Most Secure Bike Locks Tested: 8 Locks Ranked by Attack Time

Introduction

Bike locks are a delay tactic, and the only measure that really matters is how long a determined thief needs to get through one. The gap between a cheap wearable and a hardened, grinder-resistant lock is far wider than most product listings suggest.

Eight locks were put through timed angle-grinder attacks on a locked bike, with a 10-minute ceiling on each attempt. The results ranged from 54 seconds to a full attack window that could not be completed. The locks below run from the quickest to defeat to the toughest, with the security ratings and prices that sit alongside each one.

How These Bike Locks Were Tested

Every lock was attacked the same way: fitted to a bike, then cut with an angle grinder while a timer ran. Each attempt was capped at 10 minutes, and the clock stopped when the lock released. Where a lock has two locking points, both have to be cut before the bike is free, which shapes the timings below.

The group covers Sold Secure ratings from Silver through Gold to Diamond. Those ratings are a useful starting point, but the timings show that a rating alone does not predict how a lock behaves against a grinder. Prices range from around $40 to £300, and the most expensive lock is not automatically the best value.

Squire Straplock 35

The Squire Straplock 35 is a wearable lock with an RRP of $69.99 and a Sold Secure Silver rating. It is built from multiple high-tensile steel cores and is designed to sit comfortably on the body and stay friendly to the bike frame, so it travels with the rider rather than in a bag.

It was also the quickest lock to fall, releasing after 55 seconds. As a wearable for short stops in low-risk spots it still has a place, but it represents the lightest level of security in this group.

Squire Stronghold FL 850

This is a folding lock with a Sold Secure Gold rating, and the first folding design in the group. Folding locks are popular because they stow neatly, but the FL 850 revealed two weaknesses immediately. The plastic outer coating meant to protect the frame came away almost at once, and the lock released after 54 seconds.

It is also heavy and bulky to carry, which works against the convenience that usually justifies the folding format.

OnGuard Pitbull

The OnGuard Pitbull has an RRP of $39.99 and is often available online for far less, around £25. The brand markets it towards moped riders, and it carries a Sold Secure Diamond rating, which is unusual at this price.

It held out for 3 minutes and 2 seconds. That is not the longest result here, but as a combination of rating and price it is strong value for anyone who wants Diamond-level certification without a large outlay.

Kryptonite Evolution Mini

The Kryptonite Evolution Mini sells for around $85, carries a Sold Secure Gold rating, and comes with a cable for securing a second wheel or an accessory. It is one of the most commonly bought locks in this category, and the timed attack helps explain why: it lasted 4 minutes and 4 seconds.

The design detail that matters is that both arms of the shackle lock into the body. Cutting through one arm does not free the bike, so an attacker has to repeat the entire process on the second arm before the lock comes off.

Against a grinder it remains a mid-weight lock rather than a hardened one, but for everyday urban locking it buys a useful amount of time.

Squire Chain Lock 10

The Squire Chain Lock 10 costs about £90 and carries a Sold Secure Diamond rating. It uses a 10 mm hardened square alloy steel chain and is built to be worn, which makes a serious chain easier to live with day to day.

It lasted 4 minutes and 12 seconds, the best result among the lighter locks here and a clear step above the wearables that failed in under a minute.

Squire IC 850

The Squire IC 850 is a much heavier chain, again Sold Secure Diamond. Its bulk is the whole point: there is simply more steel between the thief and the bike.

That showed in the timing. The lock held out for 6 minutes and 25 seconds, placing it between the mid-weight locks and the two grinder-resistant models at the top of this list.

Squire Stronghold D16 Max

The Squire Stronghold D16 Max is sold as an anti-angle-grinder lock at £130 with a Sold Secure Diamond rating, and it is the value story of this group. The rubbery outer coating cuts away quickly, but the steel bar underneath barely scratched, and the attack ran past the full 10-minute limit without freeing the bike.

Two practical points stand out. The lock is unbelievably loud under attack, loud enough that anyone nearby will notice at once, which is a genuine deterrent in a public place. It is also a brute to carry, so a commuter who always parks in the same spot may prefer to leave it there rather than ride with it every day.

At £130 it costs less than half the price of the other grinder-resistant lock in this group, and it produced the same outcome against the clock.

Hiplok DX1000

The Hiplok DX1000 is the most expensive lock here at £300. It carries a Sold Secure Diamond rating, a lifetime warranty, and a design aimed mainly at motorbikes and e-bikes. A package that adds a mounting arm for fixing the lock to a garage floor is priced at £600.

It also delivered the strongest performance in the group. The attack ran past the 10-minute limit with the blade turning blue and a fresh battery falling to a single bar of charge, and the grinder had cut only about 4 mm into one side while the other side was nearly through. Because both sides have to be cut before the lock releases, a committed attacker would be looking at roughly 20 minutes of work.

That is the trade-off: the DX1000 is the toughest lock tested and the most expensive by a wide margin.

Buying Advice: Matching the Lock to Your Routine

The timings split into three practical tiers. Under a minute, the Squire Straplock 35 and the Squire Stronghold FL 850 are locks for quick stops where the bike is never far from view. Between three and just over six minutes sit the OnGuard Pitbull, the Kryptonite Evolution Mini, the Squire Chain Lock 10 and the Squire IC 850, which is where most everyday commuting money is best spent.

Above that, the Squire Stronghold D16 Max and the Hiplok DX1000 both survived the full 10-minute window, and the noise they make during an attack is a deterrent in itself. If the bike is parked on a street for hours at a time, this tier is where the budget belongs, and the D16 Max delivers it for well under half the price of the DX1000.

Carrying weight is the other half of the decision. The D16 Max is heavy enough that many riders would rather leave it at a regular parking spot than carry it daily, while the mid-weight locks are far easier to live with. It is also worth remembering that no lock helps if the rack or fence it is attached to can be cut more easily than the lock itself.

Conclusion

The clearest lesson from these attacks is that grinder-resistant locks earn their premium. The Hiplok DX1000 was the strongest performer overall, with the least material removed after the full attack window, though at £300 it costs more than double the Squire Stronghold D16 Max, which survived the same 10 minutes and makes far more noise while it does so.

For most riders, the D16 Max is the smarter purchase at the top end, the Kryptonite Evolution Mini and the Squire IC 850 cover the middle ground, and wearable locks remain a short-stop tool rather than real protection.