Going to have a custom frame built and hoping to get some help with decision making.

So, I found a crack in the chainstay of my beloved Spooky Gas Mask. My friend, a local builder, is gonna fill it for me to keep it on the road, but I decided that I think I'll give steel another try and get a new frame built.

Seems I've been breaking an average of one frame a year. The Spooky is actually a replacement for a broken carbon Ridley X-Trail. I ride a lot and at 180 pounds, I'm on the heavier side for competitive cyclists, so a little extra weight on the bike shouldn't make a significant impact on overall mass.

But, I also use the Spooky as a road bike at least as much as a gravel bike, as the roads that I like to ride tend to be more choppy than most gravel roads.

I also do mixed terrain and gravel racing, such as the Grasshopper Adventure Series under normal non-COVID circumstances and many of the guys that I ride with have pure road bikes as well that I have to keep up with on pure road days.

Finally, I have a super light Santa Cruz Highball that I've been riding lately when the choice is between underbiking with a gravel bike or overbiking with a mountain bike, so this bike can be more on the road end of the continuum than the MTB end.

My one complaint about the Spooky is that I wish it had fender mounts and less toe overlap when I use fenders. I tried some of those SKS Speedrocker fenders and I had to get rid of them, cuz the toe overlap was so severe. Without the fenders, there was already quite a bit of toe overlap with tires in the 40-42 range, but it was manageable enough and didn't cause any real problems.

So, I'm wondering if anyone has any thoughts on geo numbers that I should consider? I'll paste the geo of my Spooky below for reference. I'm also planning on going with a carbon fork and I want one that accommodates  fenders at the very least, but also considering something that allows for racks, such as the Enve Adventure fork or the Spork. Seems that the weight penalty isn't significant, but seeing as how I'm not sure if/when I'll do any bikepacking, a fork that performs well for sportier riding takes precedence. Any thoughts?

Here are the numbers on my Spooky. It fits me well, but I don't have much seatpost showing and I have an 80-90mm stem (forgot and I don't have the bike with me) so could go a little smaller or keep it as is.

Reach	390
Stack	605
Top Tube (effective)	575
Seat Tube C-C	525
Head Angle	72.5
Seat Angle	72.5
Head Tube	170
Chainstay	425
Wheelbase	1027
Front Centre	612
BB Drop	70
Trail	62

The steepish head angle and slack set angle make the front end effectively pretty short.
What setback is your seatpost and how far is your saddle pushed back?
A steeper seat angle might help, same for a slacker head angle.
Problem is that if you are already using an 80-90mm stem there is not a lot that you can do with front end length.
Unless- You are riding a handlebar with fairly long reach and you move to a shorter reach bar.
Can you provide more info on your current setup and position?

boots2000 wrote:The steepish head angle and slack set angle make the front end effectively pretty short.
What setback is your seatpost and how far is your saddle pushed back?
A steeper seat angle might help, same for a slacker head angle.
Problem is that if you are already using an 80-90mm stem there is not a lot that you can do with front end length.
Unless- You are riding a handlebar with fairly long reach and you move to a shorter reach bar.
Can you provide more info on your current setup and position?

Thanks for the reply! Unfortunately, I don't have my bike right now, as it's getting repaired, but the seatpost has 25mm of setback. I can confirm that the stem is 90mm and that my bars have  a short 75mm of reach. I do have the saddle pretty far forward and I like my cleats to be slammed all the way back, which of course adds to toe overlap.

Also, having given it more thought, I don't care about whatever fork I end up getting having anything more than fender mounts and the ability to accommodate 38mm tires with fenders and maybe 43mm without.

If you post your complete bike position I could mock it up on Bikecad. Playing with front end variables can get tough, especially if reach needs to be short.

I designed a custom bike for myself (I fit and design for a living) with the goal to eliminate toe clip overlap. 
I previously owned some really good gravel bikes (Scott and Open), but both had issues with lots of overlap.
My current bike has a toptube ~2cm longer than the Open and that is offset with a 2cm shorter stem (100mm)- But unlike yourself, I was riding a 120mm stem of the Open and the Scott.

boots2000 wrote:If you post your complete bike position I could mock it up on Bikecad. Playing with front end variables can get tough, especially if reach needs to be short.

I designed a custom bike for myself (I fit and design for a living) with the goal to eliminate toe clip overlap. 
I previously owned some really good gravel bikes (Scott and Open), but both had issues with lots of overlap.
My current bike has a toptube ~2cm longer than the Open and that is offset with a 2cm shorter stem (100mm)- But unlike yourself, I was riding a 120mm stem of the Open and the Scott.

