The catch
Thule Force 3 L Sport
Long equipment runs into the 175 cm ski limit.
Side by side
Thule Force 3 L Sport vs Yakima SkyBox NX 18 compared: Sport keeps neighboring rack space free, and SkyBox takes longer skis and more bags
Quick verdict
If keeping room beside the box matters more to you than maximum luggage volume, the Force 3 L Sport is the one. The SkyBox NX 18 is the one for longer skis or larger family bag loads that will fill its wider shell. Before deciding that both accessories can travel together, put every bike carrier and crossbar into the roof-load calculation.
Before you buy
Why, and what it costs you
A narrow box may simplify planning a mixed load
Subtract the box width from a 50-inch usable bar span and you get 25.3 inches left with the Sport and 14 inches with the NX 18. That gives the Sport 11.3 inches more nominal side space, before clamps and rack feet are taken into account.
Where this comes from
50 - 24.7 = 25.3. 50 - 36 = 14. None of this guarantees that a bicycle carrier will mount or clear the lid.
The catch
Yakima SkyBox NX XL
Planning side-by-side on the rack is harder with a 36-inch width.
Thule Force 3 L Sport
- Why pick it
- A narrow shell is what you need, and your skis fit within 175 cm.
- A 34 lb box suits your weight-sensitive rack setup.
- The catch
- Long equipment runs into the 175 cm ski limit.
Yakima SkyBox NX XL
- Why pick it
- Your skis run up to 195 cm.
- A full-width roof layout and 18 cu ft are both useful to your family.
- The catch
- Planning side-by-side on the rack is harder with a 36-inch width.
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What this page compares
When roof space has to serve bikes, longer skis or family luggage and stay within vehicle load limits, how do Force 3 L Sport and SkyBox NX 18 compare?
If keeping room beside the box matters more to you than maximum luggage volume, the Force 3 L Sport is the one. The SkyBox NX 18 is the one for longer skis or larger family bag loads that will fill its wider shell. Before deciding that both accessories can travel together, put every bike carrier and crossbar into the roof-load calculation.
Which one fits
Pick the situations that sound like you
Short gear in a box, plus a bike
More nominal width and payload remain for the second accessory with the Sport.
- Thule Force 3 L Sport
- Better fit
- Yakima SkyBox NX XL
- Caution
190 cm skis
Skis as long as 195 cm work with the NX 18.
- Thule Force 3 L Sport
- Not suitable
- Yakima SkyBox NX XL
- Better fit
A family’s bulky but light luggage
You get 18 cu ft with the NX 18 instead of 11.
- Thule Force 3 L Sport
- Caution
- Yakima SkyBox NX XL
- Better fit
A roof already close to its weight limit
Add up the rack, the box and every other accessory before you add cargo.
- Thule Force 3 L Sport
- Caution
- Yakima SkyBox NX XL
- Caution
In practice
Differences you will notice
A narrow box may simplify planning a mixed load
Subtract the box width from a 50-inch usable bar span and you get 25.3 inches left with the Sport and 14 inches with the NX 18. That gives the Sport 11.3 inches more nominal side space, before clamps and rack feet are taken into account.
How we worked this out
50 - 24.7 = 25.3. 50 - 36 = 14. None of this guarantees that a bicycle carrier will mount or clear the lid.
Count the bike first, then fill the box
Suppose the total roof allowance is 165 lb, the rack is 20 lb and the bicycle with its carrier is 35 lb. That leaves 76 lb of box cargo with the Sport and 57 lb with the NX 18. A larger box can have empty space that the remaining payload can’t safely fill.
How we worked this out
165 - 20 - 35 - 34 = 76. Swap the 34 for 53 and the result is 57. Work from the lowest real system limit and the weighed accessories.
A 190 cm ski flips the case for the narrow box
When 190 cm skis are coming along, the NX 18 is within its 195 cm limit and the Sport is not within its 175 cm limit. Dropping the bike or rearranging how you carry things may be needed. Forcing long skis into the narrow box is not the answer.
