Techniques and tips for replicating bike fit from bike to bike

Hi all,

Are there any simple techniques and tips to transfer a bike fit from one bike to another and ensure they are as similar as can be?

I can see myself ending up with string and lengths of wood but can’t help but think there is a dead obvious and reliable way to do this.

As background I have a CAAD12 which is like an old glove, jump on and feels like I am at home. I also have a CAAD8 as a trainer/winter bike. The sizing is not the same (52 versus 54) and indeed the measurements per size differ between the frames but I have got them within a couple of mm of each other for actual stack and reach (using -6 stem on one and -17 on another, plus varying amount of spacers).

Saddle setback is spot on, height fore/aft/middle good, both easy to do with a long spirit level and a tape. Front centre + stem (to centre line of bar top) is similar over both bikes, as is actual stack.

I am however having a really hard time getting hood position similar bike to bike, even with similar shaped bars and levers. This is both the vertical position and the ‘rotation’ left to right.

All you really need is a plumb-bob, ruler, and maybe a level if you’re using similar saddles, cranks, pedals, etc. You’ll have to get creative if stack is out of range.

Saddle position, stack and reach are all good - did you read my post?

it is not easy to find a solution but there are 4 measures that can be taken easily to set a bike fit as close as possible to another:
1- measure from center bb to center saddle
2- measure from center bb to perpendicular center saddle
3- measurement from saddle tip to handlebar
4- measure from front brake lever to front wheel hub axle (same side)

To quote myself for clarity and hopefully below diagram helps how what I am finding hard.

All the bits underlined green are good on the fit transfer, amber not so.

H - angle of hoods from horizontal, seeming like I want a few degrees tilted up towards me but when tighten the clamp they tend to move, and having the covers peeled back to get to bolts doesn’t help either.
K - angle of drops - can get this ok but even with two similar shaped bars find it hard to be spot on apart from feel, but it is critical to get right first!
Y - toe in/out of levers, another I find changes as you tighten the clamp
Z - dictated by Y, ideally I want the hood straight but the Shimano hoods are not straight although at least similar shape between models (Ultegra 6800 one bike and Dura Ace 9000 other)

You say several times that shapes / parts are "similar’. On=bsioualy similar does not equal identical. I woudl wager that is a big part of your problem. Take several “similars” and stack them on top of each other and you get “noticeable differences.”

MM’s are noticeable when it comes to fit…a little here, a little there and it starts getting noticed. That said, you body is very adaptable. Within a few minutes of riding you should not really notice the differences anymore. You don’t have to be spot-on between bikes. Shoot for close enough and call it good.

The order matters as much as the actual points of measure. You need one fixed point to start your measurements. That’s the bottom bracket. Start by setting your saddle height and setback measuring off the BB (pedals for height to be super accurate). Now the saddle is the same as the old bike so you can use it as the fixed point to reference off of to set up the bars then hoods. (It helps a lot if you use the exact same saddle and bar models on both bikes)

All the assumptions of equal saddle setback are predicated on having the same saddle model/shape on both bikes though, right? If the two saddles are different lengths or where you naturally sit on each differs then that’s another variable to account for.

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I invested in a veloangle earlier this year and I think it is super great. Even for tracking small changes in position, for me it has already paid for itself.

the first thing to do (assuming the seat height and the fore aft placement is the same) is to get a carpenters (3 foot+). With each bike level (on a level surface) from the tip of the saddle with the level set measure down to each brake hood where you place your hands, replicate this measure. Second, once this is set measure from tip of saddle to a common point on each brake hood (this is a V type measure). For this try to ensure that the front wheel is centred and the same in both. It is fiddly but doable. Also check that the distance between the hood is the same. Another way is to measure from the centre of the front wheel to the top of each hood. That assumes of course seat height etc is right but is a fair check of consistency.

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I must have explained myself really badly. I am struggling to get hoods the right angle. They move when you tighten them.

Forget everything else.

Any tips?

This $1.99 iphone app measures level and angles and nice to have. If you get a straight piece of wood or metal to rest it on, it can is amazingly good at doing a bunch of useful measuring. Its my go to saddle set up tool as you can just lay your phone on the saddle to check, or set, an angle.

There are 5 tools in this Carpenter toolkit:

  • A plumb bob, the easiest way for you to verify the verticality of lines or walls

  • A surface level, the best tool to level any flat surface

-a bubble level bar, exactly like what you see in a woodworking shop but more attractive.

  • A steel protractor, measuring angles from 0 to 180 degrees.

  • A steel ruler, supporting both inches and centimeters. By swiping it left and right, the ruler is capable to measure things much longer than your iPhone!

  • Once calibrated, the plumb bob, surface level and level bar can also be used as an inclinometer/clinometer by reading the angles on the screen.

take the distance from lever to hub center axle of the same side

if the brake/ shifter hoods will not remain in place then there is something wrong with the clamp set up under the hood you are tightening I would think. I have never seen this as a problem. Curious why this is happening?

They move when you tighten them. Once tight they do not move but are not in the precise same place as before tightening.

Sounds like a conundrum you’re in. Maybe you could have someone braze the shift/brake lever attaching “ring clamp” (not sure what it’s technically called) to the handle bars before you tighten them (probably for the last time ever). Jokingly of course :slight_smile:

Hope someone on the forum can come up with a solution for you. Simple things like this are really frustrating.