Singlespeed & Fixed Gear - Repeatedly pulling cranks.

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familyman
01-28-04, 01:47 PM
This isn't necessarily a fixie specific question, but you guys seem to be the kings of parts swapping and cheapness.
How bad is it for a square taper crankset to repeatedly pull it and reinstall it? Say I've got two bikes and I alternate weekends that I ride them. So in any given weekend I'm pulling it from one bike and putting it on the other and same the next weekend. How much damage am I going to be doing? My gut instintict tells me that doing this a few times isn't a big deal but doing it every weekend for a year will be a bad thing.
I really want to ride all my bikes and I really don't have any money.
fixedgearhead
01-28-04, 01:57 PM
This isn't necessarily a fixie specific question, but you guys seem to be the kings of parts swapping and cheapness.
How bad is it for a square taper crankset to repeatedly pull it and reinstall it? Say I've got two bikes and I alternate weekends that I ride them. So in any given weekend I'm pulling it from one bike and putting it on the other and same the next weekend. How much damage am I going to be doing? My gut instintict tells me that doing this a few times isn't a big deal but doing it every weekend for a year will be a bad thing.
I really want to ride all my bikes and I really don't have any money.
In track racing some people pull cranks quite often. Just make sure that the threads on the crank puller are well seated into the crank arm and not loosely tightened down before you extract the cranks. Lightly grease the cranks before reinstalling. I didnt, and one time stripped the threads on the inside of the crank arm fixing hole of a T.A. Cyclotourist crank arm to the tune of $115.00. Ouch. I might suggest that you check out Harris Cyclery for a Shimano Sora 165mm Crank Set. Brand new for $65.00 and it looks good too. I have them on a few of my bikes and they work great.
Fixedgearhead
RegularGuy
01-28-04, 01:59 PM
Pulling and reinstalling cranks is hard on them. It's easy to strip the threads. It can distort the taper, so that it doesn't fit tightly anymore...especially if you are swapping them between two bottom brackets.
I suggest you buy a cheap set of cranks now, so you don't have to buy two sets later.
superchivo
01-28-04, 01:59 PM
If you did this, you would own the title "king of parts swapping and cheapness."
The only problem I've ever had with pulling cranks is that you can occasionally pull out the threads on the crank arms if the cranks are: 1) cheap 2) old and 3) you cross-thread or don't screw in the removal tool all the way.
I make it a point to lube everything on the crank puller so that the round plate that pushes against the taper doesn't bind and exert uneven force against the treads.
When it comes down to it, most cranks are aluminum and aluminum fatigues over time. Those threads aren't very thick so I would guess you could wear them out if you were pulling the cranks every weekend.
On the other hand, you will probably leave a pair on your favorite bike and end up rotating a pair to a different bike every now and then. This probably isn't a big deal.
Someone will have to call the Myth Busters to get a definitive answer to this one.
roadfix
01-28-04, 02:06 PM
If you want to continue pulling & re-installing cranks, it's a good idea to use a torque wrench every time so you don't over-torque and eventually enlarge the crank tapers.
George
familyman
01-28-04, 02:21 PM
I've got a torque wrench and I do use it installing cranks. I probably won't do this much. Maybe for a month or two (so 8 or 10 times max) but it will get me on the road that much sooner. Some things are absolutely necessary to ride the new bike, like a rear wheel to fit the dropouts. Some are not, like the brakes/hbar/seat/seatpost that I can just swap over in a few minutes. The smaller I can make the NEED pile the sooner I can justify those purchases and get on the road.
And the cranks in question are already cheap $35 cranks. Kinda wish I had bought two sets at that price. Who knew?
any well-established bike shop should have a box full of used cranks they'll sell you cheap.
captsven
01-29-04, 08:39 AM
Square taper crank types are almost always aluminum and the bottom bracket spindle is steel of some type. The aluminum "forms" to the steel. Eventually the aluminum crank will round out. I have had this happen before and you get play between the two.
This takes alot of time but it does happen. Over torqueing does not help either. I have never used a torque wrench and this could have something to do with it.
miamijim
02-02-04, 04:09 PM
The aluminum usually rounds out due to riding with a loose crankarm. Something you try is using 'one-key' releases for the the crankarms.
http://www.biketoolsetc.com/index.cgi?id=78555291341&d=single&c=Tools&sc=Crank&tc=Thread%20Repair&item_id=SN-CAP
or something smilar.....
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