Latif

Hi, I've got a question about the filing of the front derailleur slot. My bike is a 2018 Domane SL5 gravel and I ordered the 46-30 600 series crank and 810 derailleur from our local trek shop and was going to have them do the install. When they realized the slot wouldn't allow the DR to get low enough they decided they didn't want the liability of filing the slot if in the unlikely chance it would lead to failure and possibly end up needing a new frame.
I'm thinking of giving it a go myself although it's beyond my bike tinkering experience level.I guess my question is around what your experience was when you did the filing and did you have any trepidation around whether there was enough material left for the strength of the hanger?
Any advice would be greatly appreciated. My hunch is to give it a go. I fully understand my shops position, it's a great scene there and they're a benefit to our community. They're willing to install the crank as I don't have a decent torque wrench and I'm not confident enough for that part of the job.

Thanks, Latif

Emilio700

Was I worried I would screw it up? Not really. It helps that I have some design and engineering background. I simply took some measurements, saw how much material needed to be removed and I'm familiar with high modulus carbon fiber and how strong it is. I didn't file the entire front derailleur slot all at once. I did it in increments reinstalled the derailleur, checked everything.

I was a factory team race mechanic for a while so this kind of thing doesn't really intimidate me. If you're not comfortable I would leave it to someone who is. But simply approaching it methodically and being patient will work even if you're not experienced.

Latif

Hey, thanks so much. That confirms the approach I would take. I'm totally comfortable with the filing part, been working with my hands for 50 years but mostly with wood. Will be heading over to the shop to pick up the parts and get going on it. Looking forward to expanding my mechanical experience.

Pizzaiolo Americano 

Instead of filing the slot, you could use this adapter:

​​​​​​https://wickwerks.com/products/fit-link-adapter/

It works great. I used it on my Domane.

Emilio700

Cool. That should work too.

Latif

Thanks for the Wickwerks link. What size large chainring were you dropping down to on your Domane? I see that FSA has a similar solution for $20 but both look like they would put the derailleur too low assuming the attachment bolt travels through the adapter and that it would hit the braze on hanger if 2-3mm lower was all that's needed for a 46t ring.Not having the parts in hand doesn't help as there may be something I'm missing due to my inexperience. I measured about 6-7mm meat left in the hanger at the top and assuming it's the same at the bottom, filing 2mm seems safe to me. Will have the GRX cranks on tomorrow and will see how much I need. I also watched a video showing that it might not be necessary to use a GRX front derailleur as he was able to get his Ultegra front out far enough with his GRX crank. Will give it a try with the 105 front and report back.
Thanks all for the help

Pizzaiolo Americano 

I went to a 46/36 crankset. I am back to the 50 though.

cappywh

I am looking to purchase the exact setup you have and was thinking that the 38c Rene Herse Barlow Pass would have plenty of room. I was surprised to see how close it came to the FD. Any reservations now that you have ridden it for a few months? Thanks

Emilio700

From Belgian Waffle Ride - Cedar City, UT. Oct 17

babylovege

Wow, looks great! Did you mixed an 46t chainring from 46/36 and 34t chanring from 50/34?

Emilio700

Yup. The 46T is an Ultegra ring which isn't part of a matched set. I like the Shimano ramps and the way it shifts so I stuck with an oem ring. Actually shifts better than the matched 52/36 Dura Ace on my on my road bike.

46x11 is plenty of top end on 40's. Spin out around 34mph

babylovege

I want to change my chainrings of reacto, form 50/34 ultegra to 48/31 grx
48x11 is plenty for road ride and 31x34 will help my gravel hill climbs.

Emilio700

I'm jealous of your 31T chainring. I prefer my power meter on the cranks but I must use 180 mm. The smallest PCD I can find with a power meter on 180s is Dura-Ace and that's the 34 so that's what I'm stuck with. Most of the time it's fine but there are a few climbs here and there where I wish I had something closer to a mountain bike low range.

babylovege

Oh, maybe you have really loooooong height and inseam.
I think you can buy chainrings only from GRX810 crankset... When Shimano sells it seperately.

Emilio700

pcd of GRX chainrings not compatible with 105/Ultegra/Dura Ace

dwmckee

That sort of mod is pretty easy to do and low risk if you are slow and careful. The shop may have shied away from it because they know it might take several hours but do not think you will pay $150 for it.and they can bill their mechanic out on smaller repairs at greater profit.

Robalero

I purchased a Domane at the beginning of this year and use it mostly as a gravel / rough blacktop bike as I ride mostly in the state parks. On the Domane, I had originally installed 700 x 37 tubeless on the bike but the rear tire started showing some major wear at around 700 miles so I went ahead and replaced it with a 700 x 40 and left the front the same. Lots of room on the Domane for that size tire! The bike holds up pretty well and the ride is fantastic. One thing you should know is that I am a bigger guy right now at 225 and also older (knocking on 65 years of age) and I feel very comfortable and confident on this bike. I will put anywhere from 30 to 40 miles a day on my bikes. I also have a Checkpoint ALR 5 and absolutely love that bike (got it around four months ago) but when it comes to speed, my Domane gravel is just the ticket.

Emilio700

Video from New Years Day ride. Hero9 with hypersmooth and horizon leveling, mounted on face plate of Zipp Speed SL stem.

dieselgoat

Looks like a great ride, but I didn't much gravel.

Emilio700

Headed to Belgium this week to ride the Tour of Flanders sportif (Fondo). Doing the full race distance 159 miles, 7500'. Decided not to take my Cervelo S5 disc. Wanted bigger tires, lower gears and shock absorption for the cobbles. 46/30 Absolute Black rings x 11-40 XTR cassette. Swiped the aero wheels off the road bike, slapped some Pirelli Velo TLR 32c tubeless that I'll run around 50psi. Route Werks bar bag. Gonna be a hard day.

dwmckee

By the way, if the extender drops the derailleur too low then sometimes you can raise the original mount to make the extender in needed position.

Emilio700

Been running the Wolftooth for years