ONLY showing up when the freewheel side is engaged.
Any ideas ?? The crank has seen very little use since new.
The chain is good and the sprockets, front and both on the rear, are 1/8" thick. The chain is correct type.
Riding it with the fixed rear sprocket engaged, the bike is ALWAYS silent.
But when I flip the wheel, and am riding the bike with the freewheel sprocket engaged, the bike is silent until it isn't.
In the course of a hour-long freewheel ride there will be 8 or 10 times when I will hear an audible intermittent clicking sound from down there somewhere for just a few minutes.
If I stop pedalling forward and pedal backwards for a few revolutions, the clicking disappears.
Intermittent problems are hard to diagnose but I am baffled by the noise ONLY showing up when the freewheel side is engaged.
Any ideas ?? The crank has seen very little use since new.
The chain is good and the sprockets, front and both on the rear, are 1/8" thick. The chain is correct type.
08-19-25 | 03:10 PM
#2
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From: NW Oregon
Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike
your chain might be too tight... the freewheel is complaining, or the chain is complaining.
the tightest spot only happens when the two sprockets match at their respective tightest, most out-of round, places.
try loosening the chain adjustment a little bit.
other than that, i'm no fan of GXP bottom Brackets... they tend to wear faster than most others... a Scott CX Bike i wrenched on went through one every 3 to 6 months, repeatedly... the bike was also his daily ride, 85% of the time.
the tightest spot only happens when the two sprockets match at their respective tightest, most out-of round, places.
try loosening the chain adjustment a little bit.
other than that, i'm no fan of GXP bottom Brackets... they tend to wear faster than most others... a Scott CX Bike i wrenched on went through one every 3 to 6 months, repeatedly... the bike was also his daily ride, 85% of the time.
