Joe5972

So I recently sorted the rear derailleur and cassette on this bike I got from a friend recently, and now I'm looking at the front derailleur.
This is the bike:


(Don't mind the state of my kitchen, it's partly being used as a workshop at the moment!)

I'm thinking that the front derailleur is the wrong type as:

• It's a MicroSHIFT (rest of the parts are Shimano)
• It has a spacer because the derailleur doesn't fit around the frame without it
• The indexing screws are both at opposite extremes
• The cable is at an unnatural angle
• And the shifting just isn't great.

I put some tape on it, as in the first image below, just to bring the derailleur a little closer to the top cog, because it just wasn't quite getting there otherwise, it's like the derailleur just doesn't naturally want to go that far.

In the second image below you can perhaps see that the cable is at an unnatural angle. It's like the guide wants the cable to go to the left (of the image), but it attaches on the right of the image. You can perhaps see this a bit better in the third image.

I might pick up a derailleur soon, depending on if I can figure out the right model. Will most Shimano clamp-on derailleurs work, and do the cables go the same way as the guide in the image below?

The frame is has a 32mm diameter, so it seems like the MicroSHIFT derailleur is meant for a bike with a thin frame. A road bike maybe..

Would an Atlus M310, or a Tourney, do the job? It seems that the guide wants the cable to go close to the centre of the frame, or to the cog side, instead of off to the other side.

I think I have the derailleur just about working at the moment, but it's very iffy, and it seems like a total hack-job, for example I might have to shift down to the smallest cog and then back up to get to the middle cog, and it's not a big fan of the chain not being directly in like with the rear sprocket.

Update: I got a new front Derailleur FD-M310 and it fits much better. Problem solved!

Hondo6

There should be a model number on the current front derailleur. Knowing that would be helpful to determine what the FD specs say it is designed to do.

Once you locate the model number for the installed derailleur, you might also be able to find that info yourself on Microshift's website:

https://www.microshift.com/products/...t-derailleurs/

https://www.microshift.com/products/...t-derailleurs/

If you can't find it there (e.g., if it's an older derailleur no longer in production), you might be able to find info about it using their site's search feature.

At a glance, it appears the bike has a triple front chainwheel. Without the model number of the front derailleur it's hard to be sure, but that certainly looks to me to be a front double derailleur. If so, that could be your problem.

andrewclaus

The limit screws at opposite extremes is a sign of incorrect chainline. Perhaps the crankset or bottom bracket was specified incorrectly.

The FD mounting problem isn't very clear, especially the role of the duct tape. It's not uncommon to have an engineered plastic shim. But duct tape will not work.

The jump from large to small chainring could be a dirty shifter. Try removing the cable from the FD, keep hand tension on it, and work the shifter several times, noting the number of clicks in both directions. The shifter can be cleaned out by flushing it with WD-40. Catch the drippings with a pan.

The cable guide probably isn't the problem.

hokiefyd 

I agree with a chainline problem. The Low limit screw being all the way in, and the High limit screw being all the way out, suggests the crankset is spaced further outward on the bike than this derailer is designed to work with. It looks like the front derailer has a chainline specification printed on it: 47.5 - 50 mm. To measure chainline with a triple crankset like this, measure the distance from the center of the seat tube (the tube the derailer is mounted to) to the middle chain ring. What is that measurement on the bike as it sits now?

Before buying a different derailer, measure the chainline on the bike to see what you have. If the crankset and bottom bracket cartridge aren't matched, you could have a chainline problem that will be very difficult to work with. Your solution here may be a different crankset or bottom bracket, rather than the derailer itself.

Hondo6

Good catch - I'd missed that. Guess it's a likely triple FD after all.

Hondo6

Wonder if one of these might be the OP's current derailleur - the chainline info printed on the FD in the photo matches the chainline specs for all 4:

https://www.microshift.com/models/fd-m22/

https://www.microshift.com/models/fd-m20/

https://www.microshift.com/models/fd-m30/

https://www.microshift.com/models/fd-m43

If so, Microshift says the FD-M22 is compatible with a 48/38/28 crankset, but that the others (FD-M20/30/43) are compatible with either a 42 or 44T max chainring. (Microshift lists crankset compatibility for the others as 42-34-24 for FD-M20; 42-32-22 for MD-30; and 44-32-22 for FD-M43.)

