Paul Barnard

As always, my head starts spinning when I try to come up with drive trains for builds. I want to build a drop bar bike with wide range. On the low end, I must have 19 inches or less. On the high end 95 inches or more (I might be able to go lower by a touch). I want mechanical disc brakes and do not want bar end shifters. Don't care if it's 10, 11 or 12 speed. I do want quality components. Would prefer to avoid derailleur hanger extenders.

A 40/28 Crankset and an 11-40 cassette gets me there. What shifters and derailleurs could I add? Who makes a quality 40/28 crankset that's currently available?

This is the frame I'd be building up. It's non-XD/Boost. The available drive trains should tell us something about the chainline. It seems chainline always ends up being the issue as I try to sort things out. I'd happily take a square taper crankset so that i can use BB width to get the ideal chainline.

https://lynskeyperformance.com/gr300...cable-routing/

DorkDisk

Something like a cinch crankset from Easton, with spider and single rings will get you there. Also curious about why sticking to cables? I'd only drop down to cables if I absolutely had to, like on a breakway frame.

Paul Barnard

I am not seeing how I get there with a Cinch. Can you lay out the specific parts that would do it for me?

I am running mechanical discs on two bikes. They do their job very well and are incredibly simple. I have never had an issue with them that rendered them unserviceable. I have had an issue where hydraulic brakes stuck in the closed position, necessitating a trip to the bike shop. I have never over braked with mechanical discs. I have on a hydraulic brake bike. My fault for not managing threshold braking well, but my mechs are linear enough that I doubt I would have had a get-off with them.

DorkDisk

The idea is to run the Easton (road) crank, either in crabon or Al with a RaceFace MTB 104/64 BCD spider. This will allow for the smaller chainrings you want to run.

Paul Barnard

Hmmmm. I like the way you are thinking. Would the MTB spider create a chainline issue with the chosen frame?

DorkDisk

I haven't compared the two spiders directly but any difference will be minute; chainline is more baked into the spindle widths. Easton cranks use a narrow chainline to begin with.

Another option, if you insist on square taper, is to use the White Industries crank. Due to its unique spider, it allows for a lot of chainring sizes.

Paul Barnard

You have given me some good stuff to think about. What derailleur/shifter set up will I use if I go with the White industries Crank with 40/28 chainrings and an 11-40 cassette?

DorkDisk

Personally, I'd go with GRX810 with a Dura Ace front derailleur, and 11-34 cassette, dropping the small ring size if need be. Dura Ace for the road chainline, and 11-34 to avoid Wolfteeth parts and other workarounds. I know that works for me; I don't know enough about your terrain, tire size, and cadence.

Yes, that means going hydraulic. The only reason I'd go cable discs on that new build would be if I already had a set of really, really nice STI levers.

squirtdad

this may help in looking at options https://www.bikecalc.com/gear_inches

Iride01 

I don't know that you are making a road bike with a wide range. You really are just making a road bike with a very low ratio or gear inches and a very limited upper range.

While you might have some unique circumstances, I can only imagine you ride uphill all the time or are riding off the paved road in 12 inch deep very loose gravel.

Not that I think you are being foolish for trying to do so, but just that you haven't described how this will benefit you, me or any other.

Paul Barnard

I love that site. That's how I know that 40/28 11-40 give me what I need! Now it's just a matter of identifying the compatible pieces. That's where I need the help of the members here.

Paul Barnard

Several factors find me wanting that kind of gearing. I live in the flatlands but do vacation in the mountains several times a year. The thin air and long and/or steep climbs challenge legs and lungs that aren't accustomed to that kind of climbing. My knees are also shot and complain if I push big gears up mountains. I also plan on an extended tour when I retire. The desired gearing also gives me about 28 MPH at 100 rpm, so that will do all I would ever need it to do in terms of top speed.

3alarmer 

.
...not sure I understand why you wouldn't just put drop bars on an older mountain bike, bought used, and modify whatever else you need to change, like the brakes and levers ? So I'll just butt out.

Paul Barnard

Great idea. I normally don't butt in unless I feel like I can add value to a discussion.

DorkDisk

No, its not a road bike, its a "gravel" bike. It fits 45mm tires. Many people with gravel bikes are looking into lower gearing, hopefully this will help them.

squirtdad

looking a bit

I would do GRX with 48/31 crank and the deore 11-42 cassette, RX810 rear derailler this gets you everything but mechanical disk brakes, but with integrated components that will work together

Gravel is a wide range, seems more people thing of it as more road with a bit higher gearing, than MTB with super low gearing....which is supported by manufacturer offerings

Paul Barnard

Thanks for spending a little time digging in. Mechanical disc is a must for me.

tyrion

How about an old Dura Ace/Ultegra/105 3x10?

DorkDisk

As someone who spins small gears, its not just a matter of low gear inches at one end; the gaps matter alot when your cadence is high. I really like small gap cassettes with range via chainrings, it suits my style better. Something like 48/31 with 11-42 would have too much high end for this spinner and the gaps would drive me nuts.

GRX is compatible with Ultegra/DuraAce cable STI. I'm not sure 810 or 812 will clear your large cog without doohickies.

XT/XTR and a tanpan adaptor will work with Ultegra/DuraAce STI

Sorry, not a SRAM guy but from I understand they are very compatible between road/MTB.

squirtdad

Just looking at all the specs i see this could really be a challenge/limitation. nothing current for shimano or Sram offer anything but hydraulic disk (either 1x or 2x) So you would have to experiment to see if combo of say GRX rear derailler (there is a model will handled up to 42), deore 11-42 cassette and a road rim break shifter (105 or ultegra) would work, especially with the brake pull matching the discs.

Iride01 

Fair enough. Do you really need 19 gear inches? At a comfortable 80 rpm you'll not even be going 5 mph. Or are you expecting to do grades in excess 8% as an average ride instead of a brief bump on an climb averaging 4 to 5 percent?

Are you riding gravel as another surmised?

I'm mainly just not sure you are going to find a 11-40 rear that works with STI's. Even Shimano's GRX says that the STI's in that group are limited to road type rear DR's which currently have a 34 tooth max. The 11-40 cassette in the GRX group requires a mountain bike rear DR and that will require something other than a STI on your drop bars.

But..... I might be wrong. It's something I have not looked at much since I don't have the conditions here to warrant that low a gearing.

squirtdad

goofed all of this up in my confusion with single and double deraillers...... so deleting misleading information........ apologies

the sticker is OP wanting mechanical disk, so possible 8000 ultegra STI Shifters (or 105 7000) for rim brakes. the shifting should work,for 11 speed but don't know about the brake pull for rim brakes vs what is needed for mechanical disk.

squirtdad

here is a thread on sti with mechanical disk that may help....have not read it all (have to get back to work) https://www.bikeforums.net/bicycle-m...able-pull.html

Paul Barnard

Gevanalle makes shifters that work with Shimano MTB derailleurs. Microshift does as well, but only in 1X. The only problem remaining with the Gevanalle route is finding a crank that would give me the correct chainline. Gevanalle does offer a long pull option.

Paul Barnard

I went ahead and ordered the frame. Polished with anodized blue lettering and badging. It's going to be a great looking bike. I won't be in any rush in getting it built out.