mdelrossi

Hello,
I've always done my own wrenching.
On my old 1990 Cannondale when I spin the cranks backwards to get the pedal in position to clipping in the crank spins extremely easily. However when I do this on my new Trek Domane they spin backwards but not as freely. Should I pull the BB apart and re-lube or just leave it alone?

Other than that the bike is great.
Thanks
mdr

HillRider

I'd bet the new bottom bracket is a cartridge or sealed bearings and you can't lube or adjust it in any way. The drag is likely from new tight seals and it will get better with more miles.

bobotech

Doubt it helps with your new bike but the other day, a guy brought in an old bike to work on at my coop. The crank would not spin easily at all when you spun it backwards. After we lubed the chain and the rear derailleur pulleys, it spun backwards just fine and free. Just was a mixture of a sticky chain and sticky derailleur pulleys.

I don't think a new bike should have that issue though.

mdelrossi

Thanks, it spins, just not like he perpetual motion machine my older bike has. I'll try lubing the chain and pulleys, they are a bit sticky. Any suggestions on the lube?
Thanks
mdr

Homebrew01

Could be more friction in the cassette hub too.

ThermionicScott 

Could be that the Cannondale's crank bearings are on the loose side -- might be good to check them.

ultraman6970

I dont see whats the problem. Do you ride your bike backwards?

bobotech

Well yeah, it could be a problem if you can't spin the pedal backwards. Whenever I get my pedal ready to take off, I have to spin it backwards so my right foot can get ready to push down on the pedal.

rithem

lube freehub or freewheel ... squirt triflow of prolink gold something light to to free up sticky grease some. don't go nut on it just enough to smooth it out, do the crank turn forward when wheel should coast ... off the ground or in workstand for that test

tomacropod

Does your new Domane go faster than your 1990 Cannondale? The resistance in unloaded bearings is interesting to compare, but does not correlate strongly to the resistance in bearings that are loaded laterally or radially. Your new crank and bearing assembly has more drag because of how the bearings and seals work, but all things considered, transmits power more efficiently to the rest of your drivetrain.

Also, the Bontrager Race wheels, and lower, have a lot of drag in the freehub, until the seal wears in. Tip, put a lot of grease on each side of the BB92 bearings to help keep water out, you'll help the bearings last longer.

- Joel (just assembled my 2013 Domane 5.2)

mdelrossi

@rithem
Thanks for the info, I was going to do that but I haven't found any "maintenance" guidelines, and I ddn't want to F up my new bike.
I used to repack my bearings all the time, but with these new fangled bearings I didn't know if it would be ok.
Would it be ok to spritz some Tri Flow into the hubs as well as the BB?

@tomacropd
Thanks, I have the 2.0 version. Not necessarily depends on the day
I have the "Approved alloy hubs" would Tri Flow help them as well?


Thanks for all your help.
mdr

LateNite

+1

rithem

No Don't bother with the hub or BB. light oil like the 2 I stated between the cassette and spokes it is a tight space you will need the needle applicator on the lube bottle to get in there. Typically all bearings use grease never oil... this is only to loosen up the sticky grease in the Free Hub. Depending on the quality of the hubs the grease may or may not be insufficient. I am sure this will do the trick just make sure you get it in the right place.

dddd

I've seen more than one cartride-style bottom bracket that had the same reverse-drag issue.

There's something going on inside the bearings, I think that the bearing retainers eventually carve their own path through the thick lubricant, but only in the foreward direction. Reverse rotation immediately induces viscous drag.

Perhaps it also has to do with the seal's contact as HillRider suggested, since the rubbing surfaces might angle themselves into a "one-way-clutch" sort of orintation at the microscopic level.

I would call this semi-common, and no cause for concern.

I would remove the chain though, and repeat the test to see where the friction is originating.

Some of Shimano's sealed (non-ball-bearing) pulleys have enormous amounts of seal drag that will benefit from a slight bit of oil, and I used to lube these before every race. For non-sealed pulleys though, I prefer to flood the gap around the metal shield with a dozen drops of motor oil, with the bike laying on it's side, before doing the usual chain lubing/wiping (the excess oil will run out onto the chain). A useful quick improvement for old bikes especially, with thickened lubricant often causing much turning resistance.

oldbobcat

May I as one question--is that with or without the chain attached. If it's without the chain, it's something in the bottom bracket, probably tight seals or too much side load on the bearings (I've seen this in more than one brand new bike). If it's with the chain, that is the hub is trying to push the chain forward while you're trying to coast or pedal backwards, the problem is in the cassette body of the hub. Either way, if it's a brand new Domane I'd have the dealer look at it.

dddd

It was always the bottom bracket itself in the cases to which I was referring.

I've seen plenty of draggy freehub bodies too though, which causes chain droop when the bike is freewheeling along while being ridden.
Just last month, an older Dura-Ace 7s freewheel I was using became draggy after an o-ring apparently got swollen from lube. I had to remove the somewhat-redundant o-ring to restore free rotation.

mdelrossi

Thank you for the suggestions.
I don't have the tools necessary to get to and take apart the cassette free hub or BB yet .
But I was able to get some Tri Flow into the cassette free hub area and I also re-packed the front wheel bearings they were grinding a bit . A bit of Tri Flow on the chain as well and the cranks feel a bit smoother. I only have 150 miles on the bike so until I get my tools I'll keep on riding, and hopefully every thing will smooth out.
Thanks again.

mdr

Shinjukan

Is the rear wheel fully seated properly? Sometimes having the cassette teeth not properly meshing with the chain results in poor back-pedalling of the crankset.