Matching Bike Fit to a Second Bike

MULTIPLE BIKE BLUES

If you’re fortunate enough to have multiple bicycles; tell me if this sounds familiar: You have spent endless time and possibly funds perfecting the position on your main bicycle. It’s flawless. You feel like you could ride on it all day, in all conditions without pain – and then get on it again tomorrow and do it all over.

Then you get on the other bike. And, while you’ve taken some measurements and tried to match it up to the first one – stuff still isn’t right. It could be any number of things that you don’t experience on the first bike: Maybe your knees hurt, you have hand numbness, get saddle sores, have after-ride headaches, or just plain don’t feel as strong or fast. Maybe it is something else entirely. Whatever it is, you know something isn’t right in spite of your effort to fix it. What now?

bikes

In a similar post; I gave you an outline of some different bike fit symptoms, what may be causing them, and potentially how to fix it. Ultimately; the underlying theme though was to seek the help of a qualified and professional fitter. I’m going to do a similar thing here: walk through the bike’s contact-points and offer some suggestions; but the help of a professional is still priceless here and many shops offer services to help match the riding position between multiple bikes for less cost than having each one fitted individually.

That said: let’s move on. Bikes can seemingly be set up to fit identically when you measure them; but there are a variety of small details that govern why your body may not be sliding into the same position when you ride the others. Let’s take a look, starting with some standards:

FIRST, ESTABLISH WHAT IS CORRECT; THEN MEASURE AND DOCUMENT IT

Honestly, I could write volumes on measuring a bike to document a riding position. Perhaps if I get enough requests in the comments I’ll actually sit down and outline my process and post it – but you’ll have to be patient because my fitting charts document no fewer than 22 data points and detail is critical because we’re talking about millimeters here…

That aside, this all assumes that you already have a bike that is riding “perfectly” or as pain- and discomfort-free as is possible (we’ll call this bike “Bike 1”). If you have had a fitting done; you may have been supplied with the final dimensions, but even those measurements can require some “interpreting” since there are some specialty measurements (and some fitters like myself have some odd favorites). So understand that you may be best off taking your own measurements for documentation sake so that you know how to apply them to the bike you’re trying to improve ( we’ll call this bike “Bike 2”) .

Some day I may supply my own chart here for your use, but until then Park Tool has some good charts in .pdf format that are detailed enough to get you started. (Find them by clicking here)

The Park Tool link also has decent and detailed instructions for measuring your position – so I won’t re-invent the wheel here. If you want my methods (which are even more OCD than Park’s…); if you and your friends leave enough comments (seriously…it’s going to take like 50…) asking for my methods, I’ll take the time. (you’d better click on a bunch of Google ads though too…blogging hasn’t made me rich and my kids are hungry and growing…) 🙂

HERE’S THE REST OF WHAT YOU NEED:

Pen or pencil
Paper (ideally; Park Tool chart found above )
Tape measure ( I like metric as it typically has smaller demarcations – millimeters instead of 1/16 inches)
Bubble level ( I use an aluminum 4′ carpenter’s level )
Plumb Bob ( to determine absolute vertical )
Appropriate wrenches for the bolts to be adjusted (a metric allen wrench set and a few screwdrivers usually does the trick. You may also need some torx wrenches.)
Torque Wrench (recommended)

FINALLY:

This guide is designed to be used in the order it is written. Not because I’m a maniacal egotistical task-master, but because it works. Your discomfort may only be with one of the areas listed; but until you know for certain that the other areas are in the proper place you don’t know if the location in question is the problem or the symptom. Be sure to follow each point – print it out and check off each spot if that helps. When you start making adjustments is when you’ve found the problem area(s). Now, let’s get into it…

SADDLE:

Might as well get the tough stuff out of the way first. We start here because it is the anchor point of your body on the bike; get this wrong and nothing else matters.

The number one saddle mistake I see that can throw off your positioning is neglecting to note the position of the seat “setback” relative to the bottom bracket – or where the cranks pass through the frame. Being off by just a little bit here changes your weight distribution on the bike and how your muscles respond in the act of pedaling (among other things…). So let’s address this.

The best option here is to use the same saddle on all your bikes since you will sit in different places on different saddles due to their varying shapes and dimensions. Find one that works and stock up because if you’re anything like me; as soon as you commit to it, the manufacturer will change or discontinue it! Second best option: ride similar saddles on each bike. Third best – be patient and search high and low for saddles that have similar dimensions; but that is a daunting if not impossible task.

The bottom line here is that if you’re not paying attention to your saddle selection first; your saddle position is a shot in the dark and will be unique on each bike. That said; we must establish some important points before we talk about what to look for:

The length of the saddle: measure from tip to tail and take note of the length.
The center of the saddle: make a mark at the halfway point of the tip to tail length. Concerned about making a mark on your white “euro-chic” saddle? All the cool Pros riding perfectly fitted bikes have one, so…
The width of your saddle: measure the widest part of the tail of the saddle; edge to edge. This is not a definitive measurement of the seating area; but it’s better than guessing.

