Hope is based in the UK and designs and machines all of their hubs in their UK plant. They’ve offered road hubs for years, and their latest Pro4 disc hubs are 11spd road compatible, so you can use them on a disc road bike, but their new RS4-CL hubs are their first road-disc specific hubs. Let’s dive into the details.
First, lets talk about what’s similar. The RS4-CLs are designed, machined, and assembled in Hope’s UK plant just like the Pro4s, and they’re available in the same wide range of colors. Like the MTB hubs the axle standards are easily changed, just pull the endcaps off and push new ones on. They’re available in QR, thru-bolt, and all thru-axle road standards (no 20mm or Boost spacing), and 24 to 32 hole counts. They’re available out-of-the-box with either a Shimano or Campy freehub body. The freehub body comes off the rear hub without any tools for easy access to clean and re-grease.
The most obvious difference between the RS4-CL and Pro4s is the brake mount – the RS4-CL are centerlock, which is the most popular brake mount standard for road/gravel/CX bikes. An important difference is one you can’t see without taking the hub apart – the RS4-CL rear hub uses only two pawls instead of four like the MTB hub. This, in my opinion, is a bad idea, but one that’s easy to sidestep.
So why did they go with only two pawls instead of four, and what are the disadvantages? Fewer pawls means slightly less drag when coasting and a little less noise, those are the only advantages. The disadvantage is that the stresses on the freehub body are doubled, and that’s my rub.
Hope’s MTB hubs have always come standard with an aluminum freehub body, but there is also an optional stainless steel version. Most riders never had problems with the alloy option, and it’s lighter. But, some riders, particularly heavy or very strong riders, did have problems with the alloy freehub bodies – the pawls seats (where the pawl sits in the freehub, and where all of your pedaling effort is transferred from the freehub body to the hub shell) could actually deform, which causes problems like skipping. The harder and stronger steel freehub bodies don’t have this problem, even under very heavy and/or powerful riders, and new hubs can be purchased with the steel freehub body for no additional cost.
With the MTB hubs there were four pawls – four places for pedaling forces to travel through the freehub body. With the RS4-CLs (and the non-disc RS4) road hubs there are half as many pawls, and therefore each pawl is transferring twice the load of a MTB hub – I suspect this will cause many riders to eventually have issues with the pawl seats deforming.
But the good news – there’s a way around it. The RS4-CLs are also available with a stainless steel freehub body, and it’s actually the same one used on the MTB hubs so it comes with four pawls. You could even install a SRAM XD or 11spd Shimano alloy MTB freehub body, both of which have four pawls, but Hope doesn’t currently offer those configurations out of the box so you’d have to purchase the freehub body in addition to the hub.
I had hoped that the RS4-CLs would use the exact same alloy freehub body as the MTB hubs, only with two pawls installed, then I could simply add an additional two pawls, but it appears that the alloy RS4-CL freehub bodies are different, and they’ll only take two pawls. So if you want the lighter alloy freehub body AND want four pawls, you’ll have to purchase the freehub body in addition to the hub. The steel freehub is heavier, but it’s also stronger and no additional cost.