BB question, I think
 

This morning, taking off from a stop light, I stood up to put a HUGE mash on the pedals, probably the hardest I have ever pushed. Something slipped just a little. Not the chain or anything like that. A smooth slip of an inch or two of pedal travel. Was it the BB turning? Should I take it to the shop to be tightened? They installed it a couple of months ago. Is this anything to be concerned about immediately or is next week soon enough to get it checked?
Thanks,
Raymond

Hi Rainman,

From my meager experience (and that's not alot I can tell you), if the bb has been recently fitted, it might need time to bed in.

If you pop into your LBS, I think it would be worth getting them to check the movement of the BB...just incase.

Cheers matey

Rich

Very doubtful that it was the BB because the way it is threaded, the act of pedalling tightens it. More likely I am guessing your freehub is on it's way out. It attaches to the rear hub body and contains the mechanisms that were once contained in the freewheel.

I've stripped a few out over the years and this is how it starts. Unfortunately, there is no easy way to test this. You can keep riding and it may not happen again for a while. But, if it completely fails, you will be stranded.

You can replace the freehub. The easiest, cheapest way I have found is to buy a low end Shimano hub and use the freehub. Remove the axle and the freehub can be removed with a 10mm allen.

Thanks, guys. I think I will get the LBS to check things.

Riderx, is it possible that the BB was just being tightened slightly with the application of extra force? Both BB (3 or so months) and the hub (6 months) are new.

Thanks,
Raymond

I doubt the BB for 2 reasons: 1- as stated above you would be effectively tightening the BB as you pedal. 2 - For the type of slip that occurred, the spindle of the BB would have to be "seized" to engage and turn the cup so much at once. In other words, if the BB was loose, I would expect it to be gradually tightened during normal pedaling.

Curious that the hub is pretty new though. I would take it to the shop and have them check it out. This is just my best guess as to what is happening; I'm not a bike mechanic, I just play one on TV:D

Keep in mind, this will be one of those problems that are hard to diagnose or repeat on the workstand. You may just have to ride things until it happens again!

A test for a free wheel slip or a free hub slip. When you get into a section of pavement or dirt and you get into a big gear pedal backwards. Give a couple of revolutions forward then go backward's. If the free hub gearings are going out you will know, same goes for a freewheel. You will notive that the chain will not want to go around the cogs, and start to fall into the chain stay. No big thing though easy to fix.
Another thing, your rear hub bearings could be too tight. You can adjust them from the non drive side (left) easier than the drive side. Loosen the fixing nut, and back the coe out about a half turn. Then while holding onto the cone tighten the fixing nut back. Check this as well.

I'm with MichaelW on this one. Not much chance of it being your bottom bracket.

If it is your freewheel, it won't be long before it completely cashes on you. If your mountings are some lightweight alloy, this could be a possibility. If your freewheel and hub mountings are steel, it is strange that you would be wearing them out.

This may sound crazy, but is there any possibility that you spun out which gave you the one-inch soft pedal sensation? This happened to me this past winter. I thought something mechanical was giving in, but I found out I was spinning out a bit on icy patches.

You know, Mike, I hadn't thought of that, and it is a possibility. I was right at a cross walk with ~1 ft wide painted borders. It is possible that as I jumped up to mash the pedal I unweighted the bike enough to allow a little tire slippage before the weight load really settled again. I will just monitor the situation for now. I highly doubt that months old components are having problems already.
Thanks,
Raymond

I keep reading this thread and puzzling over the problem, and keep coming back to something so simple it's probably not what's involved. But I'll throw it out anyway.

When I've had my MTB freehub removed and replaced in the shop, or removed and replace the freewheel on my road bike myself, there's always two or three instances of slippage exactly like what you're describing, as they get tightened up again. The bike mechanic even alerted me to expect that, in the case of the shop repair. There's no way on earth to tighten the things fully other than riding them.

But you didn't say anything about recent removals, so....:confused:

Thanks, JonR, that is another possibility. I would assume there could be a little slack left in a new hub, too. Now that you mention it, I seem to recall reading that it is only necessary to put one of those parts hand tight (Freewheel? Freehub?) because they will tighten with pedaling.
Regards,
Raymond