Boardman + Ultegra 6700 + 12-30 = trouble!

tarrattarrat

First post, so please go easy on me!

I am about to undertake a ride from Paris - Marseille and fitted a large range cassette (12-30) to make it easier on the hills. So far, so good... until I tried to change gears and I heard various metallic noises that suggested all was not well...

The pics in the attached link show that on both 53 (front) / 30 (rear) the chain looks ok but when shifting even to the 39 (f) / 30 (r) the chain and rear derailleur are too close to the cassette. I have tightened the 'b' screw on the rear derailleur as far as it will go, but the rear derailleur and chain seems still to be too close to the cassette.

https://www.flickr.com/photos/123516908@N07/sets/72157644212155809/

I would appreciate some advice as to whether I need a new long arm derailleur, tighten the chain, or some other adjustment, or whether I should never have gone as far as a 12-30 (previously I had a 11-25)

Thanks in advance

Stu

47p2

That chain looks way too long, how did you measure it for length?

tarrattarrat

Thanks 47p2 - the embarrassing answer is that I didn't measure it.

I am rather useless at bike maintenance (understatement of the year!) and seem to remember that in a review of the cassette someone mentioned that the standard length ultegra chain would be fine.

Is there a rule of thumb that I could use?

dj58

The chain is to long, use this as a guide
http://techdocs.shimano.com/media/techd ... 702204.PDF

Also read this viewtopic.php?f=40004&t=12968514

DiscoBoy

Be sure to post back if you do get it to work: because your dérailleur is supposed to take a max sprocket of 28T.

antsmithmk

On 39-30 your RD should be at a 45 degree angle TOWARDS the chain rings. Needs at least 4-5 links taking out.

tarrattarrat

Thanks DJ58 - chain was way too long, have shortened it using the Shimano guide but looks like a the 30T is too big for the derailleur (which I presume is the SS version, although it doesn't have any markings)

Do you think that that GS version of the rear derailleur would work?

dj58

The GS version will take a 32T sprocket IIRC, however if you are sure that you do not have the RD-6700-A SS version which will take a 30T sprocket (30T stamped at the top of the outer pulley cage), Then you can either try and get hold of one or buy the RD-6700 GS version.

I have read on another post here that a bike shop mechanic used a longer B Tension screw on a customers bike to achieve clearance for a larger sprocket than was quoted for his particular RD. I'm trying to locate that post for you.

Here it is viewtopic.php?f=40004&t=12952412

You could try this, though some may say it is a bodge, the standard B-Tension Adjusting Screw is (M4 x 13.5mm)

tarrattarrat

Think I'll try the GS as I'd hate to have problems halfway to Marseille!

Thanks again - really appreciate your help

Stu

ba68

I think there is a later variant of the short cage 6700 rear mech that Shimano say will take a 30t, however I have the earlier model and I have it running a 30t. I had to adjust the b screw but I have about 5 mm of clearance. I would say you chain is too long. If I recall the method I used to determine the chain length was to remove the chain, run it round the 30t and the big chain ring but miss out the rear mech, bring the chain together then add two links. I had exactly the problem you describe until I did this.