My PS-SL is a little long for me. I find I’m riding way up on the nose of the seat far too often. I already have the seat pushed as far forward as possible so adjusting it is not an option. I do not plan to buy a new bike.
So I am considering replacing the 90 (I think) mm stem with a 50 or 60 mm one.
The other more expensive option suggested to me is to replace my aerobar setup with one that is adjustable sotheat i can pull the elbow rests back closer to me.
Or doing both of the above.
given that most of my riding is in the aero position, will significantly reducing my stem length affect the handling of the bike? I would rate myself as below average in bike handling skills. I got into a bad front wheel wobble last year while descending at about 55km and it scared the heck out of me. So I am nervous about handling issues.
Whenever you depart too far from the original parameters of a bike then odd things can happen. I would recommend you try moving the armrests back before going to a shorter stem. Profile makes some flip-up rests that can use a standard extension and they can move rear of the bar. Syntace pads also end up a little farther back. If you already have one of them then you may have a problem.
Cervelo straddles the line between the road and tri market. Only their customers can say whether the one-size-fits all idea works.Chad
Sounds like putting a shorter stem would be like putting a band aid on a bullet wound.
There’s tons of variable that I’m barely able to comment on let alone resolve, but it would seem to me that you have a top tube that’s too big for you.
For one who suspects they have less than average bike handling skills, shortening the stem will be a recipe for an anxiety attack.
As the stem gets shorter, the steering becomes faster (some say quicker or more “responsive”). As the stem gets longer, the steering becomes slower and less quick or responsive. This is because of the shorter arm (the shorter stem) where a small movement on a short stem produces a big change in direction (steering) whereas on a longer stem that same small movement produces a smaller change in direction/steering.
As you shorten your stem, your steering will become faster or quicker and more sensitive. For someone who lacks confidence in their steering skills, shortening their stem will reduce their confidence in their steering skills even further.
It may be somewhat difficult to notice the change from a 90 mm stem to an 80 mm stem. A small change like this will produce only a slightly difference steering response. But changing your stem length by 30 mm or more will produce a significant change in steering response that will be very hard not to notice. What you are considering is close to a 50% reduction in stem length. The change in steering response will probably be more like day compared to night versus 10 PM compared to 9 PM for the 10 mm change.
For what its worth, my own opinion would be that what you are considering could result in a bike that is very difficult for you to control to the point of being unsafe in an aero position based on the fact that you lack confidence in your steering skills with your present 90 mm stem. Yes, what you are considering is the poor man’s means of trying to make a frame that is too big fit a “too small” rider. But be fore warned, this is the last place (means) you should be trying to solve your bike problem. In fact, if you have a serious enough accident after making this change, it may be the last change you make!
Thanks for the comments. Any thoughts on changing my aerobars to ones that have adjustable armrests so that I can pull them back closer to me?
I appreciate the reccomendations from all those who have responded. The bike is a little too big for me, specifically the top tube length. Having said that, I’m not replacing the bike this year so I’m looking to do what I can adjustment wise to make it fit a little better. My LBS guys are going to California in a week or so for a F.I.S.T. clinic I presume put on by Slowman and I am waiting for them to get back from that before making any adustments to the bike.
My LBS guys were all for shortening up my stem but perhaps they were not thinking about making as radical an adjustment as I put in my original post. Would you expect a significant change in handling if I shortened the stem to 70mm? Am i better off to leave the stem alone and change aerobars?
I was in a similar situation. The P3 top tube is too long for me. To compensate, the fitter used a 90mm stem and moved my seat all the way forward. Well that was too steep for me (81-82 degrees) and I could not generate much power; especially weak on hills.
I bought a 70mm stem and moved the seat back. Felt better on the pedals and more powerful, but the steering was “twitchy”. As a fairly experienced rider I wouldn’t say it was dangerous, however, it took concentration to keep the bike straight and it cornered like crap. Looking over my shoulder was challenging. For me, that “concentration” burned up energy I’d rather apply to the pedals and was not worth the effort.
Last I tried an 80mm stem. Steering was fine and the seat tube angle was just slack enough. My free advice would be to try an 80mm stem. If that’s not short enough, make up the rest with adjustable aerobars. Hope this helps. Best of luck.
i rode the P3C 54cm with a 50mm stem during the last season in training and racing. there is nothing dangerous about this as long as you take time to get use to a more nervous bike. I did a lot of downhill in very twisty high mountain and never had problem… i rode most of my bike with short stem…bu the stem mostly give a personality to a bike…but it dosnt really make it dangerous or not…
I see your point, and perhaps over time I would have gotten used to the “more nervous bike” (BTW, that’s a fitting description). Conceptually, however, I have trouble tolerating that I should make compromises on a $2,700 bike. If the fitter had my best interest in mind, he would have recommended a bike with a more suitable frame geometry.
Of course my solution to making a bad purchase was to spend twice that on a custom ride. Shit, it’s only money, right?
you are right …when paying big bucks…you should get what you want and be happy about it and your bike shop/fitter should do a great job…
as for me, i requested a 54cm because i like to be on big frame. But i dont understand what compromise i make in getting a 5cm stem? for me, to ride a 9cm stem will be a compromise… it really depends of what you want from a bike… i dont like longer stem as it get the bike more stable and less twitchy…dont like that but nice in very high speed technical downhill.
so this season as i m riding with planet x , i ask them to put me on the medium from even if i could ride the small… now on the medium frame, i use a 7cm stem… that s how i want a bike to be…
It sounds like you should be ebaying your frame and getting the next size smaller. Optimal stem sizes are usually recommended as being 90-130mm.
Are you riding in the slack or steep position? There is a difference of about 3 cm in effective top tube length between slack and steep. If you are by chance slack, your problem could be solved by flipping the seat post to the steep position.
I rode my P2K with a 90mm stem in the steep position. Wouldn’t have wanted to go any smaller on the stem. In the slack position the effective top tube length was too long for me but worked fine steep. I rode a 54cm 650c size. My theoretically ideal size was probably somewhere between the 51 and 54 cm sizes.
As others have said, a small stem is doable, but is not optimal. A small stem will tend to make a bike handle quicker (twitchier).
A 54 cm Cervelo rode in the steep position with a 5 cm stem is definately going to be a very twitchy bike. In certain conditions, such as fast descending for example, the rider would really have to pay attention to every small movement. That wouldn’t be everybody’s cup of tea. I know it wouldn’t be mine, as I’d prefer more stability, but if you’re happy with it…
yes…it was twitchy a bit but a good one!!! it wasnt riden in a very steep comfiguration…75degrees… bike fit is very personaly and there is 1000 different recipit to perform… just need to find the right bike personality for yourself…
“Optimal stem sizes are usually recommended as being 90-130mm.”
I think there might be a couple of concepts that are at odds with each other in frame design and optimal stem length.
First, I think that this optimal stem length is something left over from road frame design, and with a stem in that length range, given a normal 72-74 degree STA and chainstay length, you’ll have good weight balance on the bike. This will give very good, stable handling.
However, when you take that same front end geometry from the roadie (which most manufacturers seem to be doing) on a TT bike, with a stem that long, you get too much weight on the front end. Remedy? Longer top tube (and thus the front center) and a shorter stem. Gets the weight balance back to where it should be.
My rig has a pretty long top tube, and I’m running a 60mm stem. Stubby-looking thing compared to the 120’s I have on my roadie. But the bike RAILS turns and is silky smooth and stable on the straights. Moreso than my custom road rigs. I’ve considered that at some point I might replace the race rig with a custom that slacks out the front end (keeping the same front center) and a longer stem, but then again, I don’t think it would really improve the handling, just the aesthetics.