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  #16  
Old 02-15-2021, 04:14 PM
Clean39T Clean39T is offline
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Quote:
Originally Posted by Bici-Sonora View Post

Current frontrunner Geo.:

61cm ST (c to t)
72.5 deg. parallel HT & ST
590mm TT
3.5 degree TT Slope
197mm HT
45mm Fork Rake
435mm Chainstays
80mm BB drop

My concerns about the geo. above. Is the BB drop too much, and should I shorten the chainstays a bit?

Part of the geo. decision also centers around parts. The more modern the build, the more I'm likely to favor a more severe TT slope.

I have three build options on hand:
  • Black Chorus 12 with Black Deda and Whiskey cockpit seatpost. Black wheel choices include DT PR Dicut Onix 1400, DT 240 and Belgium Plus, or Zondas
  • Silver Centaur 11 Group with mix of Ritchey, Erikson cockpit stuff, Ritchey Classic wheelset
  • Campagnolo DT 10 Chorus Record Group. This would be RH crankset, with repurposed Record barends as DT shifters, Chorus RD. Ritchey Classic wheelset or DT 240 and Belgium Plus, or Zondas
My votes:

Go slightly OS on the tubing so you can still feel confident on it with two bottles and a frame pack.

Steal the English style of putting braze-ons for a under-TT custom bag - so much more aero and stable than a burrito bag hanging off the front or something dangling off the saddle.

Chorus 12 is perfect for this kind of bike.

80mm BB drop is perfect with the fatter tires as compared to running 80mm w 23c.

435 chainstays are great for our height.

Slight TT slope as needed to allow a 280-300mm post and get your bars in the right spot. I'm guessing 3 deg max, hopefully less, though a bit of extra standover on a bike that could see some underbiking allroad stuff might not be bad. Just don't go over 5-deg please..

Everything else looks wonderful and very much in line with something I'd love to have myself!
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  #17  
Old 02-15-2021, 04:14 PM
Bici-Sonora Bici-Sonora is offline
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Quote:
Originally Posted by bicycletricycle View Post
also, when I think of what I now think of as the best balance of speed and comfort in a road tire I think my chapman with 700x35 RH extralights is superior to the tournesols 700x30/32 tire options. But for various reasons I think bikes with 57mm reach calipers (roughly limted to 33's?) are more compelling.

The 35's just don't feel slower but they are super comfy. I think the big trouble with going up to 35's is brakes. Long reach calipers don't work (i think?) and then you have to start debating cantis vs centerpulls vs discs. A debate which has no correct answer.

Also, which 57mm reach brakes? The nice shimano ones with alloy barrel adjusters (BR-R600?) are getting rare and expensive, the VO's work well but are a little CNC looking, I am a snob and can't be seen on Tektro's.
I love your Champman. The lines just flow on that bike. That makes me think I should consider more top tube slope than 3.5 degrees. Do you mind sharing your Chapman geo or at least the TT slope? It looks to have a steeper HTA than the STA.

I'm for sure designing this frame with RH 35mm tires in mind so it is good to hear you like them so much. I've gradually been converting most of my bikes to tubeless. From what I see online (mostly from Mike Varley's blog) 35s are possible without fenders (even perhaps 38s) on 47-57 reach brakes if the builder maximizes clearances. I have a set of VO Grand Crus in Silver and like the way they work with Campy levers. Paul Racer Ms have even more clearance. At that point though, maybe I just do mini-motos. Yours sure look great.
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  #18  
Old 02-15-2021, 05:02 PM
Bici-Sonora Bici-Sonora is offline
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Nice to get some confirmation from a rider of similar stature.
Quote:
Originally Posted by Clean39T View Post
My votes:

Go slightly OS on the tubing so you can still feel confident on it with two bottles and a frame pack.My gut tells me OS too. My MAP is OS, your Kirk is OS, and I remember Mike Kone at Boulder saying anything bigger than 60cm should probably be OS. A compromise would be to do regular OS (as opposed to double OS--so, 31.8 DT, 28.6 TT and ST

Steal the English style of putting braze-ons for a under-TT custom bag - so much more aero and stable than a burrito bag hanging off the front or something dangling off the saddle.That is a good idea that I hadn't considered. I'll take a look at Rob's site

Chorus 12 is perfect for this kind of bike.I agree, the sub-compact should be just about perfect--I'm fighting an urge to put DT shifters on it for the sake of front end cable cleanliness, but I've really liked the Campy brifters

80mm BB drop is perfect with the fatter tires as compared to running 80mm w 23c.

435 chainstays are great for our height.Good to get confirmation on that. I think it is a good middle ground. Andy pulled out some super thin Reynolds seat stays that I think will compliment the back end well.

Slight TT slope as needed to allow a 280-300mm post and get your bars in the right spot. I'm guessing 3 deg max, hopefully less, though a bit of extra standover on a bike that could see some underbiking allroad stuff might not be bad. Just don't go over 5-deg please..I agree--I'll keep it at 3 degrees

Everything else looks wonderful and very much in line with something I'd love to have myself!
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  #19  
Old 02-15-2021, 05:18 PM
Bici-Sonora Bici-Sonora is offline
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More questions: are your Chapman and Tournesol 1 1/8" steerers? And, I know you were involved with the design of that front bag--any update on production and availability? It looks better than I anticipated.
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  #20  
Old 02-15-2021, 05:57 PM
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bicycletricycle bicycletricycle is offline
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both are 1.125", they are both double oversize tubing as well. I like that size tubing for my weight but I also like the smoother ride of oversize tubing with 1" head tube. I think a nice 1" steel fork can't be beat.

