Please advise what changes to make in a custom titanium frame

[Hensem]

I want to order a custom titanium frame with Endurance geometry. In general, I love long rides and climbs, and in order to build a bike suitable for both scenarios, we decided to go with endurance geometry.
I did a bikefit, I have long legs and a short torso, and it was again confirmed that I need a bike with a very short reach and a high stack (Reach - 360mm, Stack - 570mm). After spending many hours in the BikeCad application I designed the frame. First of all, I made sure that the height of the head tube was not too long, since with a short reach, long head tubes do not look very nice.I also made sure to get the Front-Center size as large as possible to avoid the shoe touching the front wheel.
I want to order a new type of frame, with 3D printed elements, the frame looks exactly like a modern aero bike. There are ready-made sizes from the manufacturer and he gave me the opportunity to make some changes to the angle of the head tube, the drop of the BB, and also shorten the reach to the parameters I needed. I selected size 500 from the table and started making my changes.
In the head tube I want to select an angle of 72 degrees. I don't really like the drop of the 69mm BB. What do you think should I choose from 72 to 75mm? I'm also wondering if it's worth choosing a fork with Rake 50 to reduce the trail value so that the bike is more responsive when negotiating descents? And the front-center will also increase. What other changes should be made?

[morrisond]

Hi,

I use BikeCad a lot. A couple of questions.

How tall are you overall? Define Long legs and short torso? Based on your drawing I'm guessing you are you about 5'7"-5'8"(170-174CM) in height?

Is that EFTT right at 524mm? Did you do your BikeFit with an Seat tube angle of 74 Degrees and no setback?

What sized tires will you run and is this a pavement only bike? 69mm is probably way too high. With an EFTT that short and pavement only you can probably get by with a lot lower BB. Did you your builder give you a constraint on maximum BB drop?

What length Cranks do you like to run?

What number do you need for standover?

Did your builder give you a maximum Top Tube slope you can't go beyond?

It looks like you are running a ton of spacers (40-50mm), no need to slam it - but it would be nice to get it down to 20-30mm - what bar and stem are using that is minus 10 degrees?

[Peter P.]

Lengthen the chainstays to 420mm.

If you're using the default headtube length of 160mm, I assume that includes integrated headset bearings. If non-integrated bearings/cups, that's unusually long.

BB drop; a couple mm means nothing. Don't sweat it.

72 degree headtube/50mm rake-my custom road frame has those exact dimensions. With a 25mm (nominal) tire, I wouldn't call it responsive. If I had to do it again, I'd go with a 72.5/45mm combination, which is what I have on my favorite handling bike. If you're set on the 72 degree head angle, get a fork with 53mm of rake. Of course you're probably going to use a carbon fork so good luck finding a fork with that exact rake.

Toe overlap is only a concern when pulling U-turns in the parking lot. At any speed over walking speed, I wouldn't consider it.

[Hensem]

Originally Posted by morrisond

Hi,
I use BikeCad a lot. A couple of questions.

Hi.Thank you very much for the answer. I will try to answer as accurately as possible what I remember.
My height is 171cm, inner leg length is 84.4cm. About body I don't remember,I just know that by human standards my body is short.
I'm not sure exactly what seat tube angle I was fitted at, but if my memory serves me correctly, when I asked the technician what angle to choose, he said 73.5, when I asked if I could choose 74, he said it doesn't really matter, it'll have to just move the saddle in one direction or another. In about 5 hours it will be the end of the working day and I can call him and ask for all the parameters of my settings that were carried out on the day of bikefit.
I'm planning on using 28-32mm tires, probably closer to 28 and maybe if I ever need to go on a bikepacking trip on a good quality gravel road I'll go with 35mm tires.I'm planning on using 28-32mm tires, probably closer to 28 and maybe if I ever need to go on a bikepacking trip on a good quality gravel road I'll go with 35mm tires.
My builder Waltly did not give any restrictions, except that if I want to make my own size BB I will need to pay an extra $50 =))) This applies specifically to the 3D frame, if there was a regular frame it would be free.
I'm planning on using 28-32mm tires, probably closer to 28 and maybe if I ever need to go on a bikepacking trip on a good quality gravel road I'll go with 35mm tires.
My builder Waltly did not give any restrictions, except that if I want to make my own size BB I will need to pay an extra $50 =))) This applies specifically to the 3D frame, if there was a regular frame it would be free.
The cranks will be 170cm.

Has your builder given you a maximum slope for the top pipe that you cannot go beyond?

No.
I plan to use an Avian Canary or Avian Falcon II rudder, the stem angle is stated to be 10 degrees, but it looks like -10. https://avians.cc/products/avian-falcon-ii

Can I send my bikecad files ?
I'll add a photo of what the frame looks like. Waltly sent this to me.

[Hensem]

Originally Posted by Peter P.

Lengthen the chainstays to 420mm.

If you're using the default headtube length of 160mm, I assume that includes integrated headset bearings. If non-integrated bearings/cups, that's unusually long.

BB drop; a couple mm means nothing. Don't sweat it.

