Very confused about riding position(s) - mtb vs road


Retro Guru
Hi guys,

This is a sort of rambling/monologue on some thoughts that have been keeping my brain busy this last week. I recently switched back to riding a MTB (1993 Marin Palisades Trail :) ) in the city, for commuting. It wasn't much of a voluntary decision. My main bike broke down and I had to make do with what I had. Two things surprised me: the first is that over a 20km commute in London, the mtb is only 7% slower than my road bike. I was expecting worse. The other is how much more comfortable I am pedaling on it, compared again to the road bike which, for sake of information is a modern Boardman SLR8.6. And I don't mean comfortable riding position, but comfortable leg movement. I feel that my legs move more naturally and that the effort is distribute across the leg muscles, while when I'm on the Boardman, the effort is mostly on the quads. What's worse is that on the road bike there seem to be a perfect window in cadence where the pedaling feels good, but as soon as I need to grind or spin, it feels either very hard or uncoordinated. With the MTB I have much more flexibility and don't have to be in the perfect gear all the time.

I will take some time over the weekend to compare the riding positions, especially the horizontal distance between saddle and bottom bracket, as I suspect I might be too far forward on the road bike. Which would be a shame as the seat is fully slammed back. I might also consider a professional fitting on the bike, but before doing that I would like to try to understand by myself what's going on.



Retro Guru
Hard to say without knowing the size comparison of each bike and how they differ in terms of geometry and gearset specification.

Are crank lengths the same?

There is likely to be a bit more 'spring' (flex) in the Marin frame being that it's steel.


Retro Guru
It's not proving easy to compare the two frames. Not with accuracy at least. I will need to make a better effort.

Yes, crank length is the same at 170mm. It's probably way to long for me as I am 5'7 with short legs and long torso, but I haven't had the time to switch to 165mm yet. I already have the cranks, I just need to make the swap.


Devout Dirtbag
Road bikes are really meant for riding at high speeds. That 7% goes up as your effort goes up on both. You likely are not in racing shape and your quads and hip flexors are not in proper shape for road riding which is a much more demanding position for the body. You could likely benefit from sliding your road bikes seat back and raising the bars while putting on a shorter stem.

But...I also say that road bikes are pretty much useless unless you are racing...A well set-up mtb for multi terrain is always going to be more comfortable/enjoyable at a small loss in speed.

You should be riding 165mm cranks.


Senior Retro Guru
View many variables...but tightness in the quads sounds like saddle height and/or saddle position in relation to the bb (affecting actual seat tube angle). You can measure all that quite easily...just use a batten and a steel tape.

At 5-7 myself I have use 170 cranks on most bikes and it's been fine.

Interestingly, and SHOCK HORROR, on the Paris-Roubaix a test was done using cross, road and mountain for the surprise result....

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Old School Grand Master
a retro XC mtb should be set up
But...I also say that road bikes are pretty much useless unless you are racing...A well set-up mtb for multi terrain is always going to be more comfortable/enjoyable at a small loss in speed.
Nah, anything you want to cover any sort of distance on, get a *properly set up road bike*.

So not head down, arse up. Which is really for racing.

And a thing for the OP, IIRC you've shown us some pretty weird and wonderful set ups for your retro road bike, which looked horrendous to actually ride. Is your boardman actually set up properly yet?


Retro Guru
My Boardman is surely not a racing bike, but I am definitely more stretched forward than on the Marin.


Old School Grand Master
But that doesn't answer the question. If none of them are sufficiently right, you've got no baseline.
And it sounds like the Boardman isn't right anyway, short legs/long torso *usually* requires a long stem to get the stretch right, not slamming the saddle all the way back.
You really need to get someone to cast an eye over it all.


Rocky Mountain Fan
Sounds like your boardman isn't set up right.

What tyres are you running on the Marin?

With slicks I think 10% difference would be about right and given the poor state of uk roads probably a bit less due to being more comfortable.

I deffo found that last week on devon on my retro fusion MTB with wiggle 1.5 commuter tyres.

Cheers James


Retro Guru
I run Marathon 1.5 tires on the Marin.
Gatorskin 25mm on the Boardman

Things with the Boardman have improved dramatically. I changed nothing on the bike itself, but I change the way I pedal.
Riding the Marin I realized how stiff my left foot was, and I surprised myself noticing I had such limited flaxibility at the ankle, which in turn reflected into very poor pedalling form.
It's probably the result of an injury I sustained in the spring, which apparently had left me more "crippled" than I thought.
I was essentially pedalling with only one leg. It's very strange how I never really noticed it until I switched bikes.

Also, the Marin is not as comfortable as I had thought. Yes, the pedalling feels a bit more natural, I still have to investigate as to why exactly, but the overall riding position gets very tiring after the 1hr mark. And by tiring I mean mostly boring. It makes me feel as if I want to snap out of it. Which is interesting, because for very short rides it feels wonderful with the erect torso and wide handlebars, but as time passes, I feel myself longing for a more stretched position and a different grip on the bars.

The Boardman remains to be set up correctly. As you all have pointed out, something is definitely not quite right. I will start to finally install the shorter cranks (I need to find help removing the BB as it's seized...), then I will consider getting a professional fitting.

As a side note, I will soon put the Marin for sale here on the forum, as I decided to bring back to life my old Peugeot, and I have no space (mental space, mainly) for three bikes. Also, as I said above, it's not that comfortable for me, and I would rather see it getting used than keep it to gather dust.