Review / Critique my frame design

[Marvinlungwitz]

.

[nortx-Dave]

Maybe I took a too lackadaisical attitude. With Chris Bishop I had a local fitting done and carefully measured my current bike's geometry. Then I told Chris how, where and how much I ride and what I wanted in a bike and let him work his magic. Maybe I just got lucky, but it came out perfectly suited for me.

[NHAero]

@Doug Fattic
Thank you for your posts, I always learn something! Like the OP, I ride with almost no drop, and have found that I like the steep STA of 74 degrees and a no setback post. It puts more weight on the front end and lets me ride a longer TT and still have a reasonably steep HTA. If I rode with 10 cm of drop I'd need the seat further back.

I believe that some pro fitters really help people. On the other hand, if a person has ridden a lot of bikes, and watched carefully what works and what doesn't (and is able to isolate those factors), experience is a good teacher. My Strong has a 74 STA and 73 HTA and a 55 cm ETT. In October I did a 109 mile ride in VT and ended feeling good and without any pain. Given that I'm not a racer looking for the last bit of edge, isn't this an indication the bike fits me?

@Weisan
Different strokes for different folks! Ray found 72.5 HTA with a 51mm fork to be unsatisfactory unloaded, yet that geo with a 32mm tire is 56mm of trail. Seems very conventional to me (as opposed to low trail.)

[deluz]

Originally Posted by Doug Fattic

I don't think you have provided enough information to give a complete evaluation. My impression of Paceline posters is that they are a more go-fast (or at least look-fast) crowd than say the people over on the I-BOB list - where you might get slightly different comments. Anyway I'm a long time builder and will only build a frame after I have done a fitting or know who the fitter is. I don't think you have enough information unless you have a fit done.

I'm suspicious that your 74º seat angle might be too steep. It might be the right angle but that depends on the kind of riding you do - which I don't remember you telling us. The reason I think it might be too steep is because your handlebars are level with your saddle and that isn't where fit go-fast guys want their bars. It is where no-longer-skinny older and less flexible recreational riders like their handlebars. Your body shape and age play into your saddle position. For example if your upper body is carrying extra pounds, you should find out where your saddle setback balances your weight over the pedals. That reduces the load on your arms supporting your upper body weight.

I'm 5'8" too but my saddle height along the center of the seat tube line is 73.5. I use 170 cranks and prefer a much lower BB height than your 270. That is production frame height where the designer doesn't know if you are using longer cranks and pedaling through corners. Custom frames (and especially small custom frames) can lower the BB height if they are using shorter cranks (and seems like, with your short legs, 165 cranks are more than long enough) and you are not riding in pace lines pedaling through corners. A lower BB height means a you can straddle a bigger frame which means you can have a longer head tube which reduces the need for more head tube extension above your top tube.

All frame designs involve compromise. If your saddle position after a fitting shows you need a shallower seat angle, then using 700c wheels is a compromise. I'd consider 650B X 28 or 32. Smaller wheels are an advantage for you except for shopping convenience. If you are going with 42s, than they are the same diameter as a 700C by 28. The radius of the tire you chose (345) is the radius of a 700c X 32 tire. Is this the size you chose? A 28 is 340 (this all depends on the brand of tire of course). The radius of a 650b X 28 (they make them) is 320. That 20 mm can help in several ways making a smaller frame.

I think this whole exercise is pointless unless you go get a fitting first. So far you are fitting your body to a design instead of designing a frame to fit your best cycling position. This is especially true as we age. We get fatter, less flexible, want to be more comfortable and are less concerned about shaving a few seconds off of our regular route. I've had hundreds of students take one of my framebuilding classes. It is the rule rather than the exception that they learned their present position was not optimum and required adjusting their new frame design compared to what they expected. The problem was that their current bicycle prevented the from finding they best position. For example their seat angle was too steep. Just to be clear if you are a fit go fast kind of guy, than it is better to fit the body to the frame designed for handling and speed rather than comfort. My guess is that your 1st priority is comfort.

