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Forcefield Back Protector Pro Sub 4
  • Forcefield Back Protector Pro Sub 4
  • Forcefield Back Protector Pro Sub 4
  • Forcefield Back Protector Pro Sub 4
  • Forcefield Back Protector Pro Sub 4
  • Forcefield Back Protector Pro Sub 4
  • Forcefield Back Protector Pro Sub 4

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Forcefield Back Protector Pro Sub 4

The Forcefield Back Protector Pro Sub 4 is the worlds first Motorcycle back protector to transmit less than 4kn when subjected to the standard CE test.

The Pro Sub 4 has been specifically designed to test at under 4kn when subjected to the standard CE test EN1621-2. Independent testing by SATRA shows a mean test result of 3.38kn transmitted energy, making it the first motorcycle back protector in the world to attain this level of performance. Constructed with a removable and washable outer cover to give the rider the ability to keep the back protector clean and hygienic , it also makes the protector more flexible as it is not bonded at the edges, this in turn makes it more comfortable to wear, a prime consideration in the design process of any Forcefield product. As with all Forcefield Body Armour® the Pro Sub 4 has RPT (Repeat Performance Technology) ensuring continued and consistent protection even after multiple impacts. 


  • The World's first Motorcycle back protector to transmit less than 4kn when subjected to the CE test EN1621-2 (Level 2)
  • Removable and washable outer cover
  • CE Level 2 Rated Protection
  • RPT (Repeat Performance Technology)
  • Comfortable and non restrictive
  • Flexible
  • Breathable
  • Moulds to body shape
  • Adjustable waist and shoulder straps
  • Multi Sport use

Read more about this product in this WebBikeWorld.com Review

Product Style RevZilla Item # Manufacturer Product # Availability
SM 617815 FPS-4-2-S Available: Requires 2-4 business days lead time prior to shipment.
MD 617816 FPS-4-2-M In Stock: Ships within 24 hours
LG 617817 FPS-4-2-L In Stock: Ships within 24 hours
XL 617818 FPS-4-2-XL In Stock: Ships within 24 hours


