First Look: Rulezman Releases Super Short 15 & 18mm Stems – Pinkbike

Based in Finale Ligure, Rulezman Suspension claims to be the oldest suspension tuning center in Italy. It’s led by Dave Cerutti, who you may know from his YouTube channel where he posts insights and opinions and features long-running experiments like comparing double crown and single forks on an enduro bike.

It has come up with some super short stems, 15mm for single crown forks and 18mm for downhill. He explains his reasoning for this in great detail in the video above, but here’s my summary:

The rear sweep of most handlebars is around 15-18mm, so these stems place your hands exactly in line with the steering shaft (not in front like on longer stems). This gives the best steering response and predictability as the forces in both hands are symmetrical and there is no side-to-side movement while steering. To take advantage of this, you’ll need a longer frame spacing (with upscaling). That longer front hub adds more weight to the rear wheel (less on the front), so you’ll need a longer rear hub (AKA chainstay length) to compensate. Interestingly, Dave says that the 10-20mm stems that Mondraker released around 2012 were not successful because the spacing and chainstays were too short.

Personally, I think Dave makes a good point that you can’t constantly add that much load to the front tire by pushing the handlebar anyway, so making a shorter and taller stem probably won’t make a huge difference. the front wheel grip by itself. Obviously, a longer front hub will reduce the load on the front wheel, so if you want to go that route, you’ll need a (significantly) longer chainring to compensate and maintain front wheel grip. This obviously means that the wheelbase will be extended even further, which is not to everyone’s liking.

It’s also worth noting that a standard 40mm stem with 15mm of rear sweep on the handlebars puts your hands 25mm in front of the steering axle. Over a bar width of ~800mm, that’s a very slight deviation from the straight line joining the two arms and the steering shaft – nothing like the exaggerated comparison in the video and image above. As such, I don’t see a problem with riding a 40mm stem with moderate backsweep, although stems longer than 50mm do noticeably affect handling in my opinion.

Still, I think it’s nice to see more options for bike nerds to experiment with. Who knows? Maybe in a few years, we’ll all be riding bikes with a 1,400mm wheelbase, 500mm chainstay and 15mm stem.

If you want to go, you better be quick and have deep pockets. Rulezman only makes 150 stems in total. Made of 7075 aluminum with titanium bolts. prices start from 224 euros.

For more information, check out Rulezman Suspension or follow them on Instagram.