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Cervelo P3 with 1.5cm spacers - how bad/not too bad?

AstridAstrid
in General Training Discussions

Hi everyone!

Wanted to get any feedback anyone may have on this.  As may already have been discussed here in other threads, there's the Share the Ride Cervelo deal going on until end of the month ($2,000 discount if you buy 2 in-stock Cervelos from the same store).  My friend and I are both looking for tri-bikes and she can fit on a P3 well.  I can fit on a P3 too, but would fit a little better on a Cannondale Slice (did extensive bike-fitting with a Guru trainer bike at the store).  The P3 can be set up so I fit on it and it wouldn't be a stretch (little higher and shorter reach than without adjustments).  The adjustment would be that I'll have 1.5cm of spacers under the aerobars, which makes the front/handlebars less stiff.

My question to you: is that a big deal?  

Background: I currently have a road-bike with profile aerobars on it, so anything would be a great step forward, but I want to make sure I buy a bike that I won't regret!

Thanks in advance for your input.

Astrid

Comments

  • manconamancona
    This doesn't sound quite right to me as the slice (short and tall) and p3 (long and low) are usually a bit different in how they fit. But different aerobar stack heights or other adjustments might make it work.

    What length and angle stem are they putting on the P3 to make it fit?
    Is the 1.5 cm of spacers under the stem or under the aerobar pads? What other spacers are there?
    what size frame are you looking at in both?
    What aerobars are on both?

    If the only difference is 1.5cm of spacers and you are still using a normal size stem (i.e. 90-100mm and -6deg) then I would say go ahead with the P3. If they are putting a really short or upturned stem (i.e. 70 deg +6 deg) on the p3 i would personally avoid it as the bike does not really fit right and this may limit your future options if your position changes.

  • William JenksWilliam Jenks
    I agree that 1.5 cm spacers is really not a big deal, especially if you are using a flat stem (83 degrees, also called -7). Matt is asking the right questions too. I don't think that you (or anyone) will hold exactly the same fit for 10 years, so I think it's arguable that having a bit of upward AND downward adjustability could be an advantage.

    The implication of Matt's questions are about the total height of the elbow pads. You can raise them by raising the stem (raising the whole bar set) or just by changing the pedestal height between the bars and pads. The default bars on a P3 come with 2.5 mm, 12.5 mm, and 25 mm pedestals as I recall. I have mine at the 2.5, which are essentially zero lift, but that's just how it works for me... YMMV.
  • AstridAstrid

    Thanks Matt and William, very helpful!

    I just called and asked those questions.  The 1.5cm spacers will be under the stem (not aerobar pedestals).  The P3 I'm looking at (51cm) comes with a 90mm stem and they would shorten that to 80mm, but not change the angle.  It would be adjustable downwards (duh), bot not very much upwards.

     

  • manconamancona

    51 Slice frame has a stack of  494 and a reach of 371.

    51 P3  frame has a stack of 482 and a reach of 405.

    In my *opinion* those two bikes are not even close.  The P3 is 12 mm lower AND 35mm longer, that is a BIG difference.   Just to give you an idea,you would have to go 2 sizes larger and get a 56 slice to have the same reach as the 51 cervelo.

     

    An 80mm stem is not horribly short as you can kind find some 60 and 70 ones if you ever needed to go shorter.  I'm more worried about If the stem on the Cervelo is flipped up (i.e. +7 deg)  as then I think the bike is both too long and too low for you.  

    If the stem on the cervelo is flipped down (i.e.-7 deg), then 1.5cm of spacers is really no big deal.  In this case the bike is a little long for you, but the stack may be about right.

     

    That said, if your fit is litterally right between the two, then you might be able to go either way and be fine with either frame.  

    My concern is that the LBS said the slice is a better fit and therefore to get you on the Cervelo that are already setting it up decently high and very short. You will be able to easily go lower or longer in the future but shorter and higher might be a challenge and limit your options in bars/stems.

     

    BTW, I'm also a strong believer in taking both bikes for a ride and seeing which feels better.  I know that is hard in the winter but if you can pull it off, you should.

  • mgraffeomgraffeo
    I wouldn't worry about it. Go ahead and get the P3.

    You're talking about 34mm of extra reach, 10 of which is negated by going to an 80mm stem. so 24mm, or a little less than an inch. Depending on how 'in between' the two bikes your ideal fit is, the difference is probably less. If these folks know how to set you up so that the seat angle is right, you can make the rest work with a combination of stem and aerobar. Big concern would be a front end too long, and you still putting your elbows on the pads, meaning your upper body gets stretched out. If you can get your elbows to around a 90 degree bend, and be comfortable on the bars, you can make it work.

    Is it perfect, just like buying a custom bike? Probably not. Is it well within the error of buying a stock tri bike? Sure, especially if you do the work to make sure they get your front end set up right.
  • AstridAstrid

    Thanks guys!

    Now I was more curious to figure out how much closer I am to the Slice than the P3, so I looked at the positioning form of my bike fit to find the reach and stack, but those aren't filled out (? :S). For the way the form is set up it seems like they should be able to be calculated from the numbers in the DFU data section (DFU = Dynamic Fitting Unit, a Guru stationary bike). There are 4 numbers there which are all in mm's:

    SX: 132

    SY: 637

    HX: 466

    HY: 567

    To the right of it are stack and reach, just not filled out. I have tried doing some subtractions on these and googling around for this bike fitting diagram, but can't really come up with how this translates to stack and reach? If anyone happens to know, please let me know. If not, I'll give the guys another call tomorrow .

    PS. Other info on the diagram is:

    Saddle to handlebar reach = 43.7 cm

    Saddle fore-aft = 3 cm

    Which seems to lead to a reach of 40.7cm, right?

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