TRANSMISSION

Without doubt the 1.0 Fiesta’s Achilles’ heel, its gearbox is an IB5 five-speed manual, pulled from Fiestas of old. Although the change feels sharper than a Mk5 Fiesta, the ‘box suffers from the same failings.

Driven sensibly it’s okay, but hard launches and slamming through the cogs will kill the synchromesh rings.

Take a test drive, and listen for grinding on the upchange from first to second gear. Try it at low speed, then put it under load and attempt a fast change to see if it catches. There’s no synchromesh on reverse, so don’t be surprised if it’s awkward to engage.

Power isn’t the problem, but modified engines produce loads of torque – be wary of a poor remap that’s completely removed torque limiters in first and second gears, and abuse it at your peril.

Fortunately, parts are available to rebuild the gearbox, and IB5s are cheap and plentiful second-hand. If your Fiesta is a 100 or 125PS, try to find a 140PS gearbox, which has a much shorter final drive ratio (4.06:1 compared with 3.61:1) and, according to AET Motorsport, makes such a huge difference that it’s one of the first modifications any owner should make. Obviously, buying a 140 in the first place is the best option.

On the plus side, the 1.0’s clutch copes well with hard driving and extra grunt – Collins has yet to replace one – and nobody seems to be braking differentials or driveshafts. Even so, plenty of 1.0 Fiestas are used by driving schools, so check there’s no clutch slip before buying.