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Old 08-18-10, 08:24 AM   #1
soundtweakers
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Gear upgrade for Downtube FS8

What combination of rear derailleur and shifter do you recommend for a desperately needed upgrade on a DT 2008 FS8? If not too much to ask, could you give me the exact make and model as well since I'm pretty confused about all the options. I'm fine with keeping it 8-speed, and I'm looking for a combination some of you might've had success with on your Downtube FS.

I've tried the hanger straighening/youtube video method offered by Downtube, I've had a local bike shop(reputable one) do a gear tune up, but my shifting problem persist. Not sure if it would help but the shifting problem exist between 3~6 with 4th gear being the most problematic.

Thanks.
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Old 08-18-10, 08:43 AM   #2
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I'm looking at this RD http://www.bikewagon.com/Shifters-De...-p7544334.html

Will I have problems with long cage RD's, or am I limited to use medium/short cage since I have 20" wheels?

and will this shifter with with the above RD?http://www.bikewagon.com/Shifters-De...viewsTabAnchor

I welcome any brand suggestions
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Old 08-18-10, 09:09 AM   #3
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Originally Posted by soundtweakers View Post
I'm looking at this RD http://www.bikewagon.com/Shifters-De...-p7544334.html

Will I have problems with long cage RD's, or am I limited to use medium/short cage since I have 20" wheels?

and will this shifter with with the above RD?http://www.bikewagon.com/Shifters-De...viewsTabAnchor

I welcome any brand suggestions
Those are good choices for an upgrade.. I like SRAM derailleurs and thumb shifters .. make sure and check your shift cable for smooth operation and kinks before you spend the money .. might be a simpler problem than a component change... you can run any cage length on the FS-8, but the longer the cage the closer to the ground it is .. something to think about if you use it on the dirt trails.
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Old 08-18-10, 09:50 AM   #4
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SRAM is good stuff. I agree with Bruce on checking for cable kinks and such. You may also find that all you need is the shifter, as most of the delicate functions are in there. Just lube all the joints in the RD to make sure it moves freely. I found good prices on eBay for this kind of parts.

Good luck...
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Old 08-18-10, 10:37 AM   #5
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thanks guys. just want to clarify, I do have to have stick with something between 7~9 speed derailleur for my 8 speed bike, correct?
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Old 08-18-10, 11:03 AM   #6
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Originally Posted by soundtweakers View Post
thanks guys. just want to clarify, I do have to have stick with something between 7~9 speed derailleur for my 8 speed bike, correct?
The derailleur doesn't care if it's 7 8 or 9.. what matters is the shifter, and whether or not it is compatible (pull ratio) with the derailleur.. with the SRAM units you listed, they have a pull ratio of 1:1, so will play nicely together.. if you went Shimano, the pull ratio is typically 2:1 and that X4 thumb shifter will not work...
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Old 08-18-10, 11:36 AM   #7
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The derailleur doesn't care if it's 7 8 or 9.. what matters is the shifter, and whether or not it is compatible (pull ratio) with the derailleur.. with the SRAM units you listed, they have a pull ratio of 1:1, so will play nicely together.. if you went Shimano, the pull ratio is typically 2:1 and that X4 thumb shifter will not work...
so the main things to watch out for is the actuation ratio and number of gears on the shifter.
I'm going to be keeping it simple by sticking with SRAM, right now I'm gearing towards the SRAM X.7 Medium Cage RD and whatever SRAM 8 speed shifter with an 1:1 ratio.
So as long as I pick an 8 speed shifter and a derailleur both with matching 1:1 actuation ratio I should be fine, right?

thanks again
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Old 09-14-10, 09:41 AM   #8
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just got a SRAM X.7 rear derailleur(medium cage) off of Ebay, looking for an 8 speed shifter to match it now.

what do you guys think of this one?
http://www.sram.com/sram/mountain/pr...gger-shifter-0
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Old 09-14-10, 02:00 PM   #9
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Originally Posted by soundtweakers View Post
just got a SRAM X.7 rear derailleur(medium cage) off of Ebay, looking for an 8 speed shifter to match it now.

what do you guys think of this one?
http://www.sram.com/sram/mountain/pr...gger-shifter-0
That should work with your new rear derailleur. Please report back on how it all turned out esp. performance.

BTW, I plan on doing something similar, but will keep the sunrace rear derailleur for now. I will only upgrade the shifter first. Then, try that out.

Here's the one I got:

http://cgi.ebay.com/Right-Shimano-De...item4cf175c98d


Someone on this board said that the sunrace unit is pretty good, only the shifter is the weak link. We'll see. I'll also report back.
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Old 09-14-10, 03:36 PM   #10
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On my bike, the Sunrace and the grip shifter does work fine about 75% of the time right after a tune up/lube. I just can't have a slip gear in the middle of a uphill climb on 1st Ave during rush hour....pretty scary.
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Old 09-15-10, 04:48 PM   #11
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here is my RD/shifter combo finally.

Sram X.7 Rear Derailleur
Sram X.4 8 spd. trigger shifter

now, I'm good with tools and I have more than enough time to search online for tutorial, but I'm no bike tech. should I bring it to a bike shop and have it installed, or should I give it a try?
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Old 09-15-10, 04:55 PM   #12
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www.bicycletutor.com
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Old 09-16-10, 09:28 AM   #13
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thanks for the link
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Old 09-20-10, 02:01 PM   #14
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Sram X.7 Rear Derailleur
Sram X.4 8 spd. trigger shifter

conclusion.....shift like a dream!!

also got new Ergon Carbon grip, Schwalbe Marathons arriving tomorrow.....looks like I'll be catching the "upgraderisis" on this bike....what's next, wheel sets? pedals?
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