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.

Road bike axle standards.

But this does build in constraints at both extremes of the. Driver vs free hub hg mtb vs hg 11spd road vs xd. 130mm old which means rim brakes can t stress this enough. At first 135mm was the most common rear axle spacing with 150mm used for dh.

How does this affect you the bike consumer. Some wheels and forks have swappable end caps or dropout inserts allowing for the use of either 12 or 15mm front thru axles. Most every modern disc brake road cyclocross and gravel bike uses a 12 100 front hub standard and a 12x142mm rear hub standard. Not a single axle among them conforms to that envisioned future standards set.

Let s review current axle standards. 15 x 100mm 127 length 1 5. You can see more details about these measurements below. Road bike bottom bracket standards.

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. For example i have disc cross road and xc bikes. 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. 130mm old rim brake only.

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. 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. Good old fashioned quick release. But 142mm and 157mm soon superseded these standards with the extra 7mm allowing a stiffer interface with the frame.

As of 2018 fatbikes and disk brakes have led to a several new axle length standards. How to measure a bicycle thru axle most thru axles are described by four measurements and you might see them described something like this. There are two common types of hg free hubs mtb and 11spd road. It is yet another axle standard to worry about.

You ll still find inboard bearings on many budget bikes often with a solid square taper axle. Shimano s 11spd road cassettes are just a little bit wider than their mountain bike cassettes. Boyd is probably right on his where are standards headed estimate. Everything you wanted to know but were afraid to ask.