Increase trail or longer front center

Since moving out west (US) a couple years ago, practice as I might I just
can't quite descend with riders who are otherwise of my ability. Recently,
I've also been having a hard time cornering in criteriums at high speeds
(over 30mph). Lower speed laps I'm fine, but I'm closing gaps on fast laps,
and getting caught when I attack because I'm just not carrying as much speed
as my competition.

I practice plenty (have a 14 mile climb behind my house with switchbacks,
and a local training crit), and it's my 21st season of racing, so I'm going
to assume I've maximized the skills area as much as I can. The bike is also
fine when at training speeds, it's just in relatively high speed
descending/cornering situations I cannot get around the turns as quickly as
I'd like.

I'm slightly taller than average at 6'1", and don't use a lot of setback on
my road bike (7-8cm), so I suspected I might have too much weight on the
front wheel. Bathroom scale measurements indicate I don't. It's right around
43/57 front/rear.

So now I'm looking at frame geometry. I'm using a frame that has a steep
74' head angle, and a 45mm raked fork. With a 23c tire that's only about
4.9cm of trail, very low by most standards. Bike also has a pretty short
front-center of 60cm (on a 60cm frame).

My options to improve handling as I see it a

1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or 5.4
respectively, more in what most people seem to feel is a more average range
for a racing bike.

2) Get a frame with a longer front center to move cg even further back in
the wheelbase, thus keeping more weight off the front wheel in steep
descending corners (but perhaps leading to front wheel washout in flat crit
corners?).

Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
why?

On May 17, 4:31 pm, "John Verheul" wrote:
Since moving out west (US) a couple years ago, practice as I might I just
can't quite descend with riders who are otherwise of my ability. Recently,
I've also been having a hard time cornering in criteriums at high speeds
(over 30mph). Lower speed laps I'm fine, but I'm closing gaps on fast laps,
and getting caught when I attack because I'm just not carrying as much speed
as my competition.

I practice plenty (have a 14 mile climb behind my house with switchbacks,
and a local training crit), and it's my 21st season of racing, so I'm going
to assume I've maximized the skills area as much as I can. The bike is also
fine when at training speeds, it's just in relatively high speed
descending/cornering situations I cannot get around the turns as quickly as
I'd like.

I'm slightly taller than average at 6'1", and don't use a lot of setback on
my road bike (7-8cm), so I suspected I might have too much weight on the
front wheel. Bathroom scale measurements indicate I don't. It's right around
43/57 front/rear.

So now I'm looking at frame geometry. I'm using a frame that has a steep
74' head angle, and a 45mm raked fork. With a 23c tire that's only about
4.9cm of trail, very low by most standards. Bike also has a pretty short
front-center of 60cm (on a 60cm frame).

My options to improve handling as I see it a

1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or 5.4
respectively, more in what most people seem to feel is a more average range
for a racing bike.

2) Get a frame with a longer front center to move cg even further back in
the wheelbase, thus keeping more weight off the front wheel in steep
descending corners (but perhaps leading to front wheel washout in flat crit
corners?).

Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
why?

John,

My impression is that there's nothing about your bike's geometry
that's causing the problem. Most bikes within a reasonable range will
corner just fine, so long as the 'driver' is willing to. Unless your
bike loses traction at the speeds your talking about, or bursts into
flames, or whatever, it's the rider and not the bike that's causing
the problem.

Having said that, it's also quite possible that your bike IS
contributing to the problem in ways that the geometry doesn't have
anything to do with. For example, I find that I'm much more willing
to descend or corner faster on a bike with a stiffer fork and front
end. I've found that a 'loose' feeling in the front end is a bit
unnerving and the flexiness I feel is misinterpreted as the tires
about to lose traction. With a stiffer frame, I'm more confident and
thus descend/corner faster.

For example, last year I switched from a reasonably stiff titanium
frame to a Madone SL frame. Much stiffer headtube. I found that on a
certain route near my home with some moderately tight, but not
switchback tight, curves, I could take the descent at full speed and
never feel the need to back off or to brake even a little bit. On the
ti frame I always stopped pedalling and often felt compelled to scrub
a little speed before entering the turns. Just wasn't sure enough
that everything was okay. Considering that the wheels and tires were
switched from one frame to another, the big difference was the
frameset.

Of course, if you're going to switch frames to something that's
stiffer, you may as well try to maximize your position/fit on the new
one while you're at it.

Scott wrote:
My impression is that there's nothing about your bike's geometry
that's causing the problem. Most bikes within a reasonable range will
corner just fine, so long as the 'driver' is willing to.

