Castelli Free Aero Race 4 Bib Shorts

GBP 111.35
from £111.35

Save: £58.65

Size Guide

Castelli Men's Clothing Size Guide
  S M L XL 2XL 3XL
Chest (cm) 92 96 100 105 110 115
Waist (cm) 80 84 88 93 98 103
Hips (cm) 94 98 102 107 112 117
Inseam (cm) 82 83 84 85 86 87


Castelli Shoe Cover Size Guide
  S M L XL 2XL
Men's/Women's EU Size 39-40 41-42 43-44 45-46 47-48


Castelli Men's Socks Size Guide
  S/M L/XL 2XL
Men's Shoe Size (EU) 35-39 40-43 44/47


Castelli Gloves Size Guide
Men/Women <17cm 17-20cm 20-23cm 23-25cm 25-27cm >27cm


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Our no-compromise approach to creating the best cycling clothing in the world is nowhere more evident than in the 2019 Free Aero Race 4 Bibshort. This is a product that’s undergone 12 years of development and refinement, with literally millions of kilometers on the road.

The Free Aero Race Short is the all-around race short we supply to Team Sky, as well as all race teams we’ve sponsored since 2007. but that’s not enough of a reason for you to just go out and buy a pair. since these guys ride over 30,000 kilometers per year, we consider them ideal testers and continuously solicit their feedback. the difference is that we actually listen to them. and the good thing for you is that the pros are looking for comfortable shorts too, so this short is made to be minimalist and fast, but without sacrificing all-day comfort.

For this year we’ve made subtle but important refinements. The seat pad has been updated with a softer, stretchier and totally seamless top layer. The leg gripper is also stretchier and grips better yet allows for a better-quality sublimation print. The bib straps are both lighter and more comfortable while giving better support.


  • Vortex Dimpled Fabric On Legs For Aero Performance
  • Forza Fabric On Inner Legs With 38% Lycra® Content For Perfect Fit
  • Stripe Mesh Engineered Minimalist Bib Construction Keeps You Cool
  • Giro4 Leg Gripper Elastic For Better Grip Distributed Over Larger Area
  • Doppio V Construction In Front For Increased Support And Comfort
  • Flat-Lock Stitching
  • Progetto X² Air Seamless Seat Pad
Free Aero
Cycling Clothing Fit:
Race Fit
16°C to 20°C

21°C to 25°C

26°C +

How long will it take to arrive?

Please check the stock availability notice on your item when placing your order. This item is: In stock

Express Delivery

If ordered before 11pm, delivered by courier next working day.

How will I know it has been sent?

You will receive an email to confirm when your item has been sent.

You can also check the status of your order and individual items by accessing My Account details and following the prompts.

Please allow 10 working days from dispatch of your order before notifying us of any late deliveries.

It may be advisable to check with your neighbours to see if a parcel has been left with them, check any outhouses you might have where it may be left if it cannot fit through your letterbox and contact your local sorting office to see if the item has been returned to the depot as undelivered and awaiting collection.

If I'm not completely happy with my item?

Please see our returns policy.

Frequently Bought Together

Castelli Free Aero Race 4 Bib Shorts
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Castelli Free Aero Race 4 Bib Shorts
from £111.35
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Castelli Free Aero Race 4 Bib Shorts + Castelli Pro Issue Short Sleeve Baselayer

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Castelli Free Aero Race 4 Bib Shorts
This item
Castelli Free Aero Race 4 Bib Shorts
from £111.35
Select size
Select colour
Recommended item
Castelli Pro Issue Short Sleeve Baselayer
from £27.83
Select size
Select colour
Add both to basket

Customer Reviews

Overall Rating : 4.7 / 5 (10 Reviews)
  • 8 5 star reviews
  • 1 4 star reviews
  • 1 3 star reviews
  • 0 2 star reviews
  • 0 1 star reviews
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Top Customer Reviews

Where reviews refer to foods or cosmetic products, results may vary from person to person. Customer reviews are independent and do not represent the views of The Hut Group.

Castelli free aero race 4 bib shorts

This is the second pair of shorts Castelli free aero shorts I have purchased. I am 5’11”, 172lbs and the large fits me well. I find them very comfortable even on long rides.

Castelli free aero race 4 bib shorts

This is the second pair of shorts Castelli free aero shorts I have purchased. I am 5’11”, 172lbs and the medium fits me well. I find them very comfortable even on long rides.

