Converting/Drilling ISIS cranks down to 90mm

[Emile.m]

Hi, 100mm is too long for freestyle cranks!

The only other option for shorter ISIS cranks are the Koxx-one light cranks (in 90mm) but they are quite expensive and not availible in Canada...

Would it be possible to drill a second hole in Qu-Ax 114mm light cranks? Just like the dual moment, but I would get rid of the extra part (the 114mm part)



It looks like there wouldn't be much space on the side of the pedal thread if I would do so. Anyone already experienced this?

Maybe I should try with the 125/145mm, they seem wider

[agentQ]

Émile-

Your best bet would be to go with the bigger size wider cranks. I would def want a professional machine shop to do this mod. You could bring in the 100mm and show them the shape you would like in the end. Getting Steel threaded inserts would be an option.

Thu quax cranks are cheap enough that with the cost of getting some machined to your specs, they still should be considerably cheaper than the k1 cranks.

[agentQ]

The cut out on the back of the cranks could be an issue. making a steel insert maybe a better option. If you have or find a good machinist, they should have some pretty good advice.

[unicycler100]

you could just cut the pedal insert of and get it welded back on. soo cut of the pedal thered insert and cut of a little bit then weld the pedal insert back on.

[nathan]

I had a machinist friend drill a hole at 100mm in a pair of 125mm Moments. We then tapped them and put in steel inserts and the result is a great pair of cranks at 100/125mm.

If you do this, make sure you have someone who really knows what he's doing drill the holes. We used a mill, and were very very careful to align the hole so the pedal would be straight. The Q-factor and the overall shape of the Moment crank makes this hard to do. But the crank is so overbuilt that there is no problem strength-wise drilling more holes.

---Nathan

[semach.the.monkey]

Originally Posted by Emile.m

Hi, 100mm is too long for freestyle cranks!

The only other option for shorter ISIS cranks are the Koxx-one light cranks (in 90mm) but they are quite expensive and not availible in Canada...

Would it be possible to drill a second hole in Qu-Ax 114mm light cranks? Just like the dual moment, but I would get rid of the extra part (the 114mm part)

It looks like there wouldn't be much space on the side of the pedal thread if I would do so. Anyone already experienced this?

Maybe I should try with the 125/145mm, they seem wider

The 114mm cranks certainly look far too thin, so I wouldn't consider trying to drill those out. The 125/145 look a lot meatier so should take to being drilled out ok.

Originally Posted by Any Terrain

Also make sure you get the threads in 9/16 x 20tpi

I would actually recommend going down to 1/2" thread. This is a common size for BMX pedals, so should have a good range to choose from, and for freestyle will be more than capable of the job.

Also, remember that it is unlikely that you'll find a machine shop with a left handed tap, so you will be best off using threaded inserts. Therefore you will have to drill the cranks a few mm larger to allow for this (hence using 1/2" is a good idea).

I don't know how much the Koxx One cranks are in Canada, but unless you know a competent (cheap) machinist, they might still be the best value.

STM

[Emile.m]

Okay so if I do so I will go with the 145mm.

The koxx-one cranks are 100$ US at renegade.

It sucks that ISIS cranks are not availible in a smaller size than 100mm... (except for k1, but they are sooooo expensive and not easely avaiblible worldwide as qu-ax cranks)

EDIT: Thanks for all the answers!

EDIT 2: I'm using MKS Runber-X pedals, wich are like one of the best pedals for freestyle, they use 9/16 thread so I'm not going to go with 1/2.

[Borgschulze]

Any good bike shop will have pedal thread taps. Left and right.

[Emile.m]

Originally Posted by Borgschulze

Any good bike shop will have pedal thread taps. Left and right.

Sorry, but what is a pedals thread tap?

EDIT: Thank you www.google.com

[justtysen]

I have a pair of the qu-ax 125mm cranks (for freestyle ) and the cutout on the inside of the cranks makes the crank arm too shallow for a pedal hole. Maybe with a steel insert the diminished thread depth would hold but then I think crank would bend from the force on the shallow insert.

I suggest you look at cheap bike cranks for something with a more uniform construction. Since you are putting in pedal threads you could use two left side cranks (some cranks are sold individually).

[redwelly]

Originally Posted by Emile.m

Anyone already experienced this?

Yes, I have a pair of (square taper) Quax 125s with a hole machined at 97mm. I used them for the Marathon and 10km races at Unicon 14 in Denmark.

They are probably not very strong, but for smooth spinning they seem fine. I feel happy riding my 36" with them anyway.

(My camera is just playing up so I can't put up photos. I may be able to put them up another day)

Sam

[jaco_flans]

Émile, if you do that, make a pair triple hole cranks! Make a hole at 90mm like you want to do, and another the shortest point as possible, it will probably be around 30mm I think... just an idea like that.... It would be awsome!