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Forcefield Back Protector Pro Sub 4 4.8 5 56 56
It's protection not fun it is hard to review a protector when it has never been put to its ultimate use, so I can only rate protection based on test results and the revzilla description. It does fit nicely and the materials seem high quality. Airflow is not great, I tend to sweat under it on 85+ days - but I'm not sure that can be avoided with any serious back protector. A protector just cannot add comfort unless you are dashing, but then it will be all the inconvenience before July 6, 2015
Forgot it was there. Haven't crash-tested it, I'll leave that to others until I can't avoid it, but I like the peace of mind of top-level protection on the track. Once it was under my leathers, I didn't think about it until it was time to get out of them. It's not a distraction, and that's what's important to me. May 13, 2015
Back protector with extra features I am very happy with the purchase. I am 5'9' and bought the MD. It fit well all the way down to the tail bone. The Dianese Wave Pro in MD was a little too long but this is just right. The back protector is made up of separate layers of foam that can be removed for washing as well as customization if you had to. The hip straps have an added benefit of having some kidney protection flaps. They do not get in the way or pinch your waist skin/fat between your pants and support like some others do. Pretty comfortable under my Dainese jacket even when I'm wearing a size46. Forms well over the curvature of your back. I use this in conjunction with a Knox chest protector insert for track days. May 12, 2015
Excellent Back Protector Very light weight, comfortable and breathable. I use the shield on long day trips (about 500km) and I have nothing to complain about. Due to its flexibility, it adapts perfectly to your body shape. December 15, 2014
Excellent fit, light and very comfortable Very light weight and comfortable. Easy to adjust for fit, and relatively cool on a moderate, but long day. Fast shipping from RevZilla. Hope not to have to impact test it, so only rated average for protection and durability, though based on construction and design, I expect it will hold up very well. October 14, 2014
Vert comfortable. Fits properly Very comfortable due to it´s flexibility. Size M fits well in my 1.71 m (5´8") 65 kg body. In spite of it´s thickness it feels much more comfortable tan the Dainese thorax wave pro I am replacing . I use it combined with the Forcefield Elite chest protector and the combo works perfect together. September 2, 2014
Yet another fantastic Forcefield product I'm a tall female (5' 10") and have had a terrible time finding women's gear that fits. I've had to purchase guy's gear a few times and that has worked out pretty well. I had the women's Sport Lite L2, which is nearly the equivalent of this one, but it's way too short for my back. Also, the Pro Sub 4 is thicker - presumably due to better internal padding/protection. The Pro Sub 4 is a bit wide for my torso. Even so, it fits snug and is super comfortable in any riding position. The space for the shoulders is perfect - I have full range of motion. However, it seems like it would fit much wider shoulders, as it covers my shoulder blades, but that's had zero effect on my mobility when riding. If it's anything like the women's, it will mold well to my body over time, too. It breathes pretty well and extends from the lower C-region all the way down to lumbar. I feel protected. Haven't gone down in it yet, but I have tested Forcefield knee protectors and they saved my knee during a crash. My handlebar went down on my knee and the force of the impact separated the clip from the clutch and bent them both back in either direction flush with the bike. I walked away - bruised, but no lasting injury. Forcefield is awesome. Just wish I'd bought the guy's the first time around. July 5, 2014
This back protector fits & performs well! Took about 2 weeks to form to my back- now it fits like a glove! Very comfortable, even in hot weather. I use this for riding & for coaching Motorcycle Rider Training courses in the NE. The coverage is great from neck to tail bone. Doesn't interfere with my full face helmet or the riding pants I wear. I'm 5'11", 180lbs, with all average build. I recommend talking to the Revzilla tech to get the right size for your body type. I've used hard shell versions of back protectors for more than 20 years & this upgrade to a more flexible material is awesome! ~ Corvus June 9, 2014
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Have a functionality, fit, or otherwise product-specific question about the Forcefield Back Protector Pro Sub 4? Ask it here! If you have a customer service or shipping question, please direct it to our Customer Service department.

Forcefield Back Protector Pro Sub 4
Already Asked: 7 Questions, 63 Answers
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RevZilla Store asked: Why did you choose this?
G S: To protect myself in the event of a fall Nov 9, 2015
Rob M: reviews seemed strong. Looking for a top of the line back protector Aug 24, 2015
Jon W: Best in class back protection.. nothing better Jun 28, 2015
Bob C: Called & spoke to CS rep. He suggested this brand as a stand alone back protector. Good reviews on this item as well. Jun 22, 2015
Leith D: Best back protector Feb 22, 2015
Alexander N W: Wanted to try a new back protector plus it was on sale. Feb 14, 2015
Rafael D: After researching for a long time I decided for this back protector because it really seen the best one around. Now is just wait to comprove or have a disappointment. But I'm really confident that I make the right choice Feb 6, 2015
Tyler E: "The best protection you can get. And, it breathes well and conforms to your body." Dec 16, 2014
A B: It seemed silly to buy an intermediate or less expensive back protector when spine safety is the issue. I reviewed the specs on a range of protectors and this clearly is the best on the market. As far as I can tell a no-brainer. Dec 6, 2014
Tom M: I am a dad now and was looking for the best protection I could get. Nov 24, 2014
Richard M: After careful review and extensive research the "Forcefield Back Protector Pro Sub 4" simply offered the highest level of protection through unparalleled shock absorption and energy disbursement. Although a bit more cumbersome than the insert version, it's a trade off I can live with! Nov 24, 2014
Harry S: Recommendation of trusted and very experienced friend, along with very high ratings in numerous reviews and surveys. Sep 22, 2014
manuel s: Safety and quality. Haven't been disappointed. Great product. Aug 8, 2014
Wilfred F: It costs alot so it should do a better job than a cheap back protector....... right? May 28, 2014
Sunbir W: After a lot of research, found this to offer the best protection that is available in the market for the back and spine Apr 15, 2014
Justin R: Best protection Apr 12, 2014
"" ": Safest back protector on the market Feb 16, 2014
JUAN R: It´s suposed to be the best back protector. Feb 14, 2014
Jeff R: It's the best body armor made! Since you carry almost all of the Forcefield line of products, may I recommend that you take a look at carrying just a few of their other items for snow sports too? I am talking about the Board Shorts (tinyurl . com/kknpfgt), Knee Protectors (tinyurl . com/lrqhxz7), and Boom Shorts (tinyurl . com/omdsz83). Trust me. There's a market for it. I had to order shorts and knee guards from England, but would rather have paid you! Thanks! Dec 31, 2013
Mark M: Had a wreck & broke my back in 4 places. I was wearing a jacket with a CE approved spine protector. Had I been wearing this I would not have spent six weeks in hospital & not have had to learn to walk all over again. This is CHEAP INSURANCE! It is also comfortable & you forget you are wearing it. Don't be so COOL it kills you. Dec 17, 2013
Wade S: Reviews. Oct 26, 2013
John L: How could I not choose Forcefield for my spine protection. All it takes is for one fall and without the proper protection and you just can't take it back, This product screams safety fits well right out of the box, I highly support all forcefield for making the best safety products on the market. Oct 2, 2013
Athena M: I love Forcefield and did a lot of research before purchasing this. It is quite thick but very light and comfortable. Great protection but too thick under the tight fitting kangaroo suit, switched to the ladies Pro Sub 4 (which was not available when I purchased this). Sep 26, 2013
A shopper asked: How thick is this back protector? I have read in numerous reviews that you need to account for the extra room beneath your riding gear. How much extra room are we talking here? I currently have a Dainese Thorax Wave Pro (too big for me, and smaller size is unavailable). Would it take up a similar amount of room? May 20, 2014
Answer this · Send to friends Good question? Yes (1) No (0)
Justin R: It is quite thick, though in comparison to the dainese it is more flexible and more comfortable. It is probably 3/4"-1" thick.

