Brand new bike..BB spins..WTF??
#1
Junior Member
Thread Starter
Join Date: Sep 2005
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Brand new bike..BB spins..WTF??
i was standing trying get up a hill and my brand new scalpel, made this weird noise. like zzzzttt. i was at the top of a pedal stroke getting ready to rank down and the cranks just spun all the way down making that weird noise. what is it? my bike has 20 miles on it.
#2
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
Sounds like the pawls (ratchets) in the rear wheel's freehub aren't engaging 100% of the time. Was it cold out? Sometimes the lube in the freehub stiffens up enough to do that if it's cold. Or it might be faulty.
#3
I couldn't car less.
Join Date: Nov 2003
Posts: 4,397
Bikes: Ritchey P-series prototype, Diamondback, Nishiki Triathelon Pro.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by mechBgon
Sounds like the pawls (ratchets) in the rear wheel's freehub aren't engaging 100% of the time. Was it cold out? Sometimes the lube in the freehub stiffens up enough to do that if it's cold. Or it might be faulty.
The rear wheel spins free one direction, reversed as stated^ the pawls should engage -turning the cluster\wheel.
Since it's new, return the wheel to the lbs for repair rather than DIY.
The wheel is new also?
Dirt, dirty grease can effect the pawls engaging.
#4
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
The other one I can think of is if the chain manages to sit on top of the teeth of the chainring, sort of inbetween the rings, rather than meshing with them. That can produce a ZZZZZTT noise up front at the cranks, as the chain skates on top of the teeth.
edit: pic of "chainskate" attached now
edit: pic of "chainskate" attached now
Last edited by mechBgon; 12-03-05 at 02:05 PM.
#5
Junior Member
Thread Starter
Join Date: Sep 2005
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by mechBgon
The other one I can think of is if the chain manages to sit on top of the teeth of the chainring, sort of inbetween the rings, rather than meshing with them. That can produce a ZZZZZTT noise up front at the cranks, as the chain skates on top of the teeth.
edit: pic of "chainskate" attached now
edit: pic of "chainskate" attached now
#6
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
Originally Posted by kdh344
wha would cause the chain to do this? and it being a BRAND NEW bike, more than likeley which problem wold it be?
I like jeff williams' point: it's a new bike, so lean on the shop that sold it to you and have them check it out.
#8
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
I see. Practical advice for the moment: don't try out-of-the-saddle stuff until you can get that checked out. Was it cold outside when this occurred, by the way?
#10
I couldn't car less.
Join Date: Nov 2003
Posts: 4,397
Bikes: Ritchey P-series prototype, Diamondback, Nishiki Triathelon Pro.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by kdh344
no, not cold at all. i dont understand how the cranks can spin up front if the problem is at the back??
Counterclockwise, the pawls do not engage and the cluster spins backward free -not turning the wheel.
#11
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
Another example would be a car with a manual transmission. If you put the car in 1st gear, and let in the clutch as you press on the gas pedal, and the engine redlines but the car doesn't move, it isn't the engine's problem. It's the clutch. And in your case, the "clutch" is in the rear hub.
#12
Retro-nerd
What model of bicycle do you have?
__________________
Would you like a dream with that?
Would you like a dream with that?
#13
Junior Member
Thread Starter
Join Date: Sep 2005
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
the bike is a 2001. it was special ordered for a customer that backed out of the purcashe. its been sitting on the rack ever since .cannondale scalpel 2000
#14
Senior Member
Join Date: Jun 2003
Posts: 18,138
Bikes: 2 many
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 1266 Post(s)
Liked 323 Times
in
169 Posts
Originally Posted by mechBgon
The other one I can think of is if the chain manages to sit on top of the teeth of the chainring, sort of inbetween the rings, rather than meshing with them. That can produce a ZZZZZTT noise up front at the cranks, as the chain skates on top of the teeth.
edit: pic of "chainskate" attached now
edit: pic of "chainskate" attached now
#15
Jr. High School Student
Join Date: Dec 2004
Posts: 145
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by kdh344
i was standing trying get up a hill and my brand new scalpel, made this weird noise. like zzzzttt. i was at the top of a pedal stroke getting ready to rank down and the cranks just spun all the way down making that weird noise. what is it? my bike has 20 miles on it.
#16
Junior Member
Thread Starter
Join Date: Sep 2005
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by shiftinjon
Ok, so you were riding up a hill, the chain was engaged and the bike was working fine and suddenly the cranks spun all the way down. The chain skate theory is possible if this had occured immediately after a shift when the chain may have gotten hung up between rings. Did you just shift the front derailleur before this happened? If not, it is improbable that the chain would ride up between the chainrings while it was under tension from your pedaling. More probably, the rear cassette pawls are gummed up after sitting on the sales floor for years and you need to get your rear wheel serviced. Actually, any bike that has been sitting for years should be completely overhauled. Good Luck.
Last edited by kdh344; 12-04-05 at 08:33 AM.
#18
Senior Member
Originally Posted by shiftinjon
Actually, any bike that has been sitting for years should be completely overhauled. Good Luck.
#19
Senior Member
Join Date: Dec 2004
Location: NC
Posts: 253
Bikes: 2006 Novara Randonee, 2009 Fuji Cross Pro, 2013 Specialized Roubaix Pro, 2013 Allez Smartweld A5 Frankenbike, 2021 Diverge Comp Carbon
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 7 Times
in
2 Posts
Well - let me start by saying that I'm no cycle mechanic, but I think I've encountered the same thing, but after twice repeating the problem, I recognized it for what it was - popping the chain off the chainring due to flexing whilst slightly crosschained.