How we worked this out
190 is 15 cm past the Sport limit and 5 cm under Yakima’s. You still have to check binding and bag clearance.
Option A
Thule, 645650
Force 3 L Sport
Built for smaller loads that share the roof with other gear, this narrow box uses the Force 3 mounting and locking hardware.
- Best for
- A narrow shell is what you need, and your skis fit within 175 cm.
Facts we checked
- Capacity and ski length: 11 cu ft, with skis up to 175 cm
- Outside width: 24.7 in
- Weight when empty: 34 lb
- Outside length: 75.2 in
Option B
Yakima, SkyBox NX 18 XL
Yakima SkyBox NX XL
You can fit gear up to 195 centimeters long in its 18 cubic feet.
- Best for
- Your skis run up to 195 cm.
Facts we checked
- Capacity and ski length: 18 cu ft, with skis up to 195 cm
- Outside width: 36 in
- Weight when empty: 53 lb on the current product page
- Outside length: 84 in
Spec by spec
Where they really differ
| Spec | Thule Force 3 L Sport | Yakima SkyBox NX XL | In practice |
|---|---|---|---|
| Volume and ski length | 11 cu ft, skis up to 175 cm | 18 cu ft, skis up to 195 cm | The Yakima handles longer gear and more bags. The Sport saves roof width. |
| Exterior width | 24.7 in | 36 in | If a second accessory goes on the rack, plan the width properly. |
| Empty weight | 34 lb | 53 lb on current product page | The Yakima eats 19 lb more of the shared roof-load budget. |
| Exterior length | 75.2 in | 84 in | Look at front overhang and hatch movement, and work out where the empty box will be stored. |
| Opening access | Dual-sided | Dual-sided | You can load either box from whichever side you can still reach. |
Trade-offs
What each pick costs you
With Thule Force 3 L Sport
- Family luggage doesn’t have much room in 11 cu ft of interior.
With Yakima SkyBox NX XL
- At 53 lb empty, it takes payload away from bikes and cargo.
Change of plan
When the answer changes
My 190 cm skis have to go inside the box
Go with Yakima SkyBox NX XL. That length is within the NX 18’s range and beyond the Sport’s.
My approved rack has to hold a bike as well, and my skis are short
Go with Thule Force 3 L Sport. A narrower and lighter shell frees up more of both budgets.
Decision guide
How to decide
Settle whether the roof holds one load or two
The Sport appeals when a bike and box have to share the rack. Its width advantage counts for something, though the bicycle and its carrier can use up the roof payload fast. Verify clamp positions, lid travel and vehicle fit with the full mixed-accessory layout in place.
Go wide when the space solves a real load
When the box has the roof to itself, the NX 18 is a simple choice for longer skis and bulky family luggage. It brings seven more cubic feet than the Sport. Fill that space with suitably light cargo once the rack and the 53 lb box have been deducted.
Factor in access and storage too
Each opens from either side, so access alone does not favor one over the other. The larger Yakima is also 8.8 inches longer outside. Check the hatch using Yakima’s measurement method, and decide where the 84-inch shell will be kept between trips.
What this page can’t tell you
- What you see here are manufacturer fit limits and planning examples. None of it approves an installation on a specific vehicle.
- Yakima's documents disagree by about 1 lb on empty weight, so go with the heavier published figure until you have confirmed the box you receive. No winner on wind noise or fuel economy has been established.
By the numbers
What the data shows
What we found across the roof cargo boxes we compare, plus the checked facts behind each finding.
Show the facts and the math
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| Thule Force 3 L Sport |
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| |
| Yakima SkyBox NX XL |
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Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
Thule Force 3 L Sport
A narrow shell is what you need, and your skis fit within 175 cm.
See price & reviews on AmazonYakima SkyBox NX XL
Your skis run up to 195 cm.
See price & reviews on AmazonEach link opens in a new tab.
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