This probably won't be an apples to apples comparison, as the Thorax Wave pro is a whole armor jacket with chest protector - or did you mean just their bac protector?
May 20, 2014
Reply to Justin Good answer? Yes (1) No (0)
Andrew D: It's about an inch and a half thick. Unless you have a rather baggy jacket you're going to be able to see a large hump on your back with it on. With my street and steel jack size large it's pretty noticible but with my spidi leather jacket it's better. I'm about 6'2" and ordered the large and it comes down to the bottom of my tailbone which I like. I've never tried on the Dainese protector you're talking about so I can't really compare. It is rather flexible, much more than any hard shell protector. The only loss of comfort is the space it takes up. I bought it to use while stunting in a parking lot. I rarely wear it under a jacket. What I do is wear the alpinestars bionic mesh jacket with their back protector swapped for the sub4, some elbow pads, and wear a mx jersey over everything. It's great when it's hot out. Overall I'm very happy with it and I'd say if you're willing to sacrifice a moderate amount of room under the jacket for superior protection then I would buy it. Hope this helped May 20, 2014
Reply to Andrew Good answer? Yes (0) No (0)
Thiago M: The protector is around one inch thick. You do have to account for the extra room, but it's not so bad. In fact I wear it with jackets that have other forcefield inserts just as thick, so around 2 inches total. As both the jacket's and the vest are fairly flexible, it doesn't bother me much, even if quite thick. May 25, 2014
Reply to Thiago Good answer? Yes (0) No (0)
John L: Yes the Forcefield Back Protector Pro Sub 4 is slightly thicker, I had to remove the back pad that came with my suit and fits perfect. Since you suit is a little big this will help with fitting. in addition I added the Forcefield amor shorts for complete protection. Hope this helped you with making a choice. May 20, 2014
Reply to John Good answer? Yes (0) No (0)
Nick S: Based on a quick measurement, I estimate about 1.5" thick. My suit used to be too loose in the stomach and back, but with the back and chest protectors, it fills out. This is actually a good thing... May 21, 2014
Reply to Nick Good answer? Yes (0) No (0)
Francis S: It is 2 layers of 1/2" material and the thickness is from edge to edte.

