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Tech Help & FAQ

This page will attempt to shed some light on the many questions that customers have when buying wheels.  To be used as a guide only, if you are still unsure please call the office on 0800 677 1617.

Hub Choice

Probably the most common area for mistakes to be made so let's start with the most popular hub types. For the time being we will ignore Fat Bike hubs.

Front hubs

Width or OLD (the width of the hub between the faces that contact the fork) - either 100mm or 110mm

Most road bikes, gravel bikes, older mountain bikes & cheaper mountain bikes will have 100mm OLD and either a quick release skewer of a through axle with a diameter of 12mm (road/gravel/cyclocross disc brake bikes mostly) or 15mm (mountain bikes and some road/gravel cyclocross disc brake bikes). See note below regarding downhill bikes. Edit:  Road Boost is now a thing! some Gravel & Adventure bikes now have Boost spacing (110mm front and 148mm rear).

Newer mountain bikes (except the cheaper ones) will probably have Boost forks that have an OLD of 110mm and a 15mm through axle.  Boost hubs will only fit Boost forks, non-Boost hubs can sometimes be converted to fit Boost forks but it requires spacing the disc rotor mount and different end caps to increase the OLD and is not an ideal solution.  The extra 10mm width of Boost forks is between the hub flanges which improves the spoke angle, particularly on larger wheels, making them more stable.  Boost hubs are not found on 26" wheels

Note regarding Downhill forks with 20mm axles.  Earlier versions of forks such as RockShox Boxxer (dual crown long travel forks for downhill) have a 20mm axle with a 110mm OLD but they are NOT Boost (usually a normal hub with end caps that are wider and have a 20mm through axle. A Boost wheel will not fit one of these forks.  Just to confuse things further, newer downhill forks are Boost but they are still 110mm.  A Boost downhill fork should mention somewhere on the lower legs that it is Boost, it is a bit difficult to tell otherwise.

Torque end caps

Some Rockshox forks only. Torque end caps are available as an option on some wheels.  Standard end caps will fit a Torque compatible fork but Torque end caps will not fit a non-Torque fork.

Torque compatible forks have a larger diameter recess on the inside of the fork leg and the Torque end caps for the hub also have a larger diameter, this increases the contact area between the hub and the fork which is designed to increase the stiffness of the front end of the bike. Not everybody notices the difference in stiffness when fitting the Torque end caps, I think it depends on the rider and the style of riding, but one difference that people do notice is that changing a front wheel is easier with the Torque end caps. Because the end caps match the fork recess the axle lines up correctly, a wheel with standard end caps will "float around" in the larger recess while you try to line up the axle.

Rear Hubs

Road bikes with rim brakes - 130mm OLD and quick release skewer (unless the bike is quite old roughly 1988 or older)

Road/Gravel/Cyclocross bikes with disc brakes - Either 135mm quick release or 142mm through axle (135mm with 12mm and even 10mm through axle do exist but are not that common).  Most reasonable quality hubs can be easily converted from 135 to 142 by swapping end caps (also called spacers, conversion kits etc)

Mountain bikes - this is where it gets interesting - Any of the following:

135mm quick release - Older and cheaper bikes only, anything with rim brakes.

142mm through axle - Most disc brake MTBs (except the cheapest) up to the point where everything started going Boost).

Boost - 148 x 12mm through axle - Most newer MTBs except the cheaper ones.  Boost rear spacing (148mm OLD) has become the most popular standard for MTBs since they dropped the 26" wheels in favour of 29".

150mm - Older standard for downhill bikes.  The hub flanges were spaced to improve wheel stability, mostly replaced by Boost 148mm or SuperBoost 157mm.

Other downhill hubs - 7 speed downhill specific hubs can also be found in 135x12mm, 142x12mm and 157x12mm.

Boost 141 - Found on the cheaper end of the scale on "proper" MTBs,  Probably invented to cut costs, this is effectively a Boost hub with a quick release skewer (and suitable Q/R end caps).  Some Boost hubs, including Hope, can be converted from Boost (148x12mm) to Boost 141 by simply swapping the end caps.  We offer this swap when buying Hope wheels, you just need to buy the normal Boost rear wheel and select the "convert to Boost 141" option, we will then swap the end caps when the wheels arrive from Hope.  Hope don't currently offer this option on their factory built wheels.

Cannondale AI - Cannondale, in their infinite wisdom, decided to complicate things further by making some of their bikes with an offset rear end to improve wheel strength and stability, this requires a rear wheel with the rim offset to the non-drive side.  Fortunately standard wheels can be re-dished to fit and this is a service we can offer on some wheels purchased from us.  Please enquire before ordering.