Doug,

Thanks for the thoughtful comments. I will try to address as best I can.
I am 64 years old. In my 20's I used to race and in my middle age (30-50) I would go on fast group rides and ride at my limit. I am now at the point where I ride much slower due to age, injuries and health problems. Even though I am riding slower I enjoy it just as much or more. I am not fat or overweight, I weight about what I did 20 years ago which is 140lbs. There are times where I like to push myself but that is only for short periods. I already have what you call a "go fast" bike which is a Cannondale EVO. This bike is to be a complement to that bike being steel and have a more relaxed geometry. Also being a second bike I have a limited budget. I realize that many here have unlimited resources to pick any builder and get a fitting. I simply do not have $5K to spend on this. So lets just call it a semi custom bike. I am going to very lucky if my wife even lets me go ahead with this.
Even though we are the same height we have very different proportions with your saddle being over 3 inches higher than mine.
My whole life I have ridden 170mm cranks and I am not going to change that now. The BB is actually lower than my Cannondale by 10mm. Most of the bikes I have had have a 74 STA and it works fine for me. In fact I usually use a zero offset seat post. Making the STA slacker would push my saddle further back which could be problematic. I have pretty much settled on 28c tires as I ride only on the road. I have recently spent a lot of time learning about geometry and have a lifetime of experience adjusting the fit on my bicycles. I have serious doubts that a fitter is going change anything substantial. There are not that many around and how do I know if they are any good? Not trying to be cynical here just putting down my thoughts.

[deluz]

Originally Posted by Marvinlungwitz

It looks like there’s a big difference between your original drawing’s saddle height and your latest drawing (673 mm vs 650mm). Or am I missing something?

I think I explained that. The original 673 is measured from the BB to where I sit on the saddle which is behind the centerline of the seat tube. I changed it to 650 because that is what it measures to the saddle along the ST centerline which is what RattleCAD uses.

[NHAero]

I agree with what you wrote here, you know what fit works for you. As long as you don't mess up the handling, you should be good. One can fit on a bike whose handling one doesn't like.

Originally Posted by deluz

Doug,

Thanks for the thoughtful comments. I will try to address as best I can.
I am 64 years old. In my 20's I used to race and in my middle age (30-50) I would go on fast group rides and ride at my limit. I am now at the point where I ride much slower due to age, injuries and health problems. Even though I am riding slower I enjoy it just as much or more. I am not fat or overweight, I weight about what I did 20 years ago which is 140lbs. There are times where I like to push myself but that is only for short periods. I already have what you call a "go fast" bike which is a Cannondale EVO. This bike is to be a complement to that bike being steel and have a more relaxed geometry. Also being a second bike I have a limited budget. I realize that many here have unlimited resources to pick any builder and get a fitting. I simply do not have $5K to spend on this. So lets just call it a semi custom bike. I am going to very lucky if my wife even lets me go ahead with this.
Even though we are the same height we have very different proportions with your saddle being over 3 inches higher than mine.
My whole life I have ridden 170mm cranks and I am not going to change that now. The BB is actually lower than my Cannondale by 10mm. Most of the bikes I have had have a 74 STA and it works fine for me. In fact I usually use a zero offset seat post. Making the STA slacker would push my saddle further back which could be problematic. I have pretty much settled on 28c tires as I ride only on the road. I have recently spent a lot of time learning about geometry and have a lifetime of experience adjusting the fit on my bicycles. I have serious doubts that a fitter is going change anything substantial. There are not that many around and how do I know if they are any good? Not trying to be cynical here just putting down my thoughts.

[Marvinlungwitz]

Originally Posted by deluz

I think I explained that. The original 673 is measured from the BB to where I sit on the saddle which is behind the centerline of the seat tube. I changed it to 650 because that is what it measures to the saddle along the ST centerline which is what RattleCAD uses.

Gotcha, I did miss that.

[yinzerniner]

Originally Posted by deluz

Doug,

Thanks for the thoughtful comments. I will try to address as best I can.
I am 64 years old. In my 20's I used to race and in my middle age (30-50) I would go on fast group rides and ride at my limit. I am now at the point where I ride much slower due to age, injuries and health problems. Even though I am riding slower I enjoy it just as much or more. I am not fat or overweight, I weight about what I did 20 years ago which is 140lbs. There are times where I like to push myself but that is only for short periods. I already have what you call a "go fast" bike which is a Cannondale EVO. This bike is to be a complement to that bike being steel and have a more relaxed geometry. Also being a second bike I have a limited budget. I realize that many here have unlimited resources to pick any builder and get a fitting. I simply do not have $5K to spend on this. So lets just call it a semi custom bike. I am going to very lucky if my wife even lets me go ahead with this.
Even though we are the same height we have very different proportions with your saddle being over 3 inches higher than mine.
My whole life I have ridden 170mm cranks and I am not going to change that now. The BB is actually lower than my Cannondale by 10mm. Most of the bikes I have had have a 74 STA and it works fine for me. In fact I usually use a zero offset seat post. Making the STA slacker would push my saddle further back which could be problematic. I have pretty much settled on 28c tires as I ride only on the road. I have recently spent a lot of time learning about geometry and have a lifetime of experience adjusting the fit on my bicycles. I have serious doubts that a fitter is going change anything substantial. There are not that many around and how do I know if they are any good? Not trying to be cynical here just putting down my thoughts.

