First Look | Stan’s new ZTR Bravo Pro Carbon Wheelset
For many years we have seen huge steps forward in tire design, growing in volume and shedding weight, but rims have barely changed retaining their narrow sub 20mm widths. However over the last few years, there has been a shift in outlook and many designers are now considering rims and tires as a system that needs to evolve in unison.
We have seen a big push towards wider designs, and many companies are now catching on to the benefits that wider rims can bring. Stan’s aluminium ZTR FLOW rims were the standard which all others were measured by, so we were excited to receive a set of their brand new ZTR Bravo rims, a hard-hitting enduro rim made from Carbon.
The first thing you notice about the new 28 spoke ZTR Bravo wheel set is that the sidewalls are not as tall as some of the competition. The ZTR Bravo uses Stan’s Bead Socket Technology, which means that the tire sits higher on the rim, only anchoring on the bead and not the sidewall of the tire. Stan’s claim this allows the tires sidewall to expand fully and produces a fuller tyre profile. The lower profile sidewalls also should result in less chance of damage from rock strikes, something we have had issues with on deeper section carbon rims.
If a rim is too narrow the limited sidewall support makes it easy to deform the tire in hard turns, and lower pressures are a no-no. However, if you go too wide you ruin the tire profile and reduce control, and also lose the protection of the tires sidewall. The new ZTR Bravos have a 32 mm width with a 26.6 mm internal width making them about the middle of the road when it comes to wide profiles. With their low profile sidewalls, they should offer a good seat for high volume tires.
Another interesting feature of the new wheels is the new RiACT design. The first time you ride on carbon wheels the feeling of stiffness is pronounced and the improvements in acceleration and accuracy are obvious, however too much stiffness can be a disadvantage making the wheel feel overly harsh. Stan’s claim the new ZTR Bravo’s are 30% stiffer laterally, but using a clever layup process have produced a rim that absorbs radial vibrations and impacts while retaining lateral stiffness. They are confident that the new ZTR Bravo can deflect impacts that compress the wheel by up to 10 mm radially without damage or loss of tire pressure.
The Pro wheels we have been sent are based on the new Neo Ultimate hub which features a 6-pawl engagement, which bites at just 5 degrees of rotation so acceleration should be direct. The hub features oversized 6802 and 6902 bearings and a tough swaged axle so should prove durable and the flanges angle in a few degrees to improve spoke alignment and provide more consistent tension. The hubs are compatible with all axle standards (including boost) and can be supplied with Shimano or SRAM free hubs.
The wheels are built up with Sapim Custom Force 2.0/1.7/1.8 spokes and secure lock aluminium nipples. We weighed a 29” set with tape and valves fitted and the weights were 768g for the front and 878 g for the rear with a SRAM XD driver fitted, bringing them in for 1646 g which is furiously light for a 29” wheelset. They are not cheap at €1999, but the wheels come with a 2-year warranty and 3-year crash replacement scheme. A cheaper (€1699) Team version is available with standard Neo hubs and Sapim race spokes, and refreshingly the wheels are available in 26, 27.5 and 29 inch versions.
We will be building these into a hard hitting 29er rig and will bring you our first impression as soon as we have put them through some abuse on the trail.
For more information check out the Notubes website.
Words and photos: Trev Worsey
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