Slammed Stem After Bike Fit.

Discuss light weight issues concerning road bikes & parts.
Wookski
Posts: 1125
Joined: Tue Feb 23, 2016 5:51 am

by Wookski

tabl10s wrote:
Mon Jul 08, 2019 2:30 pm
Should one get a new fit or just adapt?
Just adapt, you’d be surprised at what you can get used to. All my bikes were the same fit in terms of contact points until i couldn’t stand the cherubim’s stem not being parallel with the horizontal TT. Enter -17 stem which brought the bars 12mm lower. In the drops it felt like I was kneeing myself in the chest but now it feels fine, even after 6 hours in the saddle.

by Weenie


zefs
Posts: 438
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

Well if it's that small of a difference no point in getting a new fit.

tabl10s
Posts: 528
Joined: Wed Aug 23, 2017 5:40 am

by tabl10s

velov wrote:
Tue Jul 09, 2019 6:13 am
Kind of an important point to state in your original post, No?
Was a long day.
| 2016 Rca: 11.07lbs/5.048kg...😭 | 2015 Pinarello F8: 13.04lbs/5.915kg...😩 | 2018 S-Works SL6: 12.04/5.625kg... 😥|2018 S-Works SL6 UL: 11.04/5.007kg... :cry:

devonbiker
Posts: 70
Joined: Wed May 30, 2018 1:26 pm

by devonbiker

Slammed is better because it improves the handling and sharpens up the steering. It's not just about aero gains.

I went from all the spacers under the stem on my TCR to fully slammed within a couple of months. It uses Overdrive 2 steerer with 1 1/4-inch top bearing and 1 ½-inch bottom bearing. The bike was designed be used with a slammed stem. You really aren't making the most of a racing bike's handing characteristics if you are running lots of spacers under the stem.

I am 35 and 68kg so I am in good shape. I transitioned very quickly from 40mm of spacers to 2mm and didn't experience any comfort issues. I ride faster due to less drag and felt perfectly comfortable on a recent hilly 100 mile sportive and was able to average 19 mph compaed to 17mph last year with a tall stem. My bike now corners like it's on rails.

At first I was hesitant about cutting the carbon steerer tube but I wouldn't go back to spacers now.

As a friend once said to me, better to go straight to slammed then add spacers if you feel you need to rather than the other way round, as you don't know what you are missing if you run a high stem.

Mr.Gib
Posts: 3630
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

devonbiker wrote:
Tue Jul 09, 2019 10:17 pm
Slammed is better because it improves the handling and sharpens up the steering.
This is not necessarily true. Please explain.

Whether the "handling" improves will depend if it results in a better fit. It is entirely possible to have a situation where a lower front end results in excess weight on the front wheel. That could result in worse handling not better.

Sharpens up steering? What does this mean? Do you mean the bike turns in more quickly? Responds more to bike lean? 'cause if you do that would be wrong also. Steering quickness is a product of fork offset and head tube angle. (Stem length affects steering feel and tracking stability but stem length doesn't seem to be part of this conversation).
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

devonbiker
Posts: 70
Joined: Wed May 30, 2018 1:26 pm

by devonbiker

Mr.Gib wrote:
Wed Jul 10, 2019 12:08 am
devonbiker wrote:
Tue Jul 09, 2019 10:17 pm
Slammed is better because it improves the handling and sharpens up the steering.
This is not necessarily true. Please explain.

Whether the "handling" improves will depend if it results in a better fit. It is entirely possible to have a situation where a lower front end results in excess weight on the front wheel. That could result in worse handling not better.

Sharpens up steering? What does this mean? Do you mean the bike turns in more quickly? Responds more to bike lean? 'cause if you do that would be wrong also. Steering quickness is a product of fork offset and head tube angle. (Stem length affects steering feel and tracking stability but stem length doesn't seem to be part of this conversation).
I agree if you are overweight then you might not want to slam your stem as you are putting excess weight on your wrists. But for fit adults with normal BMI, with weight around 65-75kg more weight on the front end results in better grip through corners.

Having a shorter steerer tube and bring closer to the front wheel does make the ride feel more engaging for me. But I have a racing bike with quite aggressive geometry and a relatively long top tube so slammed is the way to go with a TCR. Otherwise you may as well ride a Defy.

Mr.Gib
Posts: 3630
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

devonbiker wrote:
Wed Jul 10, 2019 8:34 am
I agree if you are overweight then you might not want to slam your stem as you are putting excess weight on your wrists. But for fit adults with normal BMI, with weight around 65-75kg more weight on the front end results in better grip through corners.
Uh, no. Sorry that's not correct. For each individual cyclist on any individual bike there is an optimum weight distribution between the two wheels when cornering regardless of the size of the rider. More weight on the front is not better unless there is not enough weight on the front in the first place, which is the same as saying the fit is wrong. Depending on bike fit, there is a good argument that moving the weight back improves cornering, something many superior descenders instinctively do. Next time you are on a technical descent, shift your weight back very slightly as you enter a tight curve, haripin, swithchback etc. You will notice the front of the bike dive toward the apex of the turn with less effort and maintain a tighter line with less effort. The bike wants to rotate in the direction of the turn when you move back. It creates a touch of oversteer and reduces the chance of the front washing out - the opposite of what you are claiming. Loading up the front may cause the bike to "push" or exhibit understeer in the turns. The opposite of what you want.

