OnGuard RockSolid 8590 Bike Lock: 5 Best U-Locks Compared (2026)

Updated November 2026

Choosing a bike lock is less about finding the strongest option on paper and more about matching a lock’s security rating, size and weight to how and where you ride. The onguard rocksolid 8590 bike lock is a popular reference point for riders who want a hardened U-lock with a generous interior, but it is not the only option worth a look. This guide compares five U-locks from well-known brands, judged on hardened steel shackle thickness, interior dimensions, weight, mounting options and the security certifications manufacturers publish.

Our Top Picks

Quick Comparison

Product	Best for	Key feature
OnGuard RockSolid U-Lock	Best overall	14 mm hardened steel shackle with a large 90 × 175 mm interior
Sportneer Bike U-Lock with Cable	Best budget-minded commuters	17 mm shackle paired with a 5 ft steel cable
Kryptonite Evolution Mini-7 U-Lock	Best lightweight daily riding	Compact 13 mm shackle with a 4 ft cable
Kryptonite Kryptolok Standard U-Lock	Best full-size frame and wheel security	12.7 mm shackle with a 4 × 9 in interior
Kryptonite Keeper 712 Chain Lock	Best flexible multi-point locking	4 ft chain with 7 mm hardened links

OnGuard RockSolid U-Lock – 14 mm (0.55 in) Hardened Steel Bike Lock, 90 mm × 175 mm (3.55 in × 6.90 in) Interior Dimensions, Angle-Grinder-Resistant Coating, X4P Quad Lock Security

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OnGuard RockSolid U-Lock – 14 mm Hardened Steel Bike Lock

Best for: Best overall

This is the lock the article is built around. It suits riders who park in urban areas, lock to racks or poles for long periods, and want a large interior that fits a full-size frame, a rear wheel and a rack in one loop.

Key specs

• 14 mm (0.55 in) hardened steel shackle
• 90 mm × 175 mm (3.55 in × 6.90 in) interior dimensions
• Angle-grinder-resistant coating
• X4P quad-lock security design

Pros

• Large interior accommodates most frame and wheel combinations
• Thick shackle is well suited to urban parking
• Quad-lock design resists common leverage attacks

Cons

• Heavier than compact U-locks, which matters on long commutes
• Larger size can be awkward to carry in a bag or on a short frame

Bottom line: A strong choice for riders who want maximum security and a generous interior and don’t mind the extra weight.

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Sportneer Bike Lock: Heavy Duty Anti Theft Bike U Lock with 5ft Security Steel Cable – 17mm Shackle Bicycle U-Locks with 2 Keys & Mounting Bracket for Road Mountain Bike, Size 7.76''x5.02'', 1.64lb

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Sportneer Bike Lock: Heavy Duty Anti Theft Bike U Lock with 5ft Cable

Best for: Best budget-minded commuters

Riders who want a U-lock and a separate cable for wheels and accessories in one package will find this combination appealing. It is aimed at commuters and casual riders rather than high-risk urban parking.

Key specs

• 17 mm shackle
• 5 ft security steel cable
• Two keys and a mounting bracket included
• Listed weight of 1.64 lb

Pros

• Thick shackle combined with a cable for extra reach
• Includes a mounting bracket and two keys
• Good value for riders who need more than one locking point

Cons

• Owners often note that the cable is less secure than the shackle
• Build quality may not match premium certified locks

Bottom line: A sensible pick for lower-risk commuting when you want versatility without a premium price-level commitment.

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Kryptonite Evolution Mini-7 Bike U-Lock, 13mm Steel Shackle, 4 ft Cable | Sold Secure Gold Certified 13mm Hardened Steel Shackle, Double Deadbolt, FlexFrame-U Mounting Bracket and 3 Keys

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Kryptonite Evolution Mini-7 Bike U-Lock, 13mm Steel Shackle

Best for: Best lightweight daily riding

The compact shape of this lock suits riders who carry their lock on the frame or in a bag and need something that doesn’t add much bulk. It pairs a 13 mm shackle with a 4 ft cable.

Key specs

• 13 mm hardened steel shackle
• Double deadbolt design
• FlexFrame-U mounting bracket
• 4 ft cable and three keys

Pros

• Compact enough for easy carrying
• Sold Secure Gold rating is listed by the manufacturer
• Double deadbolt improves resistance to tampering

Cons

• Smaller interior limits use with thick tires or wide racks
• Cable is shorter than some riders would prefer for wheel locking

Bottom line: Best for riders with lighter bikes who want a certified lock that stays out of the way on daily trips.

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Kryptonite Kryptolok Standard Bike U-Lock, Heavy Duty 12.7mm Steel Shackle | Anti-Theft High Security Bicycle Lock with FlexFrame-U Bracket, 4 in x 9 in Interior, 2 Keys and Vinyl Coating

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Kryptonite Kryptolok Standard Bike U-Lock, Heavy Duty 12.7mm Steel Shackle

Best for: Best full-size frame and wheel security

This U-lock is a well-known standard in the Kryptonite line. It suits riders who need a lock that spans a full-size frame, a wheel and a post, and who want a vinyl-coated shackle to protect paintwork.

Key specs

• 12.7 mm hardened steel shackle
• 4 in × 9 in interior dimensions
• FlexFrame-U mounting bracket
• Vinyl coating and two keys

Pros

• Interior size fits most full-size frames
• Vinyl coating reduces scratches on the frame
• Well-established brand with broad retail availability

Cons

• Thinner shackle than the OnGuard RockSolid option
• Weight is noticeable on longer rides

Bottom line: A solid mid-range choice for riders who want a standard U-lock with a generous interior and proven brand backing.

