Amt0571

I have a Dahon Mu P27 with a SRAM Dualdrive hub. Since new the cranks were never really smooth when spinning them backwards with my hand, but I assumed it was normal as al internal gears turned. Sometimes the pedals tended to turn when walking the bike, but it was something that happened few and far between as drag was not that high.

6 months ago, with around 2000km and several rainy commutes, I noticed the cones had come loose as the rear wheel had some slight side to side play. I dissassembled the hub, cleaned and relubed its internals (which where almost dry BTW), greased the cups&cones and adjusted them until there was no play. It was a bit difficult to adjust as the DualDrive has 3 cup&cones bearings that are adjusted with a single screw, so you have to find a compromise.

It's been 6 months and 500km since then, and I noticed the now the cranks turn when walking the bike almost always, not just an occasional thing as it was before. When turning the cranks backwards with my hand, I can feel they turn "freely" (or as free as they can be with all the gears turning) until some point where I can find an increase of reasistance. If I keep turning, I can easily overcome this spot until it reappears after a few more crank turns.

Is this normal IGH behaviour? may I have tightened the cones too much or something? someone else had this happen?

Mr Pink57

The trick is when you adjust a cup and cone is when you finish there should be some play, when installed properly in the dropouts there will be no play. Adjustment is probably too tight, just try again.

bike_galpal

pretty sure its not the cones.

i've had this problem a lot, and still do on some singlespeeeds i don't care about a whole lot. the problem you listed in the title can happen from too much chain tension (at least with a freewheel) but this is a bit different.

one of the following is probably a bit bent (or possibly not installed quite right):
- chainring
- rear axle
- rear cog
- bottom bracket

the reason for the cog/chainring is of course not that its bent itself into a less than perfect circle, but that its no longer laterally true, so it pulls the chain diagnollay and a slightly farther distance.

disclaimer: i might kinda be talking out of my ass?? but idk i'm pretty sure there is a lot of truth to this.

bike_galpal

this is kinda funny because its one of the first bike problems that really had me confused and one of the reasons i joined the forum, and now i'm just like, whatever.... i can't afford all new parts so something being off is super not surprising.

you can just lower the chain tension a little bit and it will be fine.

fietsbob

thicker lube in the freehub driver can do that.. take off your klick box and pull the shift rod and the hollow axle

is where you can add oil try 20 weight motor oil ... (I use Phil tenacious oil in my BSR/AW3)



Its a hybrid .. on it the end the driver is what holds the cassette ..

3 speeds its oil put on the gears seeping out that lubes the bearings,
unless you remove the axle-cones and do that separately.. with grease..


bet if 1 pedal was heavier than the other (Folding) it wouldn't do that.

Amt0571

I know how to adjust cup and cones on regular hubs. The problem is the DualDrive has 3 cup&cone bearings that are adjusted with a single nut, so it's almost impossible to have the three of them perfectly adjusted, so you have to make a compromise. Moreover, one of them is internal (it's well inside the hub), and it's difficult to know if you have overtightened them because the hub always has some slight drag and vibrations caused by the internal gears that make it difficult to notice that the bearings are not turning smoothly. I'm finding it hard to make sure they're well adjusted in this hub... I don't know if there'se a trick or something that I may be missing.

I tried to remove the wheel and spin the cassette by hand and I could feel the same resistance, so I'm fairly sure everything us straight. I can't adjust chain tension as the bike also has a derailleur (DualDrive is a 3sp hub combined with a 9sp external cassette and, in my case, a SRAM X7 derailleur).

Anyway, thanks for your suggestions.

Can't do this as the bike also has a regular derailleur with its spring loaded tensioner. Thanks for the suggestion anyway.


You have given me an idea... when I reassembled the hub, I used a thick grease for the cup&cones and also greased the pullrod (as I found some slight rust residue on it that, I assumed, came from the inside of the axle as the pullrod is aluminum). Fortunately, there was no trace of rust on the internal gears.

Anyway, I lubed the internal gears and pawls using synthetic 5W30 oil as that was what I had on hand and found it thin enough for pawls to engage correctly. Not sure if I used the correct oil, but I couldn't find any information on the SRAM website about it. They just say the hub needs no servicig as it comes "lubricated for life", which is oviously not true as it was almost dry when I opened it after just 2000km.

I noticed that the point where I can feel resistance in the cranks does not follow a pattern... sometimes I can even turn the cranks several revolutions without noticing it, this makes me think it's not a cup&cone overtightening issue.

I'm thinking that maybe some grease from the cup&cones or the shifting pullrod may have migrated inside the hub, thickening the oil and, sometimes, clogging the planetary gears increasing the resistance momentarily.

I think it's time to disassemble the hub and get the wrench out again

Thanks!

davidad

Because there is no quick release the bearings should have a little play as possible. A small amount of preload is best.