Carbon Fork Question
 

I'm looking to make the ride of an aluminum tandem more forgiving and am thinking about investing in a carbon fork.

A few questions to the experienced:
1. Does a carbon fork really make a difference?
2. I need to have Disc Brake mounts on it as it is for a CDALE R2. This is hard to find except for cyclocross forks in. Has anyone tried a cyclocross carbon fork, could this be a good alternative?
3. How do I ensure that a new carbon fork doesn't change the geometry from what seems like the tried and true 73 degree head angle of my CDale?

wound up makes a disc tandem fork:

http://www.woundupcomposites.com/tandem_duo.html

What size tires are you running and with how much air pressure? One of the least expensive ways to make what may feel like a harsh handling tandem more compliant is to use a larger diameter tire or to drop about 10 psi if you're presently running them at the max psi. Obviously, you'd want to guard against getting the rear tire too soft, lest you invite pinch flats.

1. Does a carbon fork really make a difference?

They tend to be much lighter, more compliant, and dampen vibration better than the very heavy-duty tandem-rated steel forks they are used to replace so, yes, you can usually detect quite a few changes to the ride feel and in some cases handling when one of the super-light tandem forks is used, e.g., Alpha Q X2 comes immediately to mind. The Reynolds Ouzo Pro Tandem and Wound-Up forks are both a bit heavier but also have less lateral deflection which makes for a more precise steering feel, particularly during aggressive steering inputs. There are also some heavier cross-based cantilever carbon forks on the market as well that provide similar benefits in terms of modest weight reductions / vibration dampening and the like.

2. I need to have Disc Brake mounts on it as it is for a CDALE R2.

Well, it would probably be more accurate to say that you'd need a disc-compatible fork so that you can keep your current hub and disc brake. Alternatively, and if you don't 'need' the front disc you instead go with a fork that has cantilever bosses or that works with a caliper brake... both of which will work with your asymetrical front wheel... and/or have your front wheel re-laced to a new non-disc hub as part of the fork conversion project. However, if you want to retain the disc than the Wound-Up Duo carbon fork mentioned by uspspro is about the only tandem-specific fork being marketed with disc tabs

3. How do I ensure that a new carbon fork doesn't change the geometry from what seems like the tried and true 73 degree head angle of my CDale?

Your Cannondale uses a fork with 53mm of rake and the closest carbon to that spec. would be the Reynolds Ouzo Pro Tandem @ 55mm. The others from Wound-Up (45mm) and True Temper's Alpha Q (44mm and 41mm) would both yield what would best be characterized as "sportier" handling which may or may not be a bad thing. Now, you might want to send a PM to WheresWaldo as he fitted a Nasbar/Winwood Cross fork when he made some updates to his Cannondale which you can read about HERE. I don't fully recall the entire discussion on forks well enough to cite the rake or "tandem-rated" nature of the fork; however, it's probably in the archives and/or WheresWaldo can elaborate.

I don't have experience with a tandem carbon fork but I can offer some previous threads that cover most of your questions.

Worth an upgrade?
Carbon for upgrade
Carbon fork

In a similiar situation on a Trek T2000 I went with the Wound-up fork, albeit the canti-stud model. Basically, we're tickled ****less with the result, but there is a caveat for many: You will no longer have toe clearance. This bothers me naught since I long ago got used to that on criterium bikes and track bikes, but it might bother some.

As for the benefits, ditto most of what TG said. More specifically, we were amazed at the difference in lateral rigidity when doing a double-standing climb. Maggi and I are around a 375 to 390# team, (depending on what time of year it is!), and previously the Trek had felt uncomfortably flexy when we both stood, and the Wound-up just completely eliminated that .... to the point that some other tandem teams have commented how "smooth" we look doing the double stand.

As for going with a non-tandem rated, disc brake compatible fork, I wouldn't do it. Frankly, being an old (school) rider, I couldn't bring myself to order the disc brake Wound-up even though I wanted it! Having ridden one for a season I'd probably be less skittish now, but I would still not use a non-tandem rated fork with disc brakes.

