A COIL-SPRUNG CONUNDRUM

Q: My current daily driver mountain bike is a 2021 Trek Slash that still has the original RockShox ZEB Select+ fork, but I think it’s finally time for an upgrade. I’ve been looking at the Marzocchi lineup, and their Bomber Z1 Coil looks to be well built and is at an excellent price point. I was a fan of coil forks in my younger days, but the modern offerings seem to be few and far between for high-end products. Do you think the benefits of running a coil fork outweigh, well, the weight?
Jeff Garcia
Orange, California

A: We, too, miss the days of hucking heavy coil-sprung behemoths down the mountain or off ridges in pursuit of freeride or racing glory. But, those days are behind us, and so are most coil-sprung mountain bike forks. However, some people are keeping them alive for those who still want the performance that only a coil can bring.

It looks like you are already checking out the first option that comes to mind with the Marzocchi Bomber Z1 Coil. Paying homage to the original Bomber Z1 from the 1990s, the current coil version of the Bomber Z1 is built around 36mm stanchions and their proven Grip damper to deliver off-the-top sensitivity while ramping up smoothly. When looking at the difference between the coil- and air-sprung version of the Z1 fork, it is mainly apparent in the initial stroke sensitivity and, as you mentioned, the weight.

We are currently testing the coil-sprung Z1 and generally find it to be slightly more sensitive to small bumps in the initial part of the stroke, but is more prone to blowing through all of the travel, whereas the Z1 with an air spring will have slightly less small-bump sensitivity but will be more progressive overall. To help mitigate the linear nature of the coil spring, Marzocchi integrates an air assist to increase the progressivity and help with bottom-out control, allowing you to still have the increased small-bump sensitivity with a progressive platform deeper in the travel.

This just leaves the weight, which there is no getting around. A coil-sprung fork will simply weigh more than an air-sprung fork because there is more mass and material in a coil spring than in an air spring. It doesn’t sound like you have the lightest bike out there, so we think that running a coil fork that is slightly heavier in weight won’t be a big deal compared to the small-bump sensitivity and plushness that you will gain. In our opinion, there are few better feelings than a well-tuned coil fork smashing through a rock garden and soaking up every little bump.