JDandy

I am planning to convert my mid 90's 3x7 flat bar hybrid to a more current 1x10 drop bar "gravel" bike. The bike has all of the original parts except for the wheels which have been moderately upgraded from single wall to double wall and the rear wheel is equipped with a Shimano Alivio FH-T4000 hub. I believe this hub limits me to a 10 speed cassette. As of now my component choices are:

Sunrace CSMX3 11-42 10 Cassette
Shimano Deore XT RD-M786-SGS rear Derailleur
Gevenalle GX Shifters/ Brake Levers

I am also thinking I can find a used crankset along the lines of a Shimano Dura-Ace FC-7400 and use a 42 tooth narrow-wide chainring such as this Wolf Tooth offering. The bike has cantilever brakes which I will either keep, replace with same, replace with mini-v brakes, or replace with v-brakes. The Gevenalle Shifter/ Brake Levers can be spec'd with either short or long cable pull.

Prior to Covid I was volunteering at a local bike co-op one day a week. My plan would be to the use tools and advice available from the co-op for this project but I don't know when that will be. If I am on the right track I can start accumulating parts for the build.

The most uncertainty I have is with the cassette and derailleur compatibility. Will the 10-speed derailleur clear an 11-42 Cassette or will I need (can I use) a derailleur hanger extender or other modification to make it work?

My goal is to keep things simple and relatively durable while shedding a bit of weight.

Am I on the right track? Thoughts and suggestions appreciated.

AeroGut

If you go to the site you linked regarding the XT rear derailleur, you will see that the max cog size is 36. Those specs are generally quite conservative, but 42 is still probably too big

_ForceD_

Is that shifter compatible with the derailleur? It says shimano dyna-sys. Is that the same as deore?

Dan

blamester

Even if your first attempt isn't perfect you will figure out how to make it work.
Is the shifter friction?
​​​​​​You will still have the parts for another bike and it not like it's difficult to put it back the way it was if you don't like it.

70sSanO

You’ll probably need a Wolftooth RoadLink. The shifters are compatible with Dyna-Sys.

I think you need to work put the chainline with a road crank. My need to experiment with different BB single lengths.

My only concern would be how well a hybrid to drop bar gravel (road) will ride. I’m not familiar with geometries and WB on a 90’s hybrid. It may be fine or be a real dog. Hopefully someone here can offer some real world experience.

John

JDandy

wb?

blakcloud

My guess WB is wheel base length.

70sSanO

WB is wheelbase. I think current gravel bikes are around 40” wheelbase.

I was only asking, because geometry plays a part on whether you will end up with a suitable gravel bike or a drop bar hybrid.

I have no experience with either bikes. The only conversion I can relate to was my ‘86 SR400 from drop to flat. The steering feels much quicker with flat bars, which really surprised me.

John

JDandy

Yes I saw the max cog size of 36, but as you mention, the specs are generally quite conservative so I didn't want to dismiss the derailleur without getting some feedback. It looks like the 36 tooth recommended limit is precisely what the Wolf Tooth GoatLink was made for.

No, Dyna-Sys is not the same as Deore . . . but, 10 speed Deore MTB components use the Dyna-Sys technology. The shifter and derailleur do appear to be compatible.

The shifter is indexed but can be switched to friction mode which is one of the reasons I am drawn to it; kind of a bail-out mode if the indexing fails for whatever reason. I'm kind of hoping that by doing my due diligence I will understand things enough so that I won't have to put things back the way it was but I get your sentiment.

Thanks for the heads up on the chainline and BB lengths. I'm sure I can get some advice on that from the bike co-op when it comes time to finalize the BB and crank combination. Those aren't parts I'm going to acquire and install on my own without some experienced guidence.

The one area I am pretty confident about is the geometry of the bike. I've compared the bike's geometry and wheelbase to several current gravel bikes and it is spot on. I have a lot of saddle time on the bike in its current configuration and have related that experience to what I've read about geometry characteristics, so I don't think I will be surprised or disappointed with that.

Thanks.

So, I'm adding a Wolf Tooth GoatLink to my proposed parts list above. I'm pretty sure I can also live with an 11-40 cassette and maybe a 40 tooth chainring. That should help the shifting feel, reduce chain and cassette wear, and possably help with getting the chainline correct. I'm not really married to any of the parts I've listed if someone has other suggestions. I've just gravitated towards these parts that look to be readily available, reliable, and make sense cost-wise for the bike they are going on.

AeroGut

With respect to geometry, not all hybrids are the same, but there is a general trend that the wheelbase is fairly long, so they're stable, but not nimble. The top tube is often long as well, so some people have trouble with the reach being too long with drop bars. For example, I have a mid-90's Bianchi Boardwalk that I converted to drops. It has a 54 cm c-t seat tube and a 58 cm c-c top tube. Part of that is due to a slack seat tube angle (maybe 72? I'm not sure exactly), but not all of it. I think the reach from the BB is about 43 cm. I have a long torso and short legs, so I like it that way, but not everyone finds them a good fit. Wheelbase on that bike is about 40.5 inches I believe.

JDandy

The bike I’m working with is equivalent to a 58cm road bike. It has a 580mm top tube, 430mm chain stays, and a wheelbase of 1051mm.

