WheresWaldo

I should have mentioned that the 1520g was without tire and tube. 1980g total weight of front wheel. As a point of reference my tubulars on my single bike weigh 571g Front 734g Rear w/o skewers.


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WheresWaldo

Since many have asked me via PM. The surgery I was referring to is a circumferential body lift. I had GBP in January of 2006 and that was incredibly successful in giving me my life back, I would do it again in a heartbeat. The CBL would remove all the excess skin around the abdomen and the remaining skin would be stretched and then sewn together. Some fatty deposits are also liposuctioned out to contour your body shape. Estimated weight loss from this procedure, in my case, would be 15 pounds.

swc7916

Actually, all three. Maybe your experiences are different than mine as I am a recreational rider and have never raced or worked as a bicycle mechanic.

I have seen all kinds of fit criteria - including straddling the top tube, seeing if the handlebars hide the front hub when riding, placing your elbow on the saddle nose and seeing if your middle finger reaches the stem, etc. - but none of these methods gave me a proper fit. In the 80's the Fit Kit was the newest most scientific thing going, but even it didn't recommend a comfortable fit. The shop I go to has been building custom bikes for over 30 years and has compiled their own fit data and uses this fit bike to ensure that you are comfortable on your new bike:

WheresWaldo

TG, now that I am looking at those pretty Nimble Fly wheels I am beginning to wonder if they would be strong enough for a tandem team. The regular FLY rims have been tested to and can support a 650 pound static load unlaced. They make a Clydedale rim called the HorseFly, only 340g per rim. I wonder if they can be built with high enough tension to support a 330 pound team + bike weight. I know that they typically build with between 100 and 110 Kgf, as a reference Velocity builds all their wheels to 120 Kgf (I know, I asked them).

WheresWaldo

Can we play a math game. I am going to try to figure out how a shorter fork will affect the geometry of the bike. First off, I believe the Cdale fork is 410mm in length from fork crown to center of dropouts, most aftermarket forks are 360 - 370mm or so. the difference in the head tube angle should be the following:I was suprised by how small these numbers are, but then remembered that tandems have a long wheelbase and that would tend to reduce the impact of a change in fork length.

So my question is, even if I get a smaller fork and increase the head tube angle by .03° if the trail is the same does the handling become severly impacted by the shorter/lower front end?

WheresWaldo

I know the Cdale site says the trail is 5.1 but the actual measurements and formula for trail do not indicate it is that number. The front wheel has an outside diameter of 685mm the head tube angle is 73° and the fork offset if 53mm. The math comes out to 4.9cm of trail. Please note that fork length is not a direct factor in trail.

Trail=(wheel radius*cos(head tube angle)-fork offset)/sin(head tube angle)

Also adding .03° to the head tube angle is insignificant with regard to trail, and most likely less than the manufacturing tolerance. So my question is, has anyone done the swap and noticed a significant difference in the handling of the bike? The numbers would say there shouldn't be, but is there some anecdotal evidence that says otherwise?

TandemGeek

That's why I asked...

It's an unfortunately truth that proper fit is often times never addressed except for those who are engaged in competitive pursuits or are enthusiasts who take it upon themselves to either search out a qualified bike fitter or learn the various benchmarks and techniques needed to establish efficient riding positions, with emphasis on the "S" as there are can be different "fits" for different types of bikes, events, or the time of year.

Most recreational cyclists are never properly fitted which, when combined with zero instruction on proper technique and use of gearing, contributes to many short-lived cycling interests.

Tandem buyers are also at a disadvantage in that tandems are "nominally" designed and sized for the captain's riding position, and a one-size-fits-all approach is then used for the stoker. There are other 'issues' but they're covered in previous posts that reside in the archives.

Good to hear you've been able to find a fit that works for you.

JanMM

You are allowed to lurk at the 50+ forum prior to reaching the qualifying birthday. You don't know what you are missing. Bring your own ibuprofen.

TandemGeek

From Nimble's Website: Horse FLY is nominally rated to 250 lb riders (see weight limits for details). The lateral stiffness is 25 to 40% greater than already stiff standard FLY models. It is offered in 650C and 700C models with tubular style rims. Tubulars are excellent for strength, toughness and performance (see tubular tire advice). Call us for specific tire recommendations.


No, we can't.

