Front Derailleur, Whats it for??

996JAT

I'm gonna sound really stupid, especialy since i've done nearly 1000 miles this yr on the bike.

I have a Trek 1.7 Compact with 105 set and Utegra rear. I've always used it on the inside smalleer teeth front derailleur(gear).

I've only recently changed it to the larger cog. I waited so long because once i tried the change and the chain came off.


However now its on the large front cog it seems so much more pressure is needed, even in the long lowest rear gear. The main benefit is it seems a lot quicker and i rarely get to gear3 on the back. Its definately quicker and i change the rear gears so much less.

Only pain is its got so much more resistannce. Is this normal?? An sorry for not knowing much.

Thanks

redddraggon

and

996JAT

Sorry lads.

i know stupid but true

glenevans

Well, this looks like a good place for my first post on this site. Lovely to be here.

You actually answer your question in your own post. Basically the front derailer moves the chain onto a different gear (technically it's a crank). So if you move onto the bigger ring it takes more effort to move the pedal through one revolution but you will move farther down the road. If you move to the inside smaller ring you can accelerate faster or cope with hills better but you'll have a reduced top speed. Geddit?

Glad to be of service

fast as fupp

redddraggon wrote:

and

+1 :shock:

Bhima

When cycling, you want to keep your legs spinning round at the same rate - somewhere between 80 to 110 spins per minute. Too slow and you put massive strain on your legs/joints and too fast and you waste too much energy spinning your legs round.

To stay in this range, you have to change gear. As you go up a hill, to stay at 90 RPM (for example), you'll go to easier gears as the hill gets steeper. Eventually, you will be on the lowest gear you have (on the rear wheel cogs) so you should shift to the smaller chainring on the front so that the gears are made even easier.

Get it?

blackhands

glenevans wrote:

Well, this looks like a good place for my first post on this site. Lovely to be here.

You actually answer your question in your own post. Basically the front derailer moves the chain onto a different gear (technically it's a crank). So if you move onto the bigger ring it takes more effort to move the pedal through one revolution but you will move farther down the road. If you move to the inside smaller ring you can accelerate faster or cope with hills better but you'll have a reduced top speed. Geddit?

Glad to be of service

What's technically a crank ??

rally200

er. the crank, is, er technically a crank.

996JAT

Guys it makes sense.

Sorry

No wonder on the large crank and the lowest/largest rear gear it scrapes the guard as it should be used when you build up speed

rally200

ideally you shouldn't be using that large/large combination, but with 105 or utlegra you should be able to trim so it doesn't rub.
the little trek manual that comes with the bike explains how gears work.

or is this a wind up?

996JAT

No aint a wind up,

Sorry dont read manuals am an I.T guy !!

dcab

redddraggon wrote:

and

quality

CiB

996JAT wrote:

No aint a wind up,

Sorry dont read manuals am an I.T guy !!

?? So am I, but sometimes RTFM is the way forward, rather than having a load of others do the leg work for you. Here. http://bicycleuniverse.info/eqp/gears.html

Or better still, present yourself at your LBS or wherever you bought the bike originally and ask them if they can explain it to you. Don't forget to tell them that you're an IT guy so are absolved from reading the manual that explains it.

steerpike

F***ing hell this is the beginners forum isn't it? Give the guy a break, he has posted a perfectly reasonable question in the right place. 996JAT - don't let the snobs put you off from asking questions, some of the people on this forum where evidently born with all their knowledge.

CiB

steerpike wrote:

F***ing hell this is the beginners forum isn't it? Give the guy a break, he has posted a perfectly reasonable question in the right place. 996JAT - don't let the snobs put you off from asking questions, some of the people on this forum where evidently born with all their knowledge.

No. The guy loses all cred by stating that he's an IT guy, so doesn't read manuals. If you're stuck and have tried to help yourself fair enough, come and ask any biltheringly obvious question, but claiming that IT people are in some way excused the hassle of working things out for themselves puts him on a sticky wicket. RTFM. We all have to do it at some point.

robmanic1

troll, surely???

steerpike

! think he was being a little tongue in cheek re: manuals. The guy has a beginners question and has posted it in the beginners section.

CiB

Ok.

Your bike has a cassette (cogs, gears) on the rear wheel that offers you a range of gears, from dead easy to quite hard, in roughly equal steps. For going up hills, you move the chain on to a bigger cog on the rear cassette. The bigger the rear cog, the easier it is to pedal, but the pay-off is that you'll go more slowly for the same pedalling speed. When you go down a hill or ride on the flat, change the gear to a smaller cog on the rear, so that you pedal at a slower speed but your speed is maintained, or increased. You'll soon find out which gears suit you best for any incline.

The front gear ring moves the range of gears upwards. The smaller front ring gives you a range of dead easy to quite hard. Putting the chain onto the bigger front ring moves the start & end points of the range to give you quite easy (not dead easy) to really quite hard. The two ranges overlap somewhat so you don't need to change all the way to the smallest rear / smallest front before hoiking up to the larger front ring.

If you have 9 cogs on the wheel and two front rings, you'd assume 18 gears. You don't, it's probably 12-14 gears as some combinations will be effectively the same. And as a rule of thumb, avoid riding with the chain on the largest front & rear cogs, and also avoid using the smallest front & rear together. The chain is pulling across a larger angle in these situations and will be more prone to rapid wear. A more suitable gear ratio can be found with a different combination of gears. Rule of thumb is to use the small front for the first 6 / 7 gears and the larger front ring for the gears 3 - 9. This isn't set in stone, and depends on how many rear gears you actually have - it could be 7, 8, 9, 10, even 11 on some kit nowadays.

If the chain falls of when swapping with the front dérailleur try changing more slowly, and look at the adjustment to check that it's not moving too far across. Avoid changing to the smaller front ring if the chain is already on the smallest of the rear cogs, although you shouldn't get to that position.

Headhuunter

That's much better, I was starting to feel sorry for the poor lad! Come back 996JAT, it's OK to ask basic questions on the errm Road BEGINNERS forum...

STEFANOS4784

Is every one sure this isn't a wind up? He's been a member for a year :shock: :shock: :?

STEFANOS4784

EDIT: Somehow missed the part where he said over 1000 miles :shock:
Must've taken ages

Headhuunter

STEFANOS4784 wrote:

Is every one sure this isn't a wind up? He's been a member for a year :shock: :shock: :?

The poor bloke does start by saying that he has cycled 1000 miles over the year.... It is possible just to jump on a bike and cycle without changing gears. In fact I should think it's more common than you think judging by some of the London bike commuters I see heaving away in large chainring/small gear and not changing down at all when they get to lights. I think quite a lot of people out there have absolutely zero idea how to use gears.

STEFANOS4784

Maybe..........................

Still sceptical though.

996JAT

No i've never used the large cog up front.

I even did birmingjam to london for charity run ( www.charitybikeride.com ) in July with just the small front derailleur.

Like i said the chain came off first time i tried and i found it dead hard to pedal on the larger front, but now i'm a bit better. That was during my first 50 miles on the bike.

Way quicker on larger cog and a great way to build up stronger legs when starting on the larger cog.

But someone is right, too much wear with this method.

STEFANOS4784

When you changed up to the big cog were you on the smallest cog at the back? If you were then try flipping down a few gears on the back first so it feels like your legs are spinning wildly then change up on the front. That should be easier and then you can flick through the gears at the back to find a more suitable gear.


Whilst on your ride did it never feel annoying that your top speed was, what must have seemed, very limited?

996JAT

At present i'm using big front and big gear cogs.

I've hit 30mph, Average was around 16. Not really on the hilly stuff though.

I'll try using them more and shifting the front more, i just had a feeling the chain will have more chance of slipping but have nothing to lose.

dennisn

I was marshaling(on my bike) the time trail portion of a triathlon and near the end I came across the last place rider, who was struggling against a killer head wind in a 52 front
and what appeared to be, possibly, a 14 or 15 rear cog. She was really struggling and
looked about to give it up with less the 5 miles to go. I suggested "try shifting to the small front ring, it will make it easier to pedal". She replied "how?". Makes you wonder sometimes.

Dennis Noward

CiB

You know that you're allowed to use any gear when you're out on your bike? There are no police following, no judge of fact checking on your gear use. Sorry to sound patronising, but you sound like someone with a car telling us that you only use 4th & 5th because it struggles a bit to start with but eventually goes quite quickly. Use all your gears, get used to chopping & changing, and if poss try to keep your pedalling speed [cadence] within a reasonable band - 70 - 90 should do you. But 65 is ok too. It's your bike, your legs.

eh

"i just had a feeling the chain will have more chance of slipping but have nothing to lose."

Yep I often see riders sitting on the side of the road due to slipping gears, because the changed gear, FFS. Either (1) you are taking the p*ss (2) need some help if so head to your LBS.

steerpike

eh wrote:

"i just had a feeling the chain will have more chance of slipping but have nothing to lose."

Yep I often see riders sitting on the side of the road due to slipping gears, because the changed gear, FFS. Either (1) you are taking the p*ss (2) need some help if so head to your LBS.

eh - he is here, in THE BEGINNERS SECTION of the forum, BECAUSE HE NEEDS HELP

in your own words FFS!!!!

STEFANOS4784

996JAT wrote:

I've hit 30mph, Average was around 16.

That's dam good if you were only using the small cog at the front your legs must have been going like a washing machine

You shouldn't let the gears slipping dissuade (?) you from changing gear, you may not have them indexed properly, i'm giving up now apart from to say practice changing gears