The Bike Fitting Mega-Thread

  • Yeah, I think the basic extension looks reasonable. Tough to tell from just one angle, but the hip movement might be normal for you.
  • Hard to tell on fore-aft, but you might even want to try sliding the saddle back about 5mm to see how you like the feel. Will open your reach a bit for one thing. If you like it, you may need to drop your saddle a couple of mm to offset for the “extra height” added by moving the saddle back.

Was thinking the same about going back a few mm. The hip movement might actually be due to too low load. I was doing this with somewhere around 50-60% ftp I think.
Will also experiment a bit with the handlebar position. Thanks for the input! :slight_smile:

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For fitting, I like to have the rider around Sweet Spot power unless they have a desire to focus at another power level more important to them. Hard but doable and sees what happens when they start to turn the screws a bit.

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Quick question for you all - should I aim to get my MTB setup the same as my road bike? With reference to saddle height and fore/aft around the BB.

Assuming same cranks and saddle on both.

Or is there a rationale for having different measurements in relation to the BB for road and MTB?


You should have at least a slight difference in saddle to BB measure on your road & MTB due to the higher stack height of the MTB. It’s probably ~5mm +/- depending upon which shoes / cleats you use for road & MTB.

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Forgot about the cleat differences!

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Went back to my Bike Fitter 3 1/2 years since I last saw him. Have been having major issues with left leg power and thigh pain, feeling of disconnected left foot, Saddle sores etc…

He is a physio, bike fitter and races bike at a high level - a great combo, the only problem he is out of town.

Bike was setup up correctly. Long story short it became a 90 minute physio session with a lot of dry needling to rectify what was going on in my hips (twisted pelvis)

  • 10mm functional leg length difference gone
  • Weak strength responses L leg gone
  • Co-ordination in pedal stroke back
  • Left knee tracking normally again
  • RPE down

Amazing night and day difference from the dry needling. Instant change.

Plan is in place with local physio to try and retain the gains. So relieved!


Interestingly (for me anyway), my L/R balance from Favero Assiomas had been declining from 50/50 to 48/52 over time

After the Dry Needling i was at 51/49 today - never had that before! Bound feeling in the leg was gone too.

Good episode from the Zwift Power Up podcast (although it originally appeared on the Zwift Power Up Tri podcast). Features Jim Manton from ERO Sports on bike fitting, aerodynamics, etc. and the evolution of bike fitting.

Agree 100% with his point re: forearm positioning, etc. I have been beating this drum for years…going vertical with your forearms (the preferred FIST / Slowtwitch position) is NOT a good position. You need to move your elbows forward.

He a,so talks about high hands…says it is a near universal gain for riders. He says that he has only tested one athlete for who it tested slower. I don’t know if he ws specifically referring to me, or if he remembers testing me, but i may have been that athlete. We swapped out my TriRig extensions for some Zipp EVO 110’s and only made a few laps before he called me in and we swapped them back. The data was overwhelming that it was a slower position for me, so much that he didn’t want to waste any more time testing it. Once back on my TriRig’s, my numbers improved again.

Anyway…definitely worth a listen.

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I listened to this back originally and loved the revisit too. Jim is an awesome person and fun to listen to.

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This is a quick question, and maybe the answer is really obvious. I got an SL7 a few months back and I’ve wanted to get a bike fit for a long time, more so now because I want to chop off my stem, but I’d like a 2nd opinion on the fit before I do that.

What if one of the suggestions from the fit is to change the length of my stem? I don’t think the shop will have one that would work. Would they just change everything else that they could and recommend I go try the new stem length?

I’d say check with your LBS to see how they can handle it.

This is one of the reasons I am kinda anti-integrated front ends…sure, they save a few watts and they look sexy as hell, but adaptability sucks. Bike fit is dynamic and changes over the course of time, sometimes even with the same season. Integrated front ends makes it exceedingly difficult to adapt to your position, especially if you want to change stem lengths.

I tend to run a longer stem and narrower bars than most people, and certainly more than what some product manager is gonna spec on their bikes. I could never get the combo I want on some brands (Canyon, for example).

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What advice can anyone give regarding numb has that is not increase stack height? I already have a ton of spacers and I’m out of steerer, don’t care to flip the stem, ugh. I just had a fit and I’m still dealing with some lingering numb hands and I just can’t imagine that my body is so far out of whack that even an endurance-bike level of stack height is insufficient for me. I was a bit more balanced years ago when I had the saddle further back and have been tolerating numb hands and “feeling like I’m sliding forward” ever since even with the saddle titled up a hair.

Thanks and here are the numbers:

Stack is not the couse of numb hands, it is weight distribution, try to move a saddle a bit back or down and move cleats a bit


It is almost impossible to diagnose the issue w/o a picture of you on the bike. As noted in the previous post, numb hands are usually a weight distribution issue. You have too much weight on your hands / arms and you are holding yourself up, putting pressure on your hands.


And yes… one more thing, I had a lot of hand numbnes caused by wind and deep section wheels combo because I was holding the bars too hard.

First time on a TT bike. Any tips what to tweak before first ride?

Not really a tweak but you want to be comfortable looking forward rather than staring at your front wheel. You lift your head once but on the road you want to be comfortable doing this all the time.

I’m no expert on hip angles/ saddle heights and only go on hip rocking as an indicator that something is wrong. You don’t seem to be rocking much, so I think you are just about there. But as I said I’m no expert.

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I had my eyeballs tilted all the way up but I’m not sure if I would see far enough on the road. I have 20mm’s of spacers on the front atm.

I had the same hip rocking on my road bike once and moving saddle forward seemed to help a quite a bit.

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Damn…that is a great position out-of-the-box. You’ll be fast.

I wouldn’t change anything right now…get out and ride it and see how it feels. A TT bike outside feels very different than it does inside. Start there and adjust as necessary.

(There does seem to be a little hip rocking, so you could drop your saddle a few MM, but if it is the same as your current road height, just roll with it for now)