I'm sure even John could dust me on a technical descent, but I find my descending is position-dependent. Going to a shorter stem seemed to help a lot. John's measurement of front wheel and rear wheel normal load, given preference to a reduced front wheel load, is consistent with this.

I rode San Francisco - Palo Alto this morning (41 miles), for Bike to Work Day, with a group including a guy on one of these:
http://www.electrabike.com/04/images...me_page/01.jpg

He appeared to have a very low front wheel load, with his COM almost over his rear axle. It would be interesting to see how well that would handle a twisting descent. Unfortunately, we had none on our route.

Dan

is it possible to assemble the pieces both + and - then try each setup
out in real time?

John Verheul wrote:
The bike is also
fine when at training speeds, it's just in relatively high speed
descending/cornering situations I cannot get around the turns as quickly as
I'd like.

I'm sure you could dust me on a technical descent as well... but you
are racing against pros so the competition is pretty tough. I doubt
that your frame, steering geometry, or weight distribution is an issue
here. A steep geometry with little trail is *easier* to turn... if
anything it would feel twitchy and sensitive when you want to relax. I
used to have a steep and stiff frame and I liked it better for turns
than what I have now. But hey... it's a bicycle... it takes very
little muscle to get any of them to turn.

What is actually slowing you down? You must be getting some sensation
that causes you to back off. Is there noticeable flex in the bars,
stem, or fork? Those things can contribute, but I don't think they are
very important if you have good technique. After the turn is initiated
there shouldn't be significant twisting or lateral forces on the bike.
Maybe you tend to tense up in the turns... have you had a crash
recently? Being "loose" and balanced with a light touch is important,
I think.

In article ,
"John Verheul" wrote:

Since moving out west (US) a couple years ago, practice as I might I
just can't quite descend with riders who are otherwise of my ability.
Recently, I've also been having a hard time cornering in criteriums
at high speeds (over 30mph). Lower speed laps I'm fine, but I'm
closing gaps on fast laps, and getting caught when I attack because
I'm just not carrying as much speed as my competition.

I practice plenty (have a 14 mile climb behind my house with
switchbacks, and a local training crit), and it's my 21st season of
racing, so I'm going to assume I've maximized the skills area as much
as I can. The bike is also fine when at training speeds, it's just in
relatively high speed descending/cornering situations I cannot get
around the turns as quickly as I'd like.

I'm slightly taller than average at 6'1", and don't use a lot of
setback on my road bike (7-8cm), so I suspected I might have too much
weight on the front wheel. Bathroom scale measurements indicate I
don't. It's right around 43/57 front/rear.

So now I'm looking at frame geometry. I'm using a frame that has a
steep 74' head angle, and a 45mm raked fork. With a 23c tire that's
only about 4.9cm of trail, very low by most standards. Bike also has
a pretty short front-center of 60cm (on a 60cm frame).

My options to improve handling as I see it a

1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or
5.4 respectively, more in what most people seem to feel is a more
average range for a racing bike.

2) Get a frame with a longer front center to move cg even further
back in the wheelbase, thus keeping more weight off the front wheel
in steep descending corners (but perhaps leading to front wheel
washout in flat crit corners?).

Any opinions? If I pick option 1, would you get a 40 or 43 rake fork,
and why?

I think the issue may be other than trail. Before you commit to
spending money for changing your bike, borrow one with the front end
geometry you're thinking and give it a try. 45 mm fork offset with 74
degree head angle and 700 x 23s is a bit unusual but not beyond the
pale. After all, lots of perfectly ridable bikes have trail numbers
down into the 35 mm range (and up to 60 mm or so).

How does if feel in fast corners? Do you feel like the front end is
going to wash out? Does if feel like the rear wheel is going to come
around and slide out? Are you faster around left hand bends than right
hand bends (or voce versa)?

Have you tried different tires (e.g., 700 x 25 slicks)? Have you played
with tore pressure (100 psi vs 110 psi vs 120) to see if that
beneficially changes the feel of the bike?

Are your shoulders tense? Death grip on the bars? Craning your neck to
see the line through the corner? All of those can slow you down. Some
fine tuning of your position might benefit.

"Tim McNamara" wrote in message
...
I think the issue may be other than trail. Before you commit to
spending money for changing your bike, borrow one with the front end
geometry you're thinking and give it a try. 45 mm fork offset with 74
degree head angle and 700 x 23s is a bit unusual but not beyond the
pale. After all, lots of perfectly ridable bikes have trail numbers
down into the 35 mm range (and up to 60 mm or so).

