Sti shifters

[JimmyMacK]

My recent purchase of an 08 Trek 1.2 has eased me back into road cycling after a long lay off. Took me a while to get used to the clipless pedals, the stiffness of the ride and the Sti's but all doing fine now.

But I do have a proble, the 08 Trek 1.2 has Sora rear, 2200 front and 2200 Stis. The rear Sora is nice, but the front 2200 rubs the chain when in highest gear on the top sprocket and on the lowest gear on the bottom sprocket (it is a triple chain set). My LBS have said they will change the fron mech to Tiagra when it goes for the first service, will this help solve the problem?

Next question is that in the mean time, is there anyway of using the Sti shifter to move the front mech slightly to stop the rub? Or can I adjust the mech to stop the rub myself?

 

[John the Monkey]

Shimano's technical docs could help - see the "troubleshooting" section at the end;

(This one relates to the 2200 triple front derailleur). http://techdocs.shimano.com/media/t...001/SI_5GF0B_001_En_v1_m56577569830625446.pdf

These might help too;

View: http://uk.youtube.com/watch?v=ngm6dr-1na0

http://bicycletutor.com/adjust-front-derailer/

(Bookmark bike tutor, incidentally, it's a great site).


You shouldn't need a new derailleur, imo, the old one just needs setting up properly (again, imo).

 

[bonj2]

But I do have a proble, the 08 Trek 1.2 has Sora rear, 2200 front and 2200 Stis. The rear Sora is nice, but the front 2200 rubs the chain when in highest gear on the top sprocket and on the lowest gear on the bottom sprocket (it is a triple chain set). My LBS have said they will change the fron mech to Tiagra when it goes for the first service, will this help solve the problem?

I don't think it will. Well I can't think of any reason why it would.
first just eliminate some things: are both the instances of rubbing, i.e. the rubbing when on the big rear sprocket, and the rubbing when on the small rear sprocket, both happening when the chain is on the middle chain ring?
in other words, does the chain go from touching one side of the front mech to touching the other side of it just due to the movement of the chain by the rear mech? (without the front mech moving)?

 

[JimmyMacK]

Thanks for the sites JTM. I can see a lot of reading and a little work being done going forward

Will give the adjustment a try this week will let you know how it goes.

 

[JimmyMacK]

I don't think it will. Well I can't think of any reason why it would.
first just eliminate some things: are both the instances of rubbing, i.e. the rubbing when on the big rear sprocket, and the rubbing when on the small rear sprocket, both happening when the chain is on the middle chain ring?
in other words, does the chain go from touching one side of the front mech to touching the other side of it just due to the movement of the chain by the rear mech? (without the front mech moving)?

Out on it tonight so will test the front mech out. Will post back tomorrow with results

 

[fossyant]

Won't help - you need to trim the front mech - I don't know if Sora's will let you give the mech a little push to trim....plus don't expect to get the full range of gears in each chain ring.

Set front mech limit screws not to rub in smallest chain ring, largest sprocket, and largest chain ring, smallest sprocket. Then trim when riding....

 

[JimmyMacK]

Set front mech limit screws not to rub in smallest chain ring, largest sprocket, and largest chain ring, smallest sprocket. Then trim when riding....

I apologise for my ignorance (I'm not familliar with a lot of terms yet!), but what is trimming?

I went out on it last night and found this:

Front small sprocket; chain rubbed when in smallest 2 rear sprockets
Front middle sprocket; chain rubbed when in spallest sprocket
Front large sprocket; chain rubbed when in the largest 2 sprockets

It also found it difficult to move from middle sprocket to top sprocket (although this could have been something to do with the slow speed i was riding at at the time).

Looking at the Trek website this morning it looks as though the front mech and Sti's are 2203's and not 2200's as I first stated.

Looking at the results from last night, it looks like I should def do something about the rub from the small and middle front sprockets so will get reading. But would like to know a bit more about trimming

 

[John the Monkey]

From a post I made elsewhere;

The trim (micro adjust) for the left hand lever is only on the end of the gear range, as I remember. Moving out from the smallest ring (main lever) mine goes;

1 click - small ring to middle ring
1 click - middle ring "high" trim (for running on the middle ring and smaller back sprockets)
1 more move (doesn't click on this one) up to the big ring.

Coming down again (inner lever);

1 click - trim for big ring (i.e. for running big ring and larger sprockets)
1 click - big ring to middle ring
1 click - middle ring to smallest ring

Remember that mine will be Tiagra levers - your Sora ones may not work in the same way, and may not have trim at all (look at the tech docs for the shifters). Regarding the model numbers, 2203 is from the same series as 2200, the 3 just indicates that it's designed for a triple chainset.

