Mapet

Hi, I have a Pinarello prince 2022, when I stop pedaling at high speed and rmp on the last 3 gears( 11,12,14 I believe) my chain slaps on the frame, bike shop told me the casette is ok, chain is right lenght also not stretch, bike is new two months old.
Appreciate some advise, thanks.

FBinNY 

This is about friction and torque.

There's always some friction within freehubs that has the cassette wanting to turn with the wheel. You can feel this if you sign a wheel while holding the freewheel.

The only thing countering the turning cassette is the chain's lower loop and the RD cage spring maintaining tension there.

The reason it only affects higher gears relates to torque or leverage. Bigger sprockets give the chain more leverage, so you only see the issue when the freewheel has better leverage than the chain.

There are 2 approached to solving the problem. First, and preferred, is to minimize freehub drag, making sure it's clean and lubed with a b very light oil.

If it's still a problem after luring the freehub, you might consider increasing RD cage tension. For my part, I'd rather use a chainstay protector and live with slap vs. adding friction to the system, but offered this in case you don't feel the same way.

maddog34

what rear hub is the bike equipped with?

FBinNY 

In addition to what I posted above, consider inertia.

When you're pedaling, the wheel and freewheel are spinning at decent speed. Likewise, your chain is moving forward on top.

Suddenly you stop the crank, but have no way to stop the freewheel equally fast, so on inertia alone there will be some chain spooled into the upper loop with no place to go.

If all is good, the RD cage will pull it back and retension the upper loop, but not necessarily before a slap.

Crankycrank

Take the wheel off and spin the cassette backwards looking for sticking or sluggish rotation. Since the bike is new it could just be a sticky seal on the freehub body that may loosen up which would be unusual but not impossible to cause this problem. Try the spin test and let us know what you find.

Iride01 

Bumpy road? In those small rear gears the chain is closer to the chain stay. So some slap for that reason is probably okay and why many bikes come with some protection on the top of the stay. If yours doesn't have it, then you might want to consider some helicopter tape or similar on that top length of the stay.

Otherwise it might be as others have said. Get your bike in a stand or hang the nose of the saddle on something to get the rear wheel off the ground. Turn the crank by hand and get your rear wheel turning somewhat fast. Then stop the crank and see if the chain goes slack on top. If it only does it briefly then the slack gets taken back out, you are probably good. That is probably your noise, but not entirely a big issue. If it goes slack and stays slack till the wheel spins down to a much lower RPM, then you should figure out why the free hub isn't so free anymore. Usually it's internal. But the lockring on the cassette might be rubbing on something near the dropout.

If that's not it, then us know. We love to speculate about possible causes. Sometimes wildly!

maddog34

things i've found that caused extra drag at the Freehub...
Dental floss.
Long blades of grass.
thread.
fishing line.
long human hairs.
road grit.
too darn much grease.
a poorly assembled hub with the seal partially folded over.
a bent seal after a "regrease"
Insanely sticky and thick grease.
and finally.. the worst attempt to ram extra bearings into a hub that was also completely devoid of grease.

oh, and i once found eight 1/4" balls, and one 5/16" ball in one side of a rear hub... but that was in a freewheel type hub, so it doesn't really count.

i found a freewheel hub recently where the owner had put the balls in the CENTRAL area of the hub.. not in the bearing race areas.." i can't get the axle tight enough!it just keeps wobbling!" was his complaint.... the DS spacer was missing too... a stack of custom, ground down washers were in it's place... the jam nut was inboard of the washers, directly contacting the now ruined cone... and hub. He ended up with a nice shiny new/used wheel assy.

Mapet

Wheels are fulcrum 500 ,thanks

Mapet

I will start with the freehub or maybe borow a wheel.Thanks.

maddog34

https://bicycles.stackexchange.com/q...lacement-dragI just replaced a Fulcrum racing 5 LG free hub. Once it was all together, it seems a bit tight. With the bike on the stand, when I spin the pedals, and release, the pedals continue to rotate. So the free hub is not spinning as freely as I would expect.

