Racer Tech Thread
07-29-14, 09:15 AM
#151
Senior Member
so when you have a normal, round bar vs one with compact reach, you are finding that you increase stem length by 2.5cm and reduce drop (in the stem) by 3?
cool stuff, cdr.
i use different bars on 2 bikes but they are within a few mm of drop and reach. i have some 130mm stems i might play with a bit. i've found saddle height/setback to be critical, while cockpit position is more preference (comfort + handling).
cool stuff, cdr.
i use different bars on 2 bikes but they are within a few mm of drop and reach. i have some 130mm stems i might play with a bit. i've found saddle height/setback to be critical, while cockpit position is more preference (comfort + handling).
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"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
07-29-14, 09:58 AM
#152
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At 6'3" tall and 180lbs, with an arm length of 86cm ( shoulder to palm ) and a leg inseam of 91cm, my seat height is 85cm. Stem length is 135mm. Top Tube ( 58cm frame ) is 57.5cm. Seat to handlebar drop is 16cm. The reach ( handlebar center to saddle tip ) is 62cm. handlebar width at 43cm C to C. crank length being 172.5 I had used 175's in the past but find that 172.5 allows for a more efficient cadence. It's not much but spinning at 75-80 versus a more optimal 90-95 is much more efficient over 2 to 3 hours or more.
07-29-14, 12:30 PM
#153
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See, for me a 58.5 Top tube is too long necessitating a shorter stem which then gives me a bike feel that I don't like. In other words I am then too far back so that the front end of the bike becomes unweighted somewhat and more prone to sliding out in slippery conditions when at full gaz in a turn. With neutral weight fore and aft I can drift both wheels, cannot do that if weight bias is rearward when pushing down on the outside pedal while engaging a turn.
Also I used to ski race so my preference in bike handling comes from racing Giant Slalom and Slalom. I also ride a lot in the winter in snow so two tires drifting doesn't bother me at all. I very much apply ski racing dynamics to Bike racing dynamics. They are quite similar in that you are always searching for a way to lower your center of gravity, which then allows you better control and less of a pitching effect. All about centripetal and centrifugal forces and counteracting them..
This is probably an entire thread theme but I totally disagree with the current norm of extending the inside leg / knee when cornering. This is a cornering technique derived from motorcycle racing. Completely different parameters between say a 748 Ducati and a Masi Evoluzione.
big difference being our center of gravity is pretty much north of the top tube and we need to offset that by redirecting as much of that force to the lowest point possible which is that extended outside leg. No such problem on the 748 since the motor and the wight of the bike far surpass the rider. Plus there's that option of twisting the throttle and forcing the rear to come around. Cannot do that on a bicycle, no way to put the power down since we have to pedal changing a vertical leg motion to a circular energy transfer.
Inside knee extended outward to the inside of a turn redirects weight bias to the inside of the forces pushing outward. Which then makes for additional forces to counteract while negotiating switchbacks.
Watching Bradley Wiggins descend versus some of the top descenders at the tour pretty much spells out the difference.
Also I used to ski race so my preference in bike handling comes from racing Giant Slalom and Slalom. I also ride a lot in the winter in snow so two tires drifting doesn't bother me at all. I very much apply ski racing dynamics to Bike racing dynamics. They are quite similar in that you are always searching for a way to lower your center of gravity, which then allows you better control and less of a pitching effect. All about centripetal and centrifugal forces and counteracting them..
This is probably an entire thread theme but I totally disagree with the current norm of extending the inside leg / knee when cornering. This is a cornering technique derived from motorcycle racing. Completely different parameters between say a 748 Ducati and a Masi Evoluzione.
big difference being our center of gravity is pretty much north of the top tube and we need to offset that by redirecting as much of that force to the lowest point possible which is that extended outside leg. No such problem on the 748 since the motor and the wight of the bike far surpass the rider. Plus there's that option of twisting the throttle and forcing the rear to come around. Cannot do that on a bicycle, no way to put the power down since we have to pedal changing a vertical leg motion to a circular energy transfer.
Inside knee extended outward to the inside of a turn redirects weight bias to the inside of the forces pushing outward. Which then makes for additional forces to counteract while negotiating switchbacks.
Watching Bradley Wiggins descend versus some of the top descenders at the tour pretty much spells out the difference.
Last edited by Moyene Corniche; 07-29-14 at 12:34 PM.
07-29-14, 01:45 PM
#154
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You can still do that fairly easily by continuing to weight your outside leg. I stick my inner knee out out of habit after racing sportbikes and doing thousands of laps there before bike racing. I still handle corners better than 99% of the peleton even with my inner knee going out. It also helps in crits to widen your profile and thus discourage people from diving up the inside, akin to the Rossi leg dangle I suppose.
Also, not many riders ride like that steering with the throttle to spin up the rear on purpose. It usually ends with people on their heads. Unless you come from a dirt track background, good luck with that.
Also, not many riders ride like that steering with the throttle to spin up the rear on purpose. It usually ends with people on their heads. Unless you come from a dirt track background, good luck with that.
07-30-14, 10:23 AM
#159
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This bike already has a tall headtube compared to others.
