Castelli think it’s okay to offer one size for small/medium. At their premium price that’s not good enough. I’m 66kg and sometimes I’m medium or large. Their guide said go medium. It’s tight on me. Yes you can get it on - but as a ‘spring’ weight base you might on some days wear two. You couldn’t with this size. So much so I gave these to my wife who’s a women’s size 10. (Petite) And she thought it was tight too. For their price I’d expect a proper choice of sizes not just rely on stretch fabric and say get into that.. I brought two ALE and they are good.
Product Details
Core Seamless Short Sleeve Base Layer
The Castelli Core Seamless Short Sleeve Base Layer is engineered from a blend of polypropylene and polyester yarns to create a garment that is soft, warm and stretchy. Adding an extra layer of thermal protection under a jersey, it hugs the body without restricting movement and draws moisture away from the skin to keep you dry and at a comfortable temperature. A seamless construction reduces the chances of chafing, and the base layer has a wide neck opening so it fits comfortably even under low-collared jerseys.
Features
- Polyester-polypropylene yarns provide softness, warmth, wicking and exceptional stretch
- Seamless construction
- Lighter weight fabric on side and back
- Wide neck opening to fit under short-collared jerseys
- Recommended temperature range: 8°–20°C / 46°–68°F
- Manufacturer claimed weight: 151 grams (size large)
Specifications
- Composition
- 84% POLYESTER / 16% POLYPROPYLENE
- Base Layer Weight
- Midweight
- Fabric Composition Type
- Blend
- Fit Type (General)
- Slim
- Gender
- Men's
- Insulation Level
- Light
- Material / Main Fabric
- Polyester
- Moisture Management
- Wicking
- Neckline / Collar Type
- Crew
- Primary Activity
- Cycling
- Sleeve Length
- Short Sleeve
- Temperature Use
- Cold, Mild
- Weather Protection Level
- None
- Seam Construction
- Flatlock
- Product code
- 1262487 / 54295852646746
Size Guide
| Size | XS | S | M | L | XL | XXL | XXXL |
|---|---|---|---|---|---|---|---|
| Chest (A) | 88 | 92 | 96 | 100 | 105 | 110 | 115 |
| Waist (B) | 76 | 80 | 84 | 88 | 93 | 98 | 103 |
| Hip (C) | 90 | 94 | 98 | 102 | 107 | 112 | 117 |
| Inside Leg (D) | 81 | 82 | 83 | 84 | 85 | 86 | 87 |

If you're unfamiliar with your Castelli size, we recommend you go up one size to obtain the best fit possible. Note that you do not need to size up for jackets or vests; please select your normal jersey size.
Castelli clothing is designed for its intended use and should be comfortable when on your bike in a riding position. Your garment should be snug to provide you with moisture-wicking capabilities, as an aerodynamic aid and prevent any fabric from flapping in the wind.
If you require any advice on Castelli sizing, please do not hesitate to contact us.
A. Chest: Holding the tape horizontally, measure under your armpits with your arms relaxed at your sides, around the fullest part of your chest.
B. Waist: Holding the tape horizontally, measure around your natural waistline, across the belly button, keeping the tape a bit loose.
C. Hips: Holding the tape horizontally, measure around the largest part of your hips, keeping the feet close together.
D. Inseam: Measure from the crotch to the base of the ankle bone
Reviews
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Shipping & Returns
Free UK delivery on orders over £50. Orders are dispatched within 1-2 working days and typically arrive 1-2 working days later.
Return unused items in their original packaging within 30 days of delivery. Return postage is £3.50.
Q & A
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About Castelli
At the front since 1876.
Castelli has been at the front of cycling apparel since 1876, founded in Milan as the original maker of pro race kit. From the first cycling jerseys to today's WorldTour-proven aero garments, the brand has spent nearly 150 years putting innovation onto the backs of the fastest riders in the world.
Castelli outfitted the first organised cycling teams in Italy and has been a constant presence in the pro peloton ever since. The Scorpion logo appears on more WorldTour podiums than almost any other apparel mark.





