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-   -   2021 Andy Gilmour Medium Reach Brake (https://forums.thepaceline.net/showthread.php?t=265120)

Bici-Sonora 02-16-2021 02:38 PM

Quote:

Originally Posted by Clean39T (Post 2882753)
The Deda is -8 deg, so if you plan to use that, you could bring the TT to a more reasonable -4 deg and still be a in a good spot. I say more reasonable because with longer headtubes, sloping TTs can start to look pretty ungainly. You should of course choose based on function - I'm just a sucker for form, as is well documented.

You bring up a good point about longer headtubes looking too tall on some big sloping frames. I'm already at a~205mm headtube now--I could reduce that to say 190mm--since I'm using a steel fork, it's no problem to put the stem higher if I need more stack. Of course, I wouldn't be able to put my "certified slammed" decal on the TT. That would be pretty ironic on a bike with a ~200mm headtube and ~630mm stack:)

Bici-Sonora 02-16-2021 03:12 PM

Responses in red below:

Quote:

Originally Posted by bicycletricycle (Post 2882761)
This whole project is already going downhill.
painted aluminum stems? I plead no contest
carbon forks?I was being a provocateur and it worked:)
1.125" steerers? Hey, you are the one that showed up to the game with these 1.125 steerers--which really don't look bad at all

Oversize bars always ruin (edit: not really ruin) these bikes, not because of the bars but because they ruin the proportions of the rest of the bike. Bigger bars = bigger stem = bigger steerer tube = funny looking little fork blades in comparison to the huge head tube. Okay, but can I have bars that won't slip over rough terrain? I say this mostly in jest, as I have 25.4 and 26.0 bar bikes that I ride off-road a bunch. Still, I kinda got used to that 31.8 life with Dan's Kirk. Not gonna lie, it felt good and I like the Whisky 6 degree flare bars for the road

My Tournesol and on my first Chapman both have 1.125" steerer tubes and regular fork blades and I think the fork blades look out of proportion with the headtube so on my blue chapman I used these really big Sachs fork blades to help smooth the transition some. I'm assuming this is your RS crown: what is the width (50mm?) and does it only come in 1.125? Why doesn't RS have the tech details on his site? Am I supposed to just intuit it?

Here is the link: https://www.richardsachs.com/product...-0-fork-crown/

I would just run rene herse parallel bars (On the my tournesol right now, 25.4mm clamp which is annoying, nitto has some options) and keep the front all smaller dimensioned. Have these on my MAP, love them, but I find the shape isn't as good for brifters. I need to weigh function as part of the equation too

I think a lot of this is just annoying nit picking, oh well.The nit picking is what keeps me coming back:)


coffeecherrypie 02-16-2021 03:12 PM

Quote:

Originally Posted by bicycletricycle (Post 2882761)
This whole project is already going downhill.
painted aluminum stems?
carbon forks?
1.125" steerers?

Oversize bars always ruin (edit: not really ruin) these bikes, not because of the bars but because they ruin the proportions of the rest of the bike. Bigger bars = bigger stem = bigger steerer tube = funny looking little fork blades in comparison to the huge head tube.

My Tournesol and on my first Chapman both have 1.125" steerer tubes and regular fork blades and I think the fork blades look out of proportion with the headtube so on my blue chapman I used these really big Sachs fork blades to help smooth the transition some. They don't ride as nice but they do feel a little more "precise" I guess. I do like a lot of the modern bar shapes but I also love RH parallel bars and nitto noddles. The long flat ramps behind the hoods are so comfortable.

I would just run rene herse parallel bars (On the my tournesol right now, 25.4mm clamp which is annoying, nitto has some options) and keep the front all smaller dimensioned.

I think a lot of this is just annoying nit picking, oh well.

OOS lugged chapman with normal blades-
https://live.staticflickr.com/1960/4...c2a1c4ea_c.jpgIMG_6516 by bicycletricycle666, on Flickr

OOS Tournesol with normal legs-
https://live.staticflickr.com/65535/...801e2823_c.jpgUntitled by bicycletricycle666, on Flickr

OOS tubes with oversize RS fork kit-
https://live.staticflickr.com/65535/...a707cced_c.jpgUntitled by bicycletricycle666, on Flickr

cool ellis, look OOS with normal legs-
https://live.staticflickr.com/65535/...54682c64_c.jpgellis by bicycletricycle666, on Flickr

english, small tubes, NACA profile fork legs I think -
https://live.staticflickr.com/65535/...a21eb4aa_c.jpgenglish by bicycletricycle666, on Flickr

Wow that pink bike looks amazing. Is that some kind of custom stem?