If you follow the chest size +1" for your jacket or suit, you should be fine.
May 20, 2014
Reply to Francis Good answer? Yes (0) No (0)
Tim F asked: Hey. I'm just under of 5 11", 32" waist, 178lbs. I took the torso measurment as advised by forcefield and keep coming up 21-22". I'm usually a medium in everything and the 22" puts me into an XL. Would you think the L would do it? thanks. tim Aug 18, 2013
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Mary R: I'm not sure why this thing says my name is Mary, but whatever. I'm personally 5'9", 160 lbs, and about a 31 inch waist and I ordered a medium and it fits but it may be a hair too small. But it's so close that a large would have been too long. Best thing I can tell you to do is order a large because that should work for you as put it on with the gear you plan to wear with it, helmet too. The back protector should cover your tailbone with the tip, all the way up to your neck pretty much. Should be about an inch of space between the top of the back protector and your helmet. Make sure it's not bunched up or caught on your gear too as that would give you an inaccurate idea of how it fits. If its too short, go up to an XL if its way too long (doubtful) go down a size. Most likely though, I'd guess a large would do you. But it's worth it to send it back if its not right because the more uncomfortable it is, the more likely you are to not wear it or become distracted while riding. Hope that helps! Aug 19, 2013
Reply to Mary Good answer? Yes (0) No (0)
Kenneth H: Hi! I have had one for sometime now and use it always! Even when above 100 degrees - live in Yuma!

The medium is fine for me. I am 68 to 69 inchs tall.
The waist has lots of adjustment and that should not be a problem also.

I would guess the large would work fine for you. You can try it and if do not like the fit. I am sure RevZilla will change it out.

I have not tested it effectiveness and hope never to but I will not ride without it on.

Yuma, AZ
Aug 19, 2013
Reply to Kenneth Good answer? Yes (0) No (0)
Michael C: Hi Tim, don't know if large or extra will work best. I bought one earlier this year for racing and bought an extra large. I'm 6'1, 180 pounds, and have a 32 to 34 waist. I have an athletic build. Works under my leathers great. Would buy again if ever needed. Excellent product. Hope this helps some. Good luck. Mike Aug 21, 2013
Reply to Michael Good answer? Yes (0) No (0)
James H: Tim, I couldn't tell you for sure. Bought mine for racing last year and honestly never had a chance to try it. Sorry couldn't help you out. Anthony's reviews are usually very helpful in making decisions on size. Plus, their return policy is awesome if you are not satisfied. Aug 20, 2013
Reply to James Good answer? Yes (0) No (0)
Peter CStaff: Hey Tim. Yes, I think the L would do it for you. I'm 6', 34" waist, 195lb and bought the XL based on their measurements. I think I'm going to actually sell the one I got and buy get the L when I have a chance. Hope that helps! Aug 19, 2013
Reply to Peter Good answer? Yes (0) No (0)
Mike B: Hey Tim,
I'm 6" and just shy of 215 pounds. I wear a large and it covers my spine just perfectly. I think the Large would suit you too and the XL would be too much. Hope that helps.
Sep 1, 2013
Reply to Mike Good answer? Yes (0) No (0)
manuel s: Hi Tim,

I'm 5'9" 180 lbs. I got the Large and it thinks it's a bit long. Wish I would have ordered the medium. Hope that is of help.
Aug 19, 2013
Reply to manuel Good answer? Yes (0) No (0)
Kenneth H: Hi! On my response the other day! Forgot! Torso measurments is the most important. Want max back coverage possible.

