cman

I have a DBS(Norway) and a friend has Monarch(Sweden) bike both with one piece cranks. The are different than the standard American version. We can get the locknut, washer and bearing races removed from the crank. The problem lies in the bearing cups. The bearing cups must be removed to remove the cranks. I tried hammering out from the backside and unscrewing the cups (both left and right). Nothing has worked for either of us.

Does anybody have any insight.?

rmfnla

Never seen one of those but it appears from your photo that that inner ring (the rusty one) unscrews from the crank. Try tapping a punch into the notches, assuming you don't have a tool that fits (I certainly don't).

After that, who knows, but I would bet that once you get that ring off it will be more apparent what to do next.

RockyMtnMerlin

Hey your sig is the state fish of Hawaii! Coool!

LWaB

OP has already got that far.

cman

Correct. Just need to remove bearing cups but cant' tell if they are threaded and which direction.

rmfnla

Got it; a photo showing how far you have gotten would have made that clear.

I would guess that they are threaded based on the knurled outer surfaces of the cups; no reason to do that if they are just press-fit.

This is what is so frustrating about trying to troubleshoot by Internet; if I could just get my hands on 'em!

(This is also why I usually post wise@ss remarks rather than repair input; if a picture is worth a thousand words holding the part is worth a thousand pictures.)

Prodigy4299

Unfortunately I can offer no insight other than the fact that I recommend you e-mail a bike shop in Copenhagen or Oslo. They will surely be happy to help you and they all speak impeccable English.

And, by the way, my girlfriend's bike has the same cranks. Does that mean it's a DBS as well, or did other companies also make these cranks?

240GL

Oh, I've had a few DBS bikes through the years! (DBS = "Den Beste Sykkel" = "The Best Bike". Well.) Which model is yours? I have never had to remove a crank, but they should be pretty similar to your Ashtabula cranks. The bearing cups are press fit and should be hammered out. I will have a look tonight and see if there is a diagram in my DBS service booklet. If so I'll post a scan.

CHenry

[Bolds mine.]

Try a pin spanner first; that is what this part looks to use.

cman

I would appreciate that. My friend got his bearing cups out last night. Threaded on both sides. regular threads on the right and reverse on the left.

240GL

From my old Norwegian repair book (my poor translation, don’t blame the book!) – “fourteen easy steps”. The letters refer to the scanned picture at the bottom. Hope this helps.

“To remove the (Fauber) crank special tools are needed. One for the nut (top) and another for the cup (bottom). Start the job on the left side of the bike.

1. Using the special key unscrew the nut (a) backwards.
2. The securing washer (b) is now loose. Remove it.
3. Left dustcap (c) is also loose. On the inside there are two teeth that fit the notches in the cone (d).
4. Use the dustcap to unscrew the conus. Keep in mind that it is left-threaded, screw backwards.
5. Loosen the left cup (f) using the special tool by screwing backwards. Remove the ball bearing frame (e) and the cup.
6. The crank arm (g) will now seem loose, but before you remove it you need to loosen the right hand side using the special tool.
7. Now the crank arm can be eased out of the bicycle frame.
8. Clean the ball bearings in kerosene and re-pack them with grease. Replace worn parts.
9. If the chainwheel (j) needs replacing, unscrew the right hand side conus – which is right-threaded. Lift off the right hand side dustcap.
10. The chainwheel can now be replaced. If you place the ball bearing frame in the cup, you will observe that it rests deeper than what is the case for the left cup.
11. Installation is reverse of removal. Keep in mind the different thread direction left and right.
12. Finally, check that the crank rotates easily. If it is too tight or loose, loosen the nut. The tightening is adjusted by rotating the dustcap.
13. Retighten the nut properly.
14. Make a last check to ensure that everything works as it should.

Juha

Why Copenhagen? I thought Monark was Swedish? Though I'm sure bike shops in Copenhagen would be able to help too.

--J

cman

240GL- Thanks for the description and pic. Seeing the tool should help me figure the bearing cup removal. The hammer and punch has not worked to turn the bearing cups.

rmfnla

Looks identical to an Ashtabula set-up.

cman

except the ashtabula crank can be taken apart with a pipe wrench...an ashtabula crank can be removed from the frame without removing the bearing cups and the bearing cups on a ashtabula crank are pressed in and not threaded.

wroomwroomoops

It's interesting to note that the instructions translated from the Nrwegian by 240GL mention the removal of the bearing cups by "screwing backwards" - which I guess means counter-clockwise, which makes sense (most of the time in life). The special tool, if I am reading this correctly, is some pin spanner. I have the variable ParkTools pin spanner that would probably work for this purpose.

CdCf

You don't really need a pin spanner. Just use a screwdriver and a mallet, and punch tangentially. Works for both loosening and tightening.

wroomwroomoops

*walks away and whistles some Beethoven tune*

CdCf

Fair enough, but then a pin spanner won't work either... I've used both methods, and screwdriver+mallet is by far the most effective, if a bit more destructive to the metal...

rmfnla

I'm not convinced that both are not the case here.

When you do get it apart please tell us how it played out.

indianmannen

I know this thread was last active Dec -07 but i have some picture that might help cman or anyone else with this kind of bottombracket.

https://happymtb.org/forum/file.php/1/file=65399

Mount the tool (if you've got one, a screwdriver, nail or screw with the right size works too) and start to unscrew (reverse threaded):
https://happymtb.org/forum/file.php/1/file=65400

Remove these (just pull them out):
https://happymtb.org/forum/file.php/1/file=65401

Now it should look something like this:
https://happymtb.org/forum/file.php/1/file=65402

Mount your tool and start unscrewing like in step 1:
https://happymtb.org/forum/file.php/1/file=65403

rialaado

Just an update - with the help of jebejava i found this link https://fixedgearbikes.blogspot.com/2...er-bottom.html
to modernise or replace the ashtabula. you can buy them here, under KASETTIKESKIÖT - https://www.pyoratohtori.fi/

pertti_jarla

I bought the Park Tool SPA-6 pin spanner and was almost shocked when my Fauber came apart with no problem at all. The Park Tool pins were much too small, still it worked fine after I had soaked the cup with CRC & waited for a few hours. Some parts, including the right hand bearing cup, actually unscrewed by hand. A few taps with hammer + punch were needed for the left hand bearing cup, but nothing was really that hard. The crank was full of oily sand, so taking the 30 year old Fauber apart was definitely a good idea. Recommended, but soften up with CRC or something first and get a pin spanner.

3alarmer 

.
...on the off chance it might make this easier for someone down the line, here are some photos of a Fauber I just took off a DBS Golden Star that badly needs painting. Were it not for that, I'd probably not have bothered.

Used a pin punch (which will now require some redressing), a hammer of only moderate size, and a lot of CRC Freeze Off. It did not give up easily. For reference, I was confused about the threading directions at first. The drive side is regular RH threaded and the non drive side is LH thread.

Which for some probably very good reason is the reverse of most stuff these days.

fietsbob

"Thun" Bike Bottom bracket The company of that name does not make them any More as I try to look them up