I will be using a threadless stem adapter so I can easily swap stems to adjust the fit. I plan to start with a 100mm stem. I already have Salsa Cowbell handlebars which have a short reach, shallow drops, and a minimum flare.

jp911

If it were me, I would reach out to Gevanelle to talk about using their shifters with an 11-speed XT derailleur (instead of the 10-speed XT, so that you can easily use the 11-42 cassette). The actual shifting won't be the issue, but rather the use of the 11-speed derailleur jockey wheels with a 10-speed chain. I think it will probably work, but it's not my money to spend.

JDandy

Thanks. An 11 speed drivetrain would give me more and presumably easier options. I did recently E-mail "the Goats" as Gevenalle refers to themselves and they responded within hours which I took as a good sign of future customer support. Their response was "Shimano 10 and 11 speed derailleurs each need their matching shift levers." I have also contacted Microshift (it is their bar-end shifters that are used in the Gevenalle product) at least three times with similar questions and have never gotten a response.

JDandy

I stopped by a local bike shop and reviewed my plans with the owner. He said I would really like the Shimano XT derailleur but that availability right now is very limited. He didn't think he could have one before June. He has riding experience with Gevenalle shifters, and while they work, he prefers integrated shifters. He wasn't a fan of the Wolf Tooth GoatLink and recommended staying with an 11-36 tooth cassette rather than trying to extend the range of the derailleur with an aftermarket product. His recommendation was matching SRAM APEX 10 speed shifters with a SRAM GX 10 speed Derailleur and an 11-36 cassette. He also had a Sugino RD crank that requires an Octalink bottom bracket. It looked like the photos in the link but in much better shape. I'm definitely going to follow up with him about the crank as to what the arm length is and how much he would charge for it. While I'm sure the SRAM APEX and GX combo would work flawlessly, the gear range is more limited than I was hoping to achieve.

I have since noticed that Gevenalle is now showing that their GX Shifters/ Brake Levers are compatible with Microshift's Advent X drivetrain components. This comes with an 11-48 tooth cassette and a derailleur capable of covering such a wide range. I am leaning in this direction now. The Gevenalle GX shifters with the Microshift Advent X derailleur should be pretty bullet-proof and allow me to get an acceptable range out of a 1X system. The Microshift Advent X cassette looks good but I think the Sunrace cassettes look better, however, the availability of the SunRace CSMX3 cassettes may be limited. I checked with another bike shop local to me and the Microshift Advent X derailleur and cassette can be delivered in a reasonable amount of time.

Feedback, opinions, suggestions appreciated.

veganbikes

I would avoid 7400 cranks for this build (they are excellent cranks but 130bcd so limited in small chainring options) and would try and avoid octalink. Square taper is fine, ISIS is OK and external bb cranks are excellent.

Gevenalle is awesome, they do support their products well and answer fairly quickly so they are a company worth supporting.

JDandy

Is there a particular reason to avoid Octalink? I imagine availability is limited compared to square taper and external but it seems that Shimano still makes Track cranks that use Octalink. The interwebs don't seem to be especially positive about ISIS from what I've read. My only hesitancy with external is cost. The cheaper external BB cranks seem to be rather heavy. My impressions from reading could be wrong however, which is why I'm looking for feedback here. Thanks.

veganbikes

Octalink exists in rare forms here and there but there are two versions of it and they aren't all compatible and if your crank doesn't meet the specs of the Dura Ace 7710 crank in terms of BB compatibility you could be in a tougher time finding BBs they are still made in small quantity outside of the DA version but not much in quality and honestly if it were so much better than Square taper we would have seen more of it still going and less square taper but you can still find a ton of square taper stuff but not much being made in Octalink. ISIS is great because it is an open standard so anyone can use it meaning a lot more folks did so you see it on a lot of stuff including Bosch and Brose spindles on their e-bike motors. Widely adapted and used are good ways to go.

In terms of external stuff it isn't that expensive. You can get a Shimano Deore or 105 BB for like $25. The cranks can be a bit more expensive for lighter weight but honestly I wouldn't worry too much on this. There are boat anchor cranks around but you can probably find something relatively light and not ridiculous in price. Plus they are easy to work on with no crank pullers or anything like that some don't even need a cap puller or some will use a hex head cap.

JDandy

Thanks for the detailed response.

JDandy

I'm getting closer to moving forward on this build and am going to need some advice on chainline. Before I ask the question I'm going to list the parts that I actually have and expect to have in the near future.

have:
Gevenalle GX Shifters/ Brake Levers
Microshift Advent X Rear Derailleur for 1×10 Speed
Microshift Advent X 11-48T 10-Speed Cassette With Alloy Spider

expect to have:
Shimano FC-1050, 105 Crankset
Wolf Tooth 130 BCD Gravel/ CX/ Road Chainring
Wolf Tooth Set of 5 Chainring Bolts+Nuts for 1x

I've read through Sheldon Brown's All About Bicycle Chainline and Park Tool Chainline Concepts. If I understand correctly, my current front and rear chainline is 47.5. I expect the 10 speed cassette to move my rear chainline in to approximately 44.85. The 105 crank calls for a chainline of 43.5 with a bottom bracket spindle length of 113. That puts the the big ring's (which is where I expect the new single chainring to be positioned) chainline at 46. I think that the spindle length of 113 keeps my chainline within a reasonable tolerance. Square tapper bottom brackets aren't the most expensive part out there but I'd rather not be completely wrong right out of the blocks. Does it sound like the 113 BB is where I should start or do I need a different spindle length?