Monty Crank problems - now I see what you guys were talking about

I couldn’t do my 20 mile Coker attempt on thursday because the forecast called for more thunderstorms. Instead I finally got back to riding trials on the miniature golf course I was talking about a while back. It actually didn’t even rain, so I’m a little bitter that I could have gone Cokering…

Anyway, the Monty cranks are now garbage and I didn’t even break them. I see now what Nathan meant about them not staying on the axle.

This was the longest I’ve ever done any trials stuff at one time. I was putting the uni through the most abuse I’ve ever put it through (still not much abuse, considering my skill level). At first I thought the crank was just getting loose. I hammered it down and tightened the retainer nut. It kept coming loose and I kept tightening until the nut came off completely while I was riding. I didn’t even notice it come off.

When I tried to tighten the crank again, the crank wouldn’t even go down on the axle. It’s like the crank swelled up and as the hole shrunk it pushed itself off the axle. I also noticed the threads on the axle were messed up a little at the tip. Probably because I kept tightening the nut, but it was only gripping on the tipy top of the threads because the crank wouldn’t go down.

It’s bizarre. It’s like the hole on the crank tightened up like a sphincter and pooped out the axle.

Is this the issue everybody has had with monty cranks? Are they trash now, or do you think I could heat them up and get them press-fitted back on?

PS - video of the miniature golf course is coming soon. I’m just having too much fun editing it.

Re: Monty Crank problems - now I see what you guys were talking about

I don’t even know what to say about that. I bet that it will be in someone’s sig line though.


Me too

2 Sets of Monty’s. 3 rides.

It’s the left cranks, it just doesn’t go on far enough to the spindle.

Often the threads strip on the end of the axle so there is no grip to pull the crank on. Perhaps for that combination the best technique is the huge c-clamp or press that muniac talks about. That way the threads are not being used to pull on the crank, just to retain it once it is in position.


There must be some cranks that work and some that don’t. The way the hole in this crank is, there is absolutely no way you could slide the crank any further up that it was

So which Monty cranks are they, the 158’s? Or, given you are talking trials… shorter ones…?

Erin :thinking:

mine were the 158’s

I’d say if you haven’t had problems then you won’t. The nuts came off 15 minutes into my ride. Darren quickly replaced it, and my second set was wrecked after the first ride. (With me stopping to tighten the nut every 15 minutes whether I felt it wobbling or not (and I didn’t feel it) got home, and it was still wrecked.

Darren said he was gonna talk to Monty about it. Hmmm, I think I’ll go email Darren tight now, excuse me please

I don’t think that’s true. I’ve had that uni (with those cranks) since about september of last year. This is the first time I’ve had this problem.

Erin, mine were the 140’s.

You bet it will!


as a long time biketrials rider i have had the ummm… pleasure of dealing with monty cranks for about four years now. i’m the guy in my riding group that fixes everyones bikes providing me the ppertunity to witness all of the wonder that is monty…

First thing. the BLACK monty cranks are evil!
the silverish colored ones are labeled 7075-T4 or something along those lines. these cranks are made from a good quality aluminum and have never given me or anyone i know a single problem.
the BLACK colored cranks are cast from the same mold, but you can see where they GRIND OFF the 7075. these cranks are most notorious for stripping at the pedal threads.
it doesn’takes only two or three hours of riding before your pedal begins to woblle and from there your screwed. i’ve attempted using heli coils and other threaded inserts only to have them too pull out of the recycled faygo can crank arms.
most shops will charge you the same for these cranks as they do for the 7075. i’ve only found one place that noted the difference and i can’t remember where it was.

Now assuming your pedals are still in your arms, but your arms pinching your axel or bottom bracket out like a loaf…

Monty makes a trials bottom bracket for bicycles named the FAG. i’ve only broken one of these and it wasn’t pretty, it took me three years of highly abusive riding to do so… it is the only BB i’ve used with monty cranks and they’ve never given me a problem… however, i’ve had freinds attempt to use higher quality square tapered bottom brackets with the monty cranks with little success.
basically same problem. you’d feel the cranks start to wobble and you knew you had turtle head pokin out. if you didn’t stop to freshen up the tension on the crank bolts you were going to be in for quite a mess.
the problem is the lack of standardization in the square tapered system. monty’s cranks and bottom brackets are designed to work with one another, as are other brands of crank arms and BB’s or axels. the system is supposed to be universal, but most bike riders will advise against mixing BB’s and crank arm manufacturers

good locktight on the square tapers and on the axel bolts would most likely solve your probelm. it worked for some of my freinds.
makes the cranks a biatch to get off, but its better then worrying about them falling off all the time.

The other problem with monty for those of us in the USA is that Cosmopolitan motors, Monty’s US distributer, has dropped them.
as of now if you’re in America and need monty stuff you better be willing to do alot of looking.

So if anyone has the means to become a US distributer alot of unicyclists and alot more biketrials riders would be very appreciative.

peace out

How about this?

Since the cranks are pretty much trash anyway, would there be any harm in trying to grind the hole wider? Maybe I could use a file or one of the grinding heads for a Dremel? Could a ground down hole damage the axle?

I think it would very tough to use the dremel to make the hole bigger, and still square. I think that any variation away from perfectly square would make the rounding of said crank inevitable (sp?)

If you have the black cranks with the alloy label ground off of them you should chain them together, tie them to a big rock and throw them in the nearest body of water. those cranks not only suck, but they are dangerous, especially on a unicycle. they should be illegal. damn spain people.
but if your pedal threads are ok and you can read the numbers 7075 on the back of your cranks i suppose you could grind them.
7000 series aluminum doesn’t receive any sort of heat treatment after casting, so you wouldn’t be grinding away a hardened surface or anything.
i don’t think the sphincter theory is really at work here though. if the hole in your crank arm was too small it wouldn’t go on the axel. aluminum doesn’t work like a butt, you can’t just keep pushing until something goes in… :thinking:
i’m guessing putting some locktight on there should probably do the trick.
if you feel comfortable grinding though, it’s all you.

Treepotato, you’re free. Thanks for the sig, SEMPER_UNI