Bicycle Mechanics - Is this normal? (rear hub question)

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14R
02-09-11, 10:14 PM
I am under the impression my rear wheel is not as "loose" as it should be, creating a drag on my bike. Please take a look at this video and let me know if you can see something wrong with it.

Thank you in advance.

14R
http://www.youtube.com/watch?v=tkdk03jA8g0


FBinNY
02-09-11, 10:21 PM
The freewheel does seem a bit stiffer than most, but you can't tell that way. It may have an inherently stiffer ratchet mechanism, and it'll never spin as long as a 8-10 speed unit simply by virtue of being much lighter (less inertia).

The acid test is to mount the wheel attach the chain and spin the wheel. As long as the wheel itself doesn't drag and the freewheel doesn't push the chain forward enough to make the top section sag, it's OK.

14R
02-09-11, 10:24 PM
Thank you for the prompt reply. I am in the process of replacing a tube/tire. When I put everything back together I will conduct the test and make a video if necessary.

Now what if it is stiff, with the top section of my chain sagging, where do we go from there?

Once again, thank you for your help.


FBinNY
02-09-11, 10:42 PM
that's a bridge you can cross when you get to it. If you didn't notice a problem before removing it, I'd assume it's OK.

I'm not familiar enough with that freewheel system to advise you, but it's probably fixable (if it needs fixing) with a fieldstrip, clean and oiling. Some can be oiled without disassembly, and your next step would to contact Brompton or one of their dealers if necessary.

jur
02-09-11, 11:03 PM
Well at least a stiff freewheel isn't going to slow you down when you're trying to go faster.

Sheldonbrown has some tips on how to lube freewheels - IIRC it involves dribbling a drop or two of oil past the small gap between body and moving part. The cogs may need removing to see this gap.

14R
02-09-11, 11:42 PM
I did notice that the bike "drags" more than other folders I had in the past. On top of that, I noticed that the "backpedaling" wasn't as loose as usual (typical manouver on trafic lights to place the pedals in a friendly position). The next video will show what I am talking about (taking forever to upload on youtube as we speak).

Thank you for jumping in Jur.

14R
02-09-11, 11:48 PM
http://www.youtube.com/watch?v=QPr0ODOrwNQ

14R
02-11-11, 08:04 AM
Friendly bump.

FBinNY
02-11-11, 08:14 AM
I hate to say this, but it looks pretty normal to me. The mechanism is somewhat noisier than most, and maybe a hair tighter, but not enough to seem like there's a problem.

I suspect that's just the way they are, but you could check with Brompton or other owners to confirm.

davidad
02-11-11, 10:10 AM
You might drip a little heavy oil into the freewheel, but it looks OK to me. The noise is from the sping tension on the pawls in the freewheel.

14R
02-11-11, 10:56 AM
Thank you FBinNY.