Great response with some added info that helps in providing (hopefully) constructive comments

A few things from your previous posts:
-You stated an inseam of 30.5" and crankarms of 170mm, which aren't numbers too off of a typical 5'-8" fellow. My father is about the same height and he has a 28.5" inseam! But the saddle height measurement from middle-top of saddle to center of BB at 650mm seems awfully low - generally saddle height is somewhere aroung 88% of inseam height, which in your case would be ~681mm which aligns with what you're measuring as your center of BB to sit bone location. Just wondering if this saddle position is something you've always had, or something you set based on some measurements a long time ago and just never really considered changing since your body got used to it?

-The first suggestion of many others doesn't seem feasible to you, which is "see a fitter," but you should really reconsider. Your suggestion of " hav(ing) serious doubts that a fitter is going change anything substantial" couldn't be farther from the truth, especially since you're a little older and your body naturally doesn't have the flexibility it once did to adjust itself to suboptimal positions. A good fitter will be able to take the cacophony of multiple mini adjustments and combine them for a fit that optimizes your riding goals. It sounds like total BS but it's really not, five 5mm adjustments throughout your touch points really make a bigger difference than a single 25mm adjustment and the fitter will be able to judge this. If you can't find a local fitter (would help to know your location) then there are online fitting services like the one mentioned below. Or there are mobile fitters who sometimes make the rounds, like mobile mechanics in vans.
https://www.myvelofit.com/

But really cool to see this discussion and commend you getting your feet wet / hands dirty with the design details and responding to the internet horde. Keep us posted on what you decide, should be a super fun ride.

[deluz]

Originally Posted by yinzerniner

Great response with some added info that helps in providing (hopefully) constructive comments

A few things from your previous posts:
-You stated an inseam of 30.5" and crankarms of 170mm, which aren't numbers too off of a typical 5'-8" fellow. My father is about the same height and he has a 28.5" inseam! But the saddle height measurement from middle-top of saddle to center of BB at 650mm seems awfully low - generally saddle height is somewhere aroung 88% of inseam height, which in your case would be ~681mm which aligns with what you're measuring as your center of BB to sit bone location. Just wondering if this saddle position is something you've always had, or something you set based on some measurements a long time ago and just never really considered changing since your body got used to it?

-The first suggestion of many others doesn't seem feasible to you, which is "see a fitter," but you should really reconsider. Your suggestion of " hav(ing) serious doubts that a fitter is going change anything substantial" couldn't be farther from the truth, especially since you're a little older and your body naturally doesn't have the flexibility it once did to adjust itself to suboptimal positions. A good fitter will be able to take the cacophony of multiple mini adjustments and combine them for a fit that optimizes your riding goals. It sounds like total BS but it's really not, five 5mm adjustments throughout your touch points really make a bigger difference than a single 25mm adjustment and the fitter will be able to judge this. If you can't find a local fitter (would help to know your location) then there are online fitting services like the one mentioned below. Or there are mobile fitters who sometimes make the rounds, like mobile mechanics in vans.
https://www.myvelofit.com/

But really cool to see this discussion and commend you getting your feet wet / hands dirty with the design details and responding to the internet horde. Keep us posted on what you decide, should be a super fun ride.

My saddle height is based on just tweaking over the years. Also just looking at the bend in my knee with the cranks in vertical position and being able to pedal with my heels on the pedals without lifting up. Sometimes it feels a little too high or low and I adjust it a few mm but always seem to come back to this height. It could also have to do with pedaling with my feet more horizontal and not with the toes down which is what my wife does. I could try raising it a bit and stick with it to see what happens. I am not totally opposed to seeing a fitter but would need to feel going in that it would be beneficial and not throwing money away. I have already looked at myvelofit and was going to give that a try, just have not had time yet.

