A (long) bike fit question

I’m hoping anyone with some bike-fitting expertise can chime in here.

TL: DR – has anyone had success with a position that’s lower and shorter than ‘standard’ or orthodox?

Full version (long post warning):


So for a long time now I’ve had 2 recurring issues: niggling high hamstring tendinitis (which I can keep under control with exercises) and lower back pain on longer rides.

For reasons that’ll become clear, it’s worth knowing that I’m average height (177cm), but have slightly shorter than average legs for that height (80cm inseam) and slightly longer than average arms.

Anyway, I thought I’d address the issues, and shortly before Xmas arranged a bike fit with a very highly regarded bike fitter. To cut a long story short, he fitted a heel wedge in one shoe, increased saddle height slightly, increased setback slightly, dropped the bars 5mm and suggested a longer stem. This was to take some weight off my hands, get some better knee extension, and to make my relatively long upper body and arms ‘less cramped’

He also pointed out that my hamstring flexibility was poor and that was most likely the root cause of both my problems. He gave me some exercises to work on.

All of this sounded perfectly sensible.

So 6 weeks on, I’ve done the exercises diligently. There’s been a slight improvement (but not a huge one) in the back pain. The dodgy hamstring is just about coping with the new position. But all isn’t quite right and I have booked to go back for him to have another look (as it’s included in the original price.)

The current query

To cut another long story short, someone I know who is the same height as me (but with more conventional proportions) is selling his custom bike. His bike (custom geo) is set up with the bars approximately 15mm lower and 25mm closer to the saddle than mine; of that 25mm difference, about half is less setback.

I thought it wouldn’t work and was going to pass, but the seller encouraged me to take it for a short test ride (15 mins) and to my surprise it felt really good. I left saying I’ll think about it.

This weekend, I set up the winter bike as close as I could to the same position, and for the first 2.5 hours it was really surprising: more power, more connection with the saddle, and less back pain. I didn’t feel more pressure in my hands as I was expecting to, and I got better glute engagement.

However, at about the 3 hour point the back pain kicked in quite quickly, and by 4hrs (when I finished) I was suffering a bit. I felt I ended the ride in kind of a similar situation to usual, but felt that I’d had a better first 2.5 hours, if that makes sense.

So: at the end of all that, what, if anything, can I deduce from this?! I’m most interested in the fit implications rather than the potential purchase.

Any suggestions gratefully received!

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A picture would help.

But on the back pain, I’m not surprised given how different the fit is from your current bike, especially the extra drop. Could you get used to this position? Maybe, maybe not. There isn’t really anyway to know. Depending upon the current stem length / angle, changing the stem could “fix” some of the difference between your current fit and this new one.

Did you do any descending? If so, how comfortable were you? How did that feel? If not, I would definitely do that. I’d be concerned that the shorter reach is going to dramatically change the handling you are used to. And you body proportions compared to your friends could mean too much weight over the front wheel.

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Thanks for the reply.

The surprise here is the shorter and lower setup (as replicated on the winter bike) seemed to delay the onset of back pain.

Descending felt good and if anything there was less pressure on my hands despite reducing setback.

This is kind of the problem; the results seem counter intuitive.

Same sear height and saddle fore/aft? Same saddle?

For this ‘experiment’, I tried to replicate the fit on the bike for sale on my winter bike. So it’s my normal saddle and it’s what I have on both road bikes.

Replicating the fit involved:

  1. moving the saddle forward about 10mm (I say ‘about’ as it’s very hard to measure these things to the exact mm). I took account of the different lengths between the saddle on the for sale bike and my own when calculating.
  2. I maintained the original saddle height as measured through the centre of the saddle rail. As I’d moved it forward, I had to raise the post slightly to end up with the same measurement.
  3. Reach was reduced by ‘borrowing’ the 90mm stem on my wife’s bike in place of my 100mm stem. :rofl:
  4. Stack was reduced by removing 7.5mm of spacers (couldn’t do 10mm as the setup is complicated by the top cap set up).

I’m not a fitter, and definitively not a highly regarded one, but it seems odd to me to recommend a longer reach and drop to someone with hamstring flexibility issues. Also to increase the setback, as I think that closes the hip angle?

You didn’t report pain in your hands as an initial problem, so I’m not sure if that should have been a priority in changing your fit. To be honest, it sounds more like the fitter tried to give you a more aerodynamic position, instead of addressing your pain issues.

Personally, I’d try the reduced reach and a higher/your old stack. But as I said, I’m not an expert!

Can you plase explain this? I have similar setup and decending “problems”…

I am 179cm with short legs (82 inseam) and was fitted by popular fitter and he fitted me on venge 54 with 10cm stem and 9cm saddle to bar drop and put my saddle full forward. And didn’t have any pain or similar problems whole season.

If you put more weight (greater weight distribution) over the front wheel, this can slow down the front wheel response, which can make going through corners rough. Also, when you brake, you naturally shift more weight forward, which increases the power of the front brake, and decreases the power of the rear brake, so having more weight on the front wheel makes this even worse.

For a good, but long, overview of how bike geometry affects handling, read this 2018 Cyclingtips article

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One thing that could be worth a try is switching the saddle from your friends bike onto yours and see how that rides.

When I did a bike fit, changing the saddle would totally change the position of my pelvis and the back angle that I was comfortable with.

It is all about the natural angle of your sit bones and the angle of the saddle where your sit bones make contact.

Oh boy, so many variables here. So don’t take my post as saying I know what’s going on, this is just speculation.

It sounds to me as if you prefer the “new” bike’s geometry (I mean the bike that you are considering buying). That happened to me, too, when I tried an aggressive road bike for the first time. I had bought a used endurance road bike for a very good price, but just didn’t like the way it felt and handled. Perhaps you just prefer the way this bike handles. In my book, fit >> components.

Secondly, it sounds to me as if your muscles fatigued after a few hours in an unusual position. That happened to me, too, when I tried to get more aero, after two hours or so, my muscles would fatigue and I couldn’t hold the position any longer for prolonged periods of time. That can be trained.

Lastly, a word about bike fitters: this isn’t an exact science. I have had several bike fits, including from a former world tour team pro mechanic and a former world tour pro. The former pro did wonders with my cleats. He just knew what to do. But he lowered my saddle by too much (I have long limbs and when I got really aero, my knees would hit my arms). I raised my saddle by 5 mm or so until the interference was gone, overriding his judgement. I also overrode his judgement when it came to marking the position of my seat post (just scratch little mark into it :scream:).

But what he did sounds quite reasonable from the outside. Just don’t take it as gospel that you aren’t allowed to question or override.