Choose A Mountain Bike Frame Size Is Important

You can easily end up with the wrong mountain bike frame size. You can’t go off the listed frame size anymore. Here’s how to avoid getting it wrong.

Bad news: mountain bike frame size is all over the place. There is no consistency. One brand’s Medium/17in a bike is another brand’s Large/19in. What’s more, a lot of bike manufacturers’ – and even bike shops’ – sizing advice is often wrong too.

Ultimately you do not have a foolproof frame size. Not one that tallies with what bike brands say, nor one that is consistent from bike to bike. This means shopping for a bike is not simple, particularly if browsing online beforehand. It is not a good idea to select just one frame size and filter the results by that; select the frame size the brand recommends and also the size above.

But with all that said, to give you at least a head-start on what frame sizes to shortlist, whether you’re looking to upgrade or are trying to choose the best beginner mountain bike, here is our mountain bike size guide:

Mountain bike frame size guide

Under 5ft 2in (-157cm) = 13in to 14in (XS)

5ft 2in to 5ft 6in (157cm to 167cm) = 15in to 16in (Small)

5ft 6in to 5ft 10in (167cm to 178cm) = 17in to 18in (Medium)

5ft 10in to 6ft 2in (178cm to 188cm) = 19in to 20in (Large)

6ft 2in or above (182cm+) = 21in to 23in (XL/XXL)

What to do if you’re ‘in between’ mountain bike frame size

We’d strongly advise going for the larger of the two options. It’s easier to make a large bike fit without impairing how it handles; fitting a shorter stem and/or sliding the saddle forward on its rails arguably actually improves bike handling. Trying to make a small bike fit by putting a longer stem on it and/or sliding the saddle backward on its rails will end up impairing the bike’s handling.

The thing to bear in mind when going up a frame size is to make sure there is sufficient standover clearance. Standover is how high the top tube is at the point where you’re astride your bike and straddling it. If the bike has enough standover, you’re on to a winner.

Why are things so messed up?

The problem is that bikes have always been sized by the length of their seat tubes. There’s no reason for us to go into why this is so (short version: blame roadies) but you do need to understand that this is a big problem.

Whilst seat tube length is important it is not the most important measurement on a bike frame.

The modern move away from frame sizes being listed in numbers of inches has been an improvement. Using ‘Small’, ‘Medium’ and ‘Large’ etc instead of ’16in’, ’17in’ or ’19in’ is a much better idea.

What measurement is the most important then?

Reach.

Why is reach the most important measurement?

Reach is the distance between the bottom bracket axle and the center of (the top of) the head tube. See the diagram above.

This is a very difficult thing to measure on a bike in the flesh unless you’re happy to take plumb lines and tape measures into your local bike shop. Thankfully any bike brand worth its salt includes a reach measurement on the geometry charts of its bikes.

Why is reach the vital thing? Because it dictates how the bike fits you. It governs if a bike is too cramped or too stretched out for you.

And, unlike seat tube length, the reach cannot be adjusted. You can adjust your saddle height up or down to accommodate seat tube length. Reach cannot be adjusted. You’re stuck with it. A bike with too short a reach will always be too small.

Don’t think you can adjust incorrect reach by changing to a different stem length or by sliding your saddle on its rails backward. Changing stem length will impair how the bike steers and handles. And saddles slid far back on their rails won’t mean a thing when you’re stood up out of the saddle, and when you are seated slid-back saddles will result in inefficient pedal power and a wander, lift-prone front end.

Don’t end up with the wrong mountain bike frame size

A common result of going off sizing advice from a bike brand (or even a bike shop) is to end up with a bike that’s too short in reach and comes with a stem that’s too long.

A 6ft tall person would end up choosing a 21 inch frame mountain bike. Then the 29er Full Suspension Carbon MTB Frame MFM100 is the best option.

For more info please check our official website: https://www.trifoxbike.com/

Do you know how to maintain a carbon fiber frame?

Carbon fiber is an incredible material that has completely changed the design and performance of bicycle frames. It is lightweight, corrosion-resistant, can be molded into various required shapes, and is very strong in use. The claim that carbon fiber frames and related parts are generally brittle and unreliable is not true, but just alarmist. It is strong enough to be used in F1 and the aerospace industry, and there is no doubt that it is naturally used in the bicycle field.

If it is produced by a credible manufacturer and used correctly, there is no reason why the carbon frame will not give you enough mileage to ride happily, and now many manufacturers provide a lifetime warranty for the frame. No matter what frame material you choose, whether it is a carbon frame, a steel frame, aluminum alloy, or titanium alloy, quality is the key, and good quality is always more durable. Riding a carbon frame bike, you don’t need to deliberately change some cycling methods, but you can pay attention to the details of the daily maintenance and use of some carbon fiber bikes.

