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I need a new MTB crank set

post #1 of 20
Thread Starter 
I have a hairline crack on the 32T chainring of my MTB. It wont be too long before all the teeth shear off because of this so I need to buy a new crankset (chainrings are riveted). The set I have came with the bike and are by Lasco 170mm aluminum with steel chainrings 42-32-22. I want to upgrade to an all alloy or composite setup. I have been looking on ebay and there are deals to be had, but to be honest I have not been in the bike parts buying arena for a long time so I really don't know what to look for. I know that this is better answered in a MTB forum, but I figure there are some people here that already frequent both so what the heck. Is there anything I need to consider when making my purchase?

I want a nice rugged setup that isnt too heavy. TIA

Oh, I was considering adapting some Redline 401 BMX cranks...I thought I read somewhere that its possible and a good choice for those who want to strongest setups, anyone know? Is it even worth it?
post #2 of 20
Probably not possible. Most BMX bikes havea different BB shell.

Look for a Shimano Deore crankest. They have pretty good bang for the buck.
post #3 of 20
I have 2 Shimano XT Hollowtech II Crank sets.
Deore, LX, XT...
http://www.jensonusa.com/store/produ...+Crankset.aspx
http://www.jensonusa.com/store/produ...+Crankset.aspx
http://www.jensonusa.com/store/produ...+Crankset.aspx

I have one of these also...Pretty good, stay away from ISIS bottom brackets...
http://www.jensonusa.com/store/produ...Firex+Gxp.aspx

Watch the chain angles when going from a 'square' taper bottom bracket to one with external bearings. A spacer may be needed.
post #4 of 20
Thread Starter 
The Shimano stuff to me is so confusing they have so many models and they all looks so similar in features. Can one of you give me a brief tutorial on the lineup? Which is best, why? Which is worst and which I should stay away from?

Know anything about Race Face? I have their stem and handlebars, how are their cranks, specifically the Deus X-type?

TIA
post #5 of 20
From what is listed from lowest level to top end. Deore, LX, XT, then XTR.

XT is considered the 'work horse' of the Shimano line up. Strong and fairly light. I would stay away from XTR, unless you want to race XC.

There really isn't much difference between LX and XT. XT is a little lighter, probably a little stiffer. Deore is a little heavier yet. Probably has steel rings. If you are going to be bashing into stuff, a steel outer ring is advantageous! The alloy rings, are lighter, wear out faster, bend easier.

I'm not sure which cranks have alloy and which have steel. Some have a mix. You'll have to read the parts description.

The current standard uses this type of bearing. The crank is 2 piece with a 'through axle'
http://www.jensonusa.com/store/produ...Ii+Bb+Cup.aspx

Some of the earlier model shimano cranks used these bottom brackets.
http://www.jensonusa.com/store/produ...m+Bracket.aspx

Some even earlier used this type.
http://www.jensonusa.com/store/produ...m+Bracket.aspx

FWIW....dump the cheap bike. Take 2 G's outta the 'Big SUV' money and get a real bike!
post #6 of 20
Race Face cranks suck IMHO. They are always either loose or have too much drag. They are adjusted using spacers and you can't get it just right. The Shimano cranks have a threaded nut that adjusts the side to side play.
post #7 of 20
I know a few guys that use BMX cranks. Check danscomp.com for BMX stuff or if you want advice, try the guys at Rays MTB Park at raysmtb.com they are good people.
post #8 of 20
I've got Profile cranks on my jump bike, they'll withstand a nuclear blast. That's great if you need it, on a regular MTB I stick to MTB cranks, thay are WAY lighter and also cheaper. I've had RaceFace cranks I liked (Turbine LP) and RaceFace cranks I HATED (Atlas). I've had perfect luck with Shimano (Saint and XTR). My money in the future will go to Shimano.

Truvativ make some pretty good 'price point' cranks. I'd replace your bottom bracket along with the cranks, get external bearing bottom bracket and 2 piece cranks, they are strong, stiff and durable.

Shimano's line-up is a bit confusing, JZ laid it out well but I'd add:

Cross Country- Deore, LX, XT, XTR
AM/ Heavy Duty- Hone, Saint
post #9 of 20

options...

If you have a smooth spin, you could go retro with a Race Face Next LP and a Phil Wood square taper bb, and you'll end up with a narrower Q factor than outboard bearing cranksets. I run it as a 29/42 double and it's narrower still.

Or, for something different/cool, check out the Middleburn cranksets here: http://www.chainreactioncycles.com/C...CategoryID=576

Or, the Shimano stuff is fine. If you're mostly XC, then get LX & go ride.
post #10 of 20
My current trance had Atlas cranks/bb which kept bending and creaking. I bought a shimano Hollowtech II Deore XT/BB(what a long name lol) and truthfully I will NEVER run anything else again. The BB is holding up better, the crank ring arent bending, the front sprockets actualyl shift(the old one never would) its extremely easy to take apart to clean its takes about 10min to disasemble the entire set up.

I wont run anything but shimano octolink on any future MTB, I have seen the light.
post #11 of 20
Thread Starter 
Quote:
Originally Posted by Johnnys Zoo View Post
From what is listed from lowest level to top end. Deore, LX, XT, then XTR.

