Fenwick's FS1 bike cleaner concentrate is a highly efficient, versatile degreaser stock that forms the basis of their FS10 bike wash. Free from anything caustic, the 1 litre version makes 10 litres or so of FS10 but there's also a 5litre workshop size. Safe on all surfaces-including matt and carbon fibre, it's one of my all-time favourite cleaning products.
Precise ingredients are Coca-Cola secret but comprise non-ionic surfactants, cationic surfactants (which burrow beneath grease and grime, breaking it down on a molecular level) and Citronellal, which is basically a harmless, lemon/rose type fragrance often found in cosmetics and mosquito repellants - though Fenwicks make no claims about keeping the bugs off.
The recipe for FS10 bike wash couldn't be simpler. Pour 100ml into a 1litre bottle, fill to the brim with tap water, screw on the pump spray and the sudsy elixir is ready for blasting over filthy bikes.
Modus Operandi is identical to most bike washes I've used. Pop bike(s) outside, spray liberally from a distance of 30cm or so and then leave to marinate. Fenwick's suggest two minutes which is a tad longer than most of the bike washes I've used, but hardly a long time.
Unless you are using to wait to give drivetrains a good strip, now's the optimal time for gathering bucket(s) of warm water, sponges, brushes and other scrubbing kit.
In practice, the full 2minutes is only really necessary for caked on winter cocktails of mud, spent diesel, salt and similar contaminants.
Mud and other organic stuff slithers away in thirty seconds, more complex light to moderate gloop-including stuff clinging to rings and bottom bracket shells will budge after 45 seconds when worked into a sudsy lather using a soft/medium bristled brush.
Rinse through with tepid water and you're left with a streak free, squeaky clean steed. Effects are uniformly good across the board on painted, polished, lacquered or anodized finishes. While following manufacturer guidelines religiously is best-if only to avoid warrantee hassles; I have a tendency to tweak recipes to suit...
Making a neater blend based around a 20/80% concentrate/water mix produces a richer, faster acting mix that is just about stocky enough for shifting lighter oil based drivetrain dirt-without being unfriendly to delicate finishes. However, stripping rings, cassettes and derailleur cages bare of congealed wet lubes, or stubborn ceramic lubes calls for neat.
As a lube stripper, chain baths are the most obvious and arguably neatest method. However, I prefer the old school mechanic's technique of pouring a small amount into an old sawn-off water bottle, parking this on the seat tube cage and brushing the concentrate into the desired spots
Agitate as before, leave for two minutes or so, then rinse off. This method is also more time and product efficient on encrusted grime around the bottom bracket shell, rear triangle than bike wash. Extending waiting times by several minutes hasn't result in residual streaking or blemishes either.
Some really tenacious chain lubes required a second helping but most relented first time when rinsed in warm water. Greases vary. Simple lithium and PTFE types are easily dismissed, so long as you've got the Fenwick's foaming, left it the full two minutes and rinse surfaces with warm water. Cutting edge polymer type lubes are more tenacious and needed three treatments.
While Fenwick's is solvent free, it does evaporate, so unless decanting into a sealed container afterwards, pour small amounts and add more if necessary to avoid wastage. Adding 20ml of water to the residual amount slows this process, although I've tended to add 100ml and recycle any leftovers in my parts washer, or as a hand wash. Fenwick's have always made a point of saying its gentle enough for these duties, although you'll still need to work it into a lather and rinse with hot water to get ingrained grime from the pores.
Ultimately, there are faster acting concentrated cleaners both organic and otherwise. However, they can be quite harsh (I've cleaned patios and even drains with one neat formula). Compared with some other household names, Fenwick's performs well and in the longer term, seems kinder to surfaces and user alike.
Extremely versatile, effective and yet gentle degreaser cum bike wash. Recommended.
