Tweaking things around a bit

There’s a lot of things you can do to stock bikes to customize the fit and ride. Bike fitters may cringe at this post but I want to provide a list of things you can do to try BEFORE buying a new bike, especially a new custom bike.

Bikes from almost any manufacturer are pretty well manufactured so the majority of people won’t *need* a custom bike, but if you’re reading this post on this blog from this builder then you’re at least thinking about it or already have one. But if you’re new to Meriwether and custom bikes, maybe this will help you not buy a new bike, but if you do it’ll ensure you can supply the builder with the most information as possible to help them fabricate your ultimate ride.

Take your favorite bike and think to yourself, what is it about this bike I like the most? Most bikes are a tradeoff and you may like one thing about it the most but another thing may be lacking. Maybe it only fits 40mm tires and you’d like to fit 50’s. Maybe it climbs well but doesn’t descend as fast or confidently as you’d like. Maybe it’s an older geometry and you’d like to try something new. Or maybe it is fine and you don’t know what you would change but are sure it could ride better.

Here’s where it gets fun. If you’re a bike geek like me, you likely have a few stems and seatposts in your garage, or on different bikes you can swap around. If you do not have a few stem lengths and a straight and layback seatpost I recommend you go ask friends to borrow theirs for a day, or buy cheap ones, or at least try one of those Ritchey adjustable stems if you’re thinking about buying a custom bike. This initial investment pales in comparison to what a new bike costs. You can go as deep as you want to go but mostly you can only change position and weight distribution not frame geometry. Different forks can change steering geometry, different headsets can affect head angle, but that’s about all you can do there.

Let’s start with a 90, 70, and 50 stems and a straight and 25mm layback post. Take your bike and set it against a wall and imagine you have a bathroom scale under the rear wheel, and another one under the front wheel. Get on the bike and weight yourself as you would while riding on flat ground. If you were able to read the scales what would they say? Doing the math you could find what % of the total was on the front vs. rear wheel, your weight distribution over the axles. Generally, road bikes will be more equally weighted, slack and long MTB’s more rearward weighted. Now go out and ride the bike and see how it feels focusing on its steering, is it quick or twitchy? Or is it stable – when you hit a bump and the bars are less likely to get knocked off course? If you know the geometry you can start to associate these feel factors to the numbers on the geometry chart, but from my own experience you’ll likely not notice small changes in geometry as much as you will fit factors. So let’s mess with the fit. (Yes this holds for any style bike, MTB, allroad bike or gravel bike just use whatever you have and focus on the bike you want to get.)

Start with the longest stem and a straight seatpost (and slide the seat on the rails all the way forward). If you have a 100 or 110 leave that on. Jump on the bike and feel where your weight is distributed while seated and leaning against the wall and then while on a short spin around the block. Come back and take notes, then put on a 90mm stem and see what happens when you do the “scale” test again and ride it around the block. Does it do anything better? Worse? Like or unlike?

Next swap to a 70 stem and a layback seatpost. If you don’t have a layback post, loosen up the saddle and slide it all the way back on the rails. Redo the scale test and then go ride it around to get a feel for what has changed and what you like and don’t like about it.

One more time. Put a 50mm stem on it and slide the seat back all the way or put on the layback post. NOTE: The ideal would be to keep a constant ‘cockpit length’ (center of saddle to the center of the bars at the stem) while changing your weight distribution over the axles. This reduces the noise of fit when trying to compare weight distribution.

Next go back to the original setup but by staggering the saddle setback and stem length changes, so first slide the saddle back to centered with the shortest stem, ride it around, take notes. Then change the stem to the next longest length and slide the saddle the same distance forward is possible (or change back to the zero layback post). Do all the combos you want to try, take notes on which you like the best and worst.

What are the takeaways from this experiment? Any surprises? My own likes and dislikes about what I learned may not be the same as what you felt and learned. Did you notice your change in effective seat tube angle and saddle setback and how this changed the “knee over pedal spindle?” Did you notice the weight distribution changes on the uphills and downhills and how you had to position your body to get the most out of each? Did one version of the changes you made seem to “Fit” better even though you were trying to keep the cockpit length relatively constant?

My goal in this is to second guess the traditional bike fit norms and try new things with our bikes that we use on multiple surface types. This is especially relevant for gravel bikes and hardtail mountain bikes since if you’re like me you never ride ONLY on dirt or only on pavement yet want or expect your bike to behave well on all surfaces and grades. There will be tradeoffs but as long as none of the above changes hurt your knees or back, it at least makes you think about what you’d want in your next bike, what you’d like to try with fit and geometry. Have you ever tried a gravel bike with a 50mm stem and layback seatpost? Maybe it totally surprised you and rips even though the head angle is a steep 73 degrees. Or maybe you will realize you want a slacker head tube angle along with the short stem like on your MTB.

The next things you can try involve more expensive parts like an angleset headset (i.e., Works Components, Cane Creek, or Wolftooth depending on your head tube style). For a cheaper alternative to a new headset you can try a Cane Creek crown race spacer in 3 or 6mm. It’s not a ton of change in reality, the 6mm spacer only slackens your HTA by 0.3 deg and raises your BB 2mm. (The real use of these is to avoid the fork crown from hitting the downtube on some frames.) Or put a longer or shorter travel fork on the bike to do a similar thing. These changes in head angle and trail (and maybe offset too) will be a learning experience before investing in a new bike with a builder that may prefer different geometry than you. Research, test, challenge our assumptions, and repeat until you know what you like. The below BikeCAD drawing is of a standard 56cm gravel bike with a 100, 80, 60 stem, and saddle setback of zero, -20, and -40mm just to show what I mean. You’ll see everything stays the same geometry wise except for the effective seat tube angle (BB center to saddle center) and this obviously changes your weight distribution between the axles.

One thought on “Tweaking things around a bit

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  1. Much food for thought and action here, though I’ve meddled quiet profusely with my bike fits, this caused me to re-examine and change how and where my mass centers on the wheels. Something as simple as sliding my ass back while riding gave valuable insights into handling. Many thanks. Cheers!

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