+1 on tire pressure. Going up one tire size, and down 10-15lbs of pressure, (i.e. 28mm at 100psi, instead of 25mm at 115psi) will make at least as much difference to comfort as the fork.

Here's what Winwood says about their tandem rated fork:

Muddy Disc Cross
Designed and tested for tandem use with cantilever brakes
and with 6” rotor disc brakes (Not designed nor tested to
withstand the additional stresses of a 8” or 10” rotor)

The Cannondale fork has an axle-crown height of 395mm.

I have used a Reynolds Ouzo Pro cross ( yes,it is tandem rated) on mine with a V-brake and cable pull adapter. Compared to the fatty, I would say the ride quality is better, handling is quicker and I preferred the carbon fork to the fatty.

If weight or aero matters, the carbon fork saves about 650 grams, the brake saves maybe 250 grams? and you can run a lower spoke count wheel, saving more weight.

The other thing I preferred was because we removed the front wheel to transport it ,I find less hassle with the rim brake.

According to Nashbar and somewhere else on the web that I can't recall, their carbon cross fork is the Winwood Muddy Cross. rmachttp://www.bikeforums.net/star.gif posted the tandem info above.

I also changed out the brakes. At the time I was going for light then dependable, in that order. So moving from the Fatty, which weighed more than 1 kilo, to the Muddy Cross at just under 700 grams was a significant savings. The second advantage was, at least for us as YMMV, the trail measurement increased to a manageable number. Why Cannondale specifies forks with so much offset, 53mm IIRC is beyond me. The Muddy Cross has 45mm of offset. This made the Dale handle much more like our single bikes and riding was much more enjoyable with respect to handling.

The other difference is that the dropout to crown measurement is slightly different, I can't recall which for was bigger, but I just have a feeling that the Fatty was longer. The difference was insignificant with regard to overall geometry something on the order of 1mm - .5mm trail one way or another.

We also did not feel that there was much difference in the lateral stiffness. That may have been the result of riding pretty light single bike forks (for a while I was riding an Easton SLX fork, pretty scary when you feel like the front end is washing out). Our only limiting factor in how hard we push into corners was my stokers reluctance to really lean into fast turns.

I cannot post on the long term reliability of the fork, since we only put about 1500 miles on it before we sold the tandem. I can say that the current owners, who weigh about the same as us as a team, maybe a few pounds lighter (340-350#) are still using it, but I did give them the Cannondale Fatty also in case they wanted to switch them out.

If I had another Cannondale tandem I would make that same swap again.

I believe this will be the experience shared by any Dale owner that switches to a smaller offset fork. I think Cannondale must think all their riders are slow and want really sensitive slow speed handling, rather than good handling at higher speeds. It's just a dumb fork design choice by Cannondale. Switching forks was hands down the BEST upgrade we did, closely followed by faster wheels.

Well, some of us have put really wide tires on it and use it off-road. I now appreciate the slow speed handling.

Ahh, you are a peculiar type rmachttp://www.bikeforums.net/star.gif, next thing you'll probably tell me is that you actually ride your tandem on the trails :lol::eek:. I tried trail riding once too many roots reached up from the ground trying to swallow me whole. That is not to mention the trees that literally move in front of you daring you to hit them!

No thank you. I will stay with the safety of mulit-thousand pound automobiles and trucks with inatentive drivers if you don't mind. ;)

I spoke to Winwood directly and the gent I spoke to said that the Nashbar fork was not theirs, but the manufactuerer could be using their design, but not their spec. In speaking to Nashbar, and reading their spec, they don't mention that its tandem rated. If Winwood has it in writing, and Nashbar doesn't, I'm going with them. I'll also get the version with the canti brake studs too, just for any future changes.

Well, its 62 degrees, the snow is off the streets, its drying up, time for a ride!

go INDY.