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road.cc test report
Make and model: Fenwicks FS-1 Bike Cleaner Concentrate
Size tested: 1 Litre
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
"In 1996 we created our first bike cleaner concentrate called 'Hog Wash' If any of you have a bottle drop us a line. This was way ahead of the curve as it didn't take off due to the already mixed, ready to use bike cleaners out there. Relaunched in 2003 as FS-1 because of our belief in giving you value for money, the demand for FS-1 Bike Cleaner Concentrate increases by the day as there are now lesser concentrates on the market. This is because 1 litre of FS-1 can make up to 11 litres of ready to use bike cleaner, making it £0.91 per litre, a no-brainer really. We even have a special fill line on our FS-10 bottles at the bottom to help you out creating the perfect bike wash every time.
Like no other company we produce such highly concentrated cleaners using a complex blend of high quality liquid raw materials (others use cheaper powdered raw materials, which can leave a powdery residue when dry) FS-1 Bike Cleaner Concentrate cleans deeply and easily to leave exceptionally clean contaminant-free surfaces. Safe for you, your bike and the environment. Free from caustics, metasilicates, abrasives and silicone. Safe for use on all bike parts including carbon fibre, disc brakes, delicate anodized parts, etc. Plus it's strong enough to be a great degreaser.
Available in 1 Litre or 5 Litre Bottles". A great all-rounder and one of my favourites.
Tell us some more about the technical aspects of the product?
"How to use FS-1 as a degreaser
No need to wet bike beforehand.
Step 1: Apply neat to drive train or parts that need degreasing - can be used in any chain bath and allow to soak in for a couple of minutes before cleaning off.
Step 2: Agitate with brush or sponge.
Step 3: Rinse thoroughly with clean water.
How to use FS-1 as a bike cleaner
Using the fill level mark on a Fenwicks spray bottle dilute 1 part Fenwicks FS-1 Bike Cleaner Concentrate to 10 parts water.
No need to wet bike beforehand.
Step 1: Spray bike thoroughly with the diluted mixture.
Step 2: Allow to soak in for a couple of minutes before cleaning off.
Step 3: Agitate dirt with brush or sponge.
Step 4: Rinse thoroughly with clean water.."
Lacks the ruthless efficiency of some. However, fast-acting, easily tailored to suit different levels of grime and without doing anything nasty to delicate finishes.
With the right technique a little goes a very long way.
Nicer to use and seemingly kinder to the skin than many competitor formulas.
Tell us how the product performed overall when used for its designed purpose
Overall, there are faster acting formulas when it comes to stripping drivetrains (Some when used neat will clean patios and burn skin!), However, FS1 is still quick, kind to all surfaces and extremely versatile.
Tell us what you particularly liked about the product
Tuneable, kind to skin and can be used in a variety of ways.
Tell us what you particularly disliked about the product
Nothing given the design brief and having used it on a long term (Two year) basis.
Did you enjoy using the product? Yes
Would you consider buying the product? Definitely- 5litre workshop version for me.
Would you recommend the product to a friend? Definitely
Use this box to explain your score
Definitely one of my favourite bike cleaners to date and an excellent all rounder. Would get a 9 if it worked faster while still retaining its finish friendly nature.
About the tester
I usually ride: Rough Stuff Tourer Based around 4130 Univega mtb Frameset My best bike is: 1955 Holdsworth Road Path and several others including cross & traditional road
I've been riding for: Over 20 years I ride: Most days I would class myself as: Experienced
I regularly do the following types of riding: cyclo cross, commuting, touring, fixed/singlespeed, mtb,
Shaun Audane is a freelance writer/product tester with over twenty-eight years riding experience, the last twelve (120,000 miles) spent putting bikes and kit through their paces for a variety of publications. Previous generations of his family worked at manufacturing's sharp end, thus Shaun can weld, has a sound understanding of frame building practice and a preference for steel or titanium framesets.
Citing Richard Ballantine and an Au pair as his earliest cycling influences, he is presently writing a cycling book with particular focus upon women, families and disabled audiences (Having been a registered care manager and coached children at Herne Hill Velodrome in earlier careers)