How to change position when moving to shorter cranks
#26
Batüwü Creakcreak
Thread Starter
Join Date: Jan 2007
Location: The illadelph
Posts: 20,792
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 229 Post(s)
Liked 288 Times
in
160 Posts
Good for you. Then read my post 15. Crank length doesn't matter. Saddle position is the same regardless of crank length. One fits for balance, thus for you to keep balance the same, you want the same setback w/r to your BB with any crank length. Zinn is fitting for KOPS, which is old tech and doesn't even work for many people. Zinn would have you fit for KOPS, thus changing both balance and reach. That's not the norm anymore.
https://www.stevehoggbikefitting.com...or-road-bikes/
https://www.stevehoggbikefitting.com...or-road-bikes/
The zinn example was there to show movement of saddle necessary to keep same relative position when changing crank length I didn't say anything about kops, just the nominal direction of moving the saddle when trying to keep the knee-pedal-foot relationship the same.
You're answering a question I never asked. More power to ya!
Edit : wrote Hogg earlier but meant zinn. Corrected above.
Last edited by ridethecliche; 11-18-20 at 07:54 PM.
#27
Senior Member
Join Date: Dec 2019
Location: South Shore of Long Island
Posts: 2,800
Bikes: 2010 Carrera Volans, 2015 C-Dale Trail 2sl, 2017 Raleigh Rush Hour, 2017 Blue Proseccio, 1992 Giant Perigee, 80s Gitane Rallye Tandem
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1088 Post(s)
Liked 1,026 Times
in
723 Posts
Incorrect.
The Hogg example was there to show movement of saddle necessary to keep same relative position when changing crank length I didn't say anything about kops, just the nominal direction of moving the saddle when trying to keep the knee-pedal-foot relationship the same.
You're answering a question I never asked. More power to ya!
The Hogg example was there to show movement of saddle necessary to keep same relative position when changing crank length I didn't say anything about kops, just the nominal direction of moving the saddle when trying to keep the knee-pedal-foot relationship the same.
You're answering a question I never asked. More power to ya!
#28
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,539
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3891 Post(s)
Liked 1,940 Times
in
1,385 Posts
More likely, the fix is PT, which the OP is doing. If the PTer is any good, they should be able to correct his knee tracking. It's more likely a mechanical problem in his body, not in his bicycle. That's almost always the case, barring serious injury. Change your fitness, not your fit is my usual advice. OP is doing both at once, fine.
__________________
Results matter
Results matter
#29
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,539
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3891 Post(s)
Liked 1,940 Times
in
1,385 Posts
Incorrect.
The Hogg example was there to show movement of saddle necessary to keep same relative position when changing crank length I didn't say anything about kops, just the nominal direction of moving the saddle when trying to keep the knee-pedal-foot relationship the same.
You're answering a question I never asked. More power to ya!
The Hogg example was there to show movement of saddle necessary to keep same relative position when changing crank length I didn't say anything about kops, just the nominal direction of moving the saddle when trying to keep the knee-pedal-foot relationship the same.
You're answering a question I never asked. More power to ya!
Maybe you should just move the saddle back and forth without measuring anything and see where it feels best, in and out of the saddle, noticing changes in weight on the bars as you do so.
__________________
Results matter
Results matter
Likes For Carbonfiberboy:
#30
Batüwü Creakcreak
Thread Starter
Join Date: Jan 2007
Location: The illadelph
Posts: 20,792
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 229 Post(s)
Liked 288 Times
in
160 Posts
The Hogg article and my advice and the advice of others is not to do that, rather keep your fore-and-aft saddle-BB relationship the same. You don't seem to want advice from anyone. Fine. You might consider that you can't keep the knee-pedal relationship the same. Knee angle at 3:00 and 9:00 is going to change if you keep the 6:00 angle the same. Not only that, but you'll be moving the 9:00 pedal forward by double the crank length distance in order to keep the 3:00 foot/pedal horizontal relationship the same.
Maybe you should just move the saddle back and forth without measuring anything and see where it feels best, in and out of the saddle, noticing changes in weight on the bars as you do so.