Thanks! I really appreciate the offer. I'll measure everything when I get my bike back from repair. 

72.5 head tube?!  I just had a custom ti gravel frame built for me.  Only ridden it a few times thus far but I like how the geo turned out.  I've got long (44cm) chain stays, a slack head tube of 70.5, and lots of trail.  I figured that on gravel the slack and stable front end would allow for comfortable "no-handed" or one-handed riding while eating and drinking and getting bounced around a bit.  The BB drop is also 80mm.  These things make the bike more stable and comfortable, and me more confident while high speed descending on squirrel-y surfaces.  

nellborg wrote:72.5 head tube?!  I just had a custom ti gravel frame built for me.  Only ridden it a few times thus far but I like how the geo turned out.  I've got long (44cm) chain stays, a slack head tube of 70.5, and lots of trail.  I figured that on gravel the slack and stable front end would allow for comfortable "no-handed" or one-handed riding while eating and drinking and getting bounced around a bit.  The BB drop is also 80mm.  These things make the bike more stable and comfortable, and me more confident while high speed descending on squirrel-y surfaces.  

Interesting, yeah I was just talking my friend who is having a Ti frame built right now. He and I have pretty similar priorities in a bike of this sort, as we ride a lot of the same routes and race in the same events. He's been nerding out about all of this stuff for months, trying tons of people's bikes to figure out exactly what he wanted and it sounds like he's gonna end up with something with very similar geometry to my Spooky. I'm gonna try out some different bikes as well to see what I think. I tend to like quick handling bikes though.

Slack sta. 25mm setback. Saddle forward. Cleats slammed: Decent femur length? 

You could always go a bit shorter seat tube length to get more exposed post i.e. make use of a decent flexier/compliant option for gravel/racing. 27.2mm the more suitable diameter for that. 

I think wanting to remove that toe overlap when running fenders and tyres that size, you end up pushing out the ftc quite a bit. Even more so if you still want that steeper hta for racing/feel. Longer top tube/frame reach + shorter stem (+short-reach bar) design like you see in the latest Diverge for example. BMC URS a more extreme example. 

What I don't know is how different these frame designs feel at speed, compared to the more common geo: whether you would be ok with that.  

I'd be looking at a chainstay no longer than the Spooky. Kinked seat tube: you'd be able to go 420mm with a 42mm or so. A bit more bb drop would be nice. Decent tubeset for higher tempo. 

Reading your post made me think a little of this:-  https://forums.thepaceline.net/showthread.php?t=245238 but with longer ftc etc.

owly wrote:Slack sta. 25mm setback. Saddle forward. Cleats slammed: Decent femur length? 

You could always go a bit shorter seat tube length to get more exposed post i.e. make use of a decent flexier/compliant option for gravel/racing. 27.2mm the more suitable diameter for that. 

I think wanting to remove that toe overlap when running fenders and tyres that size, you end up pushing out the ftc quite a bit. Even more so if you still want that steeper hta for racing/feel. Longer top tube/frame reach + shorter stem (+short-reach bar) design like you see in the latest Diverge for example. BMC URS a more extreme example. 

What I don't know is how different these frame designs feel at speed, compared to the more common geo: whether you would be ok with that.  

I'd be looking at a chainstay no longer than the Spooky. Kinked seat tube: you'd be able to go 420mm with a 42mm or so. A bit more bb drop would be nice. Decent tubeset for higher tempo. 

Reading your post made me think a little of this:-  https://forums.thepaceline.net/showthread.php?t=245238 but with longer ftc etc.

Yeah, I'm probably going to go for a shorter seattube, also for the event that someday I decide I want a dropper. It's not something that I've ever felt that I wanted/needed, but I have them on all of my MTB's and a friend of mine who was a late adopter for them even on MTB's says that he likes it even more on his gravel bike than he does on his MTB.

As far as having a saddle with setback, but then having the saddle pushed forward, I had the seatpost already, decided that that's where I wanted my saddle, and then never got a straight post, because I read that saddles with setback are more flexible/comfortable and it's been fine over the years. Also, it doesn't look weird cuz I use one of those small ILE saddlebags that pretty much obscures the clamp.

