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ISCG Tab Damage

P.T.W

P.T.W

Monkey
May 6, 2007
599
0
christchurch nz
Just curious as to what peoples experiences are with damage to ISCG tabs is.
Any and all information would be appreciated, from stripped holes to broken bolts to bent or misaligned tabs, id also like to know what chain guide was used and whether the tabs where of the weld on or integral with the BB variety. Oh and ISCG old or ISCG 05
Thanks in advance:thumb:
 
P.T.W

P.T.W

Monkey
May 6, 2007
599
0
christchurch nz
Eh????:confused: I'm not talking about adapters. Some frames have the tabs welded on during fabrication while others have them machined/extruded etc with the BB so they are integral.
All I'm after is info on what (if any) damage people have experienced with their chainguide mounting tabs.
 
DirtyMike

DirtyMike

Turbo Fluffer
Aug 8, 2005
14,437
1,017
My own world inside my head
P.T.W said:
Eh????:confused: I'm not talking about adapters. Some frames have the tabs welded on during fabrication while others have them machined/extruded etc with the BB so they are integral.
All I'm after is info on what (if any) damage people have experienced with their chainguide mounting tabs.
Click to expand...
Right, like my frame is, like most all DH frames are. Your asking about how people go about repairing them when they are damaged.... Most people, when the damage/bend/strip the existing ISCG tabs, will just remove them off the frame, and switch to using a BB mount ISCG plate/adapter plate.

Most wont weld new tabs on, kills the heat treating on teh BB shell.
 
P.T.W

P.T.W

Monkey
May 6, 2007
599
0
christchurch nz
:think::think::think::think: Im pretty sure i know what I myself am talking about. NOWHERE have I mentioned repairing mangled tabs. Heck i don't even own a DH bike at the moment to have mangled tabs, And i know plenty about how to fix such an issue and the effects of welding (ive been a welder/fabricator for 17 years now).
As i said in both my previous posts...ALL I'm after is what damage people have experienced with THEIR tabs, NOT how to fix it.

Thanks for getting my thread off to a flying start:mad:
 
DirtyMike

DirtyMike

Turbo Fluffer
Aug 8, 2005
14,437
1,017
My own world inside my head
Well at least its something.

I see what your saying here..... You lookign for what caused the damage in teh first place......

Ok, my personal bikes, I havent damaged the ISCG tabs, I have always run the e13 SrS, so I end up damaging the cranks instead of the frame tabs..... iahve however twisted the hell out of the backplates though. Stripped one out once on old iscg from overtightening....

Customers bikes...... Most damage I have seen is when using either the LG1 or the G2. Some type of impact, be it rocks, logs, caseing a jump ETC.... Mostly its twisted tabs, some have been able to be facedm and be ok, 05 style only there, had a few with all three clean ripped off the shell, those were old ISCG setups. some have been cracks along the shell were teh tabs are attached....... pretty standard damage from a major impact.... the guides were also ruined as well, and usually the chainring by that time too...
 
Mulestar

Mulestar

Turbo Monkey
Sep 18, 2007
1,061
0
in the dirt
I twisted one of my tabs up pretty good on a sunday. I was using an lg1 and smashed the roller on a rock. It basically twisted the tab such that the whole guide was rubbing on the chainring.
 
D

davep

Turbo Monkey
Jan 7, 2005
3,276
0
seattle
No damage ever, but I also run either aluminum chainring bolts to attach the taco. or aluminum M6 bolts to mount the back plate.

Pretty stupid (and completely un needed) IMO to run full steel attachment points to connect a big stiff lever arm to aluminum mounts that are part of a multi thousand dollar part (frame).

That being said, tack welded threaded tubes IMO do not an ISCG mount make. A fully welded and propely designed sleeve or better yet a one peice machined bb/tab unit are certainly something I look in a hard use frame.

The replacable mounts on Knolly frames are a neat idea IMO.
 
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P

PhilipW

Monkey
Mar 13, 2007
311
0
Leominster, MA
davep said:
No damage ever, but I also run either aluminum chainring bolts to attach the taco. or aluminum M6 bolts to mount the back plate.

Pretty stupid (and completely un needed) IMO to run full steel attachment points to connect a big stiff lever arm to aluminum mounts that are part of a multi thousand dollar part (frame).

That being said, tack welded threaded tubes IMO do not an ISCG mount make. A fully welded and propely designed sleeve or better yet a one peice machined bb/tab unit are certainly something I look in a hard use frame.

The replacable mounts on Knolly frames are a neat idea IMO.
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DaveP has it right. Tack welded ISCG tabs aren't the ideal design choice for a DH rig. The ISCG-05 standard was made to confront all issues with breaking (among other things). The tabs have a wider BCD and the tabs are thicker. Steel bolts also bend before breaking.

I wrote up a blurb in the e*thirteen forum about ISCG and ISCG-05...a lot of it is elaborated from ISCG05.com, with a little more detailed input from DW.

As far as broken tabs, on the WC circuit and at the semi-pro/pro level...ISCG-OLD tabs can be made all sorts of different ways (strong or weak), and thus I have seen a few frames with broken tabs (usually the tack welded type). I havn't seen any catastrophic failure from ISCG-05 tabs yet, but I have straightened one set ridden by our factory rider who is extremely hard on equipment.
 
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