Shimano STI brake cable pull

[neilob]

When I upgraded my frame last year to a disc version I fitted a Giant Conduct cable to hydraulic converter so I could retain my Dura Ace 7800 triple shifters yet still get powerful disc braking. I am not sure that I am getting the benefit and wonder if the brake pull on these relatively elderly levers is compatible with the converter. Has the amount of cable pulled by STI levers changed in the intervening years or is it just likely that adjustment and bleeding needs better skills than I possess?

[mattsccm]

I will say that the cable pull is wrong. The Giant system came in, I think, after Shimano changed their cable pull. Had the reverse issue fitting slightly too old Durace brakes to near new shifters.

[Brucey]

…. I am not sure that I am getting the benefit and wonder if the brake pull on these relatively elderly (7800) levers is compatible with the converter. Has the amount of cable pulled by STI levers changed in the intervening years or is it just likely that adjustment and bleeding needs better skills than I possess?

since 2008 new shimano STI models (with just one exception) have 'New Super SLR' (NSSLR) cable pull which is longer than the cable pull in older shimano brake levers. 7800 predates this change.

The normal effect of this is that with older levers used with a later caliper/brake system the brake is shaping up to be powerful but the lever comes back to the bar too soon. Any deficit in bleeding a part-hydraulic system will exacerbate this.

So it could be either; if you use a NSSLR lever and the brakes are still rubbish it is probably the bleeding that is at fault.

cheers

[TheBomber]

I guess these aren’t the replies you wanted to hear. On the flip side it does mean that you have STI levers that will work well with Avid BB7 (road) cable discs. BB7s have many fans but they only work well with the older STI levers. They would also save you from the setup issues of hydraulics if you’ve been finding that difficult. If you don’t fancy cable discs and end up replacing the STIs then there is probably a ready second hand market for your old levers from those who have BB7 or other older design callipers.