Buy a torque wrench

Despite the incredible force performance in the design direction, squeezing can easily damage the carbon fiber, such as over-tightened bolts and clamps, handlebars, and seat posts are the most common causes of damage to the carbon fiber frame. All parts of a carbon fiber car will be marked with a recommended torque value in Newton meters, which can be found on the relevant parts, manuals, or on the manufacturer’s official website. If you have a carbon fiber bike, a torque wrench is necessary, it can ensure that you will not use more than the recommended torque to tighten the components. If you have previously owned a bicycle with a metal frame, you may be surprised that the force required to assemble and adjust a carbon fiber bicycle is so small.

Use carbon assembly paste

The relatively small torque required for the carbon frame and its components also has a drawback that it is easy to slip off. This especially affects the Seatpost. Don’t risk trying to tighten the Seatpost with extra, more force, you should use carbon assembly paste. This is a gel containing fine particles, similar to a thin film, which increases friction between the contact surfaces to prevent slippage. Assembling paste and torque wrench are necessary for carbon fiber car owners.

Be careful

Damage to the carbon frame caused by accidents or collisions is usually difficult to predict and avoid in advance, but some collision events that damage the carbon fiber can be easily avoided. A common situation is when the handlebar is rotated and hits the upper tube of the frame. This often happens when the bicycle is inadvertently lifted. So be careful not to let this happen when picking up the bike. In addition, try to avoid stacking bicycles on other bicycles, and do not use the seat part to lean on poles or pillars, so that the bicycle will easily slip and cause a collision with the frame. Leaning the bike on a surface such as a wall is much safer. Of course, you don’t need to be too nervous to wrap your bike with cotton wool. You just need to be more careful and take reasonable precautions to avoid unnecessary collisions.

Keep it clean

Regular cleaning can give you a chance to inspect the bike carefully to see if there are obvious signs of damage. Regardless of the material of the frame, this should be your routine during cycling. Of course, rough cleaning also needs to be avoided, which will damage the epoxy resin wrapped around the carbon fiber. If you have any questions about how to clean your bike scientifically, you can consult the manufacturer for advice. Any degreaser or cleaning products for bicycles and old-fashioned mild soapy water should be used appropriately and reasonably.

Avoid squeezing

As mentioned above, try not to over-tighten the parts. Carbon fiber is easily damaged by extrusion. Therefore, you need to be especially careful when using a repair rack or an on-board bicycle rack to clamp the frame tube. The bicycle should be fixed with minimal pressure, or a protective layer can be wrapped on the frame. Of course, you can also consider changing to a bicycle transportation method. If you want to take your bicycle on the plane, we strongly recommend using a hard special box for packing.

Don’t reverse

For metal frames and parts, for example, during the installation process of handlebars and Seatposts, it is normal and acceptable to give a certain amount of rotation or pull for fine adjustment after being fixed. However, this step will cause damage on the carbon fiber car and must be strongly avoided. The correct way is to use the recommended torque value and use the assembly paste. If the position and angle of the parts need to be adjusted, the parts should be completely loosened in advance.

Measure twice, cut once

If you need to cut carbon fiber parts, such as handlebars and the entire Seatpost, remember to measure carefully and accurately, and wrap it with tape as a mark for the cutting part. Cutting requires a special carbon saw blade, which can prevent fiber tearing and abrasion. . Never use a pen or sharp tool to mark the position on the seat post that needs to be cut, because even a small scratch may damage the carbon fiber. Instead, you can use insulating tape to paste and wrap it to mark the cut position.

Avoid chain jamming

Many people have encountered the situation of chain drop, especially when shifting gears incorrectly. In the worst case, the chain gets stuck between the smallest chainring and the chainstay after the chain is dropped, and it gets stuck instantly. For carbon fiber bikes, this is a great “pain”. When this happens, stop pedaling immediately and avoid further exertion. After returning home, thoroughly clean and relubricate your drive system. Check your chain, including wear, elasticity, etc. It is best to replace it if necessary.

Replace the brake pads

If you use alloy training wheels and carbon fiber racing wheels alternately, replacing your brake pads accordingly is the most basic. Although there are dual-purpose brake pads, the remaining metal fragments on the surface of the brake pads can easily scratch and destroy the carbon fiber rim.

If the worst happens

In the event of a crash or accident, unlike the metal frame, where the depression or bending damage can be clearly seen on the exterior, the carbon fiber may appear to be undamaged on the exterior, but it has actually been damaged. If you have such a crash and worry about your frame, be sure to ask a professional technician to do a professional inspection. Even serious damage can be repaired well. Even if the aesthetics are not perfect, it can at least guarantee safety and function.