180cm and 78 kg = XL

I am a huge fan of the top brands, but you have to be aware of their sizings. It is frustrating but its the way it is. The grear is top quality, comfortable, washes well and looks the business. You just have to know your size in their chart.

Poor quality

I bought these Castelli bibs this year, wore them 5x max, and there are tears in each suspenders. For the price, I'm really disappointed.

Really good quality bib shorts!

These bib shorts feel super good quality and the fit is amazing. I ordered a size L following Castelli's size guide, but I had to return them and order a size XL because they were very tight, especially the straps weren't long enough (I am 6ft). Other than that it feels perfect, the padding has been really comfortable from the first ride.

As expected - Awesome!

This is such an amazing bib! I have several Castelli bibs, and this is my favourite. The padding is the most comfortable I’ve ridden on. The fit is a ‘race and aero’ so be aware. The compression is as expected. The shoulder strap is minimalist but very comfortable. I don’t notice it in 3+ hour rides. If you like, flat wide straps then this isn’t for you. Overall, this is an amazing bib! I highly recommend it. I wish I bought another pair when ProBikeKit has that super sale. I’m 174cm and 77kg. I usually wear Large bibs but ordered XL based on my past Castelli purchases.

The best in their lineup

These are so good I have 3 sets. The Pregetto X2 pad is a class above the KISS 2 pad, but mainly I like the fit and materials, they feel like you are not wearing anything at all! I do 3hr+ rides twice a week in these and they are great. Just beware that fit is race tight in case you were wondering, it does say "RACE" in the name so beware of that. I am normally medium in all other brands but always buy large in Castelli and the fit is perfect in size L but as said they are on the snug side, like a second skin which is exactly what I want and what it's designed for. Don't buy this if you are a tubby guy wanting a casual, loose fitting bib short, these aren't it. I have a pair of Castelli Endurance with the Progetto X2 and those are probably more what you are looking for as they are slightly more forgiving (but not by much, still tight). Very similar to these but these are truly go faster shorts.

Top of the range

I have the previous version, the endurance version and now this model. This is so good I decided to buy another! Firstly the progetto 2 pad is superior to the KISS 2 pad but not hugely. Only makes a difference on 1.5hr + rides. definitely a must on 4h rides! But I can’t help but feel the pad is wrongly placed on this iteration of the Aero Race, slightly forward of the sit bones, that is until I realised that if you don’t pull the (reasonably tight fitting) leg grippers up further onto your quads, this moved the pad slightly further back and into your sit bones properly. The trick is when pulling them on, the trick is to grab the leg gripper with your two thumbs to spread them and the gripper up about 10-15cm above your knee before letting them go, then pulling up the leg part over your quads. YMMV but once you fit it correctly they disappear and become very comfy indeed. Have done all day rides on these and they are perfect for me. I liked the straps of the older Aero Race 3 which were raw cut, these ones have gone backwards in my opinion but are still fine. Some reviewers claim they bunch at the shoulders but I wear them with a base layer and I don’t have this issue. They stay put for me. As usual I am normally a medium and I always buy L in Castelli and this is no different. They are still very form fitting (as they should be for a race fit). Overall excellent bib shorts, premium price though, I got mine both on sale or some discount which made them more bearable, would not pay full price.


So comfortable on the bike they are the second pair that I have bought.


These are a well built pair of shorts. They’re quite light, but form the the body well. The leg grippers are much better than the previous rendition of these shorts. The straps have a good stretch but I much prefer Rapha PT lay flat straps, these bunch up on the shoulders for me. The new pad is soft and has a great thickness. But I am concerned for the width for me. I ride a 155mm saddle and I feel my sit bones are on the edge. I’ll have to see if they stay in place as I haven’t tested these fully yet. The other interesting thing is the pad cover is not attached to the pad and there is a small viewing hole big enough to stick a finger or two in or something of the like where you can see the foam. It’s not perforated. So we will see on moisture absorption. I will say I may be more inclined to stick with rapha here as well. The price I paid for these during a sale is what trumped Rapha. Overall good looking shorts though. I went with a Large although I could probably have wedged into the medium for a more compressive fit. I’m 6ft. 32.5” waist. 39” hips. 77kg. I fit medium in rapha and sportful (snug tho).

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