# The Schoolbus and the Ferrari / almost



## PMK (Oct 12, 2004)

I post this to maybe help others with their Cannondale tandems.

Our very first tandem purchased was a used 1998 MT3000 with a Moto Freeride fork. Recently we picked up a 2001 MT800 with a rigid fork.

For whatever reason, guess I'm a geek, but I have many of the older Cannondale catalogs from that era as I bought a few single bikes then and kind of stuffed the catalogs away.

The catalogs have been a good resource for specs and photos. They have also come through on geometry numbers. While most of this information can be found in Cannondales archives, they don't go back past 2000, and for some years the geometry listed is the road tandem specs, not MTB.

So with paper copies laid out, I did a lot of comparing and reading here, DF, and other sites about the newer frame. The Cannondale published specs have big differences in headtube and seatutbe angles for 98 and prior versus the 1999 and newer MTB stuff.

1999 was the first year for the rear disc brake mount style frame, the catalog however shows it as non disc mount. Speedub.Nate has a 99 here showing the disc mount http://forums.mtbr.com/showthread.php?t=366327. It also saw it the first year with a published headtube angle of 71°.

The 98 and prior years listed a Headtube angle of 73° while the 99 and after was listed as 71°. Steering feel and handling wise this is a big change. Seatube angles were also all over the place, but typically in the around 73/74 range.

So what does it all mean, on paper using Cannondales published specs, the 98 and prior bikes should have very quick steering traits, with a fairly light steering input. While the newer bikes should be somewhat more stable, and require additional steering input effort.

While all this may or may not be important, I did quickly measure some angles to compare the two bikes. Initial numbers contradict what Cannondale published and indicate that within a couple tenths of a degree, all the frames have similar angles.

Granted the rigid fork models have a steeper head angle on account of the shorter fork, but when the fork lengths are equal the angles are very close.

Bottom line best I can tell is that the early published specs of 73° are for the bikes regardless of year (up to current MTB frames) with a rigid fork. If the bike has an 18.5" axle to crown race (basically 100mm travel fork) this alters the angle to 71° regardless of model year. Cannondale never distinguished this as they sold bikes with both suspension forks and rigid forks.

Why the Ferrari and Schoolbus. The 98 with published quick handling specs is red, the 01 with published slack angles is yellow.

The reason this was important for us is that we ride some stupid tight single track where steering angle can make a difference. As time permits, I will try and post some detailed frame angles about the two versions of Cannondale tandem MTB frames.

PK


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## Drum (Jul 8, 2008)

Interesting information, but I am curious as to whether your ride experience on the two "different" bikes has born out the traditional preconceptions regarding the effect of geometry on handling?

D


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## PMK (Oct 12, 2004)

The school bus is not yet dirt ready. It still has the rigid fork which is shorter than the suspension forks. We bought it with slicks. So it needs a few things to get setup.

With the digital protractor indicating that with same length forks, the head angles will be the same, I expect the only contention will be the larger bikes longer wheelbase.

FWIW, we have no intention of changing or stripping the 98 (Ferrari), so we are already planning back to back rides on the same trail on the same day (conditions), with both bikes setup for us, except swapping pedals over.

What may come of this is why are some having floppy steering on their bike while others don't. 

Plus this may be a small index of frame differences that so far I have yet to find on the net. Then again it may be of little importance.

PK


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## Fleas (Jan 19, 2006)

I'll second the motion.

I posted here about a longer fork on a '98 MT1000:
http://forums.mtbr.com/showthread.php?t=443709



> after a real 20 mi. off-road test with both of us and whatever extra weight we were hauling in the form of food and water, where we pounded some rock gardens, dragged bottom over some dirt piles and logs, negotiated some very hairy downhill switchbacks, and yes fell down a couple times, I am upgrading my evaluation to "workable". Actually, my arms and shoulders have never, _ever_ been more relaxed on an off-road tandem ride (gaging by my lack of soreness the following day). *That on-center "vagueness" may be a benefit off-road* - it gives you a chance to relax rather than fight fight fight over every little root and rock. ...and the "floppy-ness" is not as pronounced off-road since you are hardly ever steering on flat, level ground. For a full-rigid set-up, it worked much better than my initial impression would have allowed me to believe.


And now that we do have a 2.3 Nevegal up front and a 2.3 High Roller in back, and 34T rings replaced the 38's, the bike is even more capable. I would not compare the handling to a schoolbus, though. Besides, it's green.  
In the interest of science, I will get a digital angle measurement of the HT angle as it sits now.