In my case, it was when I was getting ready to climb a really steep driveway, so I dropped into the granny on the front, but was still in the 5 or 6 position on my cassette. When I went to stand and hammer up, the flex in the frame/BB allowed the chain to touch the outer stop on the FD - and off she popped. It dropped right back on as soon as my weight was relieved from it. I then failed to figure it out, and proceeded to repeat as soon as I tried it again. After shifting the rear down a couple of stops, (well OK, all the way to the lowest gear) I was able to scale the hill without incident.
It's a possibility - especially if it only happened when hammered hard, and immediately self-corrected.
In my case, it was when I was getting ready to climb a really steep driveway, so I dropped into the granny on the front, but was still in the 5 or 6 position on my cassette. When I went to stand and hammer up, the flex in the frame/BB allowed the chain to touch the outer stop on the FD - and off she popped. It dropped right back on as soon as my weight was relieved from it. I then failed to figure it out, and proceeded to repeat as soon as I tried it again. After shifting the rear down a couple of stops, (well OK, all the way to the lowest gear) I was able to scale the hill without incident.
It's a possibility - especially if it only happened when hammered hard, and immediately self-corrected.
__________________
-------------------------------
'06 Novara Randonee
'09 Fuji Cross Pro
'13 Specialized Roubaix Pro
'13 Specialized Allez Smartweld Frankenbike
'21 Diverge Comp Carbon
-------------------------------
'06 Novara Randonee
'09 Fuji Cross Pro
'13 Specialized Roubaix Pro
'13 Specialized Allez Smartweld Frankenbike
'21 Diverge Comp Carbon
#20
Senior Member
Join Date: May 2005
Location: La La Land (We love it!)
Posts: 6,301
Bikes: Gilmour road, Curtlo road; both steel (of course)
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 273 Post(s)
Likes: 0
Liked 10 Times
in
9 Posts
Originally Posted by grolby
Stuff and nonsense. I agree that the freehub pawls might be a bit sticky or otherwise reluctant to engage, but the idea that simply sitting around is bad for a bicycle is patently absurd, especially if the bike has been indoors for most of its life. Parts are overhauled as preventive maintenance against wear incurred by mileage, not time. Sometimes grease gets gummy with time, sometimes it doesn't. The pawls might be the problem due to stickiness. This doesn't mean that the hubs, BB and headset need to be taken apart as well! Good grief!
This is probably exactly what happened. Grease does get old, especially when it sits, and the only way to fix it is to R&R (that's remove and replace). Do you think the bike has different types of grease in the other parts?
You have strong evidence that this is the problem; why ignore it ("chainskating" notwithstanding...)?
__________________
Today, I believe my jurisdiction ends here...
Today, I believe my jurisdiction ends here...
#21
The Rabbi
Join Date: Apr 2004
Posts: 5,123
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
I would check that the front chainrings are both perfectly true. If you were in your middle chainring, and its bent, it can cause the chain to ramp up onto the inside of the big ring without fully engaging and therefore slip causing the symptoms you describe. I've seen it on a number of Cannondales and other bikes out of the box--usually only happens under load on hills as you describe too, and the bike typically works fine in the stand.
#22
Junior Member
Thread Starter
Join Date: Sep 2005
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by fholt
Well - let me start by saying that I'm no cycle mechanic, but I think I've encountered the same thing, but after twice repeating the problem, I recognized it for what it was - popping the chain off the chainring due to flexing whilst slightly crosschained.
In my case, it was when I was getting ready to climb a really steep driveway, so I dropped into the granny on the front, but was still in the 5 or 6 position on my cassette. When I went to stand and hammer up, the flex in the frame/BB allowed the chain to touch the outer stop on the FD - and off she popped. It dropped right back on as soon as my weight was relieved from it. I then failed to figure it out, and proceeded to repeat as soon as I tried it again. After shifting the rear down a couple of stops, (well OK, all the way to the lowest gear) I was able to scale the hill without incident.
It's a possibility - especially if it only happened when hammered hard, and immediately self-corrected.
In my case, it was when I was getting ready to climb a really steep driveway, so I dropped into the granny on the front, but was still in the 5 or 6 position on my cassette. When I went to stand and hammer up, the flex in the frame/BB allowed the chain to touch the outer stop on the FD - and off she popped. It dropped right back on as soon as my weight was relieved from it. I then failed to figure it out, and proceeded to repeat as soon as I tried it again. After shifting the rear down a couple of stops, (well OK, all the way to the lowest gear) I was able to scale the hill without incident.
It's a possibility - especially if it only happened when hammered hard, and immediately self-corrected.
seely, on this bike there is no middle chain ring..there are only 2. neither one appeared to be bent. if this is an "out of the box" problem, how can it be fixed? ANOTHER THING...some of the the big chain ring teeth are pointed..they look almost worn out. i asked the shop owner about that he said "all high end bikes are that way..it enables the chain to move easily back and forth from the small CR to the larger CR." ever heard of that********************???
#23
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
Originally Posted by kdh344
ANOTHER THING...some of the the big chain ring teeth aren't pointed..they look almost worn out. i asked the shop owner about that he said "all high end bikes are that way..it enables the chain to move easily back and forth from the small CR to the larger CR." ever heard of that********************???
#24
Senior Member
Join Date: Mar 2004
Location: Calgary Canada
Posts: 238
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by kdh344
the bike is a 2001. it was special ordered for a customer that backed out of the purcashe. its been sitting on the rack ever since .cannondale scalpel 2000
C/Dale replaced the freehub but not the hanger,rear mech or cogset which were all destroyed.
Luckily my LBS stepped up..
'Rasher
#25
Senior Member
Join Date: Jul 2002
Posts: 6,956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
5 Posts
If it's a non-Shimano hub, then I'm with roadrasher, never did like the endless variety of Taiwanese Shimano-wannabe hubs posing as something special. DeoreLX rear hub, stat!