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I know it's LONG but really worth reading.
I read this article this afternoon about Laurence Smith redesign of a New Front End. I thought it's an excellent, different way of thinking. I think it needs some more development before its on a serious race bikes but it could be the future. Or maybe just for cruisers or a non high performance bike. But I keep wondering if the "traditional" front end wasn't doing the proper job, wouldn't the big engineering guys up at Honda, Ducati....ect change it up? I would like to read about this front end in a couple months with the some tyres that suit the front end, have rake, trail, rider height dialed in and maybe send it to a track that's suited for a 1000. What do you guys and gals think? You think its going to be the "future?" Or what would you think you would do to make the Girder handle better through high speed cornering?
This is how he designed it with some pictures.
http://thekneeslider.com/archives/20...-of-australia/
By Rennie Scaybrooks, "Can this Crazy Front End Really Replace Forks?"
Down in the depths of the bitterly boring and generally freezing city that is Canberra-Australia’s Capital Territory-Laurence Smith of Suspension Smith has been burrowing away under a ton of aluminum swarf and sweat for the past 12 months to create his version of the future of motorcycles front suspension. No forks here, he’s chopped the front off a 2004 Yamaha YZF-R1 and grafted on his own design, one that went from CAD to wood to the product you see here-machined from billet 6061 aluminum-in just under a year. He’s a determined fellow, and convinced that forks are at the end of their life span.
Smith recently took me and his Girder R1 to a bitterly cold Wakefield Park in Goulburn, New South Wales, for a spin and a critique of his design. Wakefield is an ideal 600cc track, but hard work on a 1000, and with the wind blowing some serious nut-freezing chill over the track, getting heat into the tyre would be a challenge
The R1 no longer runs the normal clip-on bars, with Smith swapping them for a bent MX-style single handlebar that gives the added advantage of more leverage when going between the triple left-hander and the fast right onto the back straight. There are no rearsets, it has standard road bodywork, a standard ’04 R1 swingarm and an Ohlins TTx30 shock from an ATV stuffed under the rider’s right hand. Other than that it’s all about the Girder.
The first lap on the R1 feels totally alien. The Girder R1 runs a 16 degrees steering angle compared to the standard R1’s 24 degrees. Yet despite this staggeringly steep steering angle the bike isn’t anywhere near as twitchy as you’d expect. The front feels almost detached from the rest of the bike-like it’s operating in its own orbit-but down the back straight, over the braking bump, the R1 feels stable and sure-footed. It’s just talking to me in a different language. Down the front straight and through the fifth gear kink under power the Girder feels great. There’s big bump that when hit means you’re on the right line but it will upset the chassis of a conventional front-ender, but the Girder ran over it as thought it wasn’t there. I shouldn’t say run over as much as floated, which is exactly the type of sensation it gives you-very BMW K1300R-like. Leading into the slow turn one right-hander the Girder brakes well with good feel from the front tyre. But here lies a problem: there’s too much weight transfer from the back but not enough weight on the front. This leads to understeer and makes it hard work to get the bike turned and accelerated out of the corner without running wide. The first 60 percent of the corner is fine, from set-up, to hard braking, to the beginning of the corner, but when on high lean angles with lots of front-end pressure the feel that was there through the fast sweepers is traded for a vagueness you don’t get on a conventional fork set-up. Laurence can alter the front end flex of his design by running the lateral Control Flex bearings at the top of the Girder at different points, but for this test he ran them with no flex as he said this part of the design was still in its early stages. He can also vary trail plus or minus 6mm. For this test trail was set at 102mm.
The R1 doesn’t dive under braking, rather it squats, and while this has the benefit of keeping trail as constant as possible it can lead to the issue of not enough weight on the tyre to flatten out the contact patch.
After cranking up the rear preload and slowing the rebound down I go out again. Understeer is nearly eradicated but the lack of front tyre heat is still a problem. However, by now I’m pretty in tune with the Girder. You can’t throw this thing around like a forked-600; the Girder likes wide, traditional racing lines, almost like a 250GP bike, not the point and squirt style customary to big litre-class monsters.
In an effort to get more heat in the tyre, Laurence drops the front ride height by 5mm, and I go out again. Although there’s now more heat in the carcass, the Girder is much more nervous, giving me some decent front end slides that weren’t there before. It also made the change of direction onto the back straight slower than before.
Laurence and I came to the conclusion the front spring was just too heavy, but the ride height he had dialed in prior to the last session was just right. My gut feeling also hints at an issue with the tyres we were running. Pretty much all tyres available are designed to run with forks not girders and I think to fully explore the potential of the design a company would need to make specific tyres for the cause. Despite this however, I do believe the design is sound, it will just take some more development to get it to the point where it is a real alternative to forks.
Since my ride Laurence has fitted a lighter spring to the Ohlins shock on the side of the girder. He’s been out on the bike at Wakefield and tells
me the front tyre heat is now up to scratch.
The potential is there. It’s beautifully designed and manufactured, but will take more experimenting to get to the point where it will be a challenge for conventional forks. The feeling it gives is alien to what I’m used to, but after a couple of laps it’s easy to understand. I’m looking forward to riding version II at Eastern Creek this year!
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Originally Posted by butcher bergs
