The chamois on a pair of tri shorts is super thin compared to the deluxe, luxurious chamois of cycling bibs.
I’m more comfortable in the fully padded bibs, so I wear them for the majority of my training rides. When I do wear tri shorts, I can feel that I’m sitting lower. Even if it’s maybe only half a centimeter, it’s definitely noticeable. I did a ride today in tri shorts and not even 20 mins in I could feel my VMO - not pain, just working a muscle in a way I’m not used to.
What’s the “to-do” here? Adjust saddle height between training rides in cycling shorts and racing in a tri kit? Set the saddle height to somewhere intermediate between where I want to sit with each different kind of short? Suck it up and do all my training in tri shorts? Some other fix?
Odd. I have some pretty thick padding in some of my PI bibs/shorts and I’ve never noticed any measurable difference in the way my saddle feels compared to my tri suit. Any difference should be 1-2mm at most, I would assume. Certainly not “half a centimeter”… I say no way on that. The chamois is going to squish down to a pretty minimal height when you put weight on your chamois via your sit bones, unless you are super light, and even then I question this difference.
As I write this, I just got back from a ride wearing thicker bibs, and I just checked–a few mm’s, at most, between the outside of the short and my bare skin (at the sit bone).
One thought came to mind… are you using the same shoes/cleats for both setups? That shouldn’t necessarily matter, either, but if the tri sole shoes were significantly thinner than your non-tri shoes (assuming you have different shoes), then maybe that is the issue?
If this really is an issue and not a placebo-type effect, then I suppose measure for both and put a small piece of masking or painter’s tape on the seatpost, mark it with a pen, and move the saddle up and down per that reference point when you ride tri vs regular shorts.
I’m looking at an actual ruler now, by my estimate it’s definitely more like 2-3mm than 5. I shifted my saddle about 3mm up today mid-ride and it felt much more normal.
Same shoes/cleats, no socks either way. I would definitely see that having an impact as well if they were different.
I don’t remember where I heard/saw this, but I know that saw a video or something and Tim Reed Pro triathlete explained that he adjusts his saddle height to compensate for his Tri kits (a speedo even still sometimes) and his bibs when he trains.
So you are not alone in making these adjustments. I have done it myself from time to time.
Turns out my constant saddle height adjustments for different cycling attire is not crazy. I forced @3dbikefit to run the numbers. Seating position difference from my @louisgarneausport@saucony team sleeved tri suit: @budgysmuggler - 1.5mm, @ridebontrager TT suit (typical training knicks chamois height) + 3mm.
Moral to the story, your chamois or lack there of CAN make a big difference to your saddle height
I would argue that “big difference” is well overblown.
Example:
700mm BB to Saddle Top (estimate for “average” rider)
170mm Crank Length
870mm Total Saddle (top) to Pedal (center) Height
4.5mm Chamois Thickness Difference (If I am reading the -1.5mm to +3.0mm correctly)
Delta = 4.5mm / 870mm = 0.005172 = 0.5% Difference in Effective Saddle to Pedal Height
That’s not even a full 1% difference. It will be a larger percentage of change for shorter riders with lower saddle height, but it would likely be tiny as well.
I know that 5mm can make a difference in saddle height, but there is a very functional range for most riders that is easily 5mm wide. As such, it would be totally practical for most riders to find a “happy medium” between kits with different chamois thickness and not mess with height changes each time.
I agree with Chad. Any performance difference blamed on a few mm in any of the bike’s dimensions (seat height, stack, reach) is all in the rider’s head. A fraction of a percent is not noticeable in real life. I think that it is more in the rider’s head than anything else. If you are compensating for chamois thickness then you would also need to compensate for sock thickness as well. And exactly where you sit on the saddle. Same goes for things like reach- a few (even 5mm) of reach difference is smaller than what you get just by moving your hands around on the hoods or drops. This also assumes that your bike fit is even accurate (and recent) enough to optimize power output to that level of accuracy. I don’t believe it.
I’m not saying there’s necessarily a quantifiable performance difference, it just feels off and I don’t like it. I did find myself moving back on the saddle trying to make up for some of the difference, so it probably is shifting my overall position a bit. I ride either sockless (hello, triathlete) or with very thin socks only, so no real difference there.
Pretty much every time I ride some part of my bike fit feels weird at the start of the ride and then feels normal at the end of the ride. And it’s not the same thing every ride. Sometimes it’s the cleats, sometimes saddle height, sometimes the bars. SO, I basically have stopped paying attention to those sorts of feelings unless they are repeatable and go on for the entire ride. My setup numbers have been the exact same since I had a bike fit.
I find the decreased chamois of tri shorts noticeable at low intensity, but not at all at race pace. Pushing the pedals harder reduces the weight on the saddle, and I’m assuming causes you to sit slightly higher too, at least as much as the difference between the two chamois.