Bici-Sonora 02-16-2021 03:22 PM

Fun to compare. You comment about using the Ritchey's 73/73 angles with the other tweaks sounds like what Dave Wages did on his DRB. Maybe I'll mock a 73/73 drawing up to see what that would look like. When I was talking to Andy Gilmour, he mentioned that he liked parallel angles when he saw my drawing. Andy told me that Leonard Zinn wrote that on big frames, bikes with parallel angles have less of a tendency to shimmy. I had not heard that before.
Quote:

Originally Posted by v531xc (Post 2882679)
Really loving this thread.

My data points to share:

The geo you outlined is really close to three bikes I have and very close to what I'd ideally make as a mash up of them all.

My Chapman is a little shorter in TT (585), the stack is a little taller, and the bb is a little higher (65mm drop) because of being designed around 650b, I wanted it to be more comfy/upright, and I underbike it a lot. 73.2/73.5 STA/HTA. 435 chainstays and it fits 44mm tires in 700c if I wanted without fenders.

With an 80mm bb drop, it might be more like 38mm or 40mm max.

My Bilenky is also similar about 59cm ST c-t, 575 eTT c-c. 80mm drop, 72/73.5 STA/HTA. 422mm chainstays and perfectly fits 33mm tires without fenders under midreach brakes.

My Bruce Gordon is 61 ST c-t, 59 TT, 70mm drop, 73/72 STA/HTA, 420mm stays without a chainstay bridge and fits a 43mm tire front and rear (700c).

I have a Ritchey Breakaway Road XL and if I were to get the bike you're getting, I'd emulate that and mash it up with the above three bikes to get the 80mm drop, ~430mm stays, ~600mm stack, ~410mm reach and 73/73 parallel ST/HT. Depending on the brakes and fork design, I assume it would fit 38mm tires.

On TT slope, My Chapman and Bilenky are both 6 degrees, iirc. They look good to me :-) Both are filet brazed.

On tubing, I agree on going OS with a bike like this. My Bilenky is OS but has a 6-4-6 top tube. I really like the flex, but its very different from the other bikes which are stiffer. the Chapman being OOS and OS and the BG being a mix of stuff.

A 1" fork would be great, as you'll get all the flex characteristics you might want. But if you want swappability with something like a Whisky mid reach fork, then you'll need to find some flexy blades to go with the 1.125" steerer. I've really liked the stuff that Richard Sachs has for the standard fork blades. And I hear good things about what Rene Herse has to offer, too.


mhespenheide 02-16-2021 03:28 PM

Quote:

Originally Posted by 8aaron8 (Post 2882544)
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.https://live.staticflickr.com/65535/...dd0ce208_b.jpg

That's crazy. I would have assumed you would need to run at least center-pulls if not canti's for those.

bicycletricycle 02-16-2021 03:28 PM

Quote:

Originally Posted by Bici-Sonora (Post 2882785)
Responses in red below:

this is the link to the fork kit, no dimensions, i can measure some for you later. blades come pre bent on these.

I know all the bikes I showed are 1.125". The reason they are all that way is for a variety of reasons but it is not because I think it is the best solution for this type of bike. It is, however, a totally great solution and I love those bikes.

The next bike I get built like this will be regular oversize and 1" though. More like my 650b rando, although it cheats a little with a tapered downtube that flares up to 1.375 at the bb. That frame has a nice flex.

I do like oversize bars, I wish they weren't all so shallow behind the hoods but I like some of the drop shapes and i especially like when they extend the 31.8mm bulge across the top. I like cloth tape and that larger size wrapped in cloth tape is perfect.

bicycletricycle 02-16-2021 03:30 PM

Quote:

Originally Posted by coffeecherrypie (Post 2882786)
Wow that pink bike looks amazing. Is that some kind of custom stem?

it is complicated, the steerer tube is attached to the stem.
https://www.englishcycles.com/custom...e-skinny-bike/

mhespenheide 02-16-2021 03:32 PM

Quote:

Originally Posted by coffeecherrypie (Post 2882786)
Wow that pink bike looks amazing. Is that some kind of custom stem?

Yes -- the stem is mounted directly to the steerer tube, and then the fork legs bolt on to that from the bottom. Deep custom; you're not changing the stem without welding up a new steerer tube as well. It's Rob English's person road bike: https://cyclingtips.com/2020/08/bike...ish-road-bike/.

xnetter 02-16-2021 03:48 PM

Quote:

Originally Posted by Bici-Sonora (Post 2882750)
...and the 3 degree top tube slope version:
https://uploads.tapatalk-cdn.com/202...2d67e47b95.jpg


Sent from my iPhone using Tapatalk

Personally I vote for the 3* slope. Nice balance of classic and modern. I had a custom XL rando bike made a couple years ago and went with 2* upslope and a modest HT extension. I'm happy with the way it looks and fits. That bike has single OS 7-4-7 TT and 8-5-8 DT and the Toei Special fork blades. Rides real nice.

