They will pilot 150 horsepower machines between houses and hedges at speeds of up to 190mph. It is thrilling and dangerous.
This year the injury roll call began early, with a trio of top Irish contenders likely to be absent when practice gets underway. Joey Dunlop, 22 times a TT winner, broke his left hand and collarbone, cracked his pelvis and lost a finger crashing out of the Tandragee 100 races in May.
Two weeks later his younger brother, Robert, broke his fibula at the North-West 200 road races. Meanwhile, on 4 May, 11 times TT winner and hot favourite Phil McCallen damaged three vertebrae in a crash at Thruxton, Hants.
All three await last-minute medical tests, with Robert Dunlop probably the most likely to be passed fit.
If we can not be quite sure who will be riding, it is easier to predict which machinery will win. This year marks Honda's 50th anniversary. The Japanese giant has chosen the Isle of Man, where it first made its mark on world racing in 1959, as the focus of its celebrations. The party includes a glittering parade of past Honda stars, many on classic factory racing machinery. Amongst the riders are Jim Redman, Freddie Spencer, Luigi Taveri, Steve Hislop and Mick Grant.
To ensure that race results do not impair their party, Honda has recruited almost every racer of note in the major classes. The loss of McCallen and Joey Dunlop is less of a blow with former TT winners Ian Simpson and Jim Moodie ready to take up the baton for honours in the blue riband Formula 1 and Senior races. The Scots ride a RC45 V-four and NSR500 two-stroke respectively, and will surely challenge for honours. Simpson will also be hot favourite in the 600cc Junior race.
Less a TT veteran, but widely tipped for his first win is Michael Rutter, son of former TT ace Tony. The 24 year-old has served his TT apprenticeship well. In last year's Senior he led McCallen, the man to beat, before sliding off. Rutter also rides a Honda RC45.
Simon Beck and Marc Flynn are two of the rare contenders not to be riding Hondas this year. Beck has lapped the island at close to 123mph, and rides Kawasakis in both the Formula 1, Senior and Production races. Flynn flies Suzuki colours.
Honda dominance - last year they took 44 of 60 top 10 places in the major solo events - could be most at risk in the Production event.
Reintroduced in 1996, the race is the world's showcase for sports roadsters. So far, Honda's Fireblade has had things all its own way.Reuse content