I did not disassemble the entire axle and hub; I just removed the worn free hub from the drive side, and replaced it with a new free hub. So, no changes, other than the free hub itself.

Will it loosen up? Is this related to the pre-load on the non-drive side of the axle? Anyone have any experience with this?


Answer:
After a couple of email exchanges with Campagnolo technical services of North America, I've confirmed that I correctly installed the new free hub (but you should do this carefully, as the pawls and/or spring can be damaged with too much pressure or twisting). The technician confirmed that the new bearings could be a bit stiff as they "break in", but that things should loosen up appropriately.

So, I will put some miles on and confirm this as the answer once things loosen up.

Edit: After about 100 miles (160 K) the bearings have loosened a bit and the wheel is spinning without dragging along the crank. So, I believe that in this case, the new fulcrum freehub body did indeed need a break-in period.

Also: as long as your wheel was stable on its axle before replacing the freehub body...don't mess with the pre-load mechanism.


What i, Maddog, would advise... Get a Better Hub that doesn't have a problem from the FACTORY... Don't waste cash on replacing a bad hub part with another bad hub part.

or.. disassemble the faulty hub, replace the too-thick grease with Shimano freehub grease, and hope you don't damage the finicky freehub while re-installing it precisely as prescribed by the Manufacturer that chose the bad grease in it originally... Good luck.

FBinNY 

How do you replace a hub? Seems to me that a new wheel is the most expensive solution to a relatively minor (fixable) issue.

Given that the example you cited, loosened up and was 100% fine on its own after a few miles, wouldn't it make more sense for the OP to wait before shelling out serious dough?

maddog34

i unlace the spokes, install the non drive side inbound spokes first, then attach the nipples to the spokes. then i insert the driv.. oh wait.. you'll remember soon.

"or.. disassemble the faulty hub, replace the too-thick grease with Shimano freehub grease, and hope you don't damage the finicky freehub while re-installing it precisely as prescribed by the Manufacturer that chose the bad grease in it originally... Good luck. " [those freehubs are also known to sometimes be damaged during installation]

those hub assemblies have issues FROM THE FACTORY, and those issues may include OTHER PROBLEMS, across the lineup.

i posted a very relevant reply to a similar problem, then gave my Professional Opinion... I'd replace the finicky hub, in it's entirety..

FBinNY 

My, " how do you replace a hub?" was rhetorical.

I understand that you posted your professional opinion, and that's fine.

Equally fine is my posting my opinion that it's expensive overkill.

In the end, the OP will solve his problem, one way or the other. Meanwhile others will form their own opinions.

maddog34

"My, " how do you replace a hub?" was rhetorical.".. as was my reply... with humor.

i've got far more important things to do than this pointless discussion with you.
i'm sure you'll find a way to stretch this thread into 40 or so posts for no good reason.
if you want to help.. price out a new freehub for a low end campy hub... then price a 105 hub that would fit the application.
then price an Uber ride home from the middle of a ruined ride.
juggle some odds.

IMO, i'd replace the hub that has issues... if the shimano grease doesn't solve the drag, and the re-grease doesn't warp the finicky freehub.

https://www.ebay.com/itm/28547005173...-53481-19255-0
seriously?

FBinNY 

My disagreement is with your last resort ---- new hub/wheel ---- first approach.

I'm old school and fix things, or make a very serious effort before replacing them. Doubly so when the economics demand the effort.

I happen to agree that grease may be cause freehub drag and, if necessary it could be replaced to advantage. OTOH, having serviced various Campy/Fulcrum versions since y2k, I don't consider them hard to service or finicky. Nor, I suspect, do most mechanics. I also have no idea what you mean when you say "warp" in this context.

If the OP wishes to try a thinner grease in the freehub, it's a relatively simple job, requiring some care, but no special skill or tools.

Tip--- wrap 2 turns of dental floss to keep pawls pocketed when assembling, then unwind it after the pawls are within the ratchet ring.