I have been looking at my bike and have decided that it would look better with some new brake mechs. The existing Raleigh ones are like the old Weinmans. I like the look of something like
this. Can someone explain where the measurements are taken. Is it vertically from the fixing bolt down to level with the shoes?
Thanks.
Yes, down the centre axis. Those are short reach calipers so are designed for bikes without mudguard clearance. Shimano BR R-450 are equilavant long reach calipers.
Be aware that these calipers are designed for forks and rear bridges that use a recessed allen nut to affix them. Older bikes use a threaded nut fixing that needs a longer bolt. You can still buy modern dual pivot brakes with the old style fixing. I believe Tektro make some.
You can also get the recessed nut type ones to work on old bikes. On the rear, a modern front brake will have a long enough bolt to fit through the old style rear bridge with enough thread exposed to fit a saddle washer and nut. On the front, the fork bolt hole can be drilled out (6mm to 8mm) so that a suitably long recessed nut (bought separately) can be fitted. The rear bridge can also be drilled out to use a recessed nut, but it's a bit harder because the seat tube is in the way.
If in doubt seek advice from your LBS.
