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Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Nov 11, 2007 1:33 pm
by dark_albert
Hi guys,
i spend a few hours in the workshop.
I tuned my Rival rear der. to 15th lower pulley.
Weigh is at 170g. Still light.
http://picasaweb.google.com/dark.albert ... sumbauSram
dark_albert
Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Nov 11, 2007 1:33 pm
by Weenie
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Posted: Sun Nov 11, 2007 4:09 pm
by marecej
what for?
Posted: Sun Nov 11, 2007 4:43 pm
by dark_albert
do you mean what sence does it make?
it saves you power. Take a look at the search funktion. there are some threads about this.
dark_albert
Posted: Sun Nov 11, 2007 10:04 pm
by CharlesM
There are also a few threads (or were) about running SRAM with something other than stock pulleys...
I believe depending on what you do, you run the risk of too much swing and rear DER failure.
Posted: Mon Nov 12, 2007 2:31 am
by SirVelo
@ dark_albert: once again a really nice execution. Well done. Do you notice any extra flex in the RD now? You'll have to post some comments after you've put some miles on it.
@ pez or anyone else reading this thread that has the answer (and sorry for the slightly off-topic thread jacking
): I have only heard of Rival RD's failing. What about the Force RD? I have some carbon pulleys (11t) and a carbon cage back plate on mine - just switched from a heavier set of KCNC pulleys. Should I be worried?
Posted: Mon Nov 12, 2007 5:31 am
by GrahamB
dark_albert wrote:it saves you power.
How many milliwatt?
Posted: Mon Nov 12, 2007 5:57 am
by too slow
All it needs now are dimples.
Posted: Mon Nov 12, 2007 11:04 pm
by djconnel
PezTech wrote:There are also a few threads (or were) about running SRAM with something other than stock pulleys...
I believe depending on what you do, you run the risk of too much swing and rear DER failure.
Shouldn't a larger diameter pulley increase the effective cage length, increasing the derailleur capacity?
Posted: Tue Nov 13, 2007 10:51 am
by Boonen
Looks good Dark-Albert! Did you manage to get the original cage off the plastic parts it's fixed to without damaging it or did you just cut it off and use the remains to fix the carbon plate to? I have been looking for options to remove the outer arm from the plastic part with the feather inside but I haven't found a way to do so without damaging it to much to get back together again in the right way.
Anyway, I love your tuning jobs so thanks for sharing
Posted: Tue Nov 13, 2007 10:58 am
by dark_albert
hi, i just cut it. i didnĀ“t found a way to rebuild it either. But i get some contact to sram right now. maybe i can get some closer infos how to rebuild it.
dark_albert
Posted: Tue Nov 13, 2007 12:40 pm
by Boonen
Sounds good. I'm working a little on one of these as well so if you find a way around the pressed in pin maybe you could let us know? It would be convenient if they would use a small m4 or so recessed bolt instead of a pressed in pin just like the cheaper Shimano derailleurs do, it would also help people with damaged derailleurs replacing only the cage if necessary.
Re: Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Aug 08, 2010 5:52 am
by djconnel
Old thread, but I asked Greg Steele, who has one of Dark Albert's mod'ed Red deraillaurs, to give the pulleys a 'spin test". My SRAM pulleys spin for two seconds, which makes me happy, because that's much better than Shimano pulleys, which don't freely spin at all (based on my tests on old Dura-Ace on and what I've read @ BikeTechReview). Anyway, here's the result:
http://vimeo.com/13964141WOW! Of course, unloaded friction isn't necessarily proportional to loaded friction, but nevertheless, that is really impressive.
Re: Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Aug 08, 2010 6:04 am
by pierre-san
OMG!
They spun forever! Impressive indeed.
Re: Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Aug 08, 2010 10:29 am
by KWalker
I tried searching, but didn't use the right combo of terms and I want to know where to get the parts and if anyone has further tested this idea. I'm thinking of doing it to my Force der.
Re: Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Aug 08, 2010 11:28 am
by djconnel
I put my best attempt at modeling the effect of the 15-T cog
here.
Here's the link to Dark Albert's service.
Re: Sram rear Der. Upgrade to 15th lower pulley
Posted: Sun Aug 08, 2010 11:28 am
by Weenie
Visit
starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓ Broad Selection ✓ Worldwide Delivery ✓
www.starbike.com