Thanks

[weisan]

Originally Posted by NHAero

@Weisan
Different strokes for different folks! Ray found 72.5 HTA with a 51mm fork to be unsatisfactory unloaded, yet that geo with a 32mm tire is 56mm of trail. Seems very conventional to me (as opposed to low trail.)

Absolutely. It varies from person to person. I have found that 30-35mm tires gave it the best combo.
I only put this up there as an "extra" datapoint for deluz pal to consider, not definitive or exhaustive by any chance.

Like i said, I really can't wrap my head around geo numbers, they don't make any sense to me, all I know is what I feel while riding and how the bike respond. This particular bike has gone through several hands since Ray gave it up for circulation - Clean39t have it in his possession for a little bit. I am just amazed at the versatility of the design, the bike has been set up for a rider like Ray, someone taller like Clean, and then finally ended up with me who is 5'8+". I have taken this bike on fast group rides, long solo rides - it just performs very predictably and up to the task. I have even "widened" the chainstays to accommodate up to 38mm tires to ride on gravel. I know there's a tradeoff somewhere along the way, but the fact that one bike can sort of "do it all" and accommodate different use cases makes it the perfect travel bike for participating in different events and various terrains. And being made of titanium, my fav. material, is icing on the cake.

Here sporting 38mm Gravel King slicks during my california trip where I ride on some really crappy mountain roads and even venture a bit into gravel.


For comparison, check out how Clean pal had it set up for someone his height (taller...much taller). Both configurations work for the rider in question.

[NHAero]

Thanks for posting myvelofit. Have you or someone you know used it?

Originally Posted by yinzerniner

Great response with some added info that helps in providing (hopefully) constructive comments

A few things from your previous posts:
-You stated an inseam of 30.5" and crankarms of 170mm, which aren't numbers too off of a typical 5'-8" fellow. My father is about the same height and he has a 28.5" inseam! But the saddle height measurement from middle-top of saddle to center of BB at 650mm seems awfully low - generally saddle height is somewhere aroung 88% of inseam height, which in your case would be ~681mm which aligns with what you're measuring as your center of BB to sit bone location. Just wondering if this saddle position is something you've always had, or something you set based on some measurements a long time ago and just never really considered changing since your body got used to it?

-The first suggestion of many others doesn't seem feasible to you, which is "see a fitter," but you should really reconsider. Your suggestion of " hav(ing) serious doubts that a fitter is going change anything substantial" couldn't be farther from the truth, especially since you're a little older and your body naturally doesn't have the flexibility it once did to adjust itself to suboptimal positions. A good fitter will be able to take the cacophony of multiple mini adjustments and combine them for a fit that optimizes your riding goals. It sounds like total BS but it's really not, five 5mm adjustments throughout your touch points really make a bigger difference than a single 25mm adjustment and the fitter will be able to judge this. If you can't find a local fitter (would help to know your location) then there are online fitting services like the one mentioned below. Or there are mobile fitters who sometimes make the rounds, like mobile mechanics in vans.
https://www.myvelofit.com/

But really cool to see this discussion and commend you getting your feet wet / hands dirty with the design details and responding to the internet horde. Keep us posted on what you decide, should be a super fun ride.

[Doug Fattic]

Originally Posted by deluz

Doug,

Thanks for the thoughtful comments. I will try to address as best I can.
I am 64 years old. In my 20's I used to race and in my middle age (30-50) I would go on fast group rides and ride at my limit. I am now at the point where I ride much slower due to age, injuries and health problems. Even though I am riding slower I enjoy it just as much or more. I am not fat or overweight, I weight about what I did 20 years ago which is 140lbs. There are times where I like to push myself but that is only for short periods. I already have what you call a "go fast" bike which is a Cannondale EVO. This bike is to be a complement to that bike being steel and have a more relaxed geometry. Also being a second bike I have a limited budget. I realize that many here have unlimited resources to pick any builder and get a fitting. I simply do not have $5K to spend on this. So lets just call it a semi custom bike. I am going to very lucky if my wife even lets me go ahead with this.
Even though we are the same height we have very different proportions with your saddle being over 3 inches higher than mine.
My whole life I have ridden 170mm cranks and I am not going to change that now. The BB is actually lower than my Cannondale by 10mm. Most of the bikes I have had have a 74 STA and it works fine for me. In fact I usually use a zero offset seat post. Making the STA slacker would push my saddle further back which could be problematic. I have pretty much settled on 28c tires as I ride only on the road. I have recently spent a lot of time learning about geometry and have a lifetime of experience adjusting the fit on my bicycles. I have serious doubts that a fitter is going change anything substantial. There are not that many around and how do I know if they are any good? Not trying to be cynical here just putting down my thoughts.

