New Crankset for Jamis Sputnik
 

I know nothing about repairing bikes. In fact, one of the reasons I ride fixed is so I have a prayer of actually fixing something when it breaks. Anyway, I have a buddy who does all my bike work and he is out of town for two months. The question: I need a new crankset for my Jamis Sputnik. You don't even want to know what happened to the old one. Can someone out there give me a reasonably light option that isn't super expensive? I think i need 175. I don't mind spending a bit of money on a good one, but I would like to get value. And, you know, some instructions on how to switch it would be cool too. Thanks in advance.

I doubt you want 175mm cranks. 170 is usually as big as you want to go on a fix. As far as what to get, do what your budget allows. A set of Bulletproof cranks and a rocket ring will run you about $40, and will probably do you fine. What kind of Bottom Bracket is on your bike?

For general bike knowledge, check out www.sheldonbrown.com .

To get your old cranks off, you will need a crank puller. They cost about $15, or you could just go to a local bike co-op and have them help you do it, if there is one near you.

alright.
1) Check if your bottom bracket is square tapered or has many splines.
http://www.wiggle.co.uk/images/truva...2006%20ind.jpg
that is sqaure
and this is splined.
http://www.interlocracing.com/ird_isis_bb.jpg
Next to pull out your cranks, use a Crank puller you can get at any bike shop.
http://www.sheldonbrown.com/images/c...er-labeled.jpg

now to put on your cranks
you just simply need a hex wrench or an allen key with good leverage

and remember, cranks go opposite to each other :)

as for what crank, find out what type of bb bracket taper you have first

Okay, I've got splines. I'll get a crank puller tomorrow. Now, what kind of cranks should I buy?

so what happened to the old ones? Did you crash them on something? I am just curious because they can't really be that old.

Midnight drunken racing around Prospect Park. I'm not proud.

Nothing to be ashamed of. In that case, buy the most you can afford- actually this was the best bike advice I ever heard:

Decide the most you can spend then spend a bit more. Business cycles typically has good prices, and have gotten me things pretty fast when I need them.

www.parktool.com

Read up before you do anything. Grease every thread you touch. Use a huge adjustable wrench for leverage to get that crank puller in all the way before you pull the crank (lest you strip it). ~35 foot pounds is a rough standard for crank torque when you're installing them. If you don't have a torque wrench and you've never installed a crank before you may want to just pay someone to do it so things don't go ... poorly. Good luck though, a search in the mechanics forum will likely give you another "first-timers" set of instructions for replacing a crankset.

- eyefloater

FSA track crankset.
It'd look spiffy with your new jamis sputnik :)

http://cgi.ebay.com/New-FSA-Carbon-P...QQcmdZViewItem

sputnik uses an isis bb, so that kinda limits your choices

Well, before you go jumping to replace the cranks, are you sure they are both broken? Shops can often order you just one arm, or maybe you just need a new ring. It's hard to say with the minimal information you gave us. Furthermore, if you did crash badly enough to destroy both of your cranks, I would check everything else on the bike really really carefully. Like the frame, wheels, bottom bracket, etc.

Also, I guess you are embarassed to admit what you did to your bike, but it is a little annoying when someone asks for advice but doesn't want to give you enough information so that you can actually help them. Sorry if it sounds like I'm getting on your case, but I would genuinely like to help you.

my friend has this crank with its external bearings and it is so freaking smooth.
although i might be thinking of the one that comes with a bb included...

He gave us plenty of information. He wants a reasonably light, modestly priced crankset. You don't need to know what happened to his old ones to answer his question.

FMF makes a splined crankset that is pretty similar to the Bulletproof BMX cranks. 110 BCD. Again, you can get a crank and chainring for around $40.

I would also make double-sure that your BB splines are in good repair before installing the new cranks. If you took a hard enough spill/crash to bend or break a crank, it's possible the BB may have taken a bashing, too.

The upside of it being broken (if it is) is being able to switch to square taper ;)

I agree with you. I know that splined is supposed to better and everything, but have had better luck with square taper.