Now, here’s the crucial details in the order you ought to compare on bike 2 and address them by adjusting or changing the components:

Saddle make/model
Saddle length
Saddle width
Saddle height to center of saddle
Saddle setback – Tip of saddle behind bottom bracket:
Saddle angle/level

HANDLEBAR AND SHIFTERS:

On a road bike, these parts probably introduce the largest number of variables in the riding position because of the many wonderful ways we can adjust them. This presents just as many ways for things to be out of adjustment too. I wrote a detailed post a while ago that can work as a guide, but the number one problem I see on all types of bike is improper handlebar rotation and poor shifter placement.. Here’s the crucial details in the order you ought to compare between bike 1 and bike 2 and address them:

Distance to handlebar from saddle
Drop to handlebar from saddle
Handlebar Model
Handlebar width
Handlebar Rotation
Handlebar Drop depth
Distance to shifters from saddle
Drop to shifters from saddle
Brake lever reach (Newer, adjustable reach levers only)

STEM AND SPACERS:

Honestly; if your stem position or dimensions were the problem, we would have uncovered that in the previous step. The right stem dimensions will allow you to correctly check off each of those items above. If those dimensions can’t come correct with reasonable adjustments (again, using this post as a guide) to handlebar and shifter positioning; then it’s time to change the stem.(Don’t cheat them into adjustment with saddle tweaks. That’s not a solution and will create new issues.)

That said; if you’ve come up lacking on the handlebar or shifter positioning and can’t figure out the solution, I suggest rolling your bike, your measurements, and your wallet down to the closest bike shop with a patient fitter or mechanic, either of whom have a teacher’s heart; and ask them to help. This will be time and money well spent over aimlessly buying stems only to return most of them before you find the solution.

Be open minded here too: I like to use long, negative-rise stems on my bikes just as much as the next guy; but I make sure the stem dimensions are right for the job first – not just picking a stem that looks cool. The stem that puts your handlebar in the right position for you to fit properly and comfortably will be the fastest and coolest because you’ll be faster and cooler (or at least more comfortable).

PEDALS AND CRANKS:

Now it’s getting good. This is an area that I can really “geek-out” about; because it’s possible to make a big difference with small adjustments. Of course – just like your saddle – similarity is the key here. If it is at all possible to use the same pedal system and shoes on your different bikes; this is the best scenario. However, you may be like me; where I use Speedplay pedals on my road bike, Shimano SPD pedals on my Cyclocross bike (which gets a lot of road miles) and Mountain bike, and platform pedals on my single-speed. This will require more attention, time, detail, and honestly some trial-and-error in matching the position. Truthfully – because of all the variables – you may never get them exactly the same.

Differences in cranks can make a big difference too. But crank length is just a small portion of the equation. You may not realize that the distance between the pedals – often referred to as “Q-factor” – is different between double and triple cranksets (2 or 3 chainrings) and may also vary from one brand to another. For example: 3 bikes with different cranksets – one Shimano double, one Shimano triple, and one FSA BB30 double will likely have 3 different Q-factors. This “stance width”; as is can also be referred to, is critical to creating proper hip-to-knee-to-foot alignment over the pedal for optimal power with minimal stress on the knees.

Different pedals may also effect stance width. And not just between different brands! Shimano Dura Ace pedals and Speedplay Titanium pedals are infamous in fitting circles for having narrower stance widths than their heavier counterparts (where do you think some of that weight savings comes from? Shorter pedal spindles…). A few millimeters per side is the only difference; but that is enough to create knee problems from one bike to another if you are not using identical brand and model of pedals between bikes.

So, as you can see, there are a lot of possibilities in this area. Here’s the crucial details in the order you ought to check on bike 2 and address them:

Pedal brand and model
Shoe/cleat brand and model
Relative differences in cleat position on the shoes (Side to side, front to back, rotation)
Shims, spacers, wedges under cleats or in shoes
Crankset brand and model
Double or triple crankset
Crank Length
Any pedal washers/spacers used

JUST THE CONTACT POINTS

So by now you may have noticed that there is no mention of frame size or dimensions here (well, until now of course…). This is for two reasons:

I’m making the assumption that you are intelligent enough to recognize when a frame is far too small or far too large to fit comfortably and safely. Since I cannot consult on every bike fit for every reader of my blog – the onus rests on you to make a safe decision. Be smart.

it is not necessary for frames to have similar dimensions in order to fit similarly. It certainly helps, but it is possible to put a rider in a similar position on two bikes that are different sizes. That said, the further you have to push the fit envelope by using extreme component dimensions to force it to fit the rider, the worse the frame will handle and perform. It is possible to create a bike that fits correctly and comfortably but is not safe to ride.

That said; the trick to matching bike fit from one bike to another is merely arranging the contact points in space relative to each other in the same fashion from bike to bike. The difficult part is working around the frame and components that get in the way! 🙂

So finally; the last ingredients to help you along the way

Patience – Don’t try to do this in a hurry. It can take 45 minutes to an hour for an expert.
Attention to detail – My mantra: millimeters matter.
Perseverance – Mever give up
Focus on the results – If you get frustrated, remember that this will help your bike be more fun to ride.

You’re sure to have questions or thoughts. Leave a comment and I’ll do my best to either help or refer you to a professional who I think can help.

© 2014 Road Rage Cycling Blog