Here is a photo of a great descender riding in a straight line. Note the weight distribution
Image

Here he is cornering - the weight distribution is further back. Note Cancellara's straight leg. Almost looks as though his seat is too high. That's becuase he is pushing his weight back a touch for the corner. Same with the Lampre rider beside him. You can see a lot of saddle nose on both of them.
Image

devonbiker wrote:
Wed Jul 10, 2019 8:34 am
Having a shorter steerer tube and bring closer to the front wheel does make the ride feel more engaging for me. But I have a racing bike with quite aggressive geometry and a relatively long top tube so slammed is the way to go with a TCR. Otherwise you may as well ride a Defy.
Engaging? what does that mean? But you have a racing bike! Wow. I think there may be a few folks here with those. Forgive the sarcasm but maybe do a little research before you hand out nonsence advice. A slammed stem will change fit, comfort, weight distribution, but it won't necessarily result in a bike that handles better. It is just as likely to result in worse handling save for whatever advantage is gained from a lower center of gravity.
Last edited by Mr.Gib on Thu Jul 11, 2019 1:26 am, edited 2 times in total.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

cajer
Posts: 206
Joined: Sun Jul 14, 2013 1:26 am

by cajer

You could just flip the stem from negative to positive rise and gain quite a bit of stack.

devonbiker
Posts: 70
Joined: Wed May 30, 2018 1:26 pm

by devonbiker

Yes, I feel more engaged when I am closer to the road. It's quite simple really.

The thing that stands out to me looking at that rider is that he is probably on a frame one size too small, as with most pro riders. So he can have a lot of seatpost showing and run a 130 stem. Look at this back, it's almost horizontal on the drops. He's slammed the stem and the frame also has a short head tube so he can get his upper back and shoulders as low as possible.

I have a bike that fits me according to the manufacturer's size charts and even with a slammed stem my back angle is about is 30-40 degrees when riding on the hoods, so my position is far from too aggressive. If I was on a medium frame instead of a ML I would probably run a spacer and/or a longer stem.

Karvalo
Posts: 745
Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

devonbiker wrote:
Thu Jul 11, 2019 8:02 am
I have a bike that fits me according to the manufacturer's size charts and even with a slammed stem my back angle is about is 30-40 degrees when riding on the hoods, so my position is far from too aggressive. If I was on a medium frame instead of a ML I would probably run a spacer and/or a longer stem.
This is the major problem with your 'advice'. You have absolutely no idea what the OPs position is. He might already have significantly more drop than you, and you're telling him things will get better if he goes lower just because it did for you, from your starting point. It's absurd to make absolute statements about what will make a bike feel better simply based on a change that worked for you.

And there's nothing magic about a race bike that makes them feel better slammed in contrast with an endurance bike.

zefs
Posts: 438
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

The bike will be more agile, just like when lowering your torso before taking a corner so not sure why you guys are arguing about that.
If it's the correct adjustment fit wise for the purpose is a different matter.

Mr.Gib
Posts: 3630
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

devonbiker wrote:
Thu Jul 11, 2019 8:02 am
Yes, I feel more engaged when I am closer to the road. It's quite simple really.
Still don't understand. What does engaged mean? More traction? You are more motivated? You can see the road better because your face is closer to it? Your going to marry your bike and you have set a wedding date? Is it really quite simple?

devonbiker wrote:
Thu Jul 11, 2019 8:02 am
The thing that stands out to me looking at that rider is that he is probably on a frame one size too small, as with most pro riders. So he can have a lot of seatpost showing and run a 130 stem. Look at this back, it's almost horizontal on the drops. He's slammed the stem and the frame also has a short head tube so he can get his upper back and shoulders as low as possible.
Frames size is irrelevant to the issue of weight back or forward when cornering. You said weight forward was better for cornering. I said no, weight back is often better. I showed a photographic example. And you wrote the above complete non-sequitur about frames size. And BTW, Cancellara is not on a smaller frame so he can "have a lot of seatpost showing" and "run a 130 stem". It is to acheive low enough shoulders without having to bend his arms so much that his triceps get fatigued. C'mon man. And I'd argue that that frame is not too small but I digress.

devonbiker wrote:
Thu Jul 11, 2019 8:02 am
If I was on a medium frame instead of a ML I would probably run a spacer and/or a longer stem.
Run a spacer? Wait a minute - you said slammed was better. Are you changing your opinion? Maybe you should just ride a Defy!

Again, forgive my sarcasm and trolling, but you need to lay off just throwing out some random combination of ideas and cliches you picked up here and there when it comes to fitting advice. It brings down what is generally a very high standard of the quality of information here on WW's. Also know when to quit.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

Mr.Gib
Posts: 3630
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

zefs wrote:
Thu Jul 11, 2019 9:43 am
The bike will be more agile, just like when lowering your torso before taking a corner so not sure why you guys are arguing about that.
If it's the correct adjustment fit wise for the purpose is a different matter.
Really??? I contend that lowering the torso doesn't change the steering properties (agility) of a bicycle. It does however increase the stability due to the lower center of gravity and reduced exposue to buffeting by air.

Realize that your argument that lowering the torso results in an increase in agility is the same as saying that raising the torso increases stability. Of course basic physics tells us that this is the opposite of what is true.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

zefs
Posts: 438
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

So what makes you turn faster? the extra stability of lower center of gravity? and how is that different with saying the bike is more agile?

Hexsense
Posts: 952
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

A bike is more agile when it has less trail number (plus short wheel base and low weight but they have much less influent than trail number). Agile = easy to change direction (or acceleration).
Either increase fork rake or increase head tube angle will do the trick very well for handling agility. Oh, reducing wheel and tire size also reduce trail number (make it more agile) too. But it would be strange to switch to 19c just to make the bike more agile than 25c.

Actually, taller C.G make it a little bit easier for the rider to change bike's direction with less lean angle too. Taller C.G. make it more agile.
Everywhere, bike or motor bike, people seems to confuse on basic things of bike handling. http://forums.superbikeschool.com/topic ... gh-or-low/

by Weenie


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