Aug 20, 2013
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Gregory B: I think so. The protector belts are adjustable. It is plenty long, extending well over the tailbone, so I don't think you would end up short. Aug 19, 2013
Reply to Gregory Good answer? Yes (0) No (0)
Maria M: My husband is 5"10' 180lbs and large is too big for him. I think medium would be a perfect fit.. Aug 19, 2013
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Robert M: I'm 6'1"/205 w/a 46" chest and have a large. IMHO the large would be to big for you. Aug 19, 2013
Reply to Robert Good answer? Yes (0) No (0)
Nikolay K: I am 6'3 and the xl fits me perfect, so if you are 5'11 i would go with the L Aug 19, 2013
Reply to Nikolay Good answer? Yes (0) No (0)
Michael G: you'll be fine ... Excellent choice by the wat... Aug 19, 2013
Reply to Michael Good answer? Yes (0) No (0)
A shopper asked: Hi guys,

Looking at the Pro Sub 4, trying to determin the right size.
I am 5'11" or 6 foot depending on the day and the ruler, I am thin though which affects the waste straps. 34" waist. According to the size chart I would probably be at the edge of medium and the beginning of large. My instinct is to go for the longer large but I am concerned the straps will be too stout.
What do ya' think?

Jul 15, 2011
Answer this · Send to friends Good question? Yes (0) No (0)
med23: I am 6'2" and 210 pounds. I use the large ProSub4 and it is perfect. I would think that the medium might be better for your height and thin build as you described. My only reservation would be if you have a very long torso...in which case you might need the extra length of the large. The straps on the large also might give you too much material and be a bit sloppy under your suit. They gave a lot of material for a huge spectrum of torsos, which you don't need to worry about. Go Medium...and Revzilla is amazing at return/exchanges so you can't go wrong. Jul 16, 2011
Reply to med23 Good answer? Yes (0) No (0)
Mike37: Adam,

I am 5'10" about 180 lbs with a 32" waist and I got the large. It actually was barely a bit to big for me but the straps have tons of velcro that you can tighten it with. The length on my back was just a bit long but I would take longer over shorter any day of the week. The back protector also fit very well under my leathers and didn't cause any discomfort while riding on the track. It also provided excellent protection when I high sided at around 80mph.

Hope this helps,

Oct 8, 2012
Reply to Mike37 Good answer? Yes (0) No (0)
Blonderhanz: I'm 6'0" at around 195 with a waist around 36-37". I just got the large Sub 4. As far as fitting the length of my spine, it is perfect. But you are concerned about the waist strap. The strap is long, even for me, and I may have to someday have it shortened. With your smaller waist the large's waist strap will be way to big, try the medium, or modify the waist belt on the large. Sep 28, 2011
Reply to Blonderhanz Good answer? Yes (0) No (0)
freepers: I had a similar conundrum. I choose the large size as for my sub 4 back protector. I went the smaller direction due to similar circumstances for my previous back protector and in retrospect should have gone the larger size.

Get someone to take three or four measurements, then average them. This will give you the best fit.

Hope this helps.
Oct 29, 2012
Reply to freepers Good answer? Yes (0) No (0)
billyb39: Adam,

I'm not sure if you made the decision yet, but I wear 36" waist pants and I just purchased the large. They are a little loose for my taste, so I'd recommend you go with the medium. If I had both side by side to try on, I probably would have purchased the medium.

Aug 1, 2011
Reply to billyb39 Good answer? Yes (0) No (0)
MrDsylexia: I too was between sizes but as Anthony in the videos always says, "if you are between sizes, go for the next one up". The Large protector fits me perfectly. I am also 5'11/6' and 38 waist, it fits fine and has a lot of room to spare/ great adjustability. Nov 17, 2012
Reply to MrDsylexia Good answer? Yes (0) No (0)
MotoLeo: Adam, I am 5'9" with a 33" waist and wear a medium. The protector fits well and I have plenty of room to adjust. I would think that you would still fit in a medium. Aug 21, 2011
Reply to MotoLeo Good answer? Yes (0) No (0)
MCMD: I'm between 6'1" and 6'2" with a 32" waist. I just bought the large and it's easy to get a good fit from the straps. Buy based on your height. Sep 5, 2011
Reply to MCMD Good answer? Yes (0) No (0)
Pedro: I'm 5'11 and 1/2" Thin too. 32 pants. I got the large and it fits perfect. Straps fit snug. Go for the extra coverage. Oct 10, 2011
Reply to Pedro Good answer? Yes (0) No (0)
WaldoT: Dear Adam,

Excellent choice! I am 6'6" and wear the large. Go with the medium instead.

