Resetting the Rear Derailleur

FISMA

What's the proper procedure to reset the rear H&L derailleur screws? Just ensure they are 50% in and 50% out? Count the number of turns it takes to fully remove them (when they are fully in) and then reverse by half the number of turns?

Thanks

The tax man

All you need to know...Link (credit to Lumen IIRC)

Lumen

When dealing with limit screws, try and get cable tension out of the equation first.

I usually first slacken off the cable completely e.g. shift into biggest sprocket at rear, click the shifter a few times to create some slack then pop the outer out of one of the cable stops. Then you can move the derailleur with your hand to check its range of movement is perfect.

anoble66

here is shimano's dura ace 7900 install video, shows you how they set the H and L limits

http://vimeo.com/5780736

Keep_Her_Lit

FISMA, the “50%” approach that you describe is unlikely to yield a satisfactory result. It’s better to think about the purpose of the H&L screws and then adjust them to ensure that they are performing their respective functions correctly.

These are limit screws, designed to prevent the chain from being pushed off the largest (L – low gear) or smallest (H – high gear) rear sprockets and into your spokes or frame, respectively.

But at the same time, they must also allow the chain to shift cleanly onto these outer sprockets without any misalignment. Otherwise, the chain may run noisily and inefficiently in these gears or, if adjusted too conservatively, may not engage with them at all.

So getting the balance right requires fairly fine adjustment and this is why the 50% approach probably won’t work. The sprockets are mounted on the wheel, while the derailleur is mounted on the frame – the offset between them will vary from one bike to the next, depending on the particular components fitted and the frame. The adjustability provided by the limit screws allows you to compensate for this variation.

I think you may find this less laborious than my explanation:

http://bicycletutor.com/adjust-rear-derailleur

BTW, you can disregard his closing comment on WD40 – “never use WD40 on any part of your bike”. He is out of his depth here. As all real cyclists know, one should regularly immerse one’s entire bicycle in a large vat of WD40.

ktz84

Keep_Her_Lit wrote: »

BTW, you can disregard his closing comment on WD40 – “never use WD40 on any part of your bike”. He is out of his depth here. As all real cyclists know, one should regularly immerse one’s entire bicycle in a large vat of WD40.

I practically do that

When I've cleaned my Titanium bike it gets WD40 sprayed all over it and then wiped down. Brings the frame up lovely