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MicroSHIFT M45 Rear Derailleur



Quirky looking mech that shifts really sweetly - a shrewd option for budget builds and/or working bikes with wider gear ratios.

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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If you're replacing a dead rear derailleur on a cheaper bike or putting together a round-town junker, the Microshift M45 shifts well and doesn't cost much.

Many folks cock a snook at lower end mechs. 'Wouldn't put that on a pram mate' is a common cat-call from some quarters but Microshift's matter-of-factly christened M45 is just the ticket for working bikes be they crossers, tourers or mountain bikes running older groupsets.

Ours was the long cage version designed to cope with 42, 32, 22 chainrings and 11-34 sprocket configurations (enough wallop to ride up down and along China's Great Wall with trailer en-tow) though there's also a short armed sibling which saves precious few grams but could prove a little snappier across less extreme set ups.

Nudging 325g by my scales, there's a definite whiff of 70s Huret/Suntour GT here, although in contemporary terms its nearest rival is Shimano's M430-sorry, I mean Alivio. Yesteryear's budget mechs were notoriously plasticky but the M45 sports a gloss black powder coated finish, aluminium alloy body and steel cage.

I was particularly impressed by its spring tension and lateral stiffness. Resin jockey wheels can't match the finesse of aftermarket types, though these should soldier on through winter's slushy mess with little fuss and perhaps the occasional drop of wet lube. Then of course, we've the inescapable fact that replacing twenty odd quid's worth of mech following a nasty spill won't add insult to injury.

Less bling has obvious advantages in higher crime areas when employed as part of a wider disguise, throwing would- be thieves off the scent, especially combined with dull enamel, stout locks and prominent location (mummifying top and down tubes with redundant inner tube, topped off with hand-painted 'bird droppings' proved a winner for me, living in London's grottier boroughs for twelve years).

Ours played nicely with my Univega's a la carte drivetrain (Microshift brifters, Alivio/LX crankset, Sun race cassette and KMC chain) pretty much immediately and has remained firm friends three hundred miles hence, skipping fore and aft faultlessly and a wee bit quicker than Alivio too.

That said, it's worth mentioning said test rig's brifters drop three cogs per nudge, accentuating its apparent superiority given the other, Alivio equipped tourer boasted lowlier Sora. Unexpected stop/starts round town and on some heavily trafficked climbs hasn't caught it napping-even shifting at slow speeds/under considerable load, immersed in bovine dung and similar unmentionables though obviously I expect it to succumb to the dreaded slop much faster than the 30,000 mile partially rebuilt LX unit it replaced.


Quirky looking mech that shifts really sweetly - a shrewd option for budget builds and/or working bikes with wider gear ratios.

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Make and model: MicroSHIFT Rear Derailleur For Mountain Bike w/ long cage

Size tested: Black

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?

Microshift's website says its a 8/9spd non-group component designed for mtb audiences. Great budget option for touring, commuting and some winter/cross builds too.

Tell us some more about the technical aspects of the product?

Model No. RD-M45L RD-M45S

Speeds 9 / 8 Speed, Long cage 9 / 8 Speed, Short cage

Max Sprocket 34T

Min Sprocket 11T

Max Front Difference 22T max.

Total Capacity 48T 39T

Guide Pulley steel bushing

Tension Pulley steel bushing

Bracket Body aluminum / black

Bracket Pivot Seal -

Plate Body Compositied

Plate Pivot Seal -

Outer Link Aluminium

Inner Link steel /black

Link Pin Bushing -

Outer Plate steel / black

Inner Plate steel / black

Rate the product for quality of construction:

Rugged and more refined than price would suggest.

Rate the product for performance:
Rate the product for durability:

Feels reassuringly solid thus far and shifts impeccably-even under provocation.

Rate the product for weight, if applicable:

325g by my scales.

Rate the product for comfort, if applicable:

Swift, slick, reliable changes in all contexts. Relax and enjoy the ride.

Rate the product for value:

Tell us how the product performed overall when used for its designed purpose

Easily on par with Shimano's Alivio, the M45 has delivered crisp, predictable shifting in all contexts and plays nicely with more esoteric drivetrains too. That said,road/cross typical builds might be better served by its short cage sibling.

Tell us what you particularly liked about the product

Refined action, reliable shifts. Nicely finished without attracting unwelcome attention, inexpensive so an obvious choice for daily drivers.

Tell us what you particularly disliked about the product


Did you enjoy using the product? Yes.

Would you consider buying the product? Definitely.

Would you recommend the product to a friend? Yes, for less glamorous/builds builds.

Overall rating: 7/10

About the tester

Age: 39  Height: 1m 81  Weight: 70 kilos

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)

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