I bought an 07 Saber and it came with the new fork that QR is putting on their aluminum bikes w/ the new FIST geometry. Similar to the old carbonaero The fork has a lot of rake (42mm on 650c), is VERY wide and deep (about 48mm) and has teardrop shaped blades. It feels fairly heavy but also very sturdy. Curious if anyone has any opinions / insight on the quality and performance of this fork. Is this some tawainese built POS that cant compare with an Easton or Reynolds? Also, I read here that the most aero forks are either very wide (like QR fork) or vary narrow (like Reynolds). Someone posted that wide forks work very well for tri-spoke wheels. Does this mean that narrow forks (like Reynolds) would be faster for deep dish spoked wheels?
A lot of work went into the design of that fork. The folks at QR worked hard to develop a very good, very aero fork with the rake specs they want. Given that it has a LOT of rake, you won’t want to swap it for another fork, since you’ll lose the pleasant handling associated with that fork.
A tri-spoke wheel NEEDS a wide fork, because of the big blades on the three “spokes.” But it’s not like it’s opposite from a deep-V spoked wheel. I.e., a wide fork is optimum for a trispoke, whereas a spoked wheel is not so sensitive to fork width since you just have the small spokes passing through. A standard spoked deep-V wheel will not be hurt by a wide fork, it just won’t be helped the way a trispoke would be.
The simple answer is that you don’t want to change your fork.
Thanks for the reply. I understand the wisdom of sticking with what the manufacturer reccomends for fork rake. My dilema comes b/c i was told by Litespeed that the 650c Saber was enginered to have a fork w/ 35mm of rake and they sent me a fork w/ 42mm. The 42mm fork is the one that is on the new aluminium QRs based on Dan’s research. Im guessing the other brands at ABG will start to adapt this geometry as well. Ves Mandaric, who i have a ton of respect for, built me a bike with the same head tube angle (72 degrees) and used a 40mm Reynolds.
Hmmm. Well, it’s not exactly clear. The 2006 geometry for the Saber was designed around a fork with 35mm of rake. BUT they did change the geometry between '06 and '07 on the Saber. It’s hard to tell how much, because the charts on litespeed.com aren’t as complete as on rooworld.com, but they did shorten the headtube, among other things. Call back after the holiday and double check with them. The geometries ARE clearly different, so you may in fact be very happy with the 42mm-rake fork.
It seems that the thinking on tri bike handling is just starting to get examined with Dan once again pushing the envelope on traditional thinking. This is an interesting and confusing subject (at least its confusing to me). On the same bike, in the same year Litespeed / QR / ABG has 2 forks that differ in rake by 7mm. The 35mm rake fork has more trail than a 42mm rake fork and hence the bike theoretically should want to ride in a straighter line. However, increasing the front center by 7mm really improves the weight distribution by taking more weight off the front wheel. This has the effect of making the bike more comfortable. Could it be that big question for bike handling is trail vs front center? Seems to me that the old school view was that a tri bike should have more trail (less fork rake) to make the bike ride in a straight line when in the aero bars. Now it seems that the thinking is that less trail and more front center (greater fork rake) makes you more stable in the aero position. I guess this makes sense considering that top-tubes / cockpit lenghts continue to get shorter (or more people are choosing to ride smaller bikes).
Could it be that big question for bike handling is trail vs front center?
I think so. But only if you look at it in the context of weight distribution and overall wheelbase. I think that as you start to see an established geometry of 78sta/72hta and the corresponding tucking in of the rear wheel, that yes, you can say trail vs. front/center is the big issue. But I think it’s within that narrow box. Fortunately, it seems that everything else is started to get standardized, the way things were with road bikes over the generations, and soon we’ll get a better idea of the complete geometry - angles, measurements, and the resulting trail, and then what fork rake you want to pair with that.
I think you’ll be happier with more rake to give you more front center and more stability. I agree with your assessment of the current situation - less trail and more front center. That’s why I think you’d be happier on the 42mm rake fork than a 35mm. But Dan is really the best person to weigh in on this, as he knows about 1000x more about geometries effect on handling since he’s had bikes purposed built with various geometries and paired them with specific forks to answer exactly what does happen when you go out and try to ride it.