Short Stem

[Marco Crow]

The current stem i hav is 70mm i just cant get use a decline with this stem

[Tri-Cycles]

I'm clearing out some lightweight (+-110g) stems at R250 each if you're looking for a replacement

 

I have everything from 90mm to 130mm available

 

http://www.tri-cycles.net/components/stems/

[Bateleur1]

Whoever did your bikefit should actually be able to give you an idea of what length stem you should have.  

 

I use the same "rule" that 100Tours mentioned and it has worked well for me.  if the person who did the bikefit is not able to help I would go to a bikeshop with your bike (Tri Cycles mentioned he can help) and get the right stem for you.

[Marco Crow]

Thank you

[DieselnDust]

75mm stem is too short for a road bikes geometry. You already have very short trail compared to a mtb so you need a longer stem to balance the bike. 

An 80 mm stem is not much of an extension so try a 90mm. 

You can also slide the saddle forward on the rails to keep the effective reach the same. You will have more weight forward as well as the extra stability of the longer stem

[NotSoBigBen]

75mm stem is too short for a road bikes geometry. You already have very short trail compared to a mtb so you need a longer stem to balance the bike.

An 80 mm stem is not much of an extension so try a 90mm.

You can also slide the saddle forward on the rails to keep the effective reach the same. You will have more weight forward as well as the extra stability of the longer stem

Does sliding the seat forward though not lead to other issues with knees and stuff? Just wondering ... I always thought seat height and knee to pedal were things you don't want to mess with too much. Reach and bar height were more to do with comfort/ bike feel and could be different for different people depending what you want to achieve ... comfort/speed

 

I may have more of an old school approach to these things I think?

[V12man]

Hi sorry this a roadbike stem size at 75mm?

You can easily go longer on a roadbike - doubt you will notice a handling difference out till about 100mm - you will notice an improvement in comfort first before the handling change - especially if you don't fit the bike properly.

[DieselnDust]

Does sliding the seat forward though not lead to other issues with knees and stuff? Just wondering ... I always thought seat height and knee to pedal were things you don't want to mess with too much. Reach and bar height were more to do with comfort/ bike feel and could be different for different people depending what you want to achieve ... comfort/speed

 

I may have more of an old school approach to these things I think?

 

No not in my experience. Its why a triathlete can jump onto a mountainbike from their tt bike and not get injured. the only measurement that should stay more or less constant is the pedel to top of saddle distance. Of course the moving the saddle forward or aft has be within reason.

15mm forward to get the rider more over the pedals isn't as bad as sliding the saddle rearward and increasing the reach.

[Noshow]

Agree 70mm is short for a road bike - I'm not suprised it feels a bit hairy on fast descents. Did the bike fitter put that shorter stem on or did the bike come with it?  I think anything less that about 90mm is a bit short. If you need less than this it might be that the bike is too big. 

 

Why don't you go back to the fitter and ask to try a longer stem - they will have all sizes they can loan you.  Alternatively ask any LBS if they will loan one to try, or buy a cheap on on here. If the reach then feels too much (the hub obscured by the bars rule of thumb) try sliding the saddle forward a bit - say up to 10mm shouldn't throw the knee/pedal alignment out too much.

 

You can also try shorter reach compact bars to bring the brake hoods back, but that is starting to get pricey.

[shaper]

No not in my experience. Its why a triathlete can jump onto a mountainbike from their tt bike and not get injured. the only measurement that should stay more or less constant is the pedel to top of saddle distance. Of course the moving the saddle forward or aft has be within reason.

15mm forward to get the rider more over the pedals isn't as bad as sliding the saddle rearward and increasing the reach.

With all due respect a TT frame has completely different geometry to a MTB and RB.  Irrespective of the bike the ankle-knee-hip angle is generally around 150 degrees irrespective of the bike due to the geometry.  A TT bike has a much steeper seatpost angle and is why the saddle is in a more forward and at a higher position to maintain this angle.

 

Moving a saddle on a RB forward will alter this angle and could well cause knee and back issues as NSBB hinted at.

 

I would not go to you for a bike fit if that is your experience!

 

Edit:  If it is not an error in fitment then the short stem will highlight the frame is too big, else if the OP fits a longer stem for handling then he will need to work on his flexibility for the increase in reach

 

Out of curiosity OP, how tall are you and your inside leg measurement?

[Pure Savage]

You need at least a 130mm on there and some yoga classes.

[DieselnDust]

With all due respect a TT frame has completely different geometry to a MTB and RB.  Irrespective of the bike the ankle-knee-hip angle is generally around 150 degrees irrespective of the bike due to the geometry.  A TT bike has a much steeper seatpost angle and is why the saddle is in a more forward and at a higher position to maintain this angle.

 

Moving a saddle on a RB forward will alter this angle and could well cause knee and back issues as NSBB hinted at.

 

I would not go to you for a bike fit if that is your experience!

 

Edit:  If it is not an error in fitment then the short stem will highlight the frame is too big, else if the OP fits a longer stem for handling then he will need to work on his flexibility for the increase in reach

 

Out of curiosity OP, how tall are you and your inside leg measurement?

 

 

total rubbish. The position in which power is generated on a TT bike is so different that riders need time to adapt to it but through that adaptation they don't get injured. Been there, have the T-shirt. Your reasoning suggests that a rider will be injured if they hop onto several different bikes in the same day. This is simply untrue. The only situation that will cause injury is too high a saddle or too long a reach. 