I also went with 1" threadless and wish I hadn't. Sort of a pain when 1.125" would have been easier in terms of choosing a stem and working with an integrated decaleur.

KJ

Bici-Sonora 02-16-2021 03:51 PM

Quote:

Originally Posted by v531xc (Post 2882679)
The geo you outlined is really close to three bikes I have and very close to what I'd ideally make as a mash up of them all.

I have a Ritchey Breakaway Road XL and if I were to get the bike you're getting, I'd emulate that and mash it up with the above three bikes to get the 80mm drop, ~430mm stays, ~600mm stack, ~410mm reach and 73/73 parallel ST/HT. Depending on the brakes and fork design, I assume it would fit 38mm tires.

,.

Here is your 73/73: https://uploads.tapatalk-cdn.com/202...c1755f46c0.jpg


Sent from my iPhone using Tapatalk

Clean39T 02-16-2021 03:57 PM

Quote:

Originally Posted by bicycletricycle (Post 2882761)

cool ellis, look OOS with normal legs-
https://live.staticflickr.com/65535/...54682c64_c.jpgellis by bicycletricycle666, on Flickr

Now that I have my Kirk back, that Ellis has moved up into my number one "I wish I could get you back.." bike - though, I also wish it had a bit different proportions - less sloping TT mostly - it rode so so nicely though. I could use my queue spot with Dave to get the same bike built but I think I'm going to go more fast-rando with that.. though probably same paint and relatively same fork.

Bici-Sonora 02-16-2021 04:21 PM

Quote:

Originally Posted by Clean39T (Post 2882815)
Now that I have my Kirk back, that Ellis has moved up into my number one "I wish I could get you back.." bike - though, I also wish it had a bit different proportions - less sloping TT mostly - it rode so so nicely though.

Maybe the sloping TT was part of the reason it rode so well? :) Do you have the geo. on that one? Might be good for this thread.

v531xc 02-16-2021 04:24 PM

Quote:

Originally Posted by Bici-Sonora (Post 2882792)
Fun to compare. You comment about using the Ritchey's 73/73 angles with the other tweaks sounds like what Dave Wages did on his DRB. Maybe I'll mock a 73/73 drawing up to see what that would look like. When I was talking to Andy Gilmour, he mentioned that he liked parallel angles when he saw my drawing. Andy told me that Leonard Zinn wrote that on big frames, bikes with parallel angles have less of a tendency to shimmy. I had not heard that before.

Hmm, I couldn't find an article by Lennard that outlined that specific issue, but did find this one that discusses shimmy for tall bikes and seems to suggest that the limited maximum front center by the UCI discourages proper bike design for taller bikes thus creating poor fitting and poor handling characteristics when that front-center dictates angles: https://www.velonews.com/gear/techni...handle-poorly/

and this one that talks about the same limitation to design with regard to head tube angle: https://www.velonews.com/gear/techni...ires-and-more/

I'm not sure what parallel angles would do to add to shimmy, per se, perhaps something about harmonic resonance, but I do think the proper diameter tubing can help resolve that, and OS or OOS would take care of any potential shimmy, is my guess

Clean39T 02-16-2021 04:41 PM

Quote:

Originally Posted by Bici-Sonora (Post 2882823)
Maybe the sloping TT was part of the reason it rode so well? :) Do you have the geo. on that one? Might be good for this thread.

https://uploads.tapatalk-cdn.com/201...32c89574e8.jpg

Detailed thread: https://forums.thepaceline.net/showthread.php?t=221638

Clean39T 02-16-2021 04:43 PM

Quote:

Originally Posted by v531xc (Post 2882824)
Hmm, I couldn't find an article by Lennard that outlined that specific issue, but did find this one that discusses shimmy for tall bikes and seems to suggest that the limited maximum front center by the UCI discourages proper bike design for taller bikes thus creating poor fitting and poor handling characteristics when that front-center dictates angles: https://www.velonews.com/gear/techni...handle-poorly/

and this one that talks about the same limitation to design with regard to head tube angle: https://www.velonews.com/gear/techni...ires-and-more/

I'm not sure what parallel angles would do to add to shimmy, per se, perhaps something about harmonic resonance, but I do think the proper diameter tubing can help resolve that, and OS or OOS would take care of any potential shimmy, is my guess

Silca Josh had some interesting comments on shimmy also in one of the most recent AJA (ask Josh anything) podcasts.. I think long stems, narrow bars, and stuff hanging on the bars could all contribute significantly to speed-wobble, which is a bit different beast than shimmy, but in the same family.


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