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Bike Medicine Purple Extreme Synthetic Lubricant was originally designed for working in industries where conditions are very harsh – offshore oil rigs, mining, and the like – and it brings a fair bit of that robustness to your humble bike chain. It works well in the dry, less so in the wet I found, and in both conditions it struggled to reach the quoted application mileages.
Over the two-month test period I have applied Purple Extreme to a range of different test bikes, all of which arrived with brand new chains. After a full clean of each chain before application, I found the lube easy to apply, with little in the way of excess drips, showing how well it is penetrating into all of the little nooks and crannies.
Bike Medicine says you can ride your bike straight away after application, but it's best to leave it overnight if you can. It's a lightweight liquid but the solvent evaporates, leaving what it calls the Extreme Pressure additive in place, with a much drier look and feel to it.
Large chunks of the test period saw dry roads, and on these the Purple Extreme lasted well, with the chains remaining clean and not picking up much in the way of dust and dirt. Both of the road bikes I was testing it on required another application after around 250 miles as the chains were starting to sound a little dry and squeaky – much less than the 400+ miles claimed by Bike Medicine.
There was also a patch of weather that meant a coating of salt on the main roads, with a resulting spray of sludge that just eats components. A new application of Purple Extreme to the road bikes stood up well – the chains did get dirty, but leaving them in the shed for a couple days to dry out didn't see any rust forming, unlike another road bike I was using that still had the original manufacturer coating on it.
The chains cleaned up easily too, with just a wipe over, and only felt like they needed relubing after around 150 miles.
In the wet and mud I wasn't so impressed, though. Using Purple Extreme on a gravel bike and taking to the trails, my drivetrain would already be noisy by the end of the route.
It wasn't raining as such but there was spray coming up from the short tarmac sections and it had been raining previously so there were some quite deep puddles. The rest of the route is a mixture of gravel, chalk, grass and mud, and it's always a challenge for any lube.
I rode this same route, which is 33 miles long and takes about three hours to complete, three days in a row, setting off each time with a new application of Purple Extreme. Returning home after each ride, the chain was sounding rough and dry.
Sticking to the road it fares a bit better in the rain. I was getting around 150 miles between applications in the wet, though it's always difficult to gauge, with conditions being so variable.
In the UK this 120ml (4oz) bottle costs £13.49. Bike Medicine recommends a typical road or mountain bike chain requires 1/4oz, about 7.5ml, of lube per application, so that's 16 applications from a single bottle. In wet conditions, or on your gravel bike, you are going to use it up quicker than Bike Medicine suggests.
It's still not overly pricey, though. Wolf Tooth also makes big claims about 400+ miles between applications of its WT-1 All Conditions Chain Lube, and while Neil was very impressed with its ability in all kinds of weather, it is £19 for just 59ml.
Green Oil's Wet Chain Lube is £7.99 for a 100ml bottle so a bit cheaper than Purple Extreme, and will last for around the same sort of mileage in wet conditions.
Overall, I wouldn't say that the Purple Extreme is quite as good as claimed, at least in general UK conditions. But accept that you'll probably be applying it more often than it says on the bottle, and when it is working it's doing so very well. Your chain stays surprisingly clean and quiet. And quiet means less friction, so your chain will last longer.
A good lube for the majority of conditions, though it doesn't achieve the mileage claims
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road.cc test report
Make and model: Bike Medicine Purple Extreme Synthetic Lubricant
Size tested: 120ml
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?
Bike Medicine says, "Bike Medicine Purple Extreme is an advanced, high performance, synthetic bike chain lubricant. It provides excellent protection for chains, open gears and exposed metal surfaces subjected to severe loading. In addition, it works extremely well even in abrasive, cold, wet or acidic environments. Purple Extreme's additive technology forms a slippery, super-tough, synthetic film on metal surfaces. That protects drivetrain parts far beyond the ability of conventional oils or waxes. Purple Extreme is the perfect chain lube for road, gravel, mountain, BMX, commuting or cross bikes."
It's good, but doesn't quite meet the claims.
Tell us some more about the technical aspects of the product?
Bike Medicine lists:
High Mileage Per Application – Most cyclists Experience 400+ Miles of Road Riding Between Applications of Purple Extreme
Best Value For Your Money! One Bottle of Purple Extreme Provides Three or More Times the Mileage of Most Competing Products
Runs Clean – Doesn't Attract Dirt
Originally Designed To Run Chains In Salt Water – Will Not Wash Off In Rain, Mud Or Snow
Smooth Running – Reduces Drivetrain Noise
All Conditions Lubrication Security – Protects From Wear Up To 400° F. and Down To -100° F.
Does Not Harden in Cold Conditions
Ultra High Film Strength – Prevents Metal To Metal Wear
Stays In Place – Does Not Shed or Fling Off
Penetrates Quickly To All Parts Of The Chain
Helps Prevent Corrosion – Stops Rust From Ruining Your Drivetrain
Purple Extreme was originally formulated to protect drive chains and wire rope in the mining business and on offshore oil rigs, in some the harshest conditions imaginable, for months at a time.
Tell us how the product performed overall when used for its designed purpose
Good in the dry, a bit lacking in the wet.
Tell us what you particularly liked about the product
Chain is very quiet when the lube is applied.
Tell us what you particularly disliked about the product
Doesn't last long, especially in tough, wet and muddy conditions.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
For its performance I'd say it is reasonably priced. It sits in between the two lubes mentioned in the review, but I'd say they both work better in the wet.
Did you enjoy using the product? Yes
Would you consider buying the product? Possibly, though I'd go for something tougher in the winter on the gravel bike.
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
It's simple to apply and works well in dry conditions, though it doesn't last as long as expected, especially in the wet and mud.
About the tester
I usually ride: This month's test bike My best bike is: B'Twin Ultra CF draped in the latest bling test components
I've been riding for: Over 20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed,
With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!