[elementality809]

Hey guys

i was tuning my derailleur today and saw 2 screws, one labeled H and the other labeled L. Does anyone know what those screws are meant for/do?

Thanks in advance!

 

[HAB]

I'm really curious to know how you were tuning your derailleur if you don't know what those do.


The third hit is particularly good.

 

[zebrahum]

If you don't know, don't touch them. Simple as that.

 

[shift96]

2 replies and you guy's couldn't just tell him what they were for? They are your limit screws for high and low gear. They prevent the chain from shifting off of the highest and lowest cog

 

[HAB]

2 replies and you guy's couldn't just tell him what they were for? They are your limit screws for high and low gear. They prevent the chain from shifting off of the highest and lowest cog

I gave him a link.

 

[shift96]

I gave him a link.

oops, my bad. Sorry

 

[ultraNoob]

2 replies and you guy's couldn't just tell him what they were for? They are your limit screws for high and low gear. They prevent the chain from shifting off of the highest and lowest cog

I gave him a link.

golly gee wilikers... whatever happened to just answering the question. It's not like the question was wierdly worded or anything.

The H screw limits how high up (big cog) the derailleur can travel, the L screw limits how low (little cog) the derailleur can travel.

 

[slowitdown]

the "attack" answers made an excellent point.

if you don't know what the limit adjust screws do, it doesn't make a lot of sense to be "tuning" your derailleur.

no doubt someone can learn how to work on a bike by making lots of mistakes and using trial-and-error. it's a lot more costly and takes a lot longer, but it's possible.

still I don't understand why someone would "tune" a derailleur if he doesn't even know how the derailleur works. it makes no sense.

but then, a lot of people associated with bicycles make no sense. usually they're the ones who don't really ride very much, but use their bikes to take digital pictures to "prove" on the internet that they "own" a rad bike. somehow, the idea of "tuning" a rear derailleur without knowing how the der works, that smacks of e-riders.

to the Original Poster --

I would suggest that you not venture into "tuning" something you don't understand. You can learn how to work on your bike for nothing if you have an internet connection, which you must have if you're posting here.

Park Tool Company has a detailed walk-through of many typical maintenance issues and fixes on its website.

I would suggest going there to learn all about your derailleur before you attempt "tuning" that derailleur.

Park Tools repair help ---> HERE

 

[caputo1989]

golly gee wilikers... whatever happened to just answering the question. It's not like the question was wierdly worded or anything.

The H screw limits how high up (big cog) the derailleur can travel, the L screw limits how low (little cog) the derailleur can travel.

Thats true for the front but it is opposite on the back.
The high gear on the back is the small cog and the low gear on the back is the big cog.

 

[caputo1989]

If you want to see them in action put the rear der in the high position (small cog) then ture the high screw in. the dreailure will move in twords the center of the bike and turning it out wil lmove the der away from the center of the bike. Same when the chain is on the low gear (big Cog). to test the positin in the high gear put the chain back on that cog and pull out (away from center) on the derailure and the chain should not come off.
Also you will want tho push in (without shifting to the center of the bike while pedaling) and let the chain drop back into place if it hesitates you need to loosten the H limit screw.
As for the low gear (big Cog) leave the derailure in the High position and once again push and pedal like the seccond High gear test, but push all the way to the center of the bike. if the chain falls off into the spokes you need to tighten the L limit screw. Once again if it hesitates into gear you need to loosten the L limit screw.

Note**** When setting any of the limit screws make sure the cable is dissconected from the derailure. Also make sure the chain is on the middle ring.

Now that you have done this make sure the shifter is in the H position giving the most cable through the housing. ( Press the small thumb shifter or twist the grip while holding the end of the cable so that you can feel that it is in the slackest position.

Now screw the barrel adjuster at the shifter all the way in then back it out 3 turns.

Now put some tension on the cable and tighten it under the bolt.

Shift down one (into a bigger ring) and if it is having trouble making it into that gear slowly back out the barrel adjust untill it makes it. Do this untill you are in the lowest gear. then go back into the higer gears one by one if they dont drop properly you need to screw the barrel in.

Front derailures are a little trickier and harder to explain in text so im not going to go into it Unless you pm me then i can write a detailed spep by step.

Good luck!

 

[shift96]

golly gee wilikers... whatever happened to just answering the question. It's not like the question was wierdly worded or anything.

The H screw limits how high up (big cog) the derailleur can travel, the L screw limits how low (little cog) the derailleur can travel.

Isn't that what I did?

 

[strangeland2]

Deleted doesnt benefit the OPs thread.

 

[zebrahum]

Ok, how about this?

http://www.amazon.com/Zinn-Mountain-Bike-Maintenance-Third/dp/1884737994

Do yourself a favor and pick up a book or find someone who's good at fixing bikes and learn as much as you can about this stuff. But my point remains, until you learn what they do, don't touch them. You are very likely to allow your bike to shift the chain off the cassette and into the spokes. This could hurt you very badly and/or cause a whole lot of expensive damage. So go learn about it before you mess with it, just like anything really.