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Acera RD on Tern folder (no standard DATT derailleur hanger?)

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Acera RD on Tern folder (no standard DATT derailleur hanger?)

Old 07-16-13, 12:40 AM
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SurlyLaika
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Acera RD on Tern folder (no standard DATT derailleur hanger?)

Will this Acera RD work on a Tern Link D8 frame? I might buy it from my friend, but I need to know that it's compatible before buying it. The reason it might not be compatible is because the Tern is a folding bike.

I read this on a blog about upgrading Dahons/Terns. I read that these bikes do not have standard DATT derailleur hangers. Is that a serious obstacle? Might the RD come with a derailleur hanger?

"Many Dahon / Tern bikes, from entry level to mid-high range bikes, such as D7 or even P9 series, use Dahon / Tern's proprietary Neos rear derailleur. This RD is designed by Dahon and used exclusively on Dahon / Tern bicycles. According to Dahon / Tern, this RD design allows for a low profile RD. You will notice that there is no regular RD hanger on the frame, but a special mounting point located on the chainstay for the RD.

So, if your bike comes with a Neos RD, it is likely that it does not have a normal RD hanger for traditional RD mounting. Sometimes you can find Dahon Speed P8 frames with a Neos RD, but also a RD hanger. This is not so common, probably only available for certain years' model.

In this case, how can you change your RD, since there is nowhere to mount a normal RD with DATT mounting? For Dahon steel frames (Boardwalk, Speed), you will need a third-party RD hanger to do that."

FWIW, my Tern did not come with a proprietary NEOS derailleur. It came with a SR Suntour RD, but it looks to be low-profile as well. I'm not sure if it's medium cage or low cage. It's pretty non-descript, just a clunky black box. The reason I want to change my derailleur is so I can fit a mega-range 11-34 on there. The cassette on there is a 12-32. That may not seem like much of a difference but it's just an 8 speed and the terrain around here is hilly!
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Old 07-16-13, 02:42 AM
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Integrated derailer hangers these days are generally associated with low-end derailers like Shimano Tourney. Functionally they're fine for everyday use, but they're definitely not low profile. Look for something called a derailleur claw, derailleur claw adaptor or something along those lines and you'll be able to mount any derailer.

I haven't used them much, but I suspect there is a chance of having issues of getting enough sideways reach out of a derailer mounted on a claw hanger. And you need enough axle protrusion to be able to fit one.

Personally, I kinda wonder if it's worth the effort for a mere two tooth improvement. 32-34 is what, 8%?
Unless you'r simultaneously troubled by not being fast enough on the flat, you might be better off looking for a smaller chainring.
To really expand the range of your gearing, I'd suggest a new rear wheel featuring a SRAM Dualdrive hub:http://www.sram.com/sram/urban/products/dualdrive-24

Or if you want it bad enough, see about fitting a Schlump Mountaindrive:http://www.schlumpf.ch/hp/schlumpf/f...riebe.engl.htm

Or you could research fitting a double crank. With a BB mounted front derailer, it might be doable.
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Old 07-16-13, 05:57 PM
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I'm also planning to change the front ring. Right now it's a 55. I think a double crankset is impossible and likely expensive. I want exactly what the mega-range does, a lower low and higher high, even by a few gear inches. I just want an easy, inexpensive solution. (I'm in Korea, bike things tend to be very expensive, especially imports)
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Old 07-16-13, 06:23 PM
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last DHon that passed thru the repair dept just had a standard hanger held on with the axle nut,
it was a rear opening dropout..


IGH are so much simpler on Folding bikes , and no low hanging RD to whack.
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Old 07-17-13, 02:45 AM
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Originally Posted by SurlyLaika View Post
I'm also planning to change the front ring. Right now it's a 55.
Good plan. But keep in mind that proportionality is the name of the game here. What tooth count are you aiming at? A 55-51 drop is fairly similar in size to your your proposed 32-34 change -comparable to a regular step between two gears. If yoi do both, it'd be like being able to downshift twice more when you're climbing.
Originally Posted by SurlyLaika View Post
I think a double crankset is impossible
Maybe, maybe not. Not having done it on that particular bike, and not having it in front of me, a reliable guess is hard to achieve.

Originally Posted by SurlyLaika View Post
... I think a double crankset is... likely expensive....
Cranks as such do come in a range, from the crude to the sophisticated. Bling will always cost, but unless excessively hampered by trade rules, a no-frills option shouldn't be that costly. Where I'm at, a basic (riveted steel rings) can be had for USD 22 or something like that.

Originally Posted by SurlyLaika View Post
...I want exactly what the mega-range does, a lower low and higher high, even by a few gear inches.
As long as you're aware that "few gear inche"s is all that your current plan is likely to give you. Let's say that you swap the 55 for a 50 and the 12-32 for a 11-34. The 12-11 is a decent compensation for the 55-50, so your highest gear pretty much stays put. And your lowest gear gets roughly comparable to having two lower gears from where you are now.
Originally Posted by SurlyLaika View Post
I just want an easy, inexpensive solution.
For easy and inexpensive, buy a (locally branded) rigid MTB with a triple, and switch to road tires, maybe a road cassette. Used may be an option, put some money aside from the purchase for servicing.
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Old 07-22-13, 11:05 PM
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My only option is a 52t instead of the 55t. The 55t gives a gear range of 32" to 85". That's pretty damn wide. I'm just going to keep it. Going to a 52 would cause me to lose 5 gear inches on the high to gain 2 on the low end. It's not an even trade off. My girlfriend can just walk it up hills that are too tough for her. Thanks for your help.
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Old 07-22-13, 11:34 PM
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What tire size does that use?
A skinnier tire (if available) would gear you down.
Example-
Going from a 20x2" to a 20x1.5" would gear you down 5%.
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