These are the current Microshift mountain FDs that use that chainline spec. None of the current Microshift road triple FDs use a 47.5-50.0 mm chainline spec.

Just another data point. Might or might not be relevant to the OP's problem.

Joe5972

Thanks for the reply.
I can't seem to find a model number, but I found some numbers on the back, which I assume are teeth numbers? It's 42-34-24 on the derailleur with what looks like a "1" at the end, but I'm thinking it might be a T for teeth?
The teeth on the bike are 48-38-28.

Hondo6

See my later comment regarding Microshift mountain triple FDs. Sounds like you have the FD-M20.

https://www.microshift.com/models/fd-m20/

That's a Microshift 7/8 speed FD; the chainring and chainline specs match what's printed on your existing FD. The other current Microshift mountain triples don't match up re: chainring specs. No current Microshift road triple FDs appear to have the same chainline spec as is printed on your existing FD.

I'll defer to others with more experience with triple FDs regarding whether this is part/all of the problem. But your chainwheels and FD do appear to be mismatched, based on Microshift's specs.

Joe5972

The duct tape does actually seem to help, as the chain was ever so slightly touching the derailleur before, but the tape bringing it forward 1-2mm does help.

I haven't cleaned the shifter yet, but I might do that, I'm gradually getting around to de-gunking everything, already cleaned the brake system, trued up the wheels, replaced a spoke, changed the rear derailleur and cassette, and just generally been fixing stuff as I go.
It looked like in the past the bike was just repeatedly lubed, but the previous gunk was never removed first.. I've been removing chunks of hard black stuff from everywhere for a few while now!

Are you sure the plastic guide isn't part of the problem? The angle is a bit more severe than it looks in the photos, and the cable almost has to go through a sharp S kind of route as it goes through and leaves the guide, and goes the opposite way after that.

Joe5972

Thanks, I never heard of 'chain line' until now!
I measured it there and it seems to be around 50mm. If I was guessing I'd say between 50mm and 51mm, but it's hard to say exactly..
The crankset is also Shimano, so I was thinking the "odd man out" was the microshift front derailleur.. I heard that different brands don't always work together.

Hondo6

If your current FD is the FD-M20, then it's Shimano mountain compatible (most of their current road and mountain derailleurs are Shimano-compatible; the specifications on their website ID those that aren't). Microshift also reputedly makes a high quality product, so I don't think that "brand mismatch" is really an issue here.

I'l defer to others with triple FD expertise regarding whether or not the chainline of your bike is "close enough" at between 50 and 51mm. But the mismatch between current FD and chainrings is a red flag to me. You're running both a 4T larger big chainring than Microshift specifies for their FD-M20 and a 2T greater difference between large and smallest rings.

This article is longish, but might be worth your time. It probably tells you more than you want to know about FDs. (smile)

https://www.sheldonbrown.com/front-derailers.html

Joe5972

Thanks. Yea, there does definitely seem to be something "wrong", I initially got that feeling when messing with the bike when I first got it, it seemed like I had to do far too much tweaking with the front derailleur, and when I'd adjust something, say the indexing, then it would fix an issue on one chainring, but cause an issue on the next one.

I picked up an Altus FDM310 on Amazon, just now, so I'll see how that works when it arrives. If it's not an improvement I can always send it back, but it was only €14 anyway. I'm hoping it will be more compatible since it says "Chainring: 42-48 teeth", and it has the same Hyperdrive logo as the one that's on my crankset. And the Altus rear derailleur that I recently put on seems to be working fine, after also replacing the 6-speed cassette with a 7-speed cassette, like it's supposed to have. And at the very least I will have a better idea of what is, and isn't, compatible with the bike.
I think the bike originally came with a Tourney set when new.

I'm thinking that my friend's bike mechanic, who previously worked on the bike, was a bit of a cowboy. My friend is a bit of a hands-off kind of guy, and he'd just hand the bike to his mechanic and say "fix it please", and he wouldn't really know or understand what was done to it. I mean, he didn't know that it had a 6-speed cassette instead of a 7-speed.
He ended up giving the bike to me because he wasn't happy with it, but it's already running much better than when he had it.

