dieterich.lawso

Hello,
I'm a complete noob to bike building and am working on my first self-built bike. It will be used for a 5 mile commute 5 days a week, and I will also ride it on gravel on the weekends as well as take it grocery shopping, etc... So the primary use is for commuting but I would like the option to take it a bit off-road and tour for the weekend if I feel called to do so.

I've specced almost everything out and would be super appreciative of anyone who has time to double-check my selected parts just to make sure nothing stands out as incompatible or out-of character. For example when picking my stem length I had no idea really what I was doing. In general I would like to not completely break the bank, but I still want to have hydraulic disc brakes and integrated brake/shifter levers which motivated my choice of groupset. Here are the parts:

Frame: Surly Straggler 58cm

Groupset: Shimano GRX 400
Front Derailleur: FD-RX400
Rear Derailleur: RD-RX400
Crank: FC-RX600-10
Casette: CS-HG50-10
Brake Levers: ST-RX400-R/ST-RX400-L
Brakes: BR-RS785 (Note that this is not the recommended brake caliper -- I need one that is post mount so I can adapt it to the straggler frame which is IS mount)
Rotors: SLX SM-RT70 160mm
Brake Hose: SM-BH90-JK-SSR
Bottom Bracket: BB-RS500
Chain: CN-HG54

Wheelset: WH-RS370-TL or WH-RX570-TL
Tires: Hutchinson Override Gravel 700c Tire 35mm or 38mm

Cockpit/etc...
Handlebars: Salsa cowbell 44cm
Seatpost: Salsa Guide Seatpost, 27.2 x 350mm, 18mm Offset, Black
Seat Collar: Salsa Lip-Lock Seat Collar 30.0 Black
Headset: Cane Creek 40 EC34/28.6 Headset
Stem: Salsa Guide Stem, 90mm, 31.8, +/-6 degree
Saddle: Brooks b17
Rear Rack: surly rear disc rack

Some specific questions I have:

1. I'm not really sure about the wheel and tire choice. I want to be realistic about the primary use of this bike as a commuter, but I don't want to go so far it's hard to have fun on the weekends. Any thoughts those options I listed or others?
2. Are there other groupsets that would allow me to have hydraulic discs but might be a bit cheaper? Like SRAM or something? Is there a significant performance difference?
3. I'm not sure on the offset of the seatpost. Should I just go to my LBS and have them size me up? They don't have any stragglers in stock so it seems hard to really figure out proper sizing... Maybe I can return the seatpost if it's not exactly what I want.

Thanks!!

HillRider

You cannot use either wheel set you list on a Straggler frame. Both of those use thru axles and the Straggler requires quick release wheels. BTW, if you go with the Straggler, be sure your front quick release is kept TIGHT and the "lawyer's lips" are in good repair. QR fork dropouts are not a good match for disc brakes unless the precautions are followed.

One alternative, and one I just built up for myself, is to use the Surly Midnight Special frame and fork which does use thru axles and I used the 700c WH-RX570 wheels on mine. The MS uses flat mount brakes and I used TRP Spyre mechanical discs but any flat mount hydraulic caliper will also work. The MS requires a 44mm headset and Cane Creek does make them. Mine was a Cane Creek 40, upper was a ZS44/28.6 and the lower an EC44/30. I've been very pleased with my MS and I think it would serve your needs too.

dieterich.lawso

Wow, thanks for the advice. I am now realizing that some of my previous issues with disc brakes were because of the quickrelease levers! I had a long haul trucker where the front wheel kept coming loose and I couldn't figure it out but it totally makes sense that the QR levers weren't tight enough to deal with the stress of the disc brakes.


I think you're right I should switch to the midnight special. It makes the groupset buying simpler because I can just use all the GRX stuff, and I've heard bad things about the straggler's rear dropouts in any case. I guess I won't get as much of the 'gravel geometry' but since this is primarily a commuter I'm fine with that.


So with that in mind -- do you have suggestions for bottom brackets that would fit my crank choice? It seems that the recommended Shimano one BB-RS500 comes only in 68mm and 70mm shell width, but the midnight special is 73mm. Can I just use any 73mm bottom bracket made by Shimano? For example the SM-BB93?


Out of curiosity, do you have racks and/or fenders set up? Did you have any trouble setting that up if so? I'm planning on adding both.

Darth Lefty 

I think you should buy a Warbird.

