Road Bike Axle Standards

Road bike bottom bracket standards.

Road bike axle standards.

Some bikes like trek s split pivot full suspension bikes use thru axles that are up to 50mm longer than the hub dropout width. 130mm old rim brake only. Shimano s 11spd road cassettes are just a little bit wider than their mountain bike cassettes. Everything you wanted to know but were afraid to ask.

But this does build in constraints at both extremes of the. There are three common types of freehubs drivers. You ll still find inboard bearings on many budget bikes often with a solid square taper axle. Mountain bikes mostly use a 15x100mm front thru axle and you might still find a few road bikes that adopted that standard early on but 12 100 is more future proof for road.

At first 135mm was the most common rear axle spacing with 150mm used for dh. 15 x 100mm 127 length 1 5. As of 2018 fatbikes and disk brakes have led to a several new axle length standards. Boyd is probably right on his where are standards headed estimate.

You can see more details about these measurements below. It is yet another axle standard to worry about. How does this affect you the bike consumer. But 142mm and 157mm soon superseded these standards with the extra 7mm allowing a stiffer interface with the frame.

130mm old which means rim brakes can t stress this enough. Let s review current axle standards. Driver vs free hub hg mtb vs hg 11spd road vs xd. How to measure a bicycle thru axle most thru axles are described by four measurements and you might see them described something like this.

Backward compatibility will continue to be necessary as frames and forks with other standards will linger for a long time. For example i have disc cross road and xc bikes. The problem of disk brakes pulling the hub out of the front dropouts see james annan s article has been addressed with through axles which insert into a fork with a hole rather than a slot at the end of each blade. Some wheels and forks have swappable end caps or dropout inserts allowing for the use of either 12 or 15mm front thru axles.

Not a single axle among them conforms to that envisioned future standards set. In this example 15mm is the diameter 100mm is the o l d 127mm is the overall length and 1 5mm is the thread pitch. It looks as if the pace of change in disc bike axle standards will slow now with 12x100mm front and 12x142mm rear thru axles dominating. Most every modern disc brake road cyclocross and gravel bike uses a 12 100 front hub standard and a 12x142mm rear hub standard.