72 degree headtube/50mm rake-my custom road frame has those exact dimensions. With a 25mm (nominal) tire, I wouldn't call it responsive. If I had to do it again, I'd go with a 72.5/45mm combination, which is what I have on my favorite handling bike. If you're set on the 72 degree head angle, get a fork with 53mm of rake. Of course you're probably going to use a carbon fork so good luck finding a fork with that exact rake.

Headtube 56mm with integrated headset bearings 52mm.
I want a bike that is responsive and comfortable when cornering on fast descents. Initially I chose a 72.5mm headtube with 45 rake, but later I started experimenting with angles.
I am currently considering two types of forks: The same size from Axle to crown - 375 and either 45 degrees rake for the fork that Waltly offers, or a choice of 45 or 50 for the no6 fork. This is a subsidiary of the famous boutique frame manufacturer No22. https://6composites.com/products/road-disc-fork

[morrisond]

Originally Posted by Hensem

Hi.Thank you very much for the answer. I will try to answer as accurately as possible what I remember.
My height is 171cm, inner leg length is 84.4cm. About body I don't remember,I just know that by human standards my body is short.
I'm not sure exactly what seat tube angle I was fitted at, but if my memory serves me correctly, when I asked the technician what angle to choose, he said 73.5, when I asked if I could choose 74, he said it doesn't really matter, it'll have to just move the saddle in one direction or another. In about 5 hours it will be the end of the working day and I can call him and ask for all the parameters of my settings that were carried out on the day of bikefit.
I'm planning on using 28-32mm tires, probably closer to 28 and maybe if I ever need to go on a bikepacking trip on a good quality gravel road I'll go with 35mm tires.I'm planning on using 28-32mm tires, probably closer to 28 and maybe if I ever need to go on a bikepacking trip on a good quality gravel road I'll go with 35mm tires.
My builder Waltly did not give any restrictions, except that if I want to make my own size BB I will need to pay an extra $50 =))) This applies specifically to the 3D frame, if there was a regular frame it would be free.
I'm planning on using 28-32mm tires, probably closer to 28 and maybe if I ever need to go on a bikepacking trip on a good quality gravel road I'll go with 35mm tires.
My builder Waltly did not give any restrictions, except that if I want to make my own size BB I will need to pay an extra $50 =))) This applies specifically to the 3D frame, if there was a regular frame it would be free.
The cranks will be 170cm.

No.
I plan to use an Avian Canary or Avian Falcon II rudder, the stem angle is stated to be 10 degrees, but it looks like -10. https://avians.cc/products/avian-falcon-ii

Can I send my bikecad files ?
I'll add a photo of what the frame looks like. Waltly sent this to me.

That is going to be a pretty bike. Yes - please get what Seat angle your fitter used and whether or not there was any setback on the post. It will help to calculate the actual distance between your where your hands touch the handlebar and your seat.

Did he use a 90mm stem as well?

PM me and I'll give you my email address where you can send the BikeCad to.

[Hensem]

Originally Posted by morrisond

PM me and I'll give you my email address where you can send the BikeCad to.

Done

[mhespenheide]

Personally, I feel like I can tell a difference between a 68mm and 74mm bottom bracket drop. It's subtle, but I prefer the 74mm drop.

[morrisond]

Originally Posted by mhespenheide

Personally, I feel like I can tell a difference between a 68mm and 74mm bottom bracket drop. It's subtle, but I prefer the 74mm drop.

Me too - or even deeper - Rockets on the Descent - BAUM goes 78-80mm on a lot of bikes.

[ridethecliche]

Holy heck that frame is cool AF!

[Buzz Killington]

about the BB drop, my current bike is 80mm, and it's awesome. With your intended use, I don't see why you'd want to be around 68mm drop. 75-80mm for sure. I'd rather be "in" the bike than "on" the bike.

[bahyow]

Concur with Buzz on BB drop. Especially if you are thinking of running larger width (bigger diameter) tires and don't need to pedal through the turns criterium style. IMO, with bikes going to larger tires...some of the BB drop rules of the past should really be revisited...but change takes time.

My current ride is a 80mm drop Serotta Ottrott, which unfortunately is limited to 25c tires. One drawback I've found is you can strike the crankarm (175mm) on parking lot speedbumps if one is in down in the 6 o'clock position, don't ask how I know this.

[.RJ]

Originally Posted by Hensem

I'll add a photo of what the frame looks like. Waltly sent this to me.

Whoa, that looks neat - is Waltly offering this now? What's the frameset cost?

[nmrt]

Apart from the looks, have you given any consideration of how to want the bike to ride? That massive HT and DT can deter from the ride quality that Ti frames are generally known for.

[deluz]

I also designed my own geometry but used RattleCad.
I am about your height but the opposite with short legs, 3” shorter.
Using more BB drop like 75mm will increase the stack so a shorter head tube can be used. since you need a short reach I would go 74 STA or even 74.5.
I think 415 for the chain stays is fine unless it interferes with your desired tire size. For 35mm tires you might need to go longer but You should be able to figure that out in BikeCad or better yet ask the builder.