15/10/2018 - Fork Offset - Does It Matter?

The new RocketMAX 29er Enduro bike, Reynolds 853, built in UK

Fork Offset and Wheelbase

Does It Matter?

Cy talks us through the latest hot topics in bike handling

The RocketMAX is a pretty progressive beast in terms of geometry, and given some of the chatter that other brands have been pushing recently I've had quite a few emails asking about what fork offset works best and what my thoughts are.

My take on fork offsets is that it's a personal preference, and the marketing budgets of other brands are making it a bigger thing that it actually is.

I have tried the RocketMAX with 42mm (short, on Lyrics), 46mm (X Fusion Trace 36 and McQueen) and 51mm (my current Cane Creek HELM29) and they all handle fine. Slightly differently, but just fine.

With my preferred bar width of 770mm across the grips I do prefer the slightly shorter offset, although I'll be honest I couldn't tell the difference between 42mm and 46mm. I have to use 785mm bars to get a similarly calm feel on the 51mm offset as it's more lively around the straight ahead position. The slightly more linear rate of response of the shorter offset works a little better with the narrower bar width.

Remember though, this is real Princess-and-the-pea stuff. It's my job to be sensitive to these things. I'd be very surprised if anyone getting a RocketMAX was anything other than really stoked on the handling so long as they had a fork they liked, set up nicely, plugged in the front, just like I am down there on Stannage last week!

The new RocketMAX 29er Enduro bike, Reynolds 853, built in UK, Stanage Edge

A few more people have questioned the wheelbase on the bike. I have always thought that people get a little too hung up on wheelbase. I have never once designed a bike with a wheelbase in mind, or an intention to keep it a particular length. Wheelbase is a dimension that occurs at the end of the process when everything else more important is established and set. It's much, much more important to have the weight balanced between the wheels. Hence the chainstay length to balance the front centre.

The RocketMAX (even in the XL size I ride) feels like you would expect a shorter wheelbase bike to feel, because when you are stood up, you are on the vertical turning axis of the bike. When a bike has a long front centre and really short rear end, the turning axis of the bike is in front of the riders centre of mass, which makes those bikes feel ponderous. The force feedback they give you is that something is moving around in front of you. That kinda 'wheelbarrow' feeling. That's what's given long bikes a bad name in my opinion. I distinctly remember being on a ride early in the life of the 2nd longshot 29er prototype last year (the green RocketMAX with black rear end you might have seen if you saw me out and about over summer/winter 2017). We were at Wharncliffe on some of the really tight, steep, berms over towards where Max, JP and the Tree Tings/Clay Spades guys sculpt their masterpieces. And despite the bike being quite a bit longer and slacker than my first prototype (which I'd never quite got working right), this bike was whipping around these tight berms with hardly any need to 'muscle' it in, felt easy to whip it through these tight turns. It was one of the main lightblub moments on the project. When I realised I had got the weight distribution right, and the bike was suddenly around me instead of 'out front' or 'all at the back'. It didn't feel long, or short, it just felt right.

You can't just focus on one number then say it's rad. It's a whole system. The iteration I tried before the final geometry was settled was a degree steeper at the front and shorter front centre. It should have theoretically made it feel livelier in tight trails, and I'll be honest, I was a little concerned about customer reaction to the geometry I was leaning towards so I pulled it back a little. It felt awful. Like REALLY awful. The front end felt too tall and unconnected. It felt really light on the steering without enough feedback. Really spooky feeling. It was a real wake up call because up to that point, everything Longshot-esque I had built and tried had been really lovely to ride, even if they weren't spot on.

The new RocketMAX 29er Enduro bike, Reynolds 853, built in UK, Stanage Edge

I tried a bunch of different bars I spent a couple of weeks full puzzling - measuring, checking, rebuilding the previous prototype - trying to figure out how a bike with a 64.5deg head angle could feel so sketchy. It came down to the lower BB on that bike (which everyone thinks is good) and the shorter front centre (still roomy, but everyone thinks shorter is good for tighter trails) combined with the 160mm travel fork raising the stack and hence bar height combined to make it hard to weight the bike nicely. All bits of 'received wisdom' which combined to make a bike that looked great on paper not work at all. In the end I popped an angleset in it to go back towards where I was with the version before and it was transformed. Even on tight, bermed singletrack it felt MILES better. I could weight the front, loads of feel and feedback through the bars, tonnes of grip, I was in the middle of the bike again so it was moving around me instead of in front of me. That was the point I commited and went with what felt best to me, regardless of the numbers 'on paper'. And that's the bike we launched.

I talk a little about offset, weight distribution - amongst many other things - in the Downtime Podcast Longshot Special I did a few months back. Click on the link below to have a listen. It's on youtube as well if you want to watch me waving my hands at the same time ;-)

The first run of RocketMAX have sold out in all sizes apart from Small, but the joy of working with the Five Land guys is that we are only a month away from some more arriving, so you can order now with confidence. This kind of responsiveness is exactly why we wanted to try and do something in the UK.

Cheers,

Cy


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