Shimano Sora vs higher range brake pull ratio

Question

I've just upgraded my commuter bike (old Trek 370) to the replaced components from my main road bike (originally 2009 specialized allez - new head and handle) and found the brake calipers aren't long enough (similar to this). They are unbranded calipers anyway so I'm looking to upgrade them.

Looking at these long reach calipers I've found they state

Must be used in conjunction with ST-4600, ST-4603, ST-5700, ST-5703, - ST-6700 or ST-7900 STIs for correct leverage ratio

As far as I can see these are Tiagra and above. I'm not sure which the Allez's shifters were (ST-3500?). What difference is there in lever ratio? I thought all shimano shifters were compatible and can't find any more details about compatibility.

Which calipers can I look at to work with my shifters?

Answer 1

The cable pull ratio was changed for the listed models, whereas previous generations were compatible with a wide range of Shimano and non-Shimano brake components.

Use Shimano's Specifications site to compare the compatibility of your levers and brake calipers. http://productinfo.shimano.com/specifications.html

Answer 2

See the comments on this question. On an old compatibility chart, Shimano says they will play nice with old brake levers, but on newer ones they say they the braking force may be much too high on their data sheets.

However, other companies make decent long reach calipers as well, such as the Tektro R556/R559 (maybe these are extra long reach by some people standards, and R539 may be long enough).