Originally Posted by
sanchoysanchez
I want to replace an old (don't know the exact year) RST tr pro i sl 7 with a rigid fork. Now my concerns:
1.- Anyone happens to know the exact geometry of that RST fork? I wrote to RST customer service to no avail.
2.- The AtC is 47cm. Assuming a 10% sag, the new fork should be around 42cm long, shouldn't it?
3.- What about the rake? How can I measure it? Maybe with a plumb?
Sag is measured as a percentage of fork travel, not overall length. So if it's a 100 mm travel fork 10% sag is 10 mm (that's low - sag is normally 20-30% - just use a zip tie to measure yours).
I couldn't find that specific fork model, but it seems to be a trekking fork so 700C wheel and maybe 50 mm of travel. Any 700C rigid fork, with the appropriate brake attachment and steerer type, that's around the same axle-to-crown should be fine. I've replaced a few suspension forks with rigid on my bikes, without paying much attention to geometry beyond a similar a-to-c, and nothing bad has happened.