I went ahead and ordered the medium. Worse case I return it, but I've run the numbers and this should work good in theory. I think the headtube was too short on my current bike, so I should be able to go longer without going lower, allowing the handling to be better and for me to stretch a bit (I think I've been a tad bit too crunched up lately and maybe been causing some odd low back pain every once in a while). Guess we'll see!
I went ahead and ordered the medium. Worse case I return it, but I've run the numbers and this should work good in theory. I think the headtube was too short on my current bike, so I should be able to go longer without going lower, allowing the handling to be better and for me to stretch a bit (I think I've been a tad bit too crunched up lately and maybe been causing some odd low back pain every once in a while). Guess we'll see!
07-30-14, 02:00 PM
#160
Senior Member
Bike fit this evening. I'm curious to see where we end up, I haven't had one in four years. I have a slightly unreasonable worry that the "right" fit will require a shorter headtube than I've got on the frame I'm riding now - my frame has practically zero resale value (custom builder no one has heard of, good sized dent in the top tube), so I won't want to hear that I should get a new one!
07-30-14, 03:27 PM
#161
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34 Year Old Scrub from NorCal has a Secret. BikeFit Pros hate him!
raise your saddle, push it forward, drop your bars.
raise your saddle, push it forward, drop your bars.
07-30-14, 08:33 PM
#162
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Yea, i am running a pretty aggressive setup now and LOVE it but im curious if ill still like it when doing zone2 base this winter.
Let us know how fit goes colby
Let us know how fit goes colby
07-31-14, 05:08 PM
#164
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Originally Posted by thechemist
I won't ever go back to anything less than 110mm stem. Stability has been a huge confidence booster with a longer stem.
@tetonrider it is interesting that you found a difference between the tarmac and venge descending/cornering. My future plan was always to drop a bike size and go with the venge over my current tarmac for several reasons. However, since adding length to my stem, I wonder if I had judged the tarmac too severely and perhaps will just drop a size for another tarmac.
@tetonrider it is interesting that you found a difference between the tarmac and venge descending/cornering. My future plan was always to drop a bike size and go with the venge over my current tarmac for several reasons. However, since adding length to my stem, I wonder if I had judged the tarmac too severely and perhaps will just drop a size for another tarmac.
Originally Posted by tetonrider
i have no problem recommending either bike (in fact, the venge is the one bike you'd have to pry out of my cold, dead hands), but i figured i'd note the slight understeer. if faced with riding a sub-100mm stem, i'd definitely look at the next lower size.
the tarmac is honestly a great handling bike. i can understand someone preferring another or simply not wanting to buy a specialized bike, but if someone rides a tarmac for a while and thinks 'meh' with respect to the handling, i think it may be more of a sign that something is not right with the setup. it's been around for a long time for a reason and is a common choice in the pro ranks for a reason (beyond just the marketing/sponsor stuff). i'd at least test the right size tarmac with a 110 or 120 stem to see what you think., but of course also test other bikes in the right size.
the tarmac is honestly a great handling bike. i can understand someone preferring another or simply not wanting to buy a specialized bike, but if someone rides a tarmac for a while and thinks 'meh' with respect to the handling, i think it may be more of a sign that something is not right with the setup. it's been around for a long time for a reason and is a common choice in the pro ranks for a reason (beyond just the marketing/sponsor stuff). i'd at least test the right size tarmac with a 110 or 120 stem to see what you think., but of course also test other bikes in the right size.
08-03-14, 09:51 AM
#165
VeloSIRraptor
08-03-14, 11:43 AM
#166
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Heh. I have a whole collection of -17 stems. 90mm (on the CX bike), 110mm, 120mm. Ran the 110 for a while, went to 120 last year, lately back on the 110. I don't actually think stem length is that critical for handling, provided your saddle is in the right place. Much will also depend upon the front-end geometry of the bike - shallower head angles and greater fork rake push the front wheel away a bit, which will definitely affect where your CG is relative to the front axle. I happen to like the handling on my current bike a bit better than I did when I was riding a Specialized S-Works E5, which required a 90mm stem for me (same geo as the Tarmac and Allez, FYI), but I never had a problem with the handling on that bike. I was perfectly happy to ride both very, very fast.
08-03-14, 03:07 PM
#167
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Today I swapped my stem from a 120mm -17* to a 140mm -17* (thanks CDR). I like it a lot. I'm more comfortable in the drops and handling is greatly improved. I will give it a couple of weeks before deciding if this is the right change. So far so good.
08-03-14, 03:52 PM
#168
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That is a pretty big change for an "advanced" racer. I assume you seat to bar drop is more and your are more stretched out.
08-03-14, 04:15 PM
#169
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No change in drop. I was always a bit crunched up in the drops, not quite neutral. I have a 130mm, but I thought it wouldn't hurt to try the 140 first for a bit and then drop back.
08-03-14, 06:18 PM
#170
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I am using a -17 degree as well. I may try one 1 cm longer.
08-03-14, 06:32 PM
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Stem wang
08-03-14, 06:52 PM
#175
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I thought I sent you a 130mm? Maybe I sent the wrong one (I had one of each size).
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"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson