Merlin Rocklobster Tig Team SL Gear Problem

byrnejamie

Hi,

I am hoping someone can help me out. I have Merlin Rocklobster Tig Team SL which I purchased a few years ago. Great bike as far as I am concerned although I have always had an issue with the gears.

When shifiting to the outer front chain-ring and the inner rear chain ring, the chain locks up. The chain goes extremely taught and it is not possible to change gear. I have to force it manually down onto a lower front chain ring.

Is there a way to fix this? It appears to me that extending the chain will make it far to slack in other gears!

Is this something that occurs to other riders? I recently read on a forum somewhere that it is fairly common that some gears are unavailable on a bike. It is a question of frame geometry?

Thanks in advance.

The Rookie

Well apart from the fact you shouldn't really be in that ring combo, it does sound like your chain may be 1 link 2 short, so wouldsuggest adding just one (pair of) link(s).

Has a new rear cassette been fitted with a larger granny ring, going from 32 to 34T for example requires extra links.

The normal chain sizing guide is to use the 2 largest rings and have just a slight angle in teh chain created by the jockey wheels, sounds like your's goes straight.

Simon

byrnejamie

Thanks for the prompt response.

Well apart from the fact you shouldn't really be in that ring combo, it does sound like your chain may be 1 link 2 short, so wouldsuggest adding just one (pair of) link(s).

No changes have been made to the original cassette or rings. I will add a couple of chain links and see what happens.

Whilst in danger of sounding like an imbecile can I ask why I shouldnt be in that ring combo?

stu8975

Big ring front and big sprocket (inner) rear puts you chain at silly angles and will weaken it fairly quick, then it will snap on you, same goes for granny ring front and smallest sprocket rear (outer0. Tis fairly common knowledge unless you are a noob. sound like you chain is too short possibly. Pic of when its in that combo? or nearest combo you can get without it locking up.

bails87

I think I should point out that you're not losing anything by not using that combo.

44:32 (big front ring and big rear ring) twists the chain and gives you a ratio of 1.375

Whereas you can get pretty much the same ratio by using the middle chainring at the front (32 teeth) and a middle-ish cog on the rear (23/24 teeth, 32/23=1.39). This will give a much straighter chainline, so the chain will last longer, you won't jam up your drivetrain and you won't destroy your rear mech.

So on the big ring at the front, use the higher (smallest) 4 or 5 cogs on the rear.
On the middle, you can pretty much use any part of the cassette, but it doesn't hurt to stick to the middle 7.
On the small ring at the front, use the lower (biggest) 4 or 5 cogs on the cassette.