hoov23

I am trying to pull the pedal cranks off my 20 year old diblasi folding bike, cotterless square spindle. removed plastic dust cover, removed allen bolt and washer. The puller should thread in and then the inner part should push off the square spindle, but mine has about a 12mm threaded part of the crank arm rather than a common 22 or so (the allen-head fixing bolt is M8x1.00 thread), so a standard puller is no good. I know this bike is wacky as anything, so I expected problems, but i wanna get this off without damaging anything.

Anybody every seen a puller around this size, or have a method of removing them otherwise? I was trying to use a 2-jaw flywheel puller to grab the crank and push off an M8 bolt threaded into the BB, good plan? So far it didnt' work but i think i can make it.

thanks.

p.s. my local bike shop has no interest in anything less than professional gear, they don't work on vintage or custom-fab stuff at all. super frustrating, no help from them.

DieselDan

You need to take the bolt out and push against the spindle with the puller.

HillRider

It sounds like you know what to do with a "conventional" square taper crank puller so if the puller threads on this crank are really 12mm or so it truly is odd.

I'd go with the 2 or 3-jaw gear puller and an M8x1.0 bolt threaded into the spindle threads as a puller and it might take a lot of force to make it work. Otherwise, a "pickle fork" puller will probably work too if you have access to one.

FBinNY, a frequent poster here, recommended a pair of opposing wedges used to remove gears from shafts as a valuable, non-damaging crank puller tool also. A search here should find that thread or PM him about it.

hoov23

thanks hillrider, i'll give it another go with the 2 jaw puller. need to get a harder bolt, i stupidly tried to push on the allen head fixing bolt and actually started to bend it and kind of skewed the allen hole..... :/ i thought about the opposing wedge idea you mentioned, i dont have a bearing separator but i need one anyway, not this cruddy one but a decent one:


p.s. this is the wacky bike im working on, i want to save that awesome sprocket but my chainline is a few mm off, i have to move it inwards somehow. it looks like a regular spider type crank but its not, the 5 rivets hold on a guard but the whole sprocket is connected to the crank arm. so i need to do some surgery to make it work

hoov23

In case anyone's interested, it shifts and rides perfectly on the smallest 5 gears of my new (old stock) Suntour New Winner ultra 6 speed freewheel (SRAM 830 chain, old Sunrace friction shifter and derailleur) but the chain slips off the chainring when im on the largest cog. I can tell though that moving the chainring inwards 5mm would solve it (there's enough frame clearance) because the chainline centers on the second smallest cog, not the third or fourth. This was because it had an unusual Everest 3-speed freewheel, that was actually a 5-speed size but with just 3 rings positioned on the outer side and dead space where the two larger cogs would be. Whever designed that came up with a creative way to be an idiot, thats for sure. But yeah on the second largest cog, the chainline's still very usable, and on the smallest cog the chainline's almost straight, so since the spacing between cogs is 5mm on an ultra 6, I figure that's what it'll take to get all 6 gears running. The question is just how, since I'd really like to keep that chainring and its 53 teeth. Im thinking in could drill out the rivets and get a bolt-on chainring and space it inwards, keeping the cool visible part but moving the teeth inwards. If I could get the crank arms off...

Bezalel

Can you get a faucet handle puller in there without bending the chainring? (With such a short chainstay, I can't imagine not having chainline or heel strike issues.)

hoov23

It's very close to the chainstay, but the folding head tube hinge is the only real interference. I'm going to need to grind part of it down. Angle grinders are awesome. The faucet puller is pretty much like the pulley puller I have, that's probably by best bet. I'm gonna work on it some more today. Thanks for all the advice.

hoov23

So not that anybody probably cares but I got the job done and I'm pretty happy about it. I've learned from this great forum and from my local obnoxious bike shops (especially Performance Bicycle in Towson, MD, the most obnoxious of all) that no puller exists for the size of Thun pedal crank arms that I have, so rather than follow their advice to give up or cut my BB spindles off, I got an M8 x 1.00 pitch bolt (same idea as hillrider suggested), drilled a hole in it so my puller would grab, and pulled that sucker off with a 2 jaw pulley puller. I'm real happy that it worked. Im trying to move my chainring inwards 5mm, so im gonna cut the outer ring off at the 5 spider-like arms, and buy a regular 130 bcd ring and bolt it on with spacers. Suck on it, Performance Bicycle! Thanks guys for not telling me I'm wasting my time with this.





^ in this pic you can see that it almost looks like the crank arm had originally a regular 22mm and it was "repaired" with some kind of insert and re-tapped to 12mm, but it's just not the case, it really is a wacky size. Thun is apparently a rare brand I think, but I love that chainring I have with the chainguard so I'm hanging on to em.

hoov23

btw,





I just got the white Kenda tires, it had a Vredestein and a Swallow that were totally bald (I wanted Vredesteins but couldn't find a US source). I bought this in Amsterdam in 2006as a "recycled" bicycle that was recovered by police, given a new serial, and I bought it for 20 euros as a basket case. I love this bike and brought it back to Baltimore when I moved back here 4 years ago. Wasn't ever sold here, but Di Blasi is a really cool company with a great history, look em up on wikipedia if you're interested. I wrote the wiki page