Supposedly there are new Stormchasers coming, that might be geared, but got delayed by da ‘rona

Badger6

Also, post mount calipers. 785s are decent, but they are the first gen road disc calipers (2014/15 , IIRC). My gravel bike is an older frame with post mounts and it was spec'd with 785s, which wore out (rebuild didn't fix them), and I replaced with another set of 785s, which wore out, and rebuilding didn't fix. I finally just gave up, and spec'd in current generation MTB calipers, since they are all post mount. Shimano does not anywhere describe mating MTB calipers to drop bar hydro levers, but they will work, just be advised that MTB calipers use a banjo connection at the caliper, so you will need to source brake hose with banjo connectors instead of straight hose that use barb/olive connection on both ends. I've got GRX Di2 levers pushing XT Series BR-M8120 (4-piston) on the front and BR-M8100 (2-piston) on the rear...and they work great, in fact much better than the 785s ever did. You could save a little coin and sub in the SLX series brakes (BR-M71xx). If you have questions on specifically how to make it work, parts required, etc., I'm happy to answer.

HillRider

Read Surly's frame spec again. The Midnight Special uses a standard 68mm English threaded bottom bracket shell, not 73 mm.

I used a Shimano Tiagra triple road crank (FC-4603) on mine with a BB-5700 HTII bottom bracket and it works perfectly.

I didn't fit a rack or fenders but Surly has recommendations for both on their website.

Darth Lefty 

It's not urgent but I want to change my Stormchaser to hydros and I think I'm likely going to do Hylex levers ($220/pair) and a 1x rear with the Paul SRAM adapter. That also lets me do it in stages. I've decided not to do brifters. They are just astonishingly expensive compared to equivalent MTB hardware, for no really clear reason. $540 at Jenson for the pair you selected, and they're the "cheap" ones. And honestly that's one reason to buy a complete bike.

GrainBrain

How sure are you on sizing? Do you know some basic stuff like what reach and stack you want? I personally like having a longer stem on gravel with a smaller frame. With a smaller frame you'd also have more seatpost exposed which would increase compliance.

dieterich.lawso

I have no idea what I was smoking... you're right it's 68mm. Thanks for the help.

dieterich.lawso

Badger, do you like the GRX-branded calipers? I think I'm gonna switch to the midnight special which can take flat-mount brakes. If the BR-RX400 aren't good then I would definitely consider doing something similar to your setup.

dieterich.lawso

Yeah, I feel that. I originally was interested in going with bar-end or downtube shifters but I just didn't end up speccing that out. Which Hylex do you recommend? The RS? I'm guessing that with 220$ brakes and ~70-100$ bar-end shifters it would be around 300$ for a whole setup vs 540$ for the brifters. Quite a savings, I'll have to think about that.

dieterich.lawso

I'm not sure at all on sizing. I am pretty sure that the frame is the size I want, but I don't really know what size stack or stem length. Bike shops around me don't really have the frames I want in stock so it's a bit hard for me to get the sizing really dialed in. Any recommendations for how to figure that stuff out beyond considering a longer stem? I guess the best thing to do would be to test ride a frame with similar geometry.

GrainBrain

What bike are you riding now and what's the size? Maybe look up how to get a bike fit and take some measurements. A 58cm frame with a 90mm stem seems off to me personally though I've seen others use it fine. I just looked up the midnight special and it seems like the reach doesn't change a whole lot from a 54cm to a 58cm but the stack changes considerably. It's road geometry with a 73° head angle.

I'd almost be tempted to get the 54cm version(!?) with a 120mm stem and 40mm of extra spacers jammed underneath.

Darth Lefty 

Iiii honestly didn't know there was more than one.

Badger6

Realized I never replied...and maybe too late now, but I will anyhow. In the post you quoted, that bike only had GRX levers, and XT level MTB calipers. I like the GRX levers for gravel. The only way to use the setup I described is to either mount the calipers to a frame that is designed for post mount calipers, or use a flat-mount to post adapter.

In the intervening time since you've asked your question, I was able to find a new Spesh Diverge, spec'd with flat mount brakes, so the GRX levers are now pushing GRX calipers. Honestly, they work fine, but I don't like them. After riding on a bike that had 4 piston stoppers on the front, the GRX stoppers (rebranded Ultegra calipers) just don't give the kind of feel I want. There is nothing wrong with the GRX calipers, they work well...but 4 pots on the front wheel just work better, more power and more modulation at the edge of lock up.