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Kryptonite Keeper 712 Bike Chain Lock, 4ft Heavy Duty Anti-Theft Lock | Weather-resistant, 120cm long, hardened steel 7mm links, 2 keys, 5/10 security rating, for motorcycles, scooters, or gates

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Kryptonite Keeper 712 Bike Chain Lock, 4ft Heavy Duty Anti-Theft Lock

Best for: Best flexible multi-point locking

A chain lock is useful when you need to wrap around irregular objects, multiple bikes or a thick post. This model suits riders who want flexibility over the rigid geometry of a U-lock.

Key specs

• 120 cm (about 4 ft) length
• 7 mm hardened steel links
• Two keys included
• Weather-resistant finish

Pros

• Flexible enough to wrap around poles, gates and multiple wheels
• Lighter than many U-locks of similar length
• Useful as a secondary lock alongside a U-lock

Cons

• Thinner links offer less resistance to cutting than a hardened U-shackle
• Heavier than its length suggests when fully coiled

Bottom line: Best as a supplementary lock or for riders who prioritize flexibility, rather than as a sole lock in high-theft areas.

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Buying Guide

Shackle Thickness and Hardening

The shackle is the part thieves target most. Thicker hardened steel generally resists cutting longer. Manufacturers often list diameters in millimeters; a 13 mm to 14 mm shackle is a common range for urban locks, while anything thinner is usually better suited to low-risk environments.

Good picks for this: OnGuard RockSolid U-Lock, Kryptonite Evolution Mini-7 U-Lock

Interior Size and Frame Fit

Measure the space you need before buying. Loop the lock through your rear wheel, frame and the object you’re securing to. A common mistake is buying a lock that fits the frame but not the wheel, which forces you to leave the rear wheel exposed.

Good picks for this: OnGuard RockSolid U-Lock, Kryptonite Kryptolok Standard U-Lock

Weight and Portability

A heavier lock resists more force, but it also tires you out on daily commutes. If you ride more than a few miles each way, weigh the added security against how often the lock will sit in your bag or on your frame.

Good picks for this: Kryptonite Evolution Mini-7 U-Lock, Sportneer Bike U-Lock with Cable

Use Case and Locking Points

Decide what you need to secure. A U-lock alone locks the frame and one wheel to a fixed object. Adding a cable or chain lets you secure a second wheel or accessories. Many riders combine a U-lock with a flexible cable or chain for this reason.

Good picks for this: Sportneer Bike U-Lock with Cable, Kryptonite Keeper 712 Bike Chain Lock

Mounting Options

Mounting brackets determine how easily you can carry the lock while riding. Several products in this list include a bracket designed to attach to the frame. Check that the bracket fits your frame tubes before purchase, since diameters vary between bike types.

Good picks for this: Kryptonite Kryptolok Standard U-Lock, Sportneer Bike U-Lock with Cable

Durability and Weather Resistance

Outdoor locks face rain, road salt and temperature swings. Look for coatings, sealed keyways and corrosion-resistant finishes. Owners often report that vinyl coatings protect paint but wear over time, so inspect the lock periodically.

Good picks for this: Kryptonite Keeper 712 Bike Chain Lock, OnGuard RockSolid U-Lock

Care and Key Management

Keep spare keys in a safe place separate from the lock, and lubricate the keyway occasionally with a dry lubricant recommended by the manufacturer. Avoid oil-based products that attract grit. Replacement keys for many locks are available, but ordering them usually requires proof of ownership.

Good picks for this: Kryptonite Evolution Mini-7 U-Lock, Kryptonite Kryptolok Standard U-Lock

FAQ

Is the OnGuard RockSolid 8590 a good bike lock?

It is a widely recognized hardened U-lock with a large interior and a thick shackle, which is why it is often used as a reference point. Whether it fits your needs depends on your frame, wheel size and how and where you park.

What shackle thickness should I look for?

For urban parking, many riders aim for a shackle in the 13 mm to 14 mm range. Lower-risk areas may accept thinner shackles, while high-theft cities generally call for thicker, hardened steel.

Do I need a U-lock and a cable together?

Not always, but a combination is useful when you need to secure a second wheel or accessories. The U-lock protects the frame and main wheel, and the cable covers the rest.

How do I know if a lock fits my bike?

Measure the space you need to loop through the frame, rear wheel and locking point. Compare those measurements with the interior dimensions listed by the manufacturer, and allow a little extra room for thicker tires.

Can I mount a bike lock to my frame?

Many U-locks include a bracket that attaches to the frame with bolts or straps. Confirm the bracket fits your tube diameter and that the lock sits securely while riding.

How should I care for my bike lock?

Store the lock in a dry place, lubricate the keyway with a manufacturer-recommended dry lubricant, and inspect the shackle and coating for damage. Replace worn keys promptly.

Are chain locks as secure as U-locks?

A chain lock offers flexibility, but thinner links can be easier to cut than a hardened U-shackle. Many riders use a chain as a secondary lock rather than the only one.

Conclusion

The OnGuard RockSolid 8590-style hardened U-lock is a strong starting point for riders who want thick steel and a generous interior. The OnGuard RockSolid U-Lock is the best overall pick in this list for urban parking. The Sportneer combination suits commuters who want a cable for extra reach, while the Kryptonite Evolution Mini-7 fits riders who prioritize a compact, lightweight lock. The Kryptonite Kryptolok Standard works well for full-size frames, and the Kryptonite Keeper 712 chain is best used as a flexible companion lock. Match the lock to your parking environment, your frame and wheel dimensions, and how far you ride each day.

Sources

• Consumer product safety information and recall notices that can affect cycling equipment (cpsc.gov)
• Road safety guidance for cyclists sharing roadways with motor vehicles (nhtsa.gov)
• Standards resources and materials-testing background relevant to hardened steel products (nist.gov)

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