XT is considered the 'work horse' of the Shimano line up. Strong and fairly light. I would stay away from XTR, unless you want to race XC.

There really isn't much difference between LX and XT. XT is a little lighter, probably a little stiffer. Deore is a little heavier yet. Probably has steel rings. If you are going to be bashing into stuff, a steel outer ring is advantageous! The alloy rings, are lighter, wear out faster, bend easier.

I'm not sure which cranks have alloy and which have steel. Some have a mix. You'll have to read the parts description.

The current standard uses this type of bearing. The crank is 2 piece with a 'through axle'
http://www.jensonusa.com/store/produ...Ii+Bb+Cup.aspx

Some of the earlier model shimano cranks used these bottom brackets.
http://www.jensonusa.com/store/produ...m+Bracket.aspx

Some even earlier used this type.
http://www.jensonusa.com/store/produ...m+Bracket.aspx

FWIW....dump the cheap bike. Take 2 G's outta the 'Big SUV' money and get a real bike!
Thanks for all the tips JZ and everyone else.

As far as replacing the bike...eventually it will come to that, thats just the natural tendancy of things...but it will be like Johnny Cash's song "One Piece at a Time". I am upto the seat, pedals, stem, and bars. Next will be the crank and chainrings, after that the main spring/shock. Most likely then the derailers. Then Ill just have to wait and see what breaks or does not work right. The frame is all aluminum and has a lifetime warranty so I am not so anxious to toss it.

One more question, you say avoid ISIS, aside from square taper and Shimano Octolink arent all (the majority of) modern mtn bike BB spindles ISIS with the difference being internal or external bearings?
post #12 of 20
I wouldn't put a lot of money into a cheap bike. Get a cheap square taper crank. Octalink or ISIS will require a new bottom bracket. All you need is a chainring, but your bike is such a POS, it came with riveted rings.

Haha, I've used bikes that came with riveted cranks as my primary form of transportation. As you know, cheap bikes work and there is no performance loss from the use of riveted cranks other than a little extra weight. The downside is when you need a new chainring, you need a whole crankset. You don't need a BB though. You probably don't need a new chainring either. I don't think teeth are going to start shearing off and if they do, use the other chainrings to get home, and order something from Nashbar at that time.

Has your girl friend seen your bike? It might have something to do with her low opinion of the Jeep brand.
post #13 of 20
Thread Starter 
She knows nothing about my bike issues....but she bought it for me! Its actually quite a nice looking bike and the only difference between it and the higher end Jeep bikes were the derailers and cranks, the frames were the same. Course they did have the $3k+ Jeep bike made for DH competition, but that was a bit excessive....Ive been down that road before (some may say I am down that road with my skis gear) but I digress.....

Ive ended up in the hospital and bed ridden for two weeks due to bike drivetrain failure so I prefer to take care of this before I end up over the bars and on my face.
post #14 of 20
I would ride it till it dies and then Just buy a cheap crank to replace your busted one. Don't spend any more than need be on a cheap bike.
post #15 of 20
Quote:
Originally Posted by Richie-Rich View Post
One more question, you say avoid ISIS, aside from square taper and Shimano Octolink arent all (the majority of) modern mtn bike BB spindles ISIS with the difference being internal or external bearings?
ISIS bottom brackets had bearing problems. I think they made the bearings smaller to avoid patent infringement on Shimano Octalink.

Square taper bottom brackets tend to be more flexible/not as strong. Bearings are internal to the bottom bracket. If I put the bike in the largest ring, and push hard while cranking, I can get the crank to hit the chainstay.

ISIS and Octalink bottom brackets are made from a piece of pipe with splines on the ends. Bearings are integral to the bottom bracket. These are stiffer than square taper. Just a side note, I've had Octalink bottom brackets with creaking problems.

External Bearing bottom brackets such as Shimano Hollowtech. Stiffer even still. The 'bottom bracket' pipe axle, is press fit into the drive side crank. The non-drive side crank slides onto splines, on the outside of the pipe axel and is secured with 2 allen screws. The bearings thread into the bike frame.

Ditto on the crank replacement...
post #16 of 20


Cook Bros. ROCKS!!!
post #17 of 20
Thread Starter 
They made some good BMX products back in the day.
post #18 of 20
Buy a cheapo Shimano Alivio square taper crankset if they break. Until then, ride it.

One problem we've noticed with ISIS BB/Cranks is that the left hand crank bolt tends to back off unless checked regularly. Often results in a messed up spline on both the BB and cranks, and the crank falling off regularly. It's great if you take care of it and keep it tight, but the instant it starts to get play, you're hooped.

I've had good luck with RaceFace cranks, but not their rings. They make a durable ring, but it's not pinned/ramped as well as Shimano, so doesn't shift as nicely. I'm a big Shimano fan.
post #19 of 20
Thread Starter 
BTW, for the curious this is my bike, mine differs in that it now has BMX Shimano DX style platform pedals, Race Face stem and bars, and a male ergo seat.

post #20 of 20
wow talk about a long top tube....
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