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Old 05-17-2006, 11:32 AM   #1
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chainring doesn't fit crank :(

I am attempting to build a trials bike out of parts, mostly everything is working fine so far, but...

I bought a 22t chainring to connect to my truvati hussefelt (probably spelled wrong) cranks. Anyway, both have the same pattern (4 bolts) but the radius of the chainring is smaller than that of the cranks. I was looking on webcyclery.com and they have 'cogs' opposed to 'chainrings' should I have gotten a cog for the front? I can post pictures if this description doesn't make any sense. Thanks



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Old 05-17-2006, 03:11 PM   #2
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Nope. Cog is completely different. You need to measure the bolt circle diameter of your cranks and get a chain ring with the same bcd.

* its easy with 4 bolt. just measure from centre of 1 hole to centre of opposite hole.



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Old 05-17-2006, 03:23 PM   #3
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yeah or u can prolly find a chart or something online. thats printable.

or just go to a bike shop. 99% should be able to help u out.

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Old 05-17-2006, 05:49 PM   #4
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you're aware that there are two sets of bolts on a 4-bolt (such as truvativ hussefelt) cranks? One is a 74mm bcd and the other is a 104mm bcd. Unless you have a chainring designed for a shimano XTR 4-bolt (which is different, and alone in being different) then it should fit. I suggest you get another ring from your LBS - they should have shimano/truvativ/etc.

- Joel

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Old 05-17-2006, 09:20 PM   #5
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Quote:
Originally Posted by tomac
you're aware that there are two sets of bolts on a 4-bolt (such as truvativ hussefelt) cranks? One is a 74mm bcd and the other is a 104mm bcd.

Actually it is 64mm and 104mm for all non-XTR cranks.
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Old 05-17-2006, 10:02 PM   #6
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^^ yes, sorry, 64mm. I was getting confused with 74/110. Fucking numbers.

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Old 05-18-2006, 03:57 PM   #7
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I'm pretty sure there's also 4 bolt, 58mm BCD. I remember looking into it a while ago. It is possible to buy a 20T 4 bolt chainring, as I was lookin to go 20/18, but that 4 bolt 20T ring is 58mm BCD, so it won't fit truvativ/raceface/fsa 4bolt. The smallest I've found that you can get for those is 22T I bet you have a 58mm BCD 4 bolt ring! Such a pain!

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Old 05-18-2006, 06:06 PM   #8
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never heard of a 58mm 4-bolt. 58/94 is the "compact" 5 bolt standard, now sadly leaving us.

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Old 05-19-2006, 06:53 AM   #9
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I'm not being beligerant, but I've heard this before:
http://www.trials-online.com/forum/viewtopic.php?t=1130&highlight=58mm+bcd
maybe I'm on crack, but I'm referencing mr toosicks

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Old 05-19-2006, 12:40 PM   #10
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Quote:
Originally Posted by tomac
you're aware that there are two sets of bolts on a 4-bolt (such as truvativ hussefelt) cranks? One is a 74mm bcd and the other is a 104mm bcd. Unless you have a chainring designed for a shimano XTR 4-bolt (which is different, and alone in being different) then it should fit. I suggest you get another ring from your LBS - they should have shimano/truvativ/etc.

- Joel
On my cranks, there is only 1 set of holes....I'm guessing the 104mm. Sorry I'm new to this stuff, what is LBS? and just out of curiosity what are cogs for?
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Old 05-19-2006, 02:34 PM   #11
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LBS = local bike store

cogs are the gears on the hub/cassette, on the rear wheel, chainrings are the gears on the cranks.

hussefelt cranks will have 1 set of threaded holes that accept a 64mm BCD chainring (22T), and one set of through holes that accept a 104mm chainring. You've probably got a bashring on the 104mm holes.

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Old 05-21-2006, 12:24 AM   #12
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I've never heard of a crankset which has only the 104mm holes but given the target market of the hussefelts it wouldn't surprise me if one had come out.

the smaller set of holes don't go right through the crankarm like the bigger ones, they're only visible (and accessible) from the inside of the crankarm (next to the frame's seattube).

I read toosicks's posts on t-o.com - I'm sure they exist but I'm equally sure they're never been used on any modern, mass produced mtb crank.

- Joel

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Old 05-22-2006, 12:16 PM   #13
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Well, i dunno why the cranks i got happened to be different than all others....but, here they are

You can see flat ovals where the holes should be....but alas they are not there. Should I just buy a different set of cranks to fit the chainring? I might try to drill the holes out myself in my school's machine shop.





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Old 05-22-2006, 05:05 PM   #14
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eureka! Cheap bastards truvativ...

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Old 05-22-2006, 06:56 PM   #15
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That's no good. I bet those are the 'DH single' or 'Singlepeed' hussefelts. That's a shame. I suppose you could find a good trials gearing if you ran, um, 32/28. You'd get excellent chain and drivetrain life

I don't know if you want to drill the holes yourself. It's likely those holes are drilled while the ISIS interface is being machined on a CNC, so their concentric to within the mills tollerances. If you drill them, that prolly won't be true... A good alternative is some FSA v-drive extreme arms, now called Maximus, apparently, for 63 bucks online... as a suggestion.
http://www.go-ride.com/prod_cranks.html

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Old 05-23-2006, 01:35 AM   #16
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check ebay for used cranks. Personally I think that the (somewhat) old 58/94 compact 5 bolt is the best mtb bolt pattern, you can go down to a 20t ring and the bashring isn't too big. Threshold make/made an awesome ring for 94 bcd. Raceface turbine cranks are probably available quite cheaply. eg:

http://cgi.ebay.com/L-K-RACEFACE-FORGED-CRANKS-170mm-NR_W0QQitemZ7244079316QQcategoryZ56193QQrdZ1QQcmdZ ViewItem

http://cgi.ebay.com/SHIMANO-XTR-Cranks-w-MRP-plate-profile-chainring-175_W0QQitemZ7244010007QQcategoryZ56193QQrdZ1QQcmd ZViewItem

http://cgi.ebay.com/New-Raceface-Evolve-DH-Crankset-170-with-113-mm-BB_W0QQitemZ7243472250QQcategoryZ56193QQrdZ1QQcmdZ ViewItem

http://cgi.ebay.com/Raceface-Turbine-LP-Crankset-170-mm-w-Titanium-BB-ti_W0QQitemZ7242968116QQcategoryZ56193QQrdZ1QQcmdZ ViewItem

too nice for trials:

http://cgi.ebay.com/Raceface-carbon-crank-set-and-titanium-bottom-bracket_W0QQitemZ7242806837QQcategoryZ56193QQrdZ1Q QcmdZViewItem

a piece of bashring history:

http://cgi.ebay.com/New-bash-Guard-frm-KOOK-Canada-like-E13-RACEFACE_W0QQitemZ7242855291QQcategoryZ56193QQrdZ1 QQcmdZViewItem

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Old 05-23-2006, 09:15 AM   #17
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i agree, compact cranks are great. I wish I could go down to 20T

g



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