Mtb with sluggish crank - what to do?

cbcbd · Jun 6, 2007

Ok, came back from a 1h30m ride this morning... sometimes during the ride I was noticing a creaking once every pedal revolution that I kind of had heard before.
But anyway, got done with my ride, rode back home and then proceeded to hose down the bike - nothing unusual. Then I go to backpedal and the turning of the cranks is very stiff - wtf!?

Anyway, so I'm looking through the park tool website and whatnot and I guess I'll be working on my bike tonight instead of doing other stuff I'd rather be doing - you know... like riding my bike... ugh

Any ideas of what is going on and what I should check out?

Marc · Jun 6, 2007

cbcbd said:
Ok, came back from a 1h30m ride this morning... sometimes during the ride I was noticing a creaking once every pedal revolution that I kind of had heard before.
But anyway, got done with my ride, rode back home and then proceeded to hose down the bike - nothing unusual. Then I go to backpedal and the turning of the cranks is very stiff - wtf!?

Anyway, so I'm looking through the park tool website and whatnot and I guess I'll be working on my bike tonight instead of doing other stuff I'd rather be doing - you know... like riding my bike... ugh

Any ideas of what is going on and what I should check out?

While creaking often comes from the crank, that's more common with square taper cranks... I'm assuming you have ISIS or some type of splined crank?

Doesn't matter anyway, if you're sure it isn't your drivetrain, I'd say this is highly likely to be a bearing problem in your bottom bracket. How old is the BB? The seals might have been so leaky that when you hosed of the bike, you got some sludge into the bearings.

Take your cranks at the 0 and 180 position and then push on one and pull on the other from one side of the bike and wiggle back them back and forth like that. If there's play, it's coming from the BB bearings.

The only real fix is a new BB.

cbcbd · Jun 6, 2007

Marc said:
While creaking often comes from the crank, that's more common with square taper cranks... I'm assuming you have ISIS or some type of splined crank?

Yep, CrankFace XC

Marc said:
Doesn't matter anyway, if you're sure it isn't your drivetrain, I'd say this is highly likely to be a bearing problem in your bottom bracket. How old is the BB? The seals might have been so leaky that when you hosed of the bike, you got some sludge into the bearings.

Take your cranks at the 0 and 180 position and then push on one and pull on the other from one side of the bike and wiggle back them back and forth like that. If there's play, it's coming from the BB bearings.

The only real fix is a new BB.

I took it in during lunch to take a look. It wasn't the drivetrain and the bike is only 1 year old. Did the wiggle test and there was no play. I couldn't get the right crank off (man, it's on there tight) before lunch was over. It seems like there is lots of gunk between the BB and crank - a cleaning might do but first I have to figure out how to take off the arms. I'm going back armed with some pb blaster or something.

JimG. · Jun 6, 2007

Maybe it needs Viagra.

Marc · Jun 6, 2007

cbcbd said:
Yep, CrankFace XC

I took it in during lunch to take a look. It wasn't the drivetrain and the bike is only 1 year old. Did the wiggle test and there was no play. I couldn't get the right crank off (man, it's on there tight) before lunch was over. It seems like there is lots of gunk between the BB and crank - a cleaning might do but first I have to figure out how to take off the arms. I'm going back armed with some pb blaster or something.

Could be a defective BB or some really tenacious sludge I guess. I'd still recommend taking the BB out and having a look if you have a spline tool to get it out.

I had a crank arm on so tight once I had to lay the frame on the ground, sit straddling the bottom bracket with one foot on the chain stay and one on the down tube, with a breaker bar on the crank puller and the other hand on the crank arm to get it loose. That's kind of last resort.

cbcbd · Jun 6, 2007

JimG. said:
Maybe it needs Viagra.

My bike's prescription ran out and I'm not sharing!!

ckofer · Jun 6, 2007

Both of my bikes have a sluggish rider.

cbcbd · Jun 6, 2007

The jury is in... Took my cranks off and left BB ring is completely seized. Freakin' a... looks like no more mtb for at least a month or two.

Now I'm gonna see if there's a warranty on this thing (I've had it for a year!), if yes then I'll get another crappy Raceface Evolv (which, according to maaany online reviews, is a POS), if not then I'll be shopping for a replacement... I'm open to suggestions.

Marc · Jun 7, 2007

That sucks man, I'm sorry. I think I have the Evolve XC on my mtb and so far have had no trouble with it. The only thing I noticed that was wrong was the shell width on my GT was slightly narrower than the BB so I have a couple of cup threads showing on one side, but it doesn't affect the functionality.

I'd def. call up whoever makes the BB and tell them what happened, esp if it was a factory assembled bike. Seized bearings on a BB that new is probably the result of a bad seal.

powers · Jun 7, 2007

Ummm.....did you know that the drive side threads are reverse? A one year old bike should not have a frozen cup unless you rode it all winter in the salt and havea tendency to blast the cranks with water when you wash it.

cbcbd · Jun 7, 2007

powers said:
Ummm.....did you know that the drive side threads are reverse? A one year old bike should not have a frozen cup unless you rode it all winter in the salt and havea tendency to blast the cranks with water when you wash it.

Yeah, i know they are reversed. I was having problems removing the cranks, not the BB - but that's all resolved.

I think you're right about the hose and water. Other than just seeing lots of water this year already, I probably hosed the BB to death.