Freehubs & Cassettes

Freehubs used to be fairly straightforward.  Most road bikes had groupsets from either Shimano, Campagnolo or SRAM and most mountain bikes only had a choice of Shimano or SRAM.  Since Shimano and SRAM used the same freehub body it was fairly simple.  The introduction of cassettes with a 10 tooth smallest sprocket by SRAM changed things a bit.

The smaller diameter of the 10 tooth sprocket required a different freehub body so SRAM invented the XD driver, however for SRAM cassettes with an 11 tooth smallest sprocket (found on the cheaper SRAM groupsets) they continued to use the Shimano freehub body, this includes the Eagle 12 speed range.  If you have SRAM gears on "off the peg" bike and are looking to replace the rear wheel it is not as simple as saying I have SRAM GX (or NX or X1 etc) as some bike manufacturers will fit a cassette from a lower groupset (or even a different make) in order to save money.  For SRAM gears, both 11 & 12 speed, the best way to tell if you need a Shimano or XD freehub is to count the number of teeth on the smallest sprocket of your cassette.  10 teeth - you need XD, any more than 10 you need Shimano.

XDR Freehub - This is the road version of the XD freehub for cassettes with a 10 tooth smallest sprocket.

Microspline - Shimano belatedly joined the 12 speed party with their (very good) range of 12 speed groupsets that all have a 10 tooth smallest sprocket and, therefore, all need a different freehub body.  Obviously they didn't want to use SRAM's XD driver so they came up with the Microspline freehub.  This (currently) only fits Shimano 12 speed mountain bike cassettes (XTR, XT, SLX & Deore).

A note on Shimano freehub bodies.  11 speed road cassettes are wider than 11 speed MTB cassettes.  DT Swiss makes different MTB and 11 speed road freehubs but many other manufacturers, including Hope and Bitex, make one Shimano freehub that fits both road and MTB which is usually supplied with a 1.85mm spacer which needs to be fitted before the cassette when using an 11 speed MTB cassette or a 10 speed road cassette.

Hope Shimano 10-11 speed freehub bodies - Hope make 2 versions, aluminium and steel. Aluminium is lighter by around 90g but can suffer from the cassette sprockets biting into the edges of the grooves, the steel version doesn’t suffer from this issue but it weighs more. The choice is down to the consumer.

Through Axles

Can be called thru axles but I am British so I will refer to them as through axles.  The axles themselves are specific to the frame or fork and not the hub.  Different thread pitches are used and the design of the dropouts on bikes and forks varies between manufacturers so do not assume that any axle will fit any bike.

Quick Release Skewers

Getting less common but still found on rim brake road bikes and some (usually cheaper) other bikes.  The terminology used to describe Q/R skewers varies but, for clarity, we are referring to the type that has a 5mm skewer that is used on bikes with open dropouts.

They width of the dropout (and the part of the hub end cap that fits into it) is 9mm on the front and 10mm on the back.  The skewer is 5mm in diameter so these are often referred to as 5mm Q/R, 9mm Q/R or 10mm Q/R.  To make things worse a few manufacturers use, or have used, a 9mm (front) and 10mm (rear) axle that works like a Q/R but looks like a through axle (in so far as they are 9 or 10mm in diameter).  Some hubs can be converted to this, rarer, configuration by swapping the end caps.

Disc Brake Rotor Mounts

Thankfully there are only 2 option that are widely used for attaching the disc brake rotor to the hub - 6-bolt or Centerlock.

A 6-bolt rotor, as the name suggests, is fitted by 6 bolts.  If you have a 6-bolt hub you can only fit 6 bolt rotors.

Centerlock.  This is a Shimano invention and is spelt using the American spelling of centre.  Widely used on Road disc bikes but also gaining a lot of ground on mountain bikes helped by the likes of DT Swiss (a long term Shimano partner) specifying it on the majority of their factory built wheels.  Centerlock rotors have a female spline fitting that fits onto a male spline fitting on the hub and is retained by a lockring that is similar to the type that fits a cassette.  Shimano Centerlock rotors are supplied with "standard" lockrings that use a cassette tool to tighten them, these are not compatible with 15mm axles (not enough space between the lockring and the encap to get the tool in).  For 15mm axles you need a lockring with external splines that is tightened with a standard external bottom bracket tool.

Centerlock hubs can be easily converted to accept 6-bolt rotors by using an adapter.