12th April 2021 / Comments (4)

How to turn an old MTB into a gravel bike

Turn your old MTB into a gravel bike

As we covered in Part 1 (Are Gravel Bikes Just 80’s Mountain Bikes?), although vintage mountain bikes are not the same as modern gravel bikes, I think that with a few tweaks they can be turned into incredibly capable alternatives to a new bike. What’s more, it’ll be cheaper and more sustainable.

If you’re gravel curious and want to dip your toe in, have an old MTB in the garage, or just like the aesthetic of vintage mountain bikes then read on and I’ll give you some tips and tricks to get the best out of these older machines.

Deep clean

Turn your old MTB into a gravel bike

Strip back and deep clean is the essential first step

I’m not talking about just spraying it lazily with a hose here. Get it sparkling. Clean the chain, spray degreaser everywhere and get everything as shiny as possible. In my experience, when a bike has decades of grime it’s usually easiest to take the whole thing apart, down to the frame, and wash the components individually (hot soapy water and a stiff brush is your friend here). Older bikes have very little in the way of proprietary parts, and so are great places to learn new mechanical skills with a very low consequence ceiling. Go on, I believe in you.

A secondary advantage of taking everything apart is you can inspect the frame thoroughly for any damage, or dangerous rust spots, and also inspect the parts for any signs of dangerous wear and tear. You’d be surprised what can sometimes lurk behind years of grease, but on the whole things will be very solidly built and should have stood up well to the abuse.

Sort the bearings

Turn your old MTB into a gravel bike

Investing time sorting out the bearings first which give you a much smoother ride

Nothing ruins the feel of a ride like crunchy bearings, so do yourself a favour and get them running smoothly again.

Things have moved on a lot from the days when square taper bottom brackets were the gold standard, but they have a lot to offer still in my eyes. They’re sturdy, simple, and the cranksets can be reinstalled countless times. However, loose bearings packed with grease are never going to beat a sealed cartridge unit (unless you’re on the track, free from the worries of grit ingress).

Likewise, replacing the headset with a sealed cartridge unit (the Tange Falcon is my go-to) will smooth out the steering action, and drastically reduce the risk of pitting the headset cups over rough ground, resulting in that awful notched headset feeling.

Unless you replace the hubs you will be stuck with either loose or caged ball bearings, but all is not lost. A deep clean and regrease will usually have them running smoothly once more (this job can be relatively fiddly, so don’t get disheartened if you give up and take it to a friendly local bike shop).

New cables and housing

Turn your old MTB into a gravel bike

It’s well worth switching out your outers as well as inners when it comes to replacing cables throughout

Old thumb shifters and brake levers are about as indestructible as bike parts come, but they’re useless if the cables and housing protruding from them are corroded and sticky. Best bet is to replace them unless they’re clearly in good condition. It’s cheap, it’s unglamorous, nobody else will notice, but it can make a huge difference.

Turn your old MTB into a gravel bike

Yikes! Replace the cables for smooth running

Improve the braking

Turn your old MTB into a gravel bike

Give your old rim brakes some TLC and they might just surprise you

Odds are the bike you’re working on will have cantilever brakes, or V-Brakes if it’s more modern. While discs have clear advantages over rim brakes, with a bit of effort you can improve the performance of the system you already have with a few little tweaks.

Firstly, clean the brake track. Big scrubby wipes are a good start, but the best thing is some paper towel and surgical spirit or bioethanol. Brake pads work best on bare metal, not on years of accumulated brake dust.

Secondly, swap the pads for something decent. Basic brake pads are always tempting as they’re cheap, but they’ll wear out faster and you simply won’t stop you as quickly. A premium set of pads (my choice is always Kool-Stop Salmon), properly adjusted with some toe-in, will have you re-thinking whether cantis are so bad after all.

Swap the tyres

Turn your old MTB into a gravel bike

Fresh rubber will make a huge difference, although your options may be a bit limited at 26″

Now for the fun bits…

A lot of vintage tyres will be under 2” in width, but in my experience you can often fit up to 2.25” rubber on these older bikes. While it may not always be the best option to go as wide as possible, it’ll certainly improve the comfort.

Very few companies are making new 26” bikes, and so tyre choice is a little limited, but that’s not to say you can’t get some very good tyres. WTB Nanos for example are an excellent do-it-all choice available in 26”, as well as options from the world of dirt jumping such as Schwalbe’s Billy Bonkers or Table Top.

There are even a handful of companies making new 26” rubber precisely because of the number of people repurposing old bikes; Ultradynamico are set to release a new set for smaller wheels this year, while Rene Herse have four of their most popular treads also available in 26” for ultimate supple points.

Change the bars

Turn your old MTB into a gravel bike

Drops or flats, straight or sweep: there’s a whole world of bars out there to experiment with

Vintage MTB bars are narrow, twitchy, and primarily flat. Do yourself a favour and pop something wider and more ergonomic on, and enjoy the additional comfort and control.

The world really is your oyster here, with a plethora of options to choose from. Brands like Nitto offer a fantastic range with the smaller clamp diameter that vintage quill stems require, or with a quill stem adapter you can pop any modern stem on and open up the world of 31.8mm bars too.

Personally speaking I like to have a lot of sweep. As these bikes are unlikely to be competitive race machines, why not just embrace the comfort?

If you really want to change the feel of the bike you can fit drop bars with relative ease. Some simple brake levers (make sure they’re the right lever pull for your brake system) coupled with bar end shifters can transform the bike completely. Just be aware this will extend the reach, so you may need to fit a shorter stem to compensate.