 

The seat post design for most road bikes does not allow very extreme movement of the saddle; 25mm fore - aft.

 

Yet Cervelo S5,  Look 795 Blade and some Giants allow the seat cradle or saddle post to be reversed to allow a more forward or aft position on the same bike with the same rider.

I have ridden several bikes belonging to people who wish to have a bike fit or mechanical work done and I'm still walking. I've even had to ride someone elses bike the last 80km of a DC and despite tight quads due to a saddle that was way too low, I was still able to hop back onto my own bike and ride it. I'm still healthy.

The point is the human body is able to adapt to various configurations. Knee Over Pedal Spindle (KOPS) is a myth. That 150 degrees you talk about relates to the distance of the point of contact (seat) to the pedals spindle and its not some sort of rule.

 

BTW I've done many bike fits and in every case the rider has been pleased with the results. Some of these has required the knee ahead of the pedal spindle, some not. In each case the rider has delivered a few watts more power and fitted more comfortably.

 

But you're welcome to disagree with me if you wish.

[Marco Crow]

Thanks guys the fitter advise me to fit a 90mm and return for adjustments.

[Dicky DQ]

If i do change to 90mm stem i would need to go back to the bike fitter

If you do change it means the bike fitter did not do his job, quite simple.

 

If you go for a bike fit the fitter is supposed to set the bike up optimally for you that includes Stem, Saddle, saddle height, Bar width, everything otherwise why have a bike fit?

[ChrisF]

If you do change it means the bike fitter did not do his job, quite simple.

 

If you go for a bike fit the fitter is supposed to set the bike up optimally for you that includes Stem, Saddle, saddle height, Bar width, everything otherwise why have a bike fit?

 

I have a theory on this ....

 

People start out on a "shop assembled" setup, and start riding .... often the only reason for a proper bike-fit is because the person starts experiencing some or other issues ....

 

 

SCARY the number of incorrect bike sizes that gets diagnosed at this stage !!

 

 

So now the bikefit specialist gets to work .... you get the wannabee "specialist" that heard from a friend that the knee-to-pedal needs to be a certain way, and the heal on the pedal, yada yada ...  Then you get those that are trained bio-keneticists, and studied the art of bike fit.  The first session is 90 minutes, of which it takes more than an hour before you get onto the bike.  BUT, now this specialist has some understanding of the person in front of them .... and the bikefit is almost a form of art to merge the science of dimensions to the bio-measurements and quirks of the rider ....

 

 

For the NEW rider there seems to be one constant though .... the optimal setup is often just far enough from what the did before that some discomfort and\or handling issues are experienced.

 

 

Do you now revert back to some half-setup that is not optimal, but makes the rider feel "comfortable" ?

 

Must the rider just suck it up and get used to it ?

 

OR, heaven forbid, is the saddle 5mm too high and the hips start rocking causing lower back issues ?

 

 

Which is why your professional bike fitters have a follow up session one month (couple of rides) after the initial setup.

 

 

 

I know that my current setup has the handle bars just that little bit higher than the optimal setup.  It works for me, at this time .....  I will be working on my core muscles, and I know that I am already a LOT more flexible than 3 years ago, let's see how my body adapt to the bike posture in the next 12 to 18 months .... I am sure that my setup will undergo minor tweaks.

 

 

Clearly this relates more to the "new rider" than the athlete that is already in shape, and merely needs a bikefit .... then the setup should be much more spot-on the first time, though I know that even these riders go back after a month for that last tweaks ....

[shaper]

total rubbish. The position in which power is generated on a TT bike is so different that riders need time to adapt to it but through that adaptation they don't get injured. Been there, have the T-shirt. Your reasoning suggests that a rider will be injured if they hop onto several different bikes in the same day. This is simply untrue. The only situation that will cause injury is too high a saddle or too long a reach. 

 

The seat post design for most road bikes does not allow very extreme movement of the saddle; 25mm fore - aft.

 

Yet Cervelo S5,  Look 795 Blade and some Giants allow the seat cradle or saddle post to be reversed to allow a more forward or aft position on the same bike with the same rider.

I have ridden several bikes belonging to people who wish to have a bike fit or mechanical work done and I'm still walking. I've even had to ride someone elses bike the last 80km of a DC and despite tight quads due to a saddle that was way too low, I was still able to hop back onto my own bike and ride it. I'm still healthy.

The point is the human body is able to adapt to various configurations. Knee Over Pedal Spindle (KOPS) is a myth. That 150 degrees you talk about relates to the distance of the point of contact (seat) to the pedals spindle and its not some sort of rule.

 

BTW I've done many bike fits and in every case the rider has been pleased with the results. Some of these has required the knee ahead of the pedal spindle, some not. In each case the rider has delivered a few watts more power and fitted more comfortably.

 

But you're welcome to disagree with me if you wish.

There you are then and I suspect the tshirt is ill fitting!

 

Have read enough that you do not understand the concept of the knee angle and is definitely not related to pedal spindle, but each to their own. A little knowledge can be a dangerous thing, especially when you mention a forward facing seat post on a specific bike and fail to address the change in saddle height required for that forward position... but instead try to use it as an example to justify to the OP to just move his RB saddle forward as per your earlier post.

 

To the OP, glad you got sorted with a new stem, hopefully will give more confidence on the descents.