First bags will be shipping in the next couple weeks. I think it will be a month or more before we have some for new sales, we need to ship all the pre sales and kickstarter first. We got nice fitting shims machined for 26 and i think 25.4mm as well

Quote:
Originally Posted by Bici-Sonora View Post
More questions: are your Chapman and Tournesol 1 1/8" steerers? And, I know you were involved with the design of that front bag--any update on production and availability? It looks better than I anticipated.
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  #21  
Old 02-15-2021, 05:59 PM
Clean39T Clean39T is offline
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Quote:
Originally Posted by Bici-Sonora View Post
Nice to get some confirmation from a rider of similar stature.
I support the regular OS w 1" steerer... Zero reason to go 1.125" if you weigh under 200lb and aren't loading it up, atmo.
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  #22  
Old 02-15-2021, 06:03 PM
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bicycletricycle bicycletricycle is offline
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chapman #4 by bicycletricycle666, on Flickr


Quote:
Originally Posted by Bici-Sonora View Post
I love your Champman. The lines just flow on that bike. That makes me think I should consider more top tube slope than 3.5 degrees. Do you mind sharing your Chapman geo or at least the TT slope? It looks to have a steeper HTA than the STA.

I'm for sure designing this frame with RH 35mm tires in mind so it is good to hear you like them so much. I've gradually been converting most of my bikes to tubeless. From what I see online (mostly from Mike Varley's blog) 35s are possible without fenders (even perhaps 38s) on 47-57 reach brakes if the builder maximizes clearances. I have a set of VO Grand Crus in Silver and like the way they work with Campy levers. Paul Racer Ms have even more clearance. At that point though, maybe I just do mini-motos. Yours sure look great.
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  #23  
Old 02-15-2021, 10:01 PM
hollowgram5 hollowgram5 is offline
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If you were closer to San Diego, I'd let you borrow the Cielo Sportif for a bit as another point of reference...
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  #24  
Old 02-15-2021, 10:16 PM
Bici-Sonora Bici-Sonora is offline
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Quote:
Originally Posted by hollowgram5 View Post
If you were closer to San Diego, I'd let you borrow the Cielo Sportif for a bit as another point of reference...

I’d take you up on that if I was in dog town. I always liked those Sportifs. IIRC, the bigger sizes have a 74 degree HTA and 72.5 STA. What size is yours?


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  #25  
Old 02-15-2021, 10:18 PM
hollowgram5 hollowgram5 is offline
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Quote:
Originally Posted by Bici-Sonora View Post
I’d take you up on that if I was in dog town. I always liked those Sportifs. IIRC, the bigger sizes have a 74 degree HTA and 72.5 STA. What size is yours?


Sent from my iPhone using Tapatalk
It's a 60. So 595 tt and 74/72.5 on the angles.

I pulled the geo a while back from the waybackmachine but it seems to be gone from that page now. (Seems to be a Chrome issue, came up just fine in firefox...)

Last edited by hollowgram5; 02-15-2021 at 10:25 PM.
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  #26  
Old 02-16-2021, 12:24 AM
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lavi lavi is offline
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This is an awesome thread.

I’m currently in the process of sorting a Ti SB. Dan is helping me keep it between the lines. Mine will be optimized for 35s. I’ve been pretty focused on discs (Klampers) for some reason. Knowing I could have some mrbs or something makes me pause for a moment. I’ll likely continue with discs in case I ever get into some gnarly gravel and want to run 650/48.

I’m dangerously close to overthinking the geo and second-guessing as I get closer to “done”.



It’s interesting that I’ll pick up a frame used or off the peg (looking at you Aethos) without much real fretting on geo. Order something custom...and I’m literally losing sleep thinking about it. My wife thinks I’ve lost it when she comes into a room and sees my staring blankly at the wall. She knows I’m (poorly) practicing geometry in my head. Lol

Continue the discussion please.
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  #27  
Old 02-16-2021, 09:56 AM
8aaron8 8aaron8 is offline
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This is a fun thread, nice to read the thought process of prospective custom frame owners. I just want to add that with the TRP 957 mid reach brakes you can indeed get a 38mm tire under it if the slots are set up at their max height. Here's a photo of the brakes with Steilacooms underneath.
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  #28  
Old 02-16-2021, 10:00 AM
Clean39T Clean39T is offline
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Quote:
Originally Posted by 8aaron8 View Post
This is a fun thread, nice to read the thought process of prospective custom frame owners. I just want to add that with the TRP 957 mid reach brakes you can indeed get a 38mm tire under it if the slots are set up at their max height. Here's a photo of the brakes with Steilacooms underneath.
Have you put a caliper on those? Curious what the actual is on whatever rims you are running..
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  #29  
Old 02-16-2021, 10:11 AM
8aaron8 8aaron8 is offline
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Quote:
Originally Posted by Clean39T View Post
Have you put a caliper on those? Curious what the actual is on whatever rims you are running..
I did, they measured spot on 38mm on 18mm internal rims, and with 21mm internal rims I got around 39ishmm.
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  #30  
Old 02-16-2021, 11:00 AM
Bici-Sonora Bici-Sonora is offline
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Quote:
Originally Posted by bicycletricycle View Post
As far as chainstay length goes. I like to have the same amount of gap between the front tire / downtube and rear wheel / seat tube. Just looks nice.
^This

I had not thought about it that way, but now I see that some of my favorite bikes have roughly the same gap front and rear. It's another thing to consider.
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