-F

PS - and I do still have the 1998 catalog that came with the bike. Geek away!


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## PMK (Oct 12, 2004)

The schoolbus term was referencing the published slacker angles, but mostly was in regards to the entire bike being yellow, while the 98 is red.

Overall, it is good for us to see the angles very close for all the years.

The posts about the steering feel had me looking very close at all of it. Now with two bikes side by side, I'll post the results and it should even let folks compare to even other brands and models.

In regards to the floppy steering, I'm leaning towards the trail dimension being more the factor with various fork brands.

PK


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## PMK (Oct 12, 2004)

Can you check the axle to crown dimension on that Surly fork?

Checking their site shows it to be a 17.5". 

FWIW, the moto freeride is 18." and the rigid cannondale fork is 16.5".

Looks like initial numbers are that with an 18.5" fork (no sag) you are around 70.5 degrees, the rigid fork is at 71.8.

PK


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## Fleas (Jan 19, 2006)

'98 MT1000 w/ Instigator fork and 2.3" Nevegal tire:

HTA = 71.7* by digital level
ATC = ~17.75 by a tape measure (Surly says 447mm = 17.59")

I can't imagine what the HTA was with the orig. fork - no wonder it was so twitchy.
Hope that helps.

-F


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## PMK (Oct 12, 2004)

Fleas said:


> '98 MT1000 w/ Instigator fork and 2.3" Nevegal tire:
> 
> HTA = 71.7* by digital level
> ATC = ~17.75 by a tape measure (Surly says 447mm = 17.59")
> ...


The rigid fork setup on the 01 feels like a road tandem, not quite as tight as our Co-Motion.

If you pull out that old catalog, you'll see your bike and a sister to our red bike, a 98 MT3000. When you go to the geometry specs, both bikes are listed as a 73 degree head angle. Unless they made two different frames, one with suspension geometry and one for rigid geometry the chart is wrong.

Backing this up, my quick check of the MT3000 showed a HT angle of 70.3 with the 18.5" fork.

With sag, our fork is probably close to your rigid fork in length.

None of this is real important, as it's all about having fun. When this wraps up, there should be some good numbers to use regarding fork length and headtube angles, and possibly ride impression for each in the dirt.

Taking it a step further, the suspended Cannondale looks to fall between a Ventana spec of 72 with an 18.5" fork and an Ellsworth.

PK


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## PMK (Oct 12, 2004)

I haven't been able to finish up the 2001 yet. It had very low miles of only around 100 or so, but I still tore it down to the frame, cleaned and have been reassembling it.

I had to modify a 170mm travel dual crown fork for 105mm of travel during it's rebuild but that's now done and installed. Wound up swapping some headsets giving the road tandem a new CK headset and the Race Face now installed on the 2001. The 2001 also is getting upgraded to BB7 brakes from v brakes. Sad part is now some single bikes have been cannibalized and will sit idle, oh well.

Looking like some cables to fab and install, timing chain tension, seats and seatposts so maybe soon I'll have those angles to post and opinions on how the handling "feels".

PK


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## PMK (Oct 12, 2004)

Well it seems change is constantly happening. 

Prior to even riding the yellow school bus, I swapped to a different fork.

The dual crown fork was removed.

I picked up a Manitou Sherman single crown fork in brand new condition for $60. Bought a firm spring and installed that.

With this bike being built for open flowing trails, I'm hoping the single crown fork will work well.

Entire bike is now built and will hopefully see some action this weekend.

PK


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## PMK (Oct 12, 2004)

Adding an update.

The Sherman fork in the short travel setting is about 10mm longer than the Moto fork on the 98. It does however ride with a bit more sag.

On to the handling. Both bikes work well in open terrain such as double track and flowing singletrack. When the speeds are less, or the trail becomes more technical, the 2001 with the slacker head angle lets you feel the difference in the effort at the bars. The steering remains fairly light felt when tacking straight and slight steering inputs left or right. As the wheel is turned more, the front end geometry of steering angle and trail make the steering get heavy. 

I did have to swap the forks suspension fluid to 10 wt for better damping.

In summary, the 2001 was built for open flowing and it performs well at that. It is more planted at faster speeds and straighter trails. 

The 98 had no purpose but to be ridden. It gets used in tight technical singletrack, and anywhere else if needed. 

As I look for what our next frame will be, comparing these bikes back to back has allowed me to find what we tend to prefer in regards to front end specs.

The ironic part in all of this was I did not expect to have such a difference.

All good though.

PK


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