I'd expect chain rub on small/small large/large combinations, tbh - you may be able to mitigate it slightly, but do bear in mind that running these extreme combinations isn't something you should do anyway (bad for the chain).

 

[MartinC]

I bought a Trek 1.2 '08 last autumn as a hack bike. The 2203 front mech is hard to set up precisely 'cos the body is plastic and not too rigid. I've got a Sora mech to waiting it in the shed to replace it when I get round to it - so your LBS's plan to replace it is sound.

The thing I did change straight away are the brake blocks - they're useless. Just put some DuraAce replacement rubbers in the shoes - makes a big difference.

 

[bonj2]

I apologise for my ignorance (I'm not familliar with a lot of terms yet!), but what is trimming?

I went out on it last night and found this:

1) Front small sprocket; chain rubbed when in smallest 2 rear sprockets
2) Front middle sprocket; chain rubbed when in spallest sprocket
3) Front large sprocket; chain rubbed when in the largest 2 sprockets

It also found it difficult to move from middle sprocket to top sprocket (although this could have been something to do with the slow speed i was riding at at the time).

Looking at the Trek website this morning it looks as though the front mech and Sti's are 2203's and not 2200's as I first stated.

Looking at the results from last night, it looks like I should def do something about the rub from the small and middle front sprockets so will get reading. But would like to know a bit more about trimming

Right. problem 1 and 3 aren't a problem because you shouldnt' be using that configuration, i.e. small to small, large to large. They are ratios that you can duplicate using combinations which don't cause such a bad chainline.

when in middle chainring and rubbing when on smallest sprocket, sounds like the mech is not over towards the large chainring enough.
Set the mech up so that it JUST doesn't rub when on middle chainring and LARGEST rear sprocket. Then if it rubs when on smallest rear sprocket then either don't use that configuration - middle chainring to smallest rear sprocket is probably duplciateable using large chainring and middle-ish rear sprocket.

IDEALLY, you should only use the largest few sprockets with the smallest chainring, the middle few sprockets with the middle chainring, and the smallest few sprockets with the big chainring. Although in practice, it's nice to be able to use all the sprockets with the middle chainring. if on the middle chainring, it rubs on one side when on big rear sprocket and rubbing on the other side when on small rear sprocket, you've got to decide which is most important to you and have it not rubbing when like that. now re-read paragraph 2 in light of this. you get me?

 

[JimmyMacK]

Thanks JTM, makes total sense now! I did try that last night but the shifters didn't seem to want to move anything any further than they had already! Like you say, could be the shifters. When iI had my old bike the frame lever levers were alwasys able to do this, I guess that when you're on a budget something has to give!

I think I'll study the set up and adjustment guides you sent me yesterday and see if that makes a difference. If not guess I'll just have to wear earphones

 

[bonj2]

trimming is moving the mech slightly using the shifter lever but not enough to cause it to shift, just enough to stop it rubbing.
for instance on my own bike, my front shifter actually has 4 indexes, supposedly 2 for the middle ring so you can trim it between them. but in practice I just use 1 for the small chainring, ignore 2, use 3 for the middle chainring and 4 for the large chainring. It rubs very slightly when on middle chainring and large rear sprocket, but i either live with this or use the small chainring.

 

[bonj2]

by the way the front cogs aren't called sprockets they're called chainrings. correct terminology!

 

[gwhite]

When setting up these triples it's better to start from the beginning and the Parktool website tells you how to do this. The Sora has a trimming device and using this will allow the use of the middle ring and largest sprocket without chain rub.
When on the smallest chainring and the largest sprocket, set the "L" screw so that it just misses the inner plate of the FD cage. Now move to the middle chainring and the largest sprocket. Set the cable tension when in this position so as the chain is as close to the inner cage plate without rubbing. Use cable adjuster to set a small gap and this cable tension should then give the correct amount sweep to move the chain to the large ring. If this cannot be done by the cable tension adjuster then the cable itself requires adjusting.

 

[Mortiroloboy]

I had Sh*man* 2200 on my winter hack, it worked, but I took it off in favour of a full Campagnolo Veloce groupset, the 2200 probaly won't last too long, it's pretty basic, some of it is even made out of plastic. have a look about for a tiagra groupset, or a mirage (Campagnolo) full groupset, it's being phased out, so you could get a real bargain.