jat255

Hey everyone,

I'm attempting to convert to drop bars on my Via Carisma (see here: https://www.bikeforums.net/showthread...d-STI-shifters)

The drivetrain is an Exage 300LX 7x3 (indexed), and I'm wondering if anyone knows if this setup would be compatible with 7x3 Sora shifters on drop bars. It seems like they should be,but it sounds like I might have some problems with the FD? I'm hoping that someone more knowledgeable about this stuff might be able to chime in how this might all fit together. Thanks!

xenologer

the rear derailer should be fine.
to make the front work, you'll probably need too reduce the derailer motion per click.
The lever arm that the cable attaches to will need to be effectively shortened.
Depending on the derailer design, this may be possible by pinchng the cable clamp 'incorrectly', with the cable routed to the wrong side of the pinch bolt. -the side closer to the cage.


sora brifters suck, for who-knows-why silly reason, the shift return lever is a little tab on the top/innerside of the shifter body; making it impossible to shift from the drop section of the bars. -so they want you to only shift from the hoods? defeating half the point of the bars being dropbars
wtf?


on my 3x7 cross bike (with shimano mtb drivetrain), Ive had good results using campagnolo 10spd ergopower brifters and swaping the cassettes spacers with slightly wider 8spd spacers.
campy 10spd cable pull ~= shimano 8spd cable pull, so it works out
the front ratchety shifting also works well with front shifting
plus you avoid the Sora flaw

bobotech

I don't have any experience with the Sora brifters but I love my bike now that I have converted it. I'm the guy who converted the Via Carisma in the other thread you linked to. I also today just finished a conversion of a modern Specialized mountain bike to drop bars using another set of STI shifters I had. SOOO much more comfortable than the flat bars.

The Exage front derailleur is setup for use with mountain bike shifters unfortunately. You *might* be able to get it to work with the brifters but it won't work that great. The cable pull for road vs MTB shifters is quite a bit different. You can fudge it a bit by putting some slack in the cable if you try to use the MTB Exage derailleur with the road Sora shifters. My Via Carisma came with a 50-40-30 crankset that ended up working great with the front derailleur I put on it after converting it. I used a Ultegra triple road bike derailleur instead of the Exage, the Exage just didn't work smoothly enough. I used the same model derailleur on the mountain bike I finished converting today that had a 48-38-28 crankset as well.

If I was you, I would try to go to a bike shop and look for a used road bike derailleur that is setup for triples. They would work better and with less fuss than trying to sort of get the MTB derailleur to work.

Kimmo 

I'll have a stab at explaining that.

As Sora is an entry-level group, most of the folks riding it are going to be casual cyclists, who I'd wager don't use the drops nearly as often as more serious cyclists (if at all), making this a sensible corner to cut in order to keep costs down.

Also, +1 no front shifting dramas with Ergos. If you can lay your hands on an old 8spd set with matching RD, they'll shift Shimano 7spd fine since it's the same 5mm spacing.

jat255

Is changing the FD a very involved process? I'm pretty much as new as you can get to bike mechanics, so there's likely to be a learning curve. The crankset that's on there right now is a 48-38-24.

Airburst

Not at all, most front derailleurs have a screw that holds the cage together, allowing it to be separated so you can change out front derailleurs without having to break the chain. The Park Tools website is very useful for new mechanics. https://www.parktool.com/blog/repair-help

Kimmo 

Setting up the FD can sometimes be a PITA with indexed systems, though... but not with Ergos.

jat255

The thing that I'm worried about is that I cannot seem to find a 7-speed trip FD. They are all 8, 9, or 10. Would I have trouble with chain rub since the 7-speed is a wider chain?

bobotech

Oh that really is a non-issue.

The 6-7-8 speed chains are all the same width. Then the 9 speed are a bit narrower and then the 10 speed are even more narrow. The 6-7-8 speed setups use spacing that is very close so that is why you can easily use a 7 speed shifter on an 8 speed cassette and vice-versa.

As for the front derailleurs, that really is a non-issue. I have used a 9 speed derailleur on my 7 or 8 speed bikes with no issues whatsoever. You have a lot more leeway with the spacing of front derailleurs than Shimano leads you to believe.

jat255

That's good to know. I think I'm getting close to figuring out all the parts for this conversion. Thanks for your help!

xenologer

7/8 use the same chain width, so an 8spd derailer should be fine
if not, slightly spreading the cage isnt too hard.

DIMcyclist

Assuming your shifter pulls the right amount of cable, the chain won't really effect your derailleur itself (at least not to an extent that can't be adjusted with the limit screws), but it will play into your cassette spacing.

Uniglide was 7.4mm (if I remember correctly) and it should be noted that in the late '80s Shimano briefly made a D/A SIS Uniglide 8sp cassette; 8sp HG & 8sp IG are still different widths (7.3 & 7.1mm, respectively), and 9sp HG is 6.6mm; of course, even narrower.

The chain & the chainring/ cassette spacing should match up. And with Shimano of course, the devil is in the details...

Kimmo 

Wait, what? Off the top of my head, Shimano's 7spd spacing is 5mm and 8spd is 4.8mm. I have NFI what dimension you're referring to.

Oh hang on, chain width?

DIMcyclist

Yeah, chain width; sorry about the confusion, Kimmo. I'm just pointing out that not all Shimano 8sp chains are the same width and that some of them were (and still are) issued concurrently. So, always best to take a close look.

If your chain's too wide for your particular cassette/ chainring spacing, it'll throw off your shifting & indexing (ergo, whether you bodge it with spacers or just use the right cassette in the first place, they've got to match up. As an example, an HG 8sp chain won't shift correctly on an IG 8sp cassette). However, the differences in the chain widths aren't really enough to actually effect the derailleur cages themselves to any great extent- as bobotech mentioned, there's plenty of leeway.