That's kind of the thing, the last bike I won a crit on (and felt more
comfortable cornering on) was my 2004 Cannondale team bike, which had a bit
more trail at 73.5 w/45mm rake. It's only in the last year or so I've been
able to choose my own bike, I always had a team bike before this.

How does if feel in fast corners? Do you feel like the front end is
going to wash out? Does if feel like the rear wheel is going to come
around and slide out?

The latter, I feel like any line adjustment I have to make I'm going to put
too much weight on the front wheel and wash the rear. Last tough descent I
raced was a couple weeks ago (points as steep as 17%, with switchbacks),
and I literally did slide the rear around a couple of the corners, which
didn't help my confidence. To be fair, the guy dropping me is an ex-euro
pro, but other local nobodies like me are able to hang better than I.

This is what got me thinking about the front center distance. But the weight
distribution tells me that's not so much the issue.

Are you faster around left hand bends than right
hand bends (or voce versa)?

Not really.

Have you tried different tires (e.g., 700 x 25 slicks)? Have you played
with tore pressure (100 psi vs 110 psi vs 120) to see if that
beneficially changes the feel of the bike?

Yes on all accounts, and no not really any difference.

Are your shoulders tense? Death grip on the bars? Craning your neck to
see the line through the corner? All of those can slow you down. Some
fine tuning of your position might benefit.

My front end is already pretty high for a racer (drop to bars is 10cm, has
been as much as 13 at points in my life), and the position is great for
everything else. I should mention I do professional bike fits myself.

Relaxing in corners...yeah I practice that, and I know that staying loose on
the bike is key. Sliding the rear wheel doesn't help with that (although I
caught the slides and stayed up), there just seems to be some feedback
coming from the bike, the "too far forward" sensation that's making me less
comfortable in high speed corners.

I should add, I'm fine on straight descents...get up over 50mph no problem,
feel comfortable, typically can move up in groups in these situations. Same
for low speed (25mph) corners in crits. It's just when we go fast (and
selections are made), I'm closing gaps after every corner.

"Ron Ruff" wrote in message
oups.com...
What is actually slowing you down? You must be getting some sensation
that causes you to back off.

That's what I'm trying to identify, and thus solve.

Is there noticeable flex in the bars,
stem, or fork? Those things can contribute, but I don't think they are
very important if you have good technique. After the turn is initiated
there shouldn't be significant twisting or lateral forces on the bike.

Same bar/stem as prior year's bikes, fork is Reynolds Ouzo Pro, have used
various front wheels, tires, tire pressures.

Maybe you tend to tense up in the turns... have you had a crash
recently? Being "loose" and balanced with a light touch is important,
I think.

Yeah, no crashes recently...although maybe I'm just getting even more
conservative as I get older. Knock on wood, I can't even remember my last
road crash (in 'cross I crash often enough though).

John Verheul wrote:
"Tim McNamara" wrote in message
How does if feel in fast corners? Do you feel like the front end is
going to wash out? Does if feel like the rear wheel is going to come
around and slide out?

The latter, I feel like any line adjustment I have to make I'm going to put
too much weight on the front wheel and wash the rear. Last tough descent I
raced was a couple weeks ago (points as steep as 17%, with switchbacks),
and I literally did slide the rear around a couple of the corners, which
didn't help my confidence.

Whoa! Sliding the rear on smooth clean pavement? Assuming that you are
using good tires, I don't know what to say about that... unless maybe
you are really leaning over the front or using the brakes... or just
going too fast for the line. You aren't pedaling I hope...

Steep technical descents are extreme, but it puzzles me more that you
are having the same problem in crits. I can't remember any crits I've
been in where a turn could not be taken at 35+ mph, if I could pick my
line. I'm sure they exist but they are not common.

You've tried different tires and pressures... have you tried a
different rear wheel?

Ron Ruff wrote:

I'm sure you could dust me on a technical descent as well... but you
are racing against pros so the competition is pretty tough. I doubt
that your frame, steering geometry, or weight distribution is an issue
here. A steep geometry with little trail is *easier* to turn... if
anything it would feel twitchy and sensitive when you want to relax. I
used to have a steep and stiff frame and I liked it better for turns
than what I have now. But hey... it's a bicycle... it takes very
little muscle to get any of them to turn.


The amount of muscle isn't the issue. It's how comfortable you feel. I feel more comfortable in turns with more stability. The bike feels like it's will track better. Twitchy and quick isn't what you want, here.

I don't know why you doubt geometry is a factor. It doesn't take much to improve a sense of control. I could easily tell the difference with 2 cm off my stem. 1-2 cm of handlebar width also makes a difference. I've not experimented with trail.

Dan

P.S. I'm a slow descender, myself, so take this for what it's worth.