Maybe you should just move the saddle back and forth without measuring anything and see where it feels best, in and out of the saddle, noticing changes in weight on the bars as you do so.
Likes For ridethecliche:
#31
Senior Member
Join Date: Feb 2018
Posts: 786
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 338 Post(s)
Liked 408 Times
in
252 Posts
Depends why you changed to shorter cranks.
Essentially, with a shorter crank you can preserve the knee angle at the top of the pedal rotation by making your saddle lower, or preserve the knee angle at the bottom of the pedal rotation by making your saddle taller, or you can do something in between, depends where the problem was (if any). If your leg was overextending with the longer cranks then obviously you don't want to jack the saddle up when you move to a shorter crank, and if you were kneeing yourself in the gut you don't want to move the saddle down with the shorter crank.
Personally, I like 170mm on my road bike, it works a touch better for me than 175mm since my legs aren't very long, but the difference between mainstream crank sizes isn't all that big.
Essentially, with a shorter crank you can preserve the knee angle at the top of the pedal rotation by making your saddle lower, or preserve the knee angle at the bottom of the pedal rotation by making your saddle taller, or you can do something in between, depends where the problem was (if any). If your leg was overextending with the longer cranks then obviously you don't want to jack the saddle up when you move to a shorter crank, and if you were kneeing yourself in the gut you don't want to move the saddle down with the shorter crank.
Personally, I like 170mm on my road bike, it works a touch better for me than 175mm since my legs aren't very long, but the difference between mainstream crank sizes isn't all that big.
#32
Super Modest
Join Date: Jun 2002
Location: Central Illinois
Posts: 23,468
Bikes: Trek Emonda, Giant Propel, Colnago V3, Co-Motion Supremo, ICE VTX WC
Mentioned: 107 Post(s)
Tagged: 1 Thread(s)
Quoted: 10965 Post(s)
Liked 4,621 Times
in
2,124 Posts
Depends why you changed to shorter cranks.
Essentially, with a shorter crank you can preserve the knee angle at the top of the pedal rotation by making your saddle lower, or preserve the knee angle at the bottom of the pedal rotation by making your saddle taller, or you can do something in between, depends where the problem was (if any).
Essentially, with a shorter crank you can preserve the knee angle at the top of the pedal rotation by making your saddle lower, or preserve the knee angle at the bottom of the pedal rotation by making your saddle taller, or you can do something in between, depends where the problem was (if any).
__________________
Keep the chain tight!
Likes For Trsnrtr:
#33
Flyin' under the radar
I thought I'd share how going from 175s to 170s changed my positioning on the bike. I have hip mobility issues from an injury that restricts how high my right leg can come up; this consequently forced me into a very forward and upright position with 175s. Here's my old position:
With 170s, I was able to keep roughly the same saddle height ~5mm, add more setback for better balance to unload my hands, but was able to go substantially lower in the front: from a +12 degree 120mm stem to a -6 degree 100mm stem w/ ~20mm fewer spacers. New position (forgive the dirty bike, I just went outside to snap a photo for this post):
So for me, going to a shorter crank length enabled me to be both more comfortable and more aero/aggressive. All this to say, experiment with your positioning now that you've got shorter cranks and see what works best for you.
With 170s, I was able to keep roughly the same saddle height ~5mm, add more setback for better balance to unload my hands, but was able to go substantially lower in the front: from a +12 degree 120mm stem to a -6 degree 100mm stem w/ ~20mm fewer spacers. New position (forgive the dirty bike, I just went outside to snap a photo for this post):
So for me, going to a shorter crank length enabled me to be both more comfortable and more aero/aggressive. All this to say, experiment with your positioning now that you've got shorter cranks and see what works best for you.
