Best
Best Long Shackle Bike U-Locks for Adult Tricycles
A U-lock is the strongest shape, but a trike's width means shackle size is the number to check.
Updated · 3 min read · 5 products evaluated
A U-lock has a rigid steel shackle and a locking crossbar, and a thick shackle resists cutting better than most chains. The trouble on a trike is space. The shackle must go around a frame member and a post, and a trike has a wide rear axle and a long frame, so a standard 4 by 7 inch loop is often too tight.
The five locks here either have a taller shackle, a wider interior or a cable that extends the reach. We sorted them by interior size, shackle thickness and what they include, and we flagged where the shackle will be too small for a trike.
Short answer
The Kryptonite Keeper is the best pick for a long shackle with 4 by 10 inch interior and a 12mm shackle. The Master Lock 8385D adds a 4 foot cable and a 0.75 inch shackle. The Master Lock 8170D has an 8 inch shackle, the Sportneer set adds a 5 foot cable, and the Kryptonite Parkview Combo is the keyless choice.
Quick Picks
Our 5 recommendations at a glance. Tap a pick for the full verdict.
Best With Cable
Master Lock 8385D U-Lock with 4 ft Cable
Wheel and frame together
Our Picks
Best Overall1 of 5
Kryptonite Keeper U-Lock
A 4 by 10 inch interior is the roomiest rigid loop here.
Best for
Looping a trike axle and a post
Why we like it
The Keeper has a 12mm hardened steel shackle, interior locking dimensions of 4 by 10 inches and weighs 2.25 pounds. It has a durable vinyl coating around the shackle to prevent scratches, comes with two keys and includes a bracket for carrying on the bike.
Compared with the Master Lock 8170D, it has a longer interior and a slightly thinner shackle, and compared with the cable sets it is simpler. The extra 10 inch length is what a trike needs, though it still will not loop a long cargo frame. Check the loop around your rear axle first.
Key specs
| Size | 4 x 10 inch interior, 12mm shackle |
|---|---|
| Weight | 2.25 lbs |
| Fit and mounting | Transport bracket included |
| Features | Vinyl coated shackle, two keys |
Specs can change between model years; confirm the exact version before buying.
Strengths
- Roomy 4 x 10 inch loop
- 12mm hardened shackle
- Vinyl coat protects paint
- Bracket included
Limitations
- No cable for extra reach
- Heavier than short U-locks
Consider it if
- Wide rear axles
- Rigid locking at a post
Skip it if
- Long cargo trike frames
Best With Cable2 of 5
Master Lock 8385D U-Lock with 4 ft Cable
A thicker shackle plus a 4 foot looped cable for reach.
Best for
Wheel and frame together
Why we like it
This set has a hardened steel U-lock body with a double locking shackle, an 8 inch shackle length, 4 inch width and 0.75 inch diameter, plus a 4 foot looped end cable and carrier bracket. It includes two keys and is described for bicycles, e-bikes and motorcycles.
Next to the Sportneer cable set, it has a thicker shackle and the Master Lock name, and next to the Keeper it adds a cable for reach but a smaller interior width. Use the cable through the wheel and the U-lock on the frame. The cable is the weak part, so do not rely on it alone.
Key specs
| Size | 8 in shackle length, 4 in width, 0.75 in diameter |
|---|---|
| Features | Double locking shackle, 4 ft looped cable, carrier bracket |
Specs can change between model years; confirm the exact version before buying.
Strengths
- 0.75 inch thick shackle
- 4 foot cable adds reach
- Double locking shackle
- Two keys and bracket
Limitations
- Cable is easier to cut
- 4 inch width is narrow for a trike
Consider it if
- Locking wheel and frame together
- Riders who want a cable
Skip it if
- Wide rear axles without the cable
Best Simple U-Lock3 of 5
Master Lock 8170D U-Lock 8 inch Shackle
A plain hardened steel U-lock with an 8 inch shackle.
Best for
Single point locking
Why we like it
The 8170D is a hardened steel U-lock with a double locking shackle, a 6 1/8 inch wide body, 8 inch shackle length, 4 inch width and 13mm diameter. It comes with two keys and a carrier bracket.
Compared with the Keeper, it is shorter in interior and uses a thicker shackle. Compared with the 8385D, it has no cable. It is a simple pick for a trike that parks close to a post. Measure the rear axle first.
Key specs
| Size | 8 in shackle, 4 in width, 13mm diameter |
|---|---|
| Features | Double locking shackle, carrier bracket, two keys |
Specs can change between model years; confirm the exact version before buying.
Strengths
- 13mm shackle
- Double locking shackle
- Carrier bracket included
- Two keys provided
Limitations
- No cable included
- Narrow for wide axles
Consider it if
- Short, simple locking
- Home parking
Skip it if
- Wide trikes far from a post
Best Long Cable Add On4 of 5
Sportneer U-Lock with 5 ft Cable
A 5 foot steel cable gives the longest extra reach in this group.
Best for
Reaching a distant post
Why we like it
The Sportneer set measures 7.76 by 5.02 inches and comes with a 5 foot steel cable and a bracket. The lock uses a zinc alloy core and alloy steel head, and the maker includes spare keys. You can use the U-lock alone or with the cable.
Compared with the Master Lock 8385D, it has a longer cable but a thinner shackle. The 5 inch interior width is better than the Master Lock's 4 inches. It is useful for tying a trike to a far post, but keep expectations modest on cut resistance.
Key specs
| Size | 7.76 x 5.02 inch lock |
|---|---|
| Features | 5 ft steel cable, bracket, spare key |
Specs can change between model years; confirm the exact version before buying.
Strengths
- 5 foot cable for reach
- 5.02 inch interior width
- Bracket included
- Spare keys included
Limitations
- Cable is the weak link
- Thinner shackle than Master Lock
Consider it if
- Distant posts
- Wheel and frame locking
Skip it if
- High theft areas on its own
Best Keyless Pick5 of 5
Kryptonite Parkview Combo U-Lock
A 12mm shackle that opens with a 4 digit code.
Best for
Riders who lose keys
Why we like it
The Parkview Combo has a 12mm hardened steel shackle and a four digit combination you can register online, so customer service can help if you forget it. It has a standard U-lock size and comes with a lifetime warranty.
Next to the Keeper it has no key to lose but a smaller, standard size, so it is the shortest reach here. It suits older riders who prefer a number to a key, if the loop is wide enough for the trike. Measure before buying.
Key specs
| Size | Standard size U-lock, 12mm shackle |
|---|---|
| Features | 4 digit combination, lifetime warranty |
Specs can change between model years; confirm the exact version before buying.
Strengths
- No key to lose
- 12mm hardened shackle
- Registered combination recovery
- Lifetime warranty
Limitations
- Standard, smaller loop
- Code can be forgotten
Consider it if
- Riders who lose keys
- Short, close parking
Skip it if
- Wide trike axles
Spec Comparison
Key figures side by side. A dash means the brand gives no figure, so ask before you buy if it matters to you.
| Model | Size | Features | Link |
|---|---|---|---|
| Kryptonite Keeper U-Lock Best Overall | 4 x 10 inch interior, 12mm shackle | Vinyl coated shackle, two keys | Check price |
| Master Lock 8385D U-Lock with 4 ft Cable Best With Cable | 8 in shackle length, 4 in width, 0.75 in diameter | Double locking shackle, 4 ft looped cable, carrier bracket | Check price |
| Master Lock 8170D U-Lock 8 inch Shackle Best Simple U-Lock | 8 in shackle, 4 in width, 13mm diameter | Double locking shackle, carrier bracket, two keys | Check price |
| Sportneer U-Lock with 5 ft Cable Best Long Cable Add On | 7.76 x 5.02 inch lock | 5 ft steel cable, bracket, spare key | Check price |
| Kryptonite Parkview Combo U-Lock Best Keyless Pick | Standard size U-lock, 12mm shackle | 4 digit combination, lifetime warranty | Check price |
How We Chose These Long-Shackle U-Locks
- Interior size
- We ranked shackle size first because a trike's width needs a larger loop.
- Shackle thickness
- Thicker hardened shackles resist cutting and prying.
- Added reach
- Cable sets were credited for reach but marked down for cut resistance.
- Opening method
- Key and code locks were weighed for riders with limited dexterity.
What to Look for in a Long-Shackle U-Lock
Interior dimensions
Interior size is the free loop between shackle and crossbar, and it limits what you can lock.
Check width and height in inches. On a trike, 10 inches of height helps more than extra thickness.
Shackle diameter
A thick shackle resists bolt cutters. 12mm and 13mm are common, and 0.75 inch is thicker.
Read the diameter in the product bullets, not just a phrase like heavy duty.
Cable or none
A cable adds reach, but it is the easiest part to cut.
Use a cable through a wheel only as a second layer, with the U-lock on the frame.
Key or combination
A combination avoids lost keys, but codes can be forgotten.
Register the code if offered, and write it down somewhere safe.
How to Choose
By Reach Needed
| Situation | Our pick | Why |
|---|---|---|
| Wide rear axle and a post | Kryptonite Keeper U-Lock | 4 x 10 inch interior |
| Frame and wheel together | Master Lock 8385D U-Lock with 4 ft Cable | Thick shackle plus cable |
| Distant post | Sportneer U-Lock with 5 ft Cable | Five feet of cable |
| Close parking, simple lock | Master Lock 8170D U-Lock 8 inch Shackle | 13mm shackle |
Key vs Combination
- Key
- The Keeper, both Master Locks and the Sportneer use keys. Keep a spare at home.
- Combination
- The Kryptonite Parkview Combo opens with a four digit code, so there is no key to lose.
Older riders who lose keys should default to the Parkview Combo if the loop fits.
For Wide Three Wheel Frames Specifically
- Look for
- At least a 4 by 10 inch interior or a cable to extend reach.
- In this comparison
- The Kryptonite Keeper has the roomiest loop, and the Sportneer set adds a 5 foot cable.
When to Spend More
- Spend more if
- You park outside regularly. The Master Lock 8385D's thicker shackle is worth it.
- Save if
- You park at home. The Master Lock 8170D is enough.
Frequently Asked Questions
Will a U-lock fit around a trike?
Only a roomy one will. The Keeper has a 4 by 10 inch interior, which loops a rear axle and a post on many trikes.
Is a cable worth adding?
For reach, yes. Treat it as a second layer, not your main lock.
What is a good shackle thickness?
12mm or more is common. 0.75 inch is thicker still.
Should I choose a chain instead?
A chain reaches farther. See /accessories/best-long-bike-chain-locks-for-tricycles/ for chains.
How do I lock a trike best?
Lock the frame to a fixed post. Read /adult-tricycle-locking-and-theft-prevention/ and consider /accessories/best-chain-locks-for-adult-tricycles/.
Bottom Line
The Kryptonite Keeper is the best long shackle pick for trikes, with a 4 by 10 inch interior. The Master Lock 8385D adds a cable, and the Parkview Combo suits riders who lose keys. Always measure your rear axle and post first.