What is a welded differential?
If you’re a fan of the drift scene, or maybe you’ve just seen one too many Fast and Furious movies, kicking up some smoke and having your car’s rear end hang out at every corner might just be on the agenda.
One of the core methods of achieving this is a welded differential.
What does a welded diff do?
Before answering that question, we may need to answer another: what does a differential do?
Put simply, the differential on a car is a device that allows the torque to be split two ways across an axle, meaning the two wheels can spin at different speeds.
In the example of a normal differential, when a car turns, the inside wheel requires less rotation than that of the outside wheel. This is because the outside of a turn has a longer distance to cover than that of the inside, and so more rotations are needed to push the car round.
When it comes to a welded diff, this process is stopped, and instead forces both wheels to rotate at the same speed.
What this results in is the inner wheel now spinning at the same rate as the outside wheel. However, while the outside wheel continues to push into the road surface, the inner wheel starts to skip across tarmac and lose traction, helping accomplish oversteer much easier.
As you can imagine, a welded differential attracts those looking to turn their car into a bit of a drift machine, especially as diff welding is among the cheapest options when hoping to achieve just that.
Welded diff: pros & cons
If you’re looking to get into drifting, and you’re on a budget, welding the differential is one of the most cost-effective ways of doing that, giving you immediate results on the track – once you know what you’re doing, that is.
While a limited-slip differential can also go some way towards helping you lose traction, a welded diff should allow you to accomplish this much easier.
As reducing traction at the rear is the only real goal of differential welding, the pros to performing such a modification stop here.
If you’re serious about welding your differential, it’s important to know about just how this will impact your car in other ways.
First and foremost, it’s very easy to make a mess of your car if you don’t know what you’re doing. Before even attempting to weld your diff, ensure a thorough inspection of your car is done, especially in regards to the drivetrain altogether.
A welded differential will put plenty of stress onto the components it’s linked to, including the axle, clutch, and even wheel bearings. You will need to be confident that welding the diff will not cause such parts to fail.
If you’re not up for the job of welding your differential yourself, then get a professional to manage the change instead, otherwise you may find the rear end of your car spitting metal pieces all over the road.
Meanwhile, for those planning on welding the differential of their daily driver, be warned that this will cause drivability issues.
Slow, tight corners will become incredibly tough to handle, while parking will likely become much more of a chore, too.
Is a welded diff illegal?
It is not illegal to have a welded differential, but you may run into trouble when looking to insure your car, or perhaps renew your vehicle’s MOT in the UK.