Descending, Speed & Stability!

[mgm777]

In May I posted the following:
I've got two bikes:

#1. Ti Legend
#2. Ti "Number after 6" (no flames please)

Both bikes are similar sized (55) and have the same angles (73). Stays are similar (41). Both have the same cockpit setups - stem, bar, seatpost, and saddle. The Legend is outfitted with DA9, the other with DA10.

Today, I decided to be a test pilot on my local neighborhood hill. After climbing up my local Alp du Huez, I raced down the back side for a short 3/4 mile thrill ride accellerating to 42 mph with a few sweeping turns thrown in for grins and giggles. I repeated this sortie three times each time alternating bikes. I confirmed what I had always suspected...the Legend is slightly more stable when descending at high speed. It is hard to describe, but I "feel" slightly more confident on the Legend. Both bikes are solid, track well, and feel very comfortable. However, for whatever reason, the Legend is slightly more confidence inspiring on a high speed descent. Why is this so?

The only significant equipment differences are:

Legend: BB drop - 7, Wheelset - Velomax Orion II 24X Front, 28X Rear
Seven: BB drop - 8, Wheelset - DT1.1 w/ White hubs 28X Front, 28X Rear (OddsnEndos)

Could the BB drop difference or the front wheel rigidity difference (24 vs. 28) account for the slight difference in perceived descending stability?

The difference in stability is so subtle that it is not disconcerting. I am simply curious. Thank you in advance.


Today, I descended down the same hill with both bikes several times. Again, I confirmed the Legend just felt a smidge more stable at speed. So, I swapped out the front wheels and put the handbuilt (DT1.1 w/ White Ind Hubs 28x) on the Seven. Voila! The Seven now feels just as stable at speed as the Legend. I can't believe that 4 spokes can make such a difference. If the difference is due to the wheels, then big props to Mike G at OddnEndos! Thanks to all who volunteered their advice back in May.
:beer:

[gasman]

Just shows that when you compare bikes you need to have the same wheels, same setup ,etc to have a valid comparison.

[stevep]

here are a few observations on speed and stability from me.
my normal ride is a new time vxr frame ( which i sell ).
my " few bikes ago " is a merlin extralight.
i recently went to europe to do some of the big climbs in the italian alps and the alps in france. i took the merlin because it has become my travel bike and rather than screw around with the A bike ... i took the merlin. this is a bike i still use a lot in the winter but not much during the season. i am comfortable on the bike.
i was amazed by the amount the merlin twisted while descending....so much more than the time...(not an ad for time...just an observation.)
the construction is quite similar to that still used by 7 in their all ti frames. kinda oversize, round tubes, db...serotta uses a much larger dt on their bikes as well as a larger tt.
i am not surprised that you feel more solid on the serotta. it is a better bike.
i think ultimately the true test of a pro bike is its ability to be stable on a fairly rough ( the galibier was a rougher road than most over there ) descent in the big mountains. this is the test that a pro bike has to pass... you can climb on anything or ride on normal flat roads on anything.
you get near the limit when descending at speed and trying to bend the bike through a switchback..

[znfdl]

When I got fit for my last Spectrum Ti, Tom designed the bike with a lower bottom bracket for two reasons.

Reason 1: Better climbing
Reason 2: Greater stability

[stevep]

i reread mgms post.
count mine as an observation. i made it after reading the first part of his and that sparked my recent exerience

[atmo]

i reread mgms post.
count mine as an observation. i made it after reading the first part of his and that sparked my recent exerience
film at eleven atmo?

[Fixed]

front center ?
cheers

[atmo]

front center ?
cheers
fixed-issimo
stevep has gone for the early bird special.
there are always long lines at the north shore
senior center atmo. insert smiley face here ___ .

[stevep]

i dont know fixed. im no frame designer..i just play one on tv.

i just know it twists like hell at speed...
but, dont get me wrong... i can ride the bike fine...just have to allow for the way it twists.

the early bird special runs out soon.
gotta go...to beat atmo to the freedom toast.

[Fixed]

the reason i said this is my merckx has a short f.c. don't want to take hands off the bars, my other bike you can ride circles with no hands . the merckx turns and handels speed and down hills great imho . I don't know much about these things i 'm just happy to ride em.
cheers

[stevep]

ill measure the thing and compare it to my other sleds.
will let you know.

[dgauthier]

Today, I descended down the same hill with both bikes several times. Again, I confirmed the Legend just felt a smidge more stable at speed. So, I swapped out the front wheels and put the handbuilt (DT1.1 w/ White Ind Hubs 28x) on the Seven. Voila! The Seven now feels just as stable at speed as the Legend. I can't believe that 4 spokes can make such a difference.

If you weigh more than 180 lbs, try 32 spokes, 3 cross, front and rear. You will never go back to low spoke count wheels.

[SoCalSteve]

If you weigh more than 180 lbs, try 32 spokes, 3 cross, front and rear. You will never go back to low spoke count wheels.

It's true! I am a believer and own 8 sets of 32 spoke wheel sets. All hand built to my specs.

Steve