I've been testing MTBs for over 30 years, here's the 5 must-have features I look for on a budget mountain bike

Calibre Line 27 T3
(Image credit: GuyKesTV)

If you're in market for a new MTB, there are loads of budget mountain bike options to choose from. So how do you decide which ones are winners and which are losers. Not just now, but further down the line when you're hooked on trail time and want to upgrade parts or replace bits you've worn out?

Our ultra-experienced bike test editor, Guy Kesteven, reveals the five must-have features you might not think about at first but matter way more than component brands and amount of gears in the long run.

And if you're unsure whether to actually buy a new bike or not, Guy has also written a guide to 6 crucial signs you need a new mountain bike.

head tube of budget hardtail

A relaxed head tube angle equals a more relaxed steering feel so you can stay confident when things get crazy (Image credit: GuyKesTV)

1. Good geometry

If the bike frame isn’t a good shape to start with, there’s nothing you can do to make it ride confidently so you can have maximum fun. Unfortunately, some cheap mountain bikes just re-use old, outdated frames to save money. 

The really important number is the head angle. This is the angle the forks sit in the frame and the smaller that number is the more stable the steering of the bike will feel. For general trail riding, you want a 67-degree head angle or less. Otherwise, the steering will feel really nervous.

A generous reach – the horizontal distance from the center of cranks to the fork top – also helps stabilize the bike. My baseline numbers are 470mm for a large frame, 450mm for a medium frame and 430mm for a small frame. If you have to size up to get the reach you need, make sure you still have enough space under the saddle to fit a dropper post if you’re looking to upgrade to one in future.

Buyer beware...

To be clear here, we’re talking about the angles of the frame tubes – not the shape of the tubes themselves. They don’t really matter in the grand scheme of things, although be aware that big, square tubes will generally give a harder ride than skinny round ones.

Rear disc brake on hardtail

Disc brakes offer much more consistent speed control than rim brakes, especially in the wet (Image credit: GuyKesTV)

2. Disc brakes

Thankfully it’s been a long time since I’ve tested a mountain bike with brakes that rub on the rims to eventually stop you. That’s because disc brakes give much more consistent braking in wet weather or on dirty trails and have become the industry standard. Ideally, you want brakes that use hydraulic fluid as they self-adjust for pad wear, but wire cable-operated disc brakes are still better than rim brakes. For more, see our article on mechanical vs hydraulic disc brakes.

If your budget doesn’t stretch that far then at least get a frame and forks that have the attachment points for disc brakes already built in.

Buyer beware...

Check with the shop what sort of replacement brake pads you’ll need for your brakes. Most budget brakes share standards with Shimano but some are a special shape which can be hard to find.

Bolt through axle on fork

Large diameter bolted axles are much more secure and safe than skinny steel 'QR' skewers designed for road bikes in the 1930s (Image credit: GuyKesTV)

3. Through-axles

‘Through-axles’ that slide through solid ends in the fork and frame are a lot more secure than old road bike style quick release (QR) axles that sit in open slotted fork and frame tips. Ideally, you want them to be ‘Boost’ standard which means 110mm wide at the front and 148mm wide at the back too. This makes the frame and forks stiffer for more accurate control and makes it much easier to upgrade with better wheels in the future.

Buyer beware...

Even at $1,000, some of the most popular mountain bikes still have QR skewers with a skinny steel rod, not a thicker through-axle. Don’t be fooled by ‘standards’ like “Boost 141mm” either as they’re not a proper Boost fit and still use a QR skewer.

A straight steerer tube on a mountain bike

A skinny head tube with a straight rather than tapered fork steerer will make it almost impossible to update to better quality suspension in the future (Image credit: Rich Owen)

4. Tapered fork fit

Another future upgrade issue I still see hiding on some four figure price tag mountain bikes are skinny head tubes with skinny straight ‘steerer’ suspension forks. To be honest, the performance of these forks isn’t much worse than other similarly cheap models so you’re not losing out much at first. However, all better quality forks and frames use a ‘tapered' steerer with a larger bottom bearing as that design is lighter and stiffer, so you won’t be able to upgrade in the future.

Buyer beware...

Speaking of cheap forks, coil-sprung versions can feel great if you’re between 70-80kg in weight. However, if you’re lighter or heavier than that try and get a fork with an air spring that can be adjusted to your weight or how hard you ride. 

27.5in tire and wheel

Fat 27.5in tires actually make a lot of sense on cheap hardtails with hard riding frames. You might struggle to get replacement tires in the not too distant future though (Image credit: GuyKesTV)

5. Twenty niner wheels

The final item on my wish list for budget mountain bikes is probably the most controversial one. Unless you’re buying an XS frame I’d say always go for 29-inch wheels if you can. Partly that’s because they roll a bit smoother and easier than 27.5in wheels so your bike will make you feel like a slightly better, fitter rider. You’ll generally find 29in wheeled bikes will have more up-to-date geometry too.

However, yet again the main issue is upgrading in the future. That’s because decent quality 27.5in wheels and tires – particularly front ones – are getting increasingly hard to find as most bikes switch to 29in.

Buyer beware...

The big issue with saying that you should always buy a bike with 29in wheels is that some of the best budget mountain bikes available now – like the Calibre Line or Jamis Faultline – still come with 27.5in wheels. Just to be really awkward, they often come with all the essential features listed above while some 29er bikes don’t. So in this case, feel free to ignore me about wheel size, just be sure to buy some spare tires while you still can (and while they’re being sold off cheap).

Guy Kesteven

Guy has been working on Bike Perfect since we launched in 2019. Hatched in Yorkshire he's been hardened by riding round it in all weathers since he was a kid. He spent a few years working in bike shops and warehouses before starting writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. To make sure he rarely sleeps and to fund his custom tandem habit, he’s also penned a handful of bike-related books and talks to a GoPro for YouTube, too.

Current rides: Cervelo ZFS-5, Forbidden Druid V2, Specialized Chisel, custom Nicolai enduro tandem, Landescape/Swallow custom gravel tandem

Height: 180cm

Weight: 69kg