Joe5972

Thanks, I'll give that a read. Hopefully the M310 (as mentioned in my previous comment) will be better. Sorry, the comments are overlapping a bit!

dedhed

What is the front shifter? Shimano mountain and road FD/shifters don't normally like to play well together.

Joe5972

The shifters are Shimano V-brake, and I'm guessing they're the originals that came with the bike, as they look like they blend well with the rest of the bike, and seem to be in the same condition as the parts around them, etc.
Nothing seems "off" with them, or the brakes.
The only thing that seems out of place really is the front derailleur.
But I'll keep that in mind when the Altus arrives. I think it originally probably had a Tourney FD, so I suppose I could look into one of those if the Altus isn't quite right for any reason. But from what I understand (which isn't much) the Altus are kind of a step up from the Tourney parts and so 'should' be compatible..
Of course I could be wrong.

hokiefyd 

At 50-51mm, the chainline is probably on the outside of what will work well, as you're finding out. It's possible that the FD-M310 will work better, even if you do have to set the limit screws on it similar to what you've had to do with your Microshift derailer.

If the M310 also doesn't shift very well, you might consider swapping to a slightly shorter bottom bracket. That can be a little more involved, in terms of tools and in terms of measurements, but it's very doable and may well improve your drivetrain efficiency and operation. A bottom bracket that's 6mm shorter than your current one will move the crankset in towards the bike by 3mm and will move the non drive side cank in towards the bike by 3mm (assuming the current and new bottom bracket aren't offset designs). I use 6mm as an example here, but you get the picture. If you end up going this route, you'd need to look at the bike and see how much room you have to move both cranks in towards the centerline of the frame. More isn't necessarily better -- but you probably could benefit from moving them in 2-3mm, assuming the cranks and chain rings would still clear the chain stays.

Since you've purchased a new FD already, I wouldn't go messing with the bottom bracket unless the shifting is still poor after fitting the new piece. But I hope the information above is helpful if you do decide to replace the bottom bracket as well.

Joe5972

I've thought pretty much the same thing myself, and I agree that it's probably a "last resort" if I just can't get a derailleur to fit. But it may also be just that the microshift derailleur doesn't rise steeply enough to accommodate the larger teeth on the chainring, so the wrong part of the derailleur is closer to the chain because of the difference in height. But that's just a bit of speculation. I suppose it could also be slightly bent.

This is how it's looking at the moment, just about getting the right clearance with the tape pushing it out a bit. And I'd say it's working about 90% right, but it's one of those things that you just know isn't quite perfect, so it's constantly nagging you in the back of your mind! If derailleurs were madly expensive and really complicated to install I'd probably leave it as it is, but for the sake of a few quid, and a few minutes fitting a new one, it's probably worth the little bit of time and money to get it right.

dedhed

But what shifter are they? Flat bar road shifters will not shift a mountain FD correctly. With V brakes they likely are mountain shifters but....

Joe5972

Ah right, sorry, I now realise that just "v brakes" was a bit broad!
They're ST-EF51-L EZ FIRE Plus, and they seem to be a MTB part according to this: DM-ST0001-05-ENG.pdf (shimano.com)

hokiefyd 

If only to get the front derailer good and properly mounted to the bike, I agree. It looks like the current one doesn't have the correct shimming arrangement going on. The FD-M310 you purchased should come with the shims you might need to get it mounted correctly and securely. Keep us posted!

Joe5972

Yea, the correct shim is a good point too. I was half thinking about 3D printing one, and giving a bit more weight to the side nearest the chainrings but I never got around to it. But it's something I could always do if the new derailleur doesn't quite solve the problem.

Joe5972

So the new front derailleur, FD-M310, did the job perfectly.
Clearance is better, indexing screws have some more room for adjustment, and the cable is guided to the correct side now, and not going against the guide.
And the new derailleur came with 2 sets of 2 shims (1 for each side of the clamp) as opposed to the single shim that was on the MicroShift derailleur.
Gear changes are better too, although I'll probably have to do a few adjustments over the next few days because the cable still has a few kinks in it from the previous derailleur, and it will probably take a few days for it to settle into the slightly different routing as the kinks work themselves out.

But overall I'm very happy with it. I've had great fun getting the bike up to scratch over the last few weeks, truing up the wheels, refurbing the brakes, bearings, fitting the parts, etc, now I think it's time to just get out on the road and enjoy it..
Thanks for all the tips and advice!