oldbobcat

Arm length is part of the equation, too. Long arms want to reach longer and (mostly) lower for the handlebar.

jasonthelee

Valid point. I don't think my arms are super short though. I measured 64 cm long following the instructions on their fitting form. Regardless, I'm sure the future old man version of me will appreciate it.

oldbobcat

I never really bothered to measure my arms like that. All I know is my legs are about 49 percent of my total height and my gorilla factor is 1.06. I've been Fit Kitted and Retuled a couple times. Fit Kit at the time didn't deal with handlebar height, so it was pretty useless. Retul suggested only minor changes. My recipe for sizing a bike is, kinda short in the top tube and not too tall up front. Trek H1.5, Giant TCR, or Scott Addict. That said, I'm on an older H2 Madone, but I had to be creative to get the handlebar low enough.

Kontact 

Advertising must really work. You can tell people that steering is tiring, and all of a sudden a road bike that is easy to ride is fatiguing because of 2cm of wheelbase.

What is really vexing is that all these endurance bikes have long trail, which is MORE work at lower speeds.

Turnin_Wrenches

No, that actually sounds like a horrible idea , generally speaking. Adding 17mm of reach is not nothin'. That's a big move, especially in combination with lowering your stack height. However, there are some things that don't quite add up.

At 5'9" with a 32" inseam you're likely on a 54cm frame. If so, a reach of 373mm seems pretty short for a 54cm bike and pretty short for a person who is 5"9. I'm surprised you don't feel cramped on the current bike. Do you have short arms / short upper body or do you just like the upright position that a short reach and tall stack provides?

As for the new race bike, a stack of 550mm doesn't sound very "racey" to me. Based on the stack alone for the two bikes, they both strike me as endurance geometry (assuming they are 54cm frames).

If I take it at face value that your current bike fits you well and you simply want a more aggressive position, I'd recommend going for a lower stack with a similar reach. Something in the neighborhood of: 380mm reach and a stack height of 325mm to 340mm might be better. You may even be able to adapt your current bike to a achieve a more aggressive position (assuming you have spacers under your stem that can be removed). If that's the case, you could remove spacers and swap out for a longer stem.

However, my best advice is to get a bike sizing by a qualified bike fitter. That bike sizing service should include a full evaluation of your body measurements, function and flexibility, starting with an evaluation of your feet. There should be no pre-determined time frame for this service. It takes however long it takes, so do not book with anyone who says they'll do it in an hour. Be prepared to spend about 3 hours (maybe more) if the process is done correctly. At the end of that sizing session a qualified professional will be able to tell you what your target geometry is for a new race bike. When doing it yourself it's easy to make unintentional mistakes that can be costly to remedy after you've already purchased the "wrong" bike. However much you spend on that sizing session will be saved (and then some) by purchasing a bike that fits you well and allows you to perform the intended function.

oldbobcat

You nailed it. Especially with slack head angles. And it makes them less stable when you hit something loose.

Kontact 

Why not more reach? When you lean forward, your reach increases.

Turnin_Wrenches

I wasn't saying that more reach is inherently bad. My main point was that adding 17mm of reach to a position that is already comfortable is a really big move. And if the OP finds out post-purchase that 390mm of reach is too long, you can't make the bike "smaller". Final result = a bike that is to long and uncomfortable to ride. The only available "remedy" for this scenario (which isn't a remedy at all) would be a super short stem, handlebars / hoods that are rotated up and back too far towards the rider, and a saddle that is slammed all the way forward, all of which present new challenges and lead to a whole new set of problems that ultimately cannot be solved.

I deal with people every day who purchased bikes (usually from other shops) that don't fit. For reasons that I do not understand, they proceed (without hesitation) to spend several hundred dollars swapping saddles, stems, and requesting a multitude of adjustments in search of comfort because they refuse to accept the fact that they bought a bike that doesn't fit. Whereas, if they had spent $150-$300 dollars with a competent bike-fit professional (before purchasing the new bike) they would have ended up with a bike they can comfortably ride and they would have saved money.

Kontact 

Why would the stem be super short? Does the OP's current bike use an already short stem?

The difference in top tube length between the two bikes is 11mm. That's because stack ignores the slope of the headtube, which makes reach 3mm shorter for every 10mm gain in stack. So a 20mm shorter stack bike (or just moving your stem down 20mm) makes the reach 6mm longer. At that point you only need a stem that is 1cm shorter to duplicate the same horizontal distance from the seat post. So you go from a 110mm stem on one bike to a 100mm stem on the new bike. How is that a problem?


I'm not saying that the OP's new bike idea will fit him fine. He should look into a fit. But there is no reason it couldn't be made to fit. He can also use a -17 degree stem or removed spacers to simulate the fit of a lower stack height. Or, he can use 20mm of spacers and one size smaller stem on the new bike to put himself in the identical position to the old one. Unless you ask for the steerer tube to be chopped, most production bikes come with 40mm of steerer tube height that the stem can be moved up and down in. You are reacting to the OP as if he's got a currently slammed stem and is going to another bike with a slammed stem. But both probably have a good amount of adjustability in an overlapping range that would allow for identical fit, if going lower doesn't work out.

Turnin_Wrenches

Your comment above (in bold letters) pretty much sums things up... especially the last part. Sure, there are lots of situations in which the bike can be made to fit. But why go through the gymnastics of that exercise when it's not necessary? Just buy a bike that fits! Why is that such a difficult concept?

Kontact 

You're not getting it. The difference between these two bikes is two spacers and one stem size. That isn't gymnastics. That's a normal variation between different models in compatible sizes. As a fitter, I saw this kind of variation all the time: No one properly fit had one size stem on all their bikes.

But you're acting like a guy riding a 58 wants to buy a 50. It's ridiculous.

Turnin_Wrenches

I'm not here to argue. I stated my reasons very clearly as to why I think the geometry of the potential new race bike is possibly "a bridge too far". Since the OP has only provided a limited amount of info, the best any of us can do is to highlight the areas where there may be "red flags" and say "hey, you may want to look closer at "X" before you drop a bunch of coin on a bike that might not fit". The reach number looks like a red flag to me, and I think the solution would likely involve more than more than a couple of spacers and a 10mm shorter stem.

I have no problem with the fact that you've come to a different conclusion; I simply do not agree with your assessment (to put it mildly).

Road Fan

I’d like to try that self fitting technique, where you got such a useful arm measurement. Can you link me to a website where the instructions are given?

jasonthelee

Just saw your message, I'll try to attach screenshot of form.

Kontact 

This is a math problem. If you have an objection to my math, you post where my arithmetic is wrong and what numbers you are using that show different. Either the stem difference is as I stated or it is not. No need for opinions.

And if it is as I stated, all the OP has to do is assess whether the new bike will allow for that difference or not.

Turnin_Wrenches

I think our greatest disagreement stems from the fact that you think you have enough info to propose any type of solution. My post, which you quoted above, makes that clear... yet you believe that I'm attacking your math. Odd.

I'm also at a loss to understand why you continue to try and bully me into agreeing with you. With regard to the basic question that started this thread, we've come to different conclusions based on the info provided. Disagreement happens; it's OK. Why is that so difficult for you to accept?

P.S. I am unsubscribing from this thread and will not return. It's a road to nowhere.