Add some accessories

Turn your old MTB into a gravel bike

Racks, bags, baskets or bar ends, make your build your own!

Pop a rack on. Add a saddlebag. Add a basket. Order a full set of custom bikepacking luggage. The bike is already heavy, but it’ll have the gearing to accommodate, so go wild and give yourself the ability to pack the kitchen sink. Ultralight is dead, long live waxed canvas.

Swap the gearing

Turn your old MTB into a gravel bike

1X gearing might limit range compared to an old school triple, but the simplicity is marvellous

With a bit of mechanical know-how it is possible to completely update the drivetrain to a 1x setup, complete with a wide range cassette at the rear, if that’s your cup of tea. Even if it isn’t, the simplicity of a 1x system can be achieved by simply replacing the triple chainrings with a single narrow-wide chainring, though you will be marginally more likely to drop your chain as old derailleurs are clutchless, and you will have a vastly reduced gear range. On the flip side it looks cool as hell and you’ve only got one shifter to think about.

Mod the frame

Turn your old MTB into a gravel bike

Adding bosses to the frame and fork can give you many more luggage options

The final, and most drastic alterations to make will be easiest if your bike of choice is made of steel. Fortunately most of them will be, which makes life easy.

Not happy with rim brakes? Get a local framebuilder to braze you on some disc tabs.

Want more mounts for more bottle cages, or larger anything cages? Get a local framebuilder to braze you in some new mounts (I added two bosses to each of my fork legs for extra water storage).

Bored with the trappings of gearing and want to go fixed? Swap the dropouts for something more horizontal. You will sacrifice some of the paintwork, but channel your inner Mad Max and roll with it.

Fresh coat of paint

Turn your old MTB into a gravel bike

Modern paints like Spray.Bike make home paint jobs fun and easy

Money to burn? Why not go all out and get a custom repaint? You could restore it back to its original glory, or go for something completely different. Or, if you’re feeling handy, you could give it a rattlecan job using Spray.Bike spray paint (my preferred option). Sometimes however it’s good to admire all the little dings and scrapes and embrace the #beausage life.

Over to you

Turn your old MTB into a gravel bike

There are some real bargains to be had, as long as you’re prepared to put in the elbow grease

If you’re after a vintage MTB of your own then I prefer to use Facebook Marketplace, as you can see the bike in the flesh before buying it. A few pre-flight checks before handing over the cash:

  1. Check the seatpost moves. Nothing kills a frame like a stuck seatpost
  2. Look for any signs of rust. ‘Patina’ is fine, and I quite like it, but if it looks structural then steer clear
  3. If the frame has internal cable routing then unless you trust the owner has meticulously used frame saver then best avoided, as water can get in and rot the tubes from the inside out
  4. Check the wheels aren’t tacos
Turn your old MTB into a gravel bike

Breathe some new life into an old bike and it can give you many, many miles of pure joy

Obviously the better condition it is in the less work you’ll have to put in to make it rideable, but if you’re planning to swap the majority of the parts anyway then you can find some absolute bargains.

If you’re just buying a frameset, then give the bottom bracket threads a good eye over too.

eBay is always a good option if you’re buying remotely, as there is more buyer protection, but make sure it’s got a full set of pictures and a decent description.

Finally, it’s nearly impossible to guarantee you aren’t buying a stolen bike when buying second hand, but you can get a feel from the seller just by asking lots of questions. How long have they had it? How does it ride? What components are on it, etc?

Steel frames really are a blank canvas for your ideas, however bananas they may be. Whether you keep things as standard or make some outlandish changes, the overall cost to both your wallet and the environment will likely be far less than that of buying a new gravel bike, and you’ll still have a bike that, while not designed specifically for gravel riding, is still totally capable of carrying you in speed and comfort over a wide array of surfaces.

Check out Will’s many gorgeous conversions at Zetland Cycles and let us know how you get on with your projects!

Last modified: 15th April 2021

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Alex Ball
Alex Ball
13 days ago

With the greatest respect, this article isn’t really about turning one bike into another type of bike, it’s about refreshing and upgrading an old mountain bike into another mountain bike. As an “old-school mountain biker” I was racing from the start of the mountain bike scene and gradually dropped out as the cost of race entries climbed, the races got more generic and more serious and above all less fun, and then the equipment costs climbed to the point where a set of suspension forks cost as much as my first bike. The appeal of gravel bikes is that I’m… Read more »

Will Jones
Will Jones
12 days ago
Reply to  Alex Ball

While this may have been partially true a few years ago, now that the big brands are releasing flat bar versions of their gravel bikes (Allied Able and Specialized Diverge spring to mind) I don’t think you can base a genre definition solely on the type of handlebar. Would an endurance road bike fitted with flat bars and some small knobblies become a MTB? Now that modern bikes are long and slack and squishy, and much more capable on steep gnarly terrain but less so on mellow gravel trails I’d argue that what defines a bike is the terrain it’s… Read more »

Matthew Soley
Matthew Soley
2 days ago
Reply to  Will Jones

Tomac was racing mountain bikes on drop handlebars from the very early days of downhill mtb (atb?) so I’d agree, terrain defines the bike.

Carl Falk
Carl Falk
10 hours ago

Great article. I have an old steel Independent Fabrications mountain bike I’ve been dying to convert into a “gravel” bike. Actually bought the frame new in the late 90’s. The biggest issue I’m currently grappling with is finding a suitable fork (threadless 1-1/8, 26”). They’re surprisingly hard to come by (for a decent price). This is my project for the summer. Really looking forward to bringing this bike back to life. We’ve had some epic adventures together.

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