This extra information about the kind of riding you expect to do and your body type is helpful. Many people base their next bicycle design on what they used in the past with small adjustments. This is a sensible plan but it doesn't mean it is the optimum plan. Production bikes are influenced to put the front wheel where rotating toes won't hit it or the company gets sued for rider injuries. Often this means a steep seat angle - especially on smaller bikes with shorter top tubes. I'm not saying a 74º seat angle is wrong for you but my experience says that for a guy already in his 60's and hoping to ride for many more years, the odds are it probably should be slacker because you will continue to sit more upright. However I wouldn't know until I put you on a fitting bicycle that didn't have any position restrictions to verify. I've learned over the years that many riders thought their position was okay until they had a fitting done. And then its like "oh"! These experiences are why I don't just take the word of a customer/student that they have found by themselves their optimum position based on adjusting their components on a production frame.

I built a go fast frame for myself 30 years ago when I was in my 40's so I could (barely) stay with the big boys on fast training rides. I still ride that bike today but my stem is 2 centimeters shorter and higher than it was when I built it. You should plan for this to happen to you too.

Bottom bracket height is another area where a custom frame design can be superior to the higher heights common in production frames. Those heights were established in the days of quill pedals when that point sticking beyond your foot would scrape the ground when pedaling at speed through corners. Companies took no chances with whatever length of crank or type of pedal or cornering style. They were high enough so a pedal always missed. There are big advantages I've already explained to lowering your BB height if you don't need that clearance any more. That bike I mentioned that I built for myself that used 170 cranks had a BB height of less than 260mm. I'm no longer jumping out of corners trying to stay in the draft. I didn't need a higher bracket height than and even less so now. If you aren't riding crits, you don't need a crit height height.

Just like fitters, there is a huge variety in the knowledge and ability of custom builders. The ideal is Tom Kellogg at Spectrum. He was a knowledgable fitter, and excellent builder and painter. Unfortunately he retired and not everyone has his skills.

[deluz]

Doug - thanks again I will seriously look into a fitting.

[parris]

Deluz get some recommendations as to who you want for fitting services. There are a fair number of "fitters" that have paid their money to whatever system they use and ONLY go by the data points their computer tells them. Not all but a number.

I saw it with a local couple several years ago. The two of them dropped around $1200.00 for fittings and the component recommendations of the "expert". They were stoked after the fit due to the power numbers they generated while being fitted. The problem was that neither of them could stand to be on their bikes for more than about an hour and a half due to their positions being so jacked up.

The biggest red flags I saw were with the husband. His seat was sky high and nose down. He was on 165cm cranks which wouldn't be bad EXCEPT that this dude goes around 6ft4in. It was really horrendous.

So ask around before dropping coin on a fitter.

[deluz]

Originally Posted by parris

Deluz get some recommendations as to who you want for fitting services. There are a fair number of "fitters" that have paid their money to whatever system they use and ONLY go by the data points their computer tells them. Not all but a number.

I saw it with a local couple several years ago. The two of them dropped around $1200.00 for fittings and the component recommendations of the "expert". They were stoked after the fit due to the power numbers they generated while being fitted. The problem was that neither of them could stand to be on their bikes for more than about an hour and a half due to their positions being so jacked up.

The biggest red flags I saw were with the husband. His seat was sky high and nose down. He was on 165cm cranks which wouldn't be bad EXCEPT that this dude goes around 6ft4in. It was really horrendous.

So ask around before dropping coin on a fitter.

Yep that is my concern. Virtually anybody can hang a shingle and call themselves a fitter, I certainly could do that and pass for one.
You don't need a college degree or an M.D.
I did look for somebody local and other than what they have on their website their is very little independent info. But I need to get over my skepticism and give it an honest try. Email sent waiting for a response.