>>36377242Modest Jolteon speed ties with base 114 +Spe mons, Modest compesates the lack of Life Orb and some OHKO over speed, usually those defensive mons are in fact its switch ins knowing Jolteon is usually a revenge killer or momentum spammer. Might try Timid but I personally found Modest be better in this case, since it doesn't run Specs or LO.
252 Spe Jolteon reaches 359 speed
252+Spe Jolteon reaches 395 speed
You might invest just enough on Jolteon to be faster than specific threats and even have left some HP EVs for "balk" (mostly on special side or extra chance to live Bullet Punch) like the Flame Orb Quick Feet Jolteon did in Gen 5 (enough Spe EVs to be faster than weather abusers and Dragon Dancers, but back then Hidden Power had max 70BP)
https://www.smogon.com/forums/threads/usum-uu-speedlist.3591824/https://www.smogon.com/forums/threads/sm-ou-speed-tiers.3587531/https://www.smogon.com/forums/threads/usum-speed-tiers.3624759/ (RU)
Timid looks more relevant in RU for this specific set.
To each his own, 115+ will be a problem but let's see, Aerodactyl is mostly Sash or goes Mega and you risk speed ties, Espeon is easy to wall nowadays so not a problem, just switch, Weavile if weakened and in Thunderbolt kill range will most likely switch out or opt for Ice Shard expecting an obvious Timid Jolteon (maybe not in low ladder where everyone is just reckless or unaware or doesn't really care about competitive), same goes for weakened Gengar and Tordanus in general that when +Spe outspeed Modest Jolteon, M-Absol has Sucker Punch anyway and M-Houndoom enough bulk, Starmie is most likely forced to switch out too.
Once again RU has enough fast but frail Pokemon that force you to run Timid over Modest, where it has enough Speed and power to remove or revenge kill them without extra offensive investment.