>>23316944I personally run a bulkier set (mostly HP, some defense investment and the rest in special attack/speed) but running it timid or modest with max speed investment, as you've done, is also an option.
You may not want to fully invest in speed as you may not have to. As for the speed you'll want, check out the following:
http://nuggetbridge.com/articles/vgc-14-pokemon-speed-tiers/These are based on mons at level 50 but max speed modest garde has 167 speed, while modest has 152 at this level; these numbers should translate (more or less...) to also outspeeding at level 100, so once you're happy with what it beats you can maybe take a little out of speed and dump it in HP.
Probably most notably, running timid allows garde to outspeed neutral gengar, mienshao and manetric and positive speed hydreigon.and mega garchomp.
Also, there's a reason they've advised investing 248 in HP rather than - stealth rock; stick the last 4 in defense or special defense.