Waldo T.
May 8, 2012
Reply to WaldoT Good answer? Yes (0) No (0)
Adam26: Thanks to all the respondants.
Sep 28, 2011
Reply to Adam26 Good answer? Yes (0) No (0)
A shopper asked: Is there a similar level chest protection? May 15, 2014
Answer this · Send to friends Good question? Yes (0) No (0)
Tyler E: In terms of thickness and impact absorption, no; however, the Forcefield chest protector is more than enough. It is still thicker than most and made up of the same layering of composites and it lets the air pass through to your chest. I do not feel ready to ride unless I am wearing the Pro Sub-4 and the chest protector.
Make sure everything fits under your leathers. I got measured up for a set of custom leathers with my chest and back protector on and I am so glad that I did. While the back protector or chest protector might fit under your existing leathers, together, they are unlikely to fit unless you leather are too big. otherwise.
May 15, 2014
Reply to Tyler Good answer? Yes (0) No (0)
manuel s: I don't know if they offer chest protectors. I purchased the back protector and it's of superb quality. If the offer a chest protector I'm sure you'll be happy with it. May 15, 2014
Reply to manuel Good answer? Yes (0) No (0)
John L: All I use is forecfield products because of their quality and level of protection they offer. May 20, 2014
Reply to John Good answer? Yes (0) No (0)
Christopher S: The Forcefield Elite or Race Lite chest protectors might work for you. I use the latter. May 15, 2014
Reply to Christopher Good answer? Yes (0) No (0)
Wendell L: Forcefield elite chest protector. May 19, 2014
Reply to Wendell Good answer? Yes (0) No (0)
Rob B: I don,t know May 15, 2014
Reply to Rob Good answer? Yes (0) No (0)
Ed V asked: How well will this fit under an Atem suit? Sep 18, 2014
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Tyler E: This is an excellent product; however, it does add quite a bit of volume to the body. Whether it fits depends upon how tight/loose your jacket and pants are. I wear my back protector (and a Forcefield chest protector) under a two-piece suit that was made to measure; the additional volume of this equipment is such that I took my measurements with the gear on, adding inches to my circumference. I have an off-the-rack one-piece race suit that is a snug fit and thus this set-up (even without the chest protector) does not fit in that suit. Oct 16, 2014
Reply to Tyler Good answer? Yes (0) No (0)
Max R: Sorry, Ed. I can't confirm that for you.

I wear my back protector (and a Forcefield chest protector) under a leather AGV Sport jacket with the jacket's original back pad removed. The tail piece of the back protector protrudes out of the jacket, but I'm not a big fashion guy, so it doesn't bother me. I'd rather be protected.

The setup does occupy additional space inside the jacket, but I'm still comfortable. So, I guess it depends on how snugly your suit fits to start with.
Sep 27, 2014
Reply to Max Good answer? Yes (0) No (0)
Benjamin K asked: I currently use an older Technic/Knox full back protector, but it is 10 years old and of the one shot variety. I am very impressed with the specs on the L4 unit and the fact that taking a hit will not deplete from its ability to take another impact at the same point. However, it seems to be made out of a rubbery material and I am wondering how long it's good for until it starts decomposing? Is there a warranty? Feb 25, 2014
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Kenneth H: Hi! I do not know if any warranty? I have one and like it, not sure now how long I had it - I guess about 2 years or so. It is very good and seem to me will last many years! I live where it gets to around 45 C or 120 F in the summer! I have no problems with the sub4 and ware it when every I ride my bikes. both on and off the road.

Yes, expensive, but I believe will be happy with it over the short and long run - I am!
Oh! If tight jacket - will need to get a bigger size with the sub4.
Mr H
Mar 2, 2014
Reply to Kenneth Good answer? Yes (0) No (0)
Michael G: This is an excellent product , multi-impact , will save your bacon
hope you never have to us it , but if you do, you will be glad , get a chest protector too .. Be Safe
Feb 28, 2014
Reply to Michael Good answer? Yes (0) No (0)