잘못하면 프레임이 휠수도 있다는거...

프레임 일체형의 경우엔 달아볼만 하다고 생각 되지만.... 저도 효용성에 대해서 잘 모르는지라 ^^;;
행어를 교체할 수 있는 프레임이라면 샵에서도 권장하지 않더군요.

행어벵어에 대한 잘못된 상식입니다.
허브가 장착된어있는 프레임이라면 아무런 문제가 없습니다. 참고셈...^^
http://www.bikeallday.com/BikeLaboratory/bl_detail.asp?BL_CODE=67&CK_CODE=&PAGESIZE=15&PAGENO=4&S_TITLE=&S_CONTENT=&S_KEYWORD=&S_TITLE_2=&S_CONTENT_2=&S_KEYWORD_2=&TOP_CAT=&L_CAT=&M_CAT=&S_CAT=

제조사로부터의 답변입니다. (MTBR에서 긁어왔습니다.)
요약하자면 작은 충격으로부터는 보호하지만, 큰 충격에는 디레일러나 프레임에 손상이 갈 수 있다고 합니다. 하지만 또 그정도 충격이라면 니 몸부터 걱정하라고 하네요 ^^;

You are correct. By reinforcing the derailleur hanger, the chances of damage elsewhere in the system are increased in some circumstances.

Many times the derailleur is impacted against something during a ride. Sometimes there is a big impact with a lot of damage, and sometimes a smaller impact. In the case of a smaller impact, without the hanger banger, the derailleur hanger bends. Sometimes you can bend the derailleur hanger straight again, sometimes you must replace it. Sometimes, when the chain is on the biggest cog of the cassette, and the derailleur hanger bends in a little bit, the derailleur goes into the spokes, causing a lot of damage to the derailleur, frame, and even the wheel. I have also seen many cases where the derailleur hanger bends while not riding the bike, such as on a car carrying rack with other bikes, or in parking against other bikes.

The hanger banger will eliminate all problems stemming from these smaller impacts. The hanger banger will also make your shifting work better.

In the case of the large impact to your derailleur, the hanger banger will hold the derailleur secure, sometimes causing the derailleur to break, and in rare cases causing the frame dropout to be damaged. However, in these cases, quite often this would have happened with or without the hanger banger, and you might have to be more worried about injury to your body and greater damage to the bicycle over all.

The short story is that you are correct, and that in an extreme case the hanger banger may cause a problem, but this is a rare case and you can be the judge of whether or not you wish to have a hanger banger.

I hope this answered your concerns. We have not yet made the indestructible solution, we have just reduced the chances for damage in most cases.

Regards.
Peter Hammons
North Shore Billet
www.northshorebillet.com

얼마전에 행어 뱅어 사서 달았는데 저는 도움 많이 됐습니다. 잘못 구르는 바람에 앤드는 고사하고 드레일러, 프레임까지 먹을 수 있었는데 행어 뱅어만 조금 상하고 다른데는 멀쩡..ㅋㅋ 처음엔 멋으로 샀는데 제값 하던걸요??

당연히 행어분리형 자전거면 쓰실 이유가 없습니다.