#34
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,539
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3891 Post(s)
Liked 1,940 Times
in
1,385 Posts
I thought I'd share how going from 175s to 170s changed my positioning on the bike. I have hip mobility issues from an injury that restricts how high my right leg can come up; this consequently forced me into a very forward and upright position with 175s. Here's my old position:
With 170s, I was able to keep roughly the same saddle height ~5mm, add more setback for better balance to unload my hands, but was able to go substantially lower in the front: from a +12 degree 120mm stem to a -6 degree 100mm stem w/ ~20mm fewer spacers. New position (forgive the dirty bike, I just went outside to snap a photo for this post):
So for me, going to a shorter crank length enabled me to be both more comfortable and more aero/aggressive. All this to say, experiment with your positioning now that you've got shorter cranks and see what works best for you.
With 170s, I was able to keep roughly the same saddle height ~5mm, add more setback for better balance to unload my hands, but was able to go substantially lower in the front: from a +12 degree 120mm stem to a -6 degree 100mm stem w/ ~20mm fewer spacers. New position (forgive the dirty bike, I just went outside to snap a photo for this post):
So for me, going to a shorter crank length enabled me to be both more comfortable and more aero/aggressive. All this to say, experiment with your positioning now that you've got shorter cranks and see what works best for you.
__________________
Results matter
Results matter
#35
Senior Member
I'm having a hard time understanding how lowering your knee by ~3/16" allowed you to drop your bars by what looks like 3" as well as further closing your hip angle by going to a setback seatpost. From your post, I'd assume that your hip issue was that your hip angle had a minimum limit.
#36
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,539
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3891 Post(s)
Liked 1,940 Times
in
1,385 Posts
Actually I think he increased his reach and by a good bit. It's a slightly shorter stem alright, but he moved his bars down 18°, plus he moved his spacers from under the stem to on top of it and moved his saddle back. If you feel like it. print the two photos and draw it out.
Note that I'm not criticizing RVAV. I'm just pointing out that shorter cranks may have had little to do with his ability to reposition himself on his bike. His new fit looks excellent, absolutely what a road bike is supposed to look like. I know several folks who've become more comfortable on their bikes after lowering their bars and increasing reach. It works.
Note that I'm not criticizing RVAV. I'm just pointing out that shorter cranks may have had little to do with his ability to reposition himself on his bike. His new fit looks excellent, absolutely what a road bike is supposed to look like. I know several folks who've become more comfortable on their bikes after lowering their bars and increasing reach. It works.
__________________
Results matter
Results matter
#37
Senior Member
Join Date: Aug 2014
Posts: 2,433
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 741 Post(s)
Liked 412 Times
in
230 Posts
Actually I think he increased his reach and by a good bit. It's a slightly shorter stem alright, but he moved his bars down 18°, plus he moved his spacers from under the stem to on top of it and moved his saddle back. If you feel like it. print the two photos and draw it out.
Note that I'm not criticizing RVAV. I'm just pointing out that shorter cranks may have had little to do with his ability to reposition himself on his bike. His new fit looks excellent, absolutely what a road bike is supposed to look like. I know several folks who've become more comfortable on their bikes after lowering their bars and increasing reach. It works.
Note that I'm not criticizing RVAV. I'm just pointing out that shorter cranks may have had little to do with his ability to reposition himself on his bike. His new fit looks excellent, absolutely what a road bike is supposed to look like. I know several folks who've become more comfortable on their bikes after lowering their bars and increasing reach. It works.
https://yojimg.net/bike/web_tools/stem.php
#38
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,539
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3891 Post(s)
Liked 1,940 Times
in
1,385 Posts
__________________
Results matter
Results matter
#39
Senior Member
Join Date: Aug 2014
Posts: 2,433
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 741 Post(s)
Liked 412 Times
in
230 Posts
I have used this site before when I was trying to adjust the cockpit on my track bike. It is the first site that pops up when doing a Goggle search stem comparison tool. There are a bunch of other sites that can tell you the difference in reach and height of two stems.
#40
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,539
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3891 Post(s)
Liked 1,940 Times
in
1,385 Posts
I have used this site before when I was trying to adjust the cockpit on my track bike. It is the first site that pops up when doing a Goggle search stem comparison tool. There are a bunch of other sites that can tell you the difference in reach and height of two stems.
Answer: reach is the same, except that tilting the bars down until level moved the hoods further away and of course moving the saddle back..
__________________
Results matter
Results matter