You asked for recommendations, I've shared with you what I'm aware of in terms of available products and offered some comments on how those products will compare with what you presently have. The Alpha Q X2 is the only real odd-ball in the bunch when it comes to the tandem-rated carbon forks in that the Reynolds uses a 395mm fork length because that's what Santana spec'd for their tandems. Wound-Up uses 387mm because that's what Co-Motion spec'd. The Alpha Q CX tandem used 395mm which is a common cyclocross length and the X2 is just really short @ 374mm... single road bike length, if you will.

In the tandem steering trail spectrum where almost all of the tandems have 73 degree head tubes, your Cannondale's steering geometry is more like Santana's and Trek's (and also Burley's when they were still making tandems) than it is anything else. Going from memory...

Bilenky @ 57mm of rake with 73.5* headtube
Santana, Trek, Burley @ 55mm of rake
Cannondale @ 53mm of rake
Co-Motion & Trek T2000 w/carbon fork @ 50mm of rake
Burley Race w/Alpha Q CX carbon fork @ 48mm of rake
Co-Motion & Calfee tandems with Wound-Up forks @ 45mm of rake
Co-Motion & Calfee tandems with Alpha Q X2 forks @ 44mm of rake

If you talk to people who have ridden different examples of these tandems, while the difference in "the numbers" is small, the "feeling" and "handling" of the tandems is quite different. We changed the custom steel fork on our Erickson out for an Alpha Q X2 with 48mm of rake (now discontinued) and it changed the way that tandem "feels" and "handles". Our second Erickson tandem was built around the shorter Alpha Q X2 fork with 48mm of rake and it "felt" and "handled" differently than the other Erickson tandem that has the retrofit Alpha Q fork. Our new tandem is being built around an Alpha Q X2 fork with 44mm of rake: I have no idea how it will "feel" or "handle" compared to our other two tandems. However, none of these tandems "feel" or "handle" the way a Cannondale road tandem does: they are very different.

Bottom Line: If you change out your Cannondale's steel fork with a nominal 53mm of rake for a fork with less rake it will change the way your tandem "feels" and "handles" (Period). If you buy an Alpha Q X2 fork, the front end of your tandem and bottom bracket will be about an 1" lower than it is now. (Period). You will need to decide if these are changes you'd be willing to accept.

oldacura

Once again the obsession with weight. While I applaud your personal weight loss & the adoption of a healthy lifestyle, what is one willing to spend to reduce bike weight a little bit? For a team + bike weight of 370#, 5# is only a 1.3% reduction. On the flats, it won't make any difference. If you presently climb a hill at 10 mph, maybe you'll be able to increase that to 10.13 mph. Is that significant?

We've been passed by teams on heavier bikes & have passed other teams on lighter bikes. The weight of the bike rarely makes any difference.

WheresWaldo

I called and spoke directly to Nimble, they have no problems with using their HorseFly rim with a total 370 pound team. That was provided that the disks are removed and we go to a rim brake. He was very serious about that request. He also felt that a better solution was the Clydesdale Crosswind (tri-spoke) rear and a standard HorseFly front, again provided it was not a disk wheel.

I have no issues with removing the disks.

Ok, I also understand that if I change out the fork I will have to go to a different offset, yes I understand that that will impact steering geometry. TG you mentioned "feel" and "handling" many times in your response but not once have you mentioned if the change caused an improvement or not. I know there is a change, and if I have to use a fork with less offset it will impact the trail by lengthening it, which will result in slower steering. I want to know, when you did that was it good or bad, I already know its different.

OA, look weight is weight is weight, five pounds whether off me or the stoker or the bike is still 5 pounds less to carry. Sometimes is is not about speed, so what if I can climb .13 mph faster, maybe what I really want is to climb at the same 10 mph, but be just a little less fatigued at the top.

I have passed lighter guys on lighter bikes also, and have been passed by heavier guys on heavier bikes, there is more to riding than worrying about who passes whom. But thank you anyway on the comment about my weight loss, it has been quite a journey.

TandemGeek

That's because Good or Bad is highly subjective. I happen to prefer long steering trail on tandems, but then again my wife and me are relatively compact people: 5'8" @ 160 & 5'2" @ 110. Going from our Santana with short trail to our first Erickson with long trail was a dramatic shift, but at the end of the day the Erickson tandems have always been preferrable.

Which DO YOU prefer? Here's how I have characterized them in the past.

Shorter fork trail on a tandem (e.g., Santana) favors low speed maneuverability by providing lighter steering effort and faster steering responsiveness to handlebar inputs. Many teams will describe this as being "more stable" because, at least at slow speeds, it "feels" that way. Tandems with shorter fork trail take less effort and attention to steer in a straight line at slower speed and are resistant to inadvertent movements by the stoker, aka (stoker induced steering). However, tandems with shorter trail also tend to understeer in aggressive or high speed cornering maneuvers which is not always desirable.

Longer fork trail on a tandem (e.g., Co-Motion with Wound-Up Fork) favors high speed cruising and aggressive cornering. This is because of their inherently greater straight line stability and smooth responsiveness to leaning inputs and countersteering. Many teams will describe tandems that handle well at speed as being "more stable" because, at least at higher speeds and for aggressive cornering, it "feels" that way. However, at slower speeds, steering tends to be heavier and less responsive which is often described as being twitchy. Moreover, for teams with stokers that are exceptionally tall, or who tend to move around along or "rock" when they ride, a tandem with long fork trail can make steering control a laborious task that can also be undesirable.

TandemGeek

That sounds backwards.... I would think they'd want you to use a disc brake instead of a rim brake given the amount of heat that a tandem with rim brakes can put into the wheels. In fact, Rolf offers tandem-rated carbon wheelset that can ONLY support a dual-disc configuration. Rolf, Co-Motion and Advanced Composites collectively developed this carbon wheelset and a disc-compatible Wound-Up carbon fork for tandems. I'm not sure if it has been a hot seller or not.

WheresWaldo

Thank you for the explanation. I have never been particularly fond of or averse to the handling of the tandem. I just never gave it much thought. It is very different than the single bikes we ride with trail numbers all in the 5.7-6.0cm range. I think I would welcome a change lengthening trail. We do absolutely no loaded touring of any kind, and our rides are almost always with singles, as their just aren't that many tandem riders in my part of town SE of Charlotte. It sounds like it would be an actual improvement in high speed performance beyond the weight savings.

My Stoker is small at only 5'2" and is a much smoother pedaler than I am, so I have no issues with rocking. Although sometimes on social rides she has the tendency to forget she is on the back of a tandem and will turn almost completely around to talk to the other riders.

TandemGeek

Oh, come on... Everyone knows that shaving grams from a bike is analogous to taking Viagra.

A lighter, stiffer bike just "feels" better and makes each ride more enjoyable while often times inspiring us to ride just a little longer and harder than we would had we not shaved those grams.

WheresWaldo

Here is what he told me, The torque loads on the wheels in a disk brake are much greater than on a rim brake wheel, by an order of magnitude, no other explanation or supporting data. He also dismissed the heat issue with the proviso that it would apply if we were in the habit of riding down mountain grades. he did say in that case that a drum(drag) brake would be acceptable as a secondary means of controlling speed.

I know I have read accounts here and elsewhere of heat induced tire blowouts, they were all clinchers as I recall. Have you had or seen any of these reports on tubulars. There are a plethora of new tubulars in wider widths with the rise in popularity of cyclocross. It could be a viable option for a tandem team. On my single bike I ride tubulars 100% of the time with no reservations, nor have I lacked any confidence in their ability to stay on the rim through the toughest riding situations

RickinFl

In my long tandem career, I don't recall ever knowing of anyone that used tubulars on their big bike. Heard of them being used in velodrome, but not on the road. Might be an interesting experiment if you could find tubular rims that could stand up to tandem (ab)use. Not sure that the tires wouldn't detach and roll off under hard cornering given the weight of a tandem. If you try it, just don't use your face as a brakepad

Nice looking Cannondale by the way. How long have you been riding it? Is your daughter the numero uno stoker?

Rick

zzzwillzzz

you shouldn't have a problem rolling a properly glued tubular even on a tandem, but if it got hot from a descent and the glue softened up, i think it would be more likely to roll off than a clincher would be to blow off from too much pressure due to heat from braking.

joe@vwvortex

IMO - everything is a trade off. If you don't decend long downhills at high rates of speed - drop the discs for cantilever brakes. Pauls canti's are much lighter than any other alternatives. If you aren't concerned with flats - run super lightweight tires and tubes. As for wheels - DaVinci wheels are about the lightest handbuilt wheels i've seen at1,958 for the set and they run WI hubs. Their cranks are also some of the lightest tandem cranks out there as well. Next lightest i've found are the old FSA CF with ti bb's. Of course your talking gram counting here. Switching to Egg beater pedals with ti spindles will also save alot of weight as well. Bars, posts and small items aren't going to get you much for your $$$.

The next thing is to go with a much lighter frame - such as a Calfee CF or CoMo Macchiato.

You can discuss grams or you can discuss pounds. You can discuss hundreds of dollars or thousands of dollars. It all depends on what you want. I hate changing flats - so I use heavier tires and tubes. I like having all the brake I can have when doing long fast downhills at over 60mph so I have a rear disc (and want a front regardless of the added weight). I'm willing to have extra weight for those things.

Panito123

Just my observations regarding effects on handling of the C’dale tandem with different fork geometries that may be relevant to this trend. I purchased the carbon fork offered at Chuchsbikes.com and installed it on my C’dale. The ride was significantly different than with the stock fork. To me the bike felt twitchy at slow speeds and was more sensitive to my stoker’s movements. However, at high speed and on turns, the bike felt very stable. This is definitely the result of the fork being about 20mm shorter than the stock fork and having less rake (43 mm). The change in handling is not bad is just something one needs to get used to. We used this fork for a quite a while without any problems. I liked the handling better than with the stock fork as it definitely felt more like my single bike.

Lately I came across a good deal on a Reynolds Carbon Cyclocross fork. I did some research and found that it was approved for tandem use and it was about ½ lb lighter than the one I was using. After installing this fork (395mm length and 45mm rake) the handling changed slightly. The bike is now a little less sensitive to the stoker’s movements. It still handles great. However, under hard braking, I see a bit of deflection on the fork but it does not seem to affect handling.

My C’dale is now right at 36 pounds including pedals, bottle cages, etc. I do not think that I could drop the weight anymore without spending big money or using parts that may not be robust. How heavy are most tandem bikes? I do not know but at 36 lbs I guess mine is about average for a decent tandem. I will post a picture of my tandem so that you guys can advice me as to how to make it better.

Also, does any one else have used the Reynolds cross fork? I am interested on your opinions.

Great forum, GREAT people and sound advice! Thanks guys.

WheresWaldo

Sounds like a challenge. I might just try it. It would seem to me that I could dump the disks, go with something like Paul's or the new Kore Cantis and save a bunch of weight.


Rims would most likely have to be Velocity Pro Elites. The Pro Elites are basically a tubular version of the Deep-V in a 36H configuration.


Tires could be something like these Tufos that come in a 28 and 30mm width:

Or any of a number of 25mm tubulars from various manufacturers.

Rick, I used to ride and race 20 years ago, then gave up cycling entirely shortly after having my daughter. She got me back into cycling in March 2006. We have had the Tandem since just before Christmas 2005. That was before my GBP surgery, so we just sat and stared at it until I was able to start riding some 4 months later. My daughter is my only stoker. My wife refuses to get on the tandem. I could not even get her to go around the block with me. So my daughter and I ride together. I have ridden with a few others but that was for short sprints nothing more than a mile or two.

WheresWaldo

Here is the thing about tubular glue, this is anecdotal mind you, it is basically contact cement and has a rather high breakdown temperature. I have tried removing the glue from aluminum rims with a heat gun and it basically had no effect. Now chemically, it is easy to remove, nearly any solvent will soften the glue enough to remove it. I am just not sure it would be affected by the heat generated by braking as much as a clincher is. Besides most tubulars are rated for 10-12 bars pressure, much more than the 8 bars I typically run, so no real fears of blowouts either.

WheresWaldo

Great info, I am going to look at the Alpha Q cross, it is still available in a 47mm offset and I will look for the Reynolds to compare, but I think I have a new winter project. I was going to work on a winter bike first, the frame is at the powder-coaters right now and should be done by the end of the week. I may just box that up and build another set of wheels, this time for the tandem.

Panito123

As mentioned here is picture of my tandem. According to my scale it is right at 36 lbs as built. Does any one have a lighter C'dale? What did you do to make it lighter/better?

zzzwillzzz

yeah, that's why after warming up on my clinchers for a race, i pulled out my sewups out of the hot car and they were definitely not ridable as the glue was very soft and the tire would have rolled for sure on the first corner

pros also occassionally roll tubulars on steep descents in races like the tour de france from overheating the rims