The frame that you linked does look similar to what I'm looking for. I feel that my Spooky descends well. The bike that it replaced was the Ridley X-Trail and my decent times seem a little faster on the Spooky, while my climb times were faster on the Ridley. Here is how the numbers compare (Spooky on the left, Ridley on the right):

Reach	390	392
Stack	605	610
Top Tube (effective)	575	585
Top Tube (actual)		567
Seat Tube C-T		570
Seat Tube C-C	525	530
Head Angle	72.5	71.5
Seat Angle	72.5	72.5
Head Tube	170	195
Chainstay	425	422
Wheelbase	1027	1038
Front Centre	612
Standover		861
BB Drop	70	70

I'm meeting with my frame builder later today, so hopefully I'll have some more ideas then. Currently, this is the fork that I'm leaning towards having it built around:  https://6composites.com/products/gravel-fork

boots2000 wrote:If you post your complete bike position I could mock it up on Bikecad. Playing with front end variables can get tough, especially if reach needs to be short.

I designed a custom bike for myself (I fit and design for a living) with the goal to eliminate toe clip overlap. 
I previously owned some really good gravel bikes (Scott and Open), but both had issues with lots of overlap.
My current bike has a toptube ~2cm longer than the Open and that is offset with a 2cm shorter stem (100mm)- But unlike yourself, I was riding a 120mm stem of the Open and the Scott.

I got my Spooky back. Which measurements would you need? Seatpost height and setback? Not sure how exactly I measure saddle position other than by where it is on the rails or where the nose is relative to the BB or steertube. What do you suggest? Thanks again!

Do you have a plumb or can you make one? That is the best way.
Or you can position your bike with the back wheel touching a wall. Measure from wall to tip of saddle. Measure from wall to center of bb. Calculate the difference.

boots2000 wrote:Do you have a plumb or can you make one? That is the best way.
Or you can position your bike with the back wheel touching a wall. Measure from wall to tip of saddle. Measure from wall to center of bb. Calculate the difference.

I dont' have a plum, nor any string for that matter, but it loks like my saddle is about 7cm behind the center of the BB and saddle height looks to be around 75cm from the center of the BB.

Also need-
Reach from tip of saddle to center of stem
Difference between saddle and bar height

AmericanTemplar wrote:

I dont' have a plum, nor any string for that matter, but it loks like my saddle is about 7cm behind the center of the BB and saddle height looks to be around 75cm from the center of the BB.

Nice Instagram photos.

I used to live in Larkspur, but that was way before mountain biking was invented.    Good windsurfing though.  ;-)

boots2000 wrote:Also need-
Reach from tip of saddle to center of stem
Difference between saddle and bar height

I'm guessing you mean tip of saddle to the center of the clamp area on the stem? That's about 52cm and there's around 5cm do drop from the top of saddle to the top of my bars.

chas wrote:

Nice Instagram photos.

I used to live in Larkspur, but that was way before mountain biking was invented.    Good windsurfing though.  ;-)

Thanks! Yeah, I ride in Marin quite a bit. Shame that you were there before MTBing was an option. I always look back at the various places I've lived and think of how much more awesome those places would have been had I been into cycling. But, sounds like you took advantage of another good activity in the area.

Ok- I mocked this up to the best possible with the info provided. 
I think that the Spooky may actually have shorter front center than listed.
I also think that this bike is too big for you (toptube length and stem combo).

Question- Do you need your bars as high as they are?

2nd try- I forgot to change bb height to 70mm

In a bike design for you, you are always going to be struggling with toptube length, vs. front center.
I suggest a design with about a 71 degree head angle and a longer rake fork like a Seven Matador. You would benefit from the 55mm rake.
You also might consider the shortest reach bars that you can find in order to be able to make use of a slightly longer toptube. I like Salsa bars for this- They have some that are 65mm reach.

Here is a custom design in the noodling stage-

boots2000 wrote:In a bike design for you, you are always going to be struggling with toptube length, vs. front center.
I suggest a design with about a 71 degree head angle and a longer rake fork like a Seven Matador. You would benefit from the 55mm rake.
You also might consider the shortest reach bars that you can find in order to be able to make use of a slightly longer toptube. I like Salsa bars for this- They have some that are 65mm reach.

Here is a custom design in the noodling stage-

Thanks so much! The second pdf doesn't show up, unfortunately. 

To answer your question from before, I don't think that I'd want my bars any lower. I would say that I'm already in a fairly aggressive position.

I met with my frame builder yesterday for some initial talks about what I want. We didn't talk a lot about actual numbers, other than that he though 425mm chainstays would work for the tire clearance that I wanted. I had been eyeing this fork:  https://6composites.com/products/gravel-fork. I asked him about the offset and axle to crown and he thought that that would work, but he doesn't know the numbers on my current bike yet and how it's setup. Was gonna bring it by to him at some point to take measurements. I'll share your drawing with him as well.