But anyway, I'm ordering a Shimano BB today or tomorrow - I've heard that they are much smoother than the RF BB and do work with RF cranks.

Marc · Jun 7, 2007

Yup, all they have to have are ISIS (International Spline Interface Standard) splines.

Marc · Jun 7, 2007

Wait a minute, isn't it the non drive side threads that are reverse? The non drive crank spins counter, and the drive crank spins clockwise... I'm pretty sure it's the non drive side threads that are reverse, because you would want it to tighten as you pedal, not the other way around.

I haven't torn down my crank this year yet though and I always forget.

cbcbd · Jun 7, 2007

Marc said:
Wait a minute, isn't it the non drive side threads that are reverse? The non drive crank spins counter, and the drive crank spins clockwise... I'm pretty sure it's the non drive side threads that are reverse, because you would want it to tighten as you pedal, not the other way around.

I haven't torn down my crank this year yet though and I always forget.

Nah, you're right. I'm sure that's what he meant and I just read it that way... but yeah - drive side is clockwise to tighten, non-drive is counter.

AHM · Jun 7, 2007

A couple thoughts.

1. RF BB's are junk. I have had three or four and that is enough. RF moved most production to China a while back, this drastically reduced the quality of their components.
2. Pulling your crank arms was tough ? Are you using a crank extractor ?? It is pretty easy to pull crank arms.
3. Hosing off your bike: Do not direct high pressure water at bearing seals. Very few of your bearings are actually high quality sealed bearings. Most employ a simple rubber seal. Even a "sealed bearing" like in a Chris King HS or hub, just has a simple rubber seal and a snap ring. rebuild your headset at least once a season.
4. Shimano BB's: work extremely well and are pretty cheap. I actually replace them annually and ride about 1500 off road miles a season.
5. Drive train rebuilds: rebuilding your drivetrain-->cleaning cassette, rings, derailleurs, and a check of the BB, should occur a couple times a season, depending on where you ride. I would not however, take apart my drive train all the time. Consider regular chain replacements to keep the more expensive rings and cogs from excessive wear. I actually change chains every 20 - 22 rides and use about 4 chains a season. This keeps my cogs and rings lasting basically three seasons, unless one gets bent.
6. If you are changing rings and cogs, consider 8 speed. The chains last longer, the cogs last longer and there is less ghost shifting.
7. Any questions let me know: bike mechanic for over 20 years.

Marc · Jun 7, 2007

Do you know how long RF started producing in China AHM?

My RF is coming up on five years old now and is still tight and smooth.

Also kind of ironic you mention 8 speed... one of my roadie friends recently got hit by a car (not serious) but wracked up her bike and basically got enough in a settlement to build a new one and went from 9 to 10 speed. I questioned her on it and she was surprised to hear me tell her to expect more broken chains, more wear, more replacement, and also the annoying fact you need a special made thinner chain tool.

I have a feeling component manufacturers really got used to the cycle of adding a cog every few years and having everyone buy totally new drive trains (who bought into the marketing hype anyway). I think they've finally reached the end with 10 spds unless they start delving into hybrid cassette/gear hub systems which I guess are still weight prohibitive for most roadies.

AHM · Jun 9, 2007

RF etc.......

RF went to China about 2004. It was about the same time they started changing their tune when you called them on the phone for bearing cups, taper locks etc. I actually use a square taper still, since I had a bunch of $$ tied up in RF cranks pre the splined era. I look forward to the upgrade, but with high end cranks, its costly, so I'll ride square taper a bit longer.

Do you rebuild the BB or are you on original bearings. If you have a sealed bearing BB that has std replaceable, pseudo non-serviceable (you can pry off that seal and add grease), sealed bearings, the best way to replace is by calling a bearing shop. This saved me tons off of what a shop wanted to charge.

Not nuts on totally adding gears. Stocked up on 8 speed parts, so I have a ton. Enjoy the season, should be a good weekend to ride in the northeast. I'll be out this afternoon.....

Marc · Jun 9, 2007

I take it out every year and inspect the BB; they're sealed bearings, and I did exactly that to one side one year because it felt a little resistive. I was able to get some or most of the old grease out (I think) but it was hard to tell how dirty it was because I think it was light brown colored bearing grease to begin with. I stuffed some white lithium in and haven't touched it since. Everything seemed alright so I didn't bother with the other side. If the bearings start to wear to a point where they loosen I'll just replace the BB.

I might have to go see a bearing shop about my road wheels though, now that you mention it. I have old Spinergy Rev X super stiffs and from what I can tell, the cartridge bearings are pressed in. I called up Spinergy (they have a place in CT) and they don't touch them anymore.

czimborbryan · Jun 21, 2007

powers said:
Ummm.....did you know that the drive side threads are reverse? A one year old bike should not have a frozen cup unless you rode it all winter in the salt and havea tendency to blast the cranks with water when you wash it.

I've done just that for almost ten years and my BB still works fine. The BB above is a lemon - 100%.

cbcbd · Jun 21, 2007

czimborbryan said:
I've done just that for almost ten years and my BB still works fine. The BB above is a lemon - 100%.

Eh, yeah... no worries, I got a Shimano XTR BB